Make Your Own Fertilizer

Fertilizers Home Made Formulas


Fertilizers Home Made Formulas Summary


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Synthetic Nitrogen Fertilizers

According to Liebig's principle, N supply of soils required leguminous crop species which not only supplied crops directly required for men but a substantial part of leguminous crops was required for animal forage. Hence men and animals competed for fertile soils. This situation changed drastically when the chemical production of N fertilizers was invented (Haber-Bosch technique). Now farming was possible without animals, which was the preposition for the separation of crop farming from animal farming. This had an enormous impact on the economics of farming and a disastrous one on ecology. In many animal farming systems land is overdressed with farmyard manure or slurry. In the Netherlands, the average surplus of mineral N, mainly nitrate, for all dairy farms is in the range of 200-400 kgNha . This quantity of plant-available N would suffice to produce 6000-12 000 kg wheat grain per ha per year. This surplus of N leads to an enormous nitrate leaching with a risk for the groundwater...

Fertilizers Lead to the Depletion of Oxygen in Aquatic Ecosystems

The use of synthetic fertilizer increased seven to eight times over the last forty years (Figure 2). The major effects of fertilizer come from Excess fertilizers lead to eutrophication. As fertilizers enter water systems, they cause an explosion of growth by algae and aquatic plants. When those organisms die they are decomposed by microbes that quickly deplete the oxygen in the water, thus killing animals such as fish and shellfish. Fertilizer runoff from industrial agriculture has created forty large, oxygen-starved dead zones around the world. A dead zone the size of New Jersey forms at times where the Mississippi River drains into the Gulf of Mexico. This zone receives fertilizer from a tremendous agricultural area, including Kansas, the Dakotas, Iowa, and Illinois.


Fertilizers are the primary cause of groundwater contamination beneath agricultural lands. Both inorganic (chemically manufactured) and organic (from animal or human waste) fertilizers applied to agricultural lands provide nutrients such as nitrogen, phosphorous, and potassium that fertilize the land and stimulate plant growth. A portion of these nutrients usually leaches through the soil and reaches the groundwater table. Phosphate and potassium fertilizers are readily adsorbed on soil particles and seldom constitute a pollution problem. However, only a portion of nitrogen is adsorbed by soil or used by plants, and the rest is dissolved in water to form nitrates in a process called nitrification. Nitrates are mobile in groundwater and have potential to harm infant human beings and livestock if consumed on a regular basis (Hassan 1974).

Using fertilizer

The attractiveness of grassland to some types of geese can be increased by re-seeding unproductive swards with more nutritious grasses, such as Perennial Rye Grass Loliumperenne (e.g. Percival 1993), and by fertilizing the sward with nitrogenous fertilizer (Owen 1975 Percival 1993 Vickery et al. 1994). Care should always be taken to minimize run-off and leaching. Reseeding and or fertilizer application will damage any existing botanical, invertebrate, or breeding bird interest of a grassland.

The Condition of the Land

Nature never produces anything that it can not decompose and return into the pool of fresh resources. Man does. Nature returns organic wastes to the soil as fertilizer. Man often dumps such wastes in the oceans, buries them in landfills, or burns them in incinerators. Man's deeply rooted belief in continuous growth treats nature as a commodity, the land, oceans, and atmosphere as free dumps. There is a subconscious assumption that the planet is inexhaustible. In fact the dimensions of the biosphere are fixed and the planet's resources are exhaustible.

Short History of Agriculture

Agriculture appeared about 10 000 years ago in one of the regions of the Middle East south of Palestine, north of Syria and Mesopotamia. In the eighteenth and the nineteenth centuries, primitive long-fallow (slash-and-burn) agriculture was replaced by three-field agriculture in the late nineteenth and the twentieth centuries, the modern industrial (high-input) agriculture appeared in many countries. The history of agriculture is, first of all, the history of restoration and improvement of soil fertility. At first, it was restored by natural processes during the fallow stage then, due to the application of organic fertilizers and presently, at the expense of mineral and organic fertilizers and other inputs. These changes made it possible to increase agricultural production from 25 to 145 x 109Jha-1yr-1 and more (Table 1). But this increase has been accompanied by a decrease in agricultural effectiveness (the output input ratio). This phenomenon can be referred to as 'the ecology-energy...

The Future of Agriculture

'Agricultural technologies' will be developed along two different ways. First, their further intensification is expected in developing countries, since it is the only way to ensure food supply of their increasing population. Second, the further expansion of 'green' or 'organic' agriculture with minimum artificial inputs (mineral fertilizers, herbicides, insecticides, tillage, etc.), may take place in developed countries, where the cost of 'ecologically clean' food is very high. At present, the total area of 'organic' farmland in the world is 22.8 million ha (10.5 million ha in Australia, 5.2 million ha in Europe,

Managing Crop Production and Water Quality

A common application of cropping system models is to simulate various management options in different agro-ecosystems to predict effects on crop production. Crop growth models are also used in yield-gap analyses to quantify potential yield compared with actual yield that is, the models are used to estimate potential yields at multiple locations to determine how genotype x environment x management interactions can be optimized. Simulating differences in yield among varieties is typically by using the appropriate genetic phenotypic coefficients to characterize each crop variety. The cropping system models (CSM) within the DSSAT framework and the APSIM model have been extensively used for this purpose for example, the DSSAT framework has been used to derive optimum combinations of management and planting dates for various crops. Another common application of crop models is simulating interactions between crop yield and levels of agricultural inputs such as irrigation water or nitrogen...

Aggregated dispersion See dispersion

Aggregate size distribution The proportions of surface soil aggregates of different sizes in a given soil. The aggregate size distribution is affected by the application of fertilizers, the soil tillage system, and by wind erosion. It affects soil properties such as aeration, drainage, and water retention. See soil erosion soil structure soil texture.

The Intelligent Choices

Mix with fertilizer of high quality organic matter Mix with fertilizer or add to compost Need 40 kg N ha of fertilizer N for each ton of potential yield Need 40 kg N ha of fertilizer N for each ton of potential yield Figure 2 Example of farmer's decisions regarding N management for a maize crop in sub-Saharan Africa, using a decision support system for organic N management depending on resource quality, expressed as N, lignin, and soluble polyphenol content. General decision matrix (top), more detailed for N economy in a maize cropping system (bottom). Modified from Vanlauwe B, Sanginga N, Giller K, and Merckx R (2004) Management of nitrogen fertilizer in maize-based systems in subhumid areas of sub-Saharan Africa. In Mosier AR, Syers JK, and Freney JR (eds.) Agriculture and the Nitrogen Cycle. 124p. SCOPE 65. Washington Island Press. Figure 2 Example of farmer's decisions regarding N management for a maize crop in sub-Saharan Africa, using a decision support system for organic N...

Soil Productivity and Protection

NFTs that are common in the tropics are a particularly valuable resource for soil improvement. Farmlands in many parts of the developing world generally suffer from the continuous depletion of nutrients as farmers harvest without fertilizing adequately or fallowing the land. One promising way for overcoming the acute problem of low nutrient status of African soils is to enable smallholders to use fertilizer tree systems that increase on-farm food production. After years of experimentation with a wide range of soil-fertility replenishment practices, three major types of simple, practical, fertilizer-tree systems have been developed

Isotopes And Other Markers

Although useful in identifying the regional origins of migrants, and filling gaps in other information, the method of isotope analysis cannot provide anything near the geographical resolution that is possible with other approaches, such as ringing or radio-tracking. The levels of deuterium (6D), which follow patterns in rainfall, are perhaps the most useful in studies of migratory birds they give good latitudinal precision, but less good longitudinal precision (Hobson 2005). However, 615N and 613C values are of less value in this respect because drought conditions can enrich both, and natural regional variations in both are increasingly modified by human activities, such as fertilizer use and atmospheric pollution, reducing their value as geographical markers. Nevertheless, the method of isotope analysis provides better-than-nothing information for species with low recovery rates in the regions concerned, especially where analysis of several elements rather than one can give greater...

Reducing Risk versus Optimizing Resource

Another aspect of the focus on flows and releases rather than damages and endpoints is that the threats posed by releases - especially of persistent pollutants - endure and the receptors can change in a manner that later causes harms that may not be captured in a typical risk assessment. For example, cadmium deposition to agricultural soils that takes place as a result of naturally occurring cadmium contamination of phosphate fertilizers may not cause significant human health or ecological damage as long as fields are limed and thereby kept alkaline. If the fields are taken out of production, liming is likely to end. Soil pH will thereby increase, and cadmium may become biologically available and environmentally damaging (Stigliani and Anderberg 1994 Chapter 40).

Past and Current Crimes

Some of the concern today is centred on problems inherited from less enlightened ages which will be with us for many years to come. Examples include spoil heaps from mining operations, contaminated land from previous industrial sites, and pesticides which are now banned but have such a long lifetime in the environment that they will continue to pollute for many decades. Current concerns include emissions from our automobiles, waste production, production of toxic particulate matter from combustion and incineration processes, use of pesticides which build up in the food chain and the use of inorganic fertilizers in agriculture. Although more environmentally friendly methods for power production are being introduced, there is still a large-scale reliance on fossil fuel for energy production with its inevitable production of carbon dioxide. More frequently, problems occur by the release of substances into the environment which are naturally present, with the problem arising simply from...

Global Land Use Agriculture and Urbanization

One of the main spatial factors of anthropogenic impact on the biosphere is the rapid growth of agricultural lands, with accompanying change in their land use. Human activity to produce food leads to the reduction of areas of habitat for natural organisms and to a sharp increase in the area of marginal ecosystems. Improvement of agricultural technologies and wide application of fertilizers led to a fourfold rise in land productivity and sixfold rise of agricultural yield in the twentieth century. However, this was accomplished by reducing populations of organisms and biodiversity of About 23 of all usable lands in the world are subject to degradation, which leads to a reduction in its productivity. Agricultural technologies also lead to the destruction of a mid-term reservoir of biogenes, that is, soils. Significant amounts of soil are washed away. As a result of desertification, about 3 of NPP is lost, but soil organisms essentially suffer since they perish due to soil erosion and...

Sources Dispersal Reconcentration and Degradation

Virtually every form of human activity is a potential source of pollution. The popular concept of industrial discharge being the primary source of all pollution is misguided. It is just one example of a point source, i.e. a discharge which can be readily identified and located. Discharges from sewage works provide a second example. In some areas these are the major source of aquatic pollution. Sometimes, however, it is not possible to identify the precise discharge point. This can occur where the pollution originates from land masses. Examples include the run-off of nitrate salts into watercourses after fertilizer application and the emission of methane from land-fill sites into the atmosphere. These are examples of diffuse sources.

Autotrophs and Global Change

Increasing temperature, and increasing deposition of mineral nutrients should interact with rising CO2 to enhance NPP in the coming decades. Through industrial and automobile pollution, and widespread use of fertilizers, humans currently release more reduced nitrogen into the environment than all biological processes. Anthropogenic nitrogen drifts far from the application points to enrich natural soils and water, increasing potential NPP. Not all species benefit instead, a handful of rapidly growing plants and algae crowd out most other species, reducing biodiversity and simplifying the ecosystem.

Returns To Systems Integration

By-product coke ovens also produced coal tar. Coal tar was the primary source of a number of important chemicals, including benzene, toluene and xylene, as well as aniline. Aniline was the raw material for most synthetic organic dyestuffs, the first important product of the German chemical industry. Coke ovens were also the source of most industrial ammonia, which was the raw material for both fertilizers (usually ammonium sulfate) and nitric acid for manufacturing explosives such as nitroglycerine.

Integrated Industrial Ecosystems

The most influential - and possibly the only - prototype for such a system was, and still is, the Danish town of Kalundborg. In this town waste heat from a power plant and a petroleum refinery has been used to heat greenhouses and other wastes from several large industries have been successfully converted into useful products such as fertilizer for farmers, building materials, and so on. The Kalundborg example is discussed in full in Chapter 33.

Future Discounting Explanation for the Persistence of a Mixed Foraging Horticulture Strategy among the Mikea of

The most important subsistence and cash crop for Mikea was, until recently, maize grown in slash-and-burn fields called hatsake (the ethnographic present for this chapter is before the government effectively banned hatsake cultivation in 2002). Mikea invest little labor and no other inputs into their maize fields. New fields are cleared by felling and burning trees. Old fields are reused for several years and then abandoned. They are usually cleared of weeds and saplings before planting, although some farmers reduce labor costs even further by planting among the weeds. After planting, no additional labor is invested until harvest time. The fields are exposed to severe sunlight, unpredictable rainfall, poor soil nutrition, weedy competition, and predation by grasshoppers and unsupervised herds of cattle and goats. Mikea are aware of a variety of intensification techniques that could increase maize yields and reduce risk of failure, such as tillage, irrigation, manure fertilizers,...

Control of Acidification External Measures

'Neutralization in the catchment', achieved, for exam ple, by liming with calcium carbonate, magnesium, or alkali carbonate (e.g., sodium carbonate), is one way to counteract the acidification. An alternative way is to stimulate alkalinity producing processes such as micro bial sulfate reduction and microbial denitrification in the soils of the catchment, provided that sufficient supply of organic substance and N fertilizers can be guaranteed. This can be realized by adding these substances to the recultivated mining waste heaps (e.g., as liquid manure) or by establishing reactive systems with increased decom position of organic matter (e.g., fish ponds with feeding, constructed wetlands). For mining lakes, a number of measures aim at minimizing the groundwater influx. These include the installation of underground bulkheads, the draining of acidic water from the mining waste heaps, or afforestation, whereby water bound transport of acid is lowered by evaporation. Another possibility...

Bioremediation Enhancement of Degradation

Soils, sediments, marine, and freshwater all contain readily metabolizable organic matter. However, when a potentially degradable pollutant at sufficiently high concentration is introduced into the environment, the environment may become deficient in nutrients other than C. Addition of inorganic nitrogen and phosphorus then stimulates the microorganisms present in that environment to degrade the pollutant at a faster rate. In situations like these bioremediation may be achieved by just adding fertilizers containing N and P.

Effects of Soil Fertility on Species Diversity

Soil fertility can vary greatly at any given latitude and can affect species diversity. For example, Stevens et al. (2004) found that in Great Britain, species adapted to infertile conditions were systematically reduced at high levels of nitrogen deposition. In earlier studies in which fertilizers were added to small plots, enrichment resulted in a loss of species diversity (Huston 1979). However, Tilman (1987) pointed out that lower diversity in enriched plots occurs because plant communities do not have time to adapt to changed conditions. When plant communities have evolutionary time to adapt to soil conditions, those on richer soils will have higher diversity than those on poor soils. A decrease in diversity following addition of fertilizer merely indicates that certain species are better able to take advantage of changing conditions than others. The former gain a competitive advantage and crowd out the latter. However, this is a short-term result. When we speak of high diversity...

Symbiotic Nitrogen Fixation

Nitrogen-fixing microorganisms have been found in roots or other organs of many species of plants with which they establish symbiotic associations. In some cases, the diazo-trophic partner is a cyanobacterium, such as Anabaena in coralloid roots of Cycads or Nostoc in stems of Gunnera. Particularly interesting is the symbiosis between the cyanobacterium Anabaena azollae and the leaves of the aquatic fern Azolla. This symbiosis is permanent and hereditary and is the only known mutualistic symbiosis between a pteridophyte and a diazotrophic prokaryote. The Anabaena-Azolla association has received great attention for its potentiality as a biofertilizer to substitute chemical nitrogen compounds. In rice fields, for instance, it can fix over 1 kgNha- d , providing sufficient nitrogen to allow sustainable rice cultivation. Other symbioses having cyanobacteria as the N2-fixing phycobiont are those of lichens.

Rhizobia Legume Symbiosis

Most Leguminosae (about 90 ) can establish a symbiotic association with aerobic diazotrophic Gram-negative bacteria commonly referred to as rhizobia. This symbiosis takes place in roots and brings about the formation of nodules in which N2 fixation occurs. The large contribution made by these symbioses to the nitrogen availability for agronomically important legumes is well known. Medicago sativa, for instance, can fix 300kgNha yr and Vicia faba over 500 kgN ha-1 yr-1. This makes biological nitrogen fixation a major component of sustainable agricultural systems, since it has the potential to greatly limit the use of chemical nitrogen fertilizers.

Endophytic Diazotrophic Bacteria Cereal Association

Both enhancing the N2 fixation and extending this efficient system to other cereals. This would greatly reduce the use of nitrogen fertilizers with considerable economic benefits, and, above all, with enormous environmental advantages. Over two-thirds of arable lands, in fact, are dedicated to the growing of cereals, which provide 80 of the food for the world's populations.

Perspective on Biological Wastewater Treatment

An important question is to what extent wastewater, for example, municipal wastewaters and sewage sludge, should be considered a waste or valuable resource and recycled as plant nutrients in crop and in energy production. Key constraints for the growing global population are due to food and energy. Today, both extraction ofphosphorus and production of mineral nitrogen fertilizers consume extensive resources of fossil fuels. Hence, one important future aim must be to create a sustainable loop ofplant nutrients through food production and refinement, urban consumption, waste handling, and back to arable land. To achieve this, the effluent wastewater stream must contain as much phosphorus and nitrogen as possible in addition to minimal amounts of organic and inorganic toxicants.

The Distribution of Primary Production in Different Ecosystems

In tropical forests, most nutrients are stored in vegetation rather than in the soil. When the trees are removed, the nutrient-poor soils are rapidly depleted of their nutrients by frequent rains and by growing crops. Thus food crops can be grown only for a short time without massive, expensive applications of commercial fertilizers.

Influence of trees on the degradation of forest soils

Soil degradation can be a particular problem with plantation forestry and is often suspected if the growth of a subsequent similar crop is inferior to that of the original crop. The physical, biological and chemical properties of the soil, including its structure, level of organic matter, presence of toxins, and the distribution and availability of nutrients may all be involved. In forestry, gross problems are overcome by using artificial fertilizers and although in small quantities compared with agriculture and mainly involving potassium, they can still be a matter for concern, which is discussed in Section 8.6.2. However, there is evidence that not all plantations are detrimental to soils. In New Zealand, some areas have now had three cycles of Monterey (radiata) pine Pinus radiata. Maclaren (1996) concludes that there has been no decrease in productivity in subsequent rotations of planted forests and, indeed, Woollons (2000) found enhanced growth in the second rotation, though...

Root competition and specialist adaptations

Modern studies have placed an increasing emphasis on the importance of below-ground competition. Working with seven herbaceous understorey species from an unproductive old field in Michigan, Rajaniemi et al. (2003) found that increased productivity resulting from fertilizer application was associated with a loss in plant diversity. These changes were caused almost exclusively by root competition above-ground competition from more vigorous growth had small effects on the community but did not contribute to changes in diversity. This has important implications for forests indeed in Britain NPK fertilizer drift from fields caused by the wind has had an adverse effect on many woodland margins, whose soils now support larger populations of stinging nettle Urtica dioica, a strongly competitive species, and have rather lower biodiversity, than they did a few decades ago.

Techniques For Imaging The Location Of Enzymes

At the field scale, researchers use biochemical and physiological methods to investigate the functional response of soil organisms to the manipulation or preservation of soils. These applications include microbe-plant interactions and controlling plant pathogens, as well as understanding organic matter decomposition and its impact on local and global C and N cycling. Soil biologists investigate the effects of soil management (tillage, fertilizer, pesticides, crop rotation) or disturbance on the function of soil organisms. In many cases, soil microbial biomass and or soil microbial processes can be early predictors of the effects of soil management on soil quality and can indicate the expected rapidity of these changes. Monitoring of soil microbial properties is also included in environmental studies that test the use of soil microorganisms in bioremediation and composting. Future challenges in functional soil microbiology are to use our present knowledge to scale-up these data to the...

Evolving from Nonrenewables

The human economy runs almost exclusively on nonrenewable, unsustainable materials and energies. The materials used in every building and every purchase made at every store rely on nonrenewables for their distribution, are derived from nonrenewables, or are nonrenewable. The fertilizers, trucks, clothing, roads, machinery, transportation, and tools everything is inextricably linked to and dependent on the use of nonrenewables. The average food item purchased at the corner market traveled 2,000 miles before it was eaten. This is important, because when comparing organic apples to organic oranges, the distribution energy the energy consumed transporting the product to the market exceeds the food energy value. So even when the crop itself is sustainable, the distribution methods are not. The critical step in evolving from nonrenewables is to be powered and supplied locally.

Complementary resources See resource

Compost An organic fertilizer made from the breakdown by bacteria and other microorganisms of garden rubbish, kitchen vegetable waste, and other biodegradable material. Bacteria in soils are mixed with the waste and the mixture turned regularly to admit air. The organic material breaks down to a relatively stable humus-like material.

Modeling Population Dynamics

The beautiful and shallow Lagoon of Venice is under heavy pollution stress due to agricultural activities (use of fertilizers) on the neighboring mainland. Pollutants are food (nutrients) for algae, which have on occasion grown excessively to the point of suffocating themselves, then decayed and caused unpleasant odors (noticed also by the tourists). Models of algal growth are needed to support environmental management decisions and answer questions such as ''Would a reduction in the use of phosphorus-rich fertilizers reduce algal growth ''

Implications of organic matter decomposition for management and conservation

For example, in some types of agroforestry systems, leaf litter is used to increase crop yield, especially when leguminous tree leaves are used as mulch. Mulches can protect soils against erosion, decrease weed growth, release nutrients to the soil via decomposition, and moderate soil moisture loss and temperature fluctuations (Montagnini et al. 1993). Farmers frequently use leaf litter as mulch when inorganic fertilizers are too expensive and livestock manure is not available (Byard et al. 1996). Clear-cuts, especially if followed by burning of the accumulated woody debris, are particularly harmful to the ability of the ecosystem to sustain productivity. Therefore, if a tree plantation or agricultural system follows a clear-cut, management has to be geared towards nutrient conservation and replenishment in order to sustain productivity in the long term. More details on nutrient management and conservation in plantations and agroforestry are given in Chapter 6.

Commercial Applications

For the capture of H2S and volatile sulfur compounds (e.g., thiols, COS, and CS2) released during the transportation of sour liquids, a portable system is required. Am-gas Scrubbing Systems Ltd. (Calgary, Canada) manufactures both portable and stationary units that use 26 aqueous ammonia. The spent solution oxidizes to form ammonium sulfate, which is recovered from the spent absorbent and can be marketed as fertilizer. Alternate absorbents for portable units include basic hypochlorite (bleach) solutions, but the stability of the solution decreases with consumption of the base as the H2S is absorbed. A complicating factor in the use of basic fluid absorbent systems is that CO2 is also a weak acid and is absorbed to sequentially form bicarbonate (HCO3) and carbonate (CO _) ions, thereby consuming the absorbent.

Models Organism and Process Oriented

A recurrent theme that resonates throughout the field of soil ecology is the focus on organisms and population dynamics models used by community ecologists, and the use of process models at the ecosystem scale (Moore et al., 1996 Smith et al., 1998). Many ecosystem level models have included dynamics of the soil biota only implicitly, yet the intrasea-son dynamics of microbes and fauna, as is demonstrated in Chapters 4 and 5, often have a significant effect on nutrient availability and turnover. One of the more successful combinations of the organismal and process modeling approaches was by Paustian et al. (1990), who used four cropping systems (both annual and perennial crops) that varied in inorganic inputs and organic production in the growing season (1) barley without fertilizer, (2) barley fertilized with 120kgNha-1yr-1, (3) a meadow fescue field with 200kgNha-1yr-1, and (4) a lucerne field with indigenous nitrogen fixation. The conceptual models of carbon and nitrogen flows in...

Exergy Efficiency And Waste

A similar calculation for 1900 can be carried out, albeit a little less accurately. In that year the primary agricultural biomass was probably about 20 per cent less than that for 1993. The argument is that the total amount of land devoted to agriculture in the USA has changed very little since 1900 land made more productive by irrigation (mainly in California and the southwest) is roughly balanced by land lost to agriculture in the southeast and northeast as a result of extensive erosion and urbanization. Elsewhere, as in the great plains, irrigation is mainly compensation for falling water tables. Similarly, the net impact of fertilizers is largely to replace nutrients lost to harvesting and topsoil erosion. Increases in net food production can be attributed mainly to reduced need for animal feed (for horses and mules), improved seeds (yielding more grain or other useful product per

Efficiency Gains in Production

Fertilizer Trade-offs Crop production in some of the most intensely cultivated regions involves a trade-off between maximizing yields and degradation of the environment. As fertilizer application increases, crop yield has diminishing returns, but nitrate leaching increases exponentially (Figure 5.7). An increase in nitrogen from the Mississippi Basin has led to eutrophication in the Gulf of Mexico (Goolsby et al. 2001). This implies that by reducing fertilizer use slightly in some of the most heavily fertilized regions, one could see major gains in terms of nitrate pollution, and compensate this by increasing fertilizer use in some of the less fertilized regions to increase production without big consequences for eutrophication. Moreover, some measurements indicate that in the U.S. a few farms contribute to a majority of the high fertilizer application rates, so one could target these farms without major losses in production to avoid nitrate leaching into the Mississippi River. Such...

Farmers Are Not Predators

Geese can eat grass off golf courses, birds may eat noxious insects, and bacteria can help digest organic matter in sewage effluent. These valuable processes are only remotely connected to ecological efficiency. Advocates for vegetarianism quite correctly note that the amount of resources - sunlight, water, and fertilizers needed to grow animal flesh - is several times larger than that needed to produce an amount of vegetable food of equivalent or superior nutritional quality.

Key Global and Regional Results

At the largest scales, global Ecological Footprint analysis shows that the total human footprint, or demand on ecosystems, exceeds the planet's available biocapacity, or its ability to supply resources and waste sinks. Figure 1 shows that this condition of overshoot has existed since the mid-1980s. The most significant growth in Ecological Footprint over this time period has been a result of an increase in the productive land area required to meet human demands for fossil fuel energy. This energy land footprint made up nearly 50 of the total Ecological Footprint at a global level in 2002. The growth in available biocapacity over time largely reflects increases in the productivity of cropland. These increases also led, however, to increases in application of fertilizers and pesticides, the creation of which contributed to the rapidly growing Ecological Footprint over this same time period.

An Estuarine Ecohydrology Model

This model is based on the dominant ecohydrological processes in tidal estuaries. The model is best suited to estuaries that are fairly well mixed vertically. In practice this constraint is adequate for many applications because critical conditions in estuaries commonly arise during low flow conditions brought upon by dams and water extraction. These conditions are exacerbated by excess nutrients from, typically, sewage discharge, effluent from feedlots, and fertilizers from farming. Thus the physical submodel, sketched in Figure 1 , views the estuary as a series of connecting cells that exchange water by advec tion as result of the river runoff and the saltwater inflow, and by tidal mixing. The upstream cell receives fresh water, sediment, nutrient, and freshwater plankton. The downstream cell receives seawater and marine sediment, nutrients, and plankton. Cells can also exchange water and particulates with fringing wetlands both in the fresh and the saline region of the estuary. The...

Timber From The Tropics

Whilst most organic materials have this healthy environmental profile, there are a few exceptions. Cultivating plants can involve the use of insecticides, fungicides, hormone additives and synthetic fertilizers that can be responsible for increased erosion, polluted ground water and the damage or destruction of local ecological systems. This type of cultivation can also produce defects such as enlarged and mouldy cell growth in timber. Gene manipulation has been suggested as a solution to reduce the need for fungicides. By adding genes of a more resistant plant, it is possible to reduce the amount of insecticide sprayed on a crop during cultivation. This gives the modified species an 'unfair' advantage over other species in the ecosystem, however, and may lead to the collapse of the whole system. This kind of solution is at present too dangerous to accept as a long-term environmental strategy.

Services Provided by Forests

Forests in a watershed, on the hillslopes that drain into a river, influence the water quality in that river. In part this is because higher-intensity uses, such as agriculture input pollutants like nutrients and pesticides into a system while forests do not. Forests themselves also reduce sediment and nutrient runoff.Clearing trees can have an impact as soon as the next rainy season on sediment and nutrient loads in streams, as demonstrated in the classic Hubbard Brook experiment. In some cases, water users have invested in forests to keep their water supplies clean. New York City recently invested US 250 million to acquire and protect land in the Catskills watershed that supplies water to the city. By working with landowners to reduce pesticide and fertilizer application and to plant buffer strips along waterways, New York City reduced potential contamination of its drinking water. In conjunction with related conservation investments amounting to US 1.5 billion, the city thereby...

The durability of timber

However, some factors are now beginning to threaten timber's reputation. The extensive use of artificial fertilizers is probably reducing its durability, since the fast growth of cells produces a spongier, more porous timber. Fast-growing species were introduced in the 1950s and have proven to yield lower quality timber. These conditions also led to a greater need to impregnate timber with chemicals, see Chapter 19.

Soil nutrient composition

The top organic horizons provide most of the labile nutrients. With depth, the organic matter becomes more recalcitrant as the more labile nutrients are removed and less soluble, less nutritious molecules remain. The labile SOM consists of molecules readily removed from the soil by living organisms and readily soluble molecules. These have a short halflife in soils as they are removed easily by living cells, but consequently they have a higher turnover rate. This pool is reduced over several years when soil is used for agriculture. As much as half the labile organic matter, or the light fraction, is used in the first year of growing a crop on a field. Therefore, it is essential that nutrients be replenished regularly with plant debris, manure, compost or chemical fertilizers.

Cultivating and harvesting

Most cultivated plant products used in construction are by-products from the production of grain. Production of grain is often based on the extensive use of synthetic fertilizers and pesticides. Plants that have a high resistance to moulds and insect attack include hemp, elephant grass and linseed. Nevertheless, in linseed cultivation it is common to use 0.7 kg of pesticides per hectare - of which about 20 is lost to the atmosphere (Lippiatt, 2007). Alternative methods are possible, including the various types of organic farming, though in general they give lower yields. Ripe grain is usually harvested in late summer. Cutting of wheat and rye to be used for roof covering must be carried out without breaking or splitting the stalks.

Cropprotection opportunities

Only a few studies have explored interference with plant-parasitic nematode behaviour as a crop-protection tool. These studies have examined co-formulation of the sex attractant, vanillic acid, with biological control agents in pots and in the field (Meyer and Huettel, 1996 Meyer et al., 1997) to manage the soybean cyst nematode Heterodera glycines, release of CO2 as a bait (Bernklau and Bjostad 1998a,b) to increase the efficacy of pelletized mycophagous fungi (Robinson and Jaffee, 1996), manipulation of CO2 and temperature gradients to increase Baermann funnel extraction efficiency (Robinson and Heald, 1989, 1991), application of lectins to block chemosensory function (Marban-Mendoza et al., 1987), shielding of plant roots with ammonium nitrate and other repellent fertilizer salts (Castro et al., 1991) and application of tannic acid attractants to the soil as confusants (Hewlett et al., 1997).

Donald G Rogich and Grecia R Matos

And losses which are a consequence of inefficiencies in the process. After going through all the necessary processing stages the material enters the use stage, where the residence time can vary considerably depending on the material and its use. Some flows result in 'permanent' additions to the stock of built infrastructure others are discarded after only days or years of useful life. The use of materials such as fertilizers and pesticides results in an immediate, dissipative, release to the environment. As shown in Figure 22.1, some process wastes and post-use discards may be recaptured, and re-used as inputs. The recapture of material flows emitted in process is not always feasible, and those used in a dissi-pative manner are not recoverable. While in economic terms the value added to the material is consumed by use, the physical material, often in a changed form, continues to exist after it exits from the economy.

Estuarine Ecohydrology

Change in natural river flows from human activities, as well as land clearing and overgrazing that increase soil erosion. Such activities modify the natural flows (e.g., dams), and increase the riverine nutrient load (e.g., sewage discharge, animal waste from agribusiness such as pig farms and cattle feedlots, and fertilizers leaching from farms). All of these activities and processes also degrade the tidal wetlands because of the exchange of water and mass between the estuary and the tidal wetlands. The pressure on tidal wetlands is further increased by dredging, land reclamation for industry, and urbanization. For instance, nearly all estuarine marshes have been 'reclaimed' in the Netherlands and in Japan.

Processes Controlling the Stable Isotope Composition of N2O

Mass-dependent isotope effects occur during chemical transformations, with molecules containing the lighter isotope (14N) reacting faster than the molecules containing the heavier isotope (loN). As a consequence the product of a reaction is depleted in l3N relative to the isotope composition of the substrate pool. Assuming complete removal of products and no further inputs of substrate, the substrate pool will become enriched in the heavy isotope as the reaction proceeds over time. The change in the isotope composition of the substrate pool will in turn result in a progressive increase in the heavy isotope composition of the product pool as the substrate is consumed. Changes in the availability of substrates (ammonium and nitrate) for N2O production should cause, therefore, temporal shifts in the 515N of N2O produced in soils. This idea has been tested under field conditions by adding pulses of substrate (urine, fertilizer) to soil and monitoring temporal shifts in the isotope...

Producing markets the global agrochemical industry

The term agrochemical industry specifically refers to those few, large, diversified chemical companies that globally manufacture and sell the active ingredients in pesticides and fertilizers. These firms and their respective markets have also undergone dramatic recent changes. The establishment and expansion of large-scale pesticide and fertilizer development and manufacturing is a product of military technology and processing power developed during World War II. The fight against typhus and malaria on the front, coupled with the search by chemists for chemical warfare agents, led to the discovery and the development of DDT (in 1939), the discovery of the herbicidal properties of 2,4-D and MCPA (in 1944), and the first organic weed killers based on the regulation of plant hormones (Whitten 1966 Aldus 1976 Anderson et al. 2003). Under the direction of research and development by the Chemical Warfare Service of the US military, pesticide production blossomed and proved to be effective...

Macroalgae and Mariculture

Macroscopic marine algae (seaweeds or sea vegetables) form an important living resource of the near shore environment. For millennia, people have collected sea weeds for food, fodder for animals, as well as fertilizers and soil enhancers. More recently, seaweeds have become important sources of various biochemicals, such as phycocolloids, and are important in medicine and bio technology. We all use seaweed products in our daily life in some way or other. For example, some seaweed poly saccharides (sometimes referred to as phycocolloids) are used in toothpaste, soaps, shampoo, cosmetics, milk, ice cream, processed meats and other foods, air fresheners, and many other items. In many Asian countries such as Japan, China, and Korea, they are dietary staples.

Growth curve See growth

Guano The accumulated droppings of birds, bats, or seals, which are collected and used as fertilizer. Guano is rich in nutrients, especially calcium phosphate, and in places is mined on an industrial scale. It tends to accumulate at the sites of dense breeding colonies, such as seabird colonies on offshore islands or bat colonies in caves.

Disturbances to Aquatic Ecosystems

The linear configuration of stream systems (i.e., the stream continuum concept Vannote et al. 1980) makes them particularly vulnerable to disturbances that occur upstream. For example, heavy precipitation in the watershed is concentrated in the stream channel, scouring the channel and redistributing materials and organisms downstream. Fire or harvest of riparian vegetation exposes streams or wetlands to increased sunlight, raising temperatures and increasing primary production, altering habitat and resource conditions downstream, often for long time periods (Batzer et al. 2000a, Haggerty et al. 2004). Industrial effluents, runoff of agricultural materials (e.g., fertilizers), or accidental inputs of toxic materials (e.g., pesticides) affect habitat suitability downstream until sufficient dilution has occurred (S. Smith et al. 1983, Southwick et al. 1995). Eutrophication, resulting from addition of limiting nutrients, substantially alters the biological and chemical conditions of...

Direct Ecological Effects of Forest Plantation

Use of inorganic fertilizers to overcome fertility deficiencies, promote rapid growth, and sustain biomass accumulation generally has been found to have little impact on aquatic systems unless fertilizers are applied directly to streams, lakes, rivers, or adjacent riparian zones. Greater attention has focused on nutrient removals in harvests and the potential for intensive management to reduce site fertility and cause a fall-off in productivity of subsequent rotations. Claims of later-rotation productivity declines have been hard to substantiate, however, as general improvements in seed and seedling quality, genetic makeup, site preparation and competition control, and more careful harvesting that conserves site fertility have raised, rather than lowered yields. Nevertheless, there exist documented cases of lowered fertility caused by export of nutrients in the harvested wood. These localized cases have been caused by low initial fertility, often of phosphorus, potassium, or...

FUZZY Models as Part of Dynamic Models

This model describes a growth process (such models are used to model the growth of agricultural crops in soil-water-nitrogen simulations), which is controlled by the growth constant Kthe saturation constant B. The k is used to model a positive or negative influence of interaction in the population. In a plant growth model a monoculture can reduce k for example. For a concrete modeling task it is difficult to estimate these parameters. The use of a fuzzy model can help determine these parameters. The saturation parameter B depends on the soil quality s, the amount of fertilizer f and the water availability w. Using expert knowledge B could be expressed as

Definitions and Principles


Integrated waste management A

Intensive farming Farming that aims to get the maximum output from a given area of land by keeping animals in crowded conditions or growing crops in quick succession, often to the detriment of the environment. Growing several crops a year requires large amounts of fertilizer. If the rotation of crops is abandoned, this will necessitate more fertilizer and pesticide applications. Keeping livestock indoors and feeding them on concentrated foodstuffs requires the use of more drugs to control diseases associated with crowding.

Environmental Aspects and Biodiversity

Arable flora) have been identified that benefit from organic management through an increase in abun dance and or species richness. It also highlights three broad management practices (prohibition reduced use of chemical pesticides and inorganic fertilizers sym pathetic management of noncropped habitats and preservation of mixed farming) that are largely intrin sic (but not exclusive) to OF, and that are particularly beneficial for farmland wildlife. Enhanced soil fertility and higher floral and faunal diversity were found in OF experiments.

Threshold and Nonthreshold Agents

Threshold agents include various nutrients, such as phosphorus, nitrogen, silica, carbon, vitamins, and minerals (calcium, iron, zinc, etc.). When they are added or taken in excess, the organism or the ecosystem can be overstimulated, and the ecological balance may be damaged. Examples are the eutrophication of lakes, streams, and estuaries from fertilizer runoff or municipal wastewater. The threshold level and the type and extent of damage vary widely with different organisms and stresses. The thresholds for some pollutants may be quite high, while for others they may be as low as i ppm or even i ppb.

An Empirical Application For The Uk Economy

Within the MFA accounting framework water appears as a direct input (processing water) and as the water content of materials. Careful accounting for water is especially necessary when balancing materials. Similarly, oxygen and nitrogen in the air are direct inputs due to conversion processes such as incineration or production of cement and fertilizers. In our account we treat all materials with the water content when marketed. Exceptions are made for biomass for grazing, which is included with a standardized water content of 14 per cent, and timber, which is included using the water content when removed from the forest.

Turbidity Caused By Algae

If the initial turbidity lasts more than a couple of weeks, the filtering can be increased. This removes the turbidity but not its causes. If the excess growth of algae and protozoans is caused by an overly rich planting medium or by excessive fertilizing of the substrate or water (whether by natural or artificial fertilizers), the turbidity immediately reappears as soon as filtration is stopped. This will continue for as long as the surplus nutrients remain in the water, which may be months. This is one more reason for using plain sand for the bottom material.

Indirect Effects of Global Relevance

Indirect relationships important on the global or subglobal scale are often separated from their cause spatially and or temporally. For example, the dramatic increase in volcanic activity (possibly caused by the impact of an asteroid) at the end of the Mesozoic era is thought to have led to the extinction of dinosaurs, which arguably stimulated the eventual evolution of mammals (including humans). The increased production and use of fertilizers in the 1950s led to the increased phosphate inputs, eutrophication, and decrease in water quality in many lakes, ponds, and reservoirs during the subsequent decades. The increased consumption of fossil fuels in the twentieth century led to the increased emissions of carbon dioxide, which were eventually followed by global warming and an apparent increase in the frequency of natural disasters. This climate change was probably accelerated by the depletion of the planet's ozone layer due to the CFC (chlorofluorocarbon)-containing deodorants and...

Flow Of Matter In Ecosystems

However, the soil is being compromised by human activities. Erosion causes a loss of organic-rich topsoil. Agricultural practices do more to replace lost nutrients than to replace soil organic matter, which contributes to favorable physical soil properties as well as chemical ones. Increased water runoff reduces infiltration, thereby reducing weathering of bedrock and the consequent liberation of minerals. As a result, agricultural fertilizers now need to include trace minerals in some areas.

Factors That Control Populations

Factors can also affect growth in a nonadditive way. For example, growth of Impatiens parviflora was increased 33 by adding nitrogen fertilizer and 19 by adding phosphorus. However, when both were added, the increase was 100 . If there were no interaction, adding both nitrogen and phosphorus would be expected to increase growth 33 + 19 52 . This is an example of interaction, which is not accounted for in Lie-big's law. The concept of interaction is important An interaction is when the sensitivity of a variable to one factor depends on the level of another factor. Here, sensitivity can be given a precise mathematical meaning. It is related to the rate of change of one variable with respect to another. One way to express the sensitivity of variable a to variable b (sab) is

General Considerations

Inefficient irrigation practices considerably reduce crop and fruit production. Water unused in the productive process in irrigated agriculture implies a loss of energy, labor, fertilizer, irrigated soil potential, and water. Water use in agriculture can be significantly improved by optimal design and management of irrigation systems. The design and selection of irrigation and water management systems should be based on maximizing economic and social benefits, resulting in greater well-being for the population.

Farm Level Water Management Planning and Optimal

Agricultural systems are characterized by the interdependence and complexity of their components and by the variability and risk involved in their management. Agriculture is an activity with high risk levels and income that fluctuates yearly due fundamentally to variations in climatic conditions, diseases, and changes in product prices and markets. The use of chemical products as fertilizers and in disease control forms the base of modern

Humans In The Balance

In the twentieth century, fertilizer use provided the most dramatic improvement. But fertilizer use is linked to water use. The more rain or irrigation that is applied, the more fertilizer the crops can utilize. World fertilizer use has actually dropped recently, as farmers have learned to apply it more precisely. A final way to improve yields was to develop better varieties of crops, but the high-yielding varieties require higher fertilizer doses.

Types Of Thermal Dryers

Thermal drying of sludge is economical only if a market for the product is available. Although dried sludge makes a good soil conditioner and fertilizer and is convenient to use, especially for the home gardener, the cost of preparing and packaging it is seldom recouped from the profits. Accordingly, sludge drying is seldom used in the United States and does not represent an economical alternative to incineration or other disposal processes. However, if a municipality looks beyond economics and considers sludge as a natural resource, they have a strong argument for drying sludge and using it as a soil conditioner and fertilizer.

Environmental Controls of LAI

A new steady state is adjusted in the following growing seasons, especially in terms of leaf area versus root ratio. LAI sensitivity decreases (i.e., LAI saturates) indicating that something other than soil fertility is a limiting factor for canopy development. In many cases, water supply acts as a strong limitation resulting from LAI increase and related water uptake needs. The response to increasing soil water content is close to that of soil fertility. Increasing soil water availability in soils suffering from severe drought causes a significant increase in LAI. Interestingly, the response to increases in atmospheric CO2 is nonlinear. LAI curves for crops and plant communities indicate a strong response of LAI to increases in atmospheric CO2 up to the current ambient content. Afterward, the impact is more limited. At some resource thresholds, the addition of fertilizers or water will have no further influence on LAI. The saturation of LAI is likely to be indicative...

Reuse of Incinerator

Various forms of slag tiles, bricks, and concrete blocks are made from ash residues. The city of Tokyo sells a large tonnage of its multiple-hearth furnace ash to C. Itoh Fertilizer Sales Company, Ltd. Vitalin is sold under the special fertilizer category because material containing less than 12 phosphate cannot be classed as fertilizer. (Some states also require that the material have a nitrogen content of 6 or a total NPK range of 20 to 25 .)

Value Of Heatdried Sludge

Heat-dried sludge compared to sludge dried on sand beds is free of pathogens and weed seeds and is therefore safer to use. However, under normal conditions, heat-dried sludge is more powdery and more difficult to spread and mix with soil than conventional sludge. It is initially repellent to water although once it becomes partially moist, it readily absorbs more water. Therefore, heat-dried sludge must be further treated before being sold as a fertilizer.

Health Considerations

The possibility of fertilizer nutrient buildup in ground-water and surface water from sludge lagoon and landfill leachates does exist. Therefore, environmental engineers should be concerned with this possibility because high concentrations of nitrates in drinking water can have toxic effects on humans and nitrogen and phosphorus contribute to eutrophication in surface water.

Nutrients and Eutrophication in Lakes

Although it occurs naturally, addition of anthropogenic nutrients hastens this process. People contribute nutrients in the form of fertilizer runoff from lawns and agricultural lands, human waste from either treatment plant discharge or indirectly from septic tanks, and animal waste from pasture or feedlot runoff. In these cases the process is termed cultural eutrophication. Oligotrophic lakes are preferred for numerous human

Risk Management For Metals

Three main approaches for enhanced metals management now seem feasible (a) the input into the economy can be lowered (b) the output can be delayed and (c) the output can be controlled or sequestered. The first main approach, lowering of the input, can be achieved by replacement of metals in functional applications (for example, PVC for zinc gutters), by recycling or increasing the lifespan of metals with an elastic supply (for example, Cu, Pb or Zn) and by reducing inflows as contaminants, for example in phosphate fertilizer or fossil fuels. The second main approach, delaying the output, can be achieved by keeping non-functional metals within the economy (for example, fly ash in concrete or roads). This option offers time for further development of the third main

Resourcebased competition theory

Tilman, a particularly strong advocate of a mechanistic approach to competition (1976, 1981, 1982), developed what is now known as resource-based competition theory. In so doing he brought together ideas from a variety of disciplines, including microbiology, enzyme kinetics, and agricultural chemistry. For example, the idea that population growth is constrained by the depletion of critical resources can be traced to the agricultural chemist Liebig (1840) and his law of the minimum. Liebig asserted that a population increases until the supply of a single critical resource becomes limiting. For example, plant growth may continue until the amount of phosphorus, nitrogen, light, or soil moisture becomes limiting. According to Liebig's law, if plant growth is constrained by phosphorus and a farmer adds phosphorus fertilizer, plant growth will continue until another resource, such as nitrogen, becomes limiting. If the farmer adds nitrogen, then soil moisture may become the limiting factor....

Ecological Application of Mass Cultures

Microalgae, sometimes in combination with other microorganisms, are utilized to treat municipal, agricultural, food, industrial, as well as aqua- and mariculture, effluents. The main objectives for algal biotechnology are the improvement of existing systems for waste water treatment, the reduction of problematic emissions, the establishment of material circuits, and water recycling. The consumption of inorganic nutrients by autotrophi-cally growing microalgae may be used for the reduction of environmental loads. The key substances contributing to water eutrophy, for example, nitrate and phosphate, as well as important industrial and agricultural waste gases (e.g., ammonia and carbon dioxide) are the main nutrients for microalgae. Having disposed off such environmental loads, these algae can be exploited as fertilizers, and for the extraction of valuable compounds.

Nonrenewable resources

Atmospheric gaseous nitrogen can be used directly only by certain nitrogen-fixing bacteria (e.g. Clostridium, Nostoc, Rhizobium). They convert nitrogen to ammonia, nitrites, and nitrates, which are released into the soil by excretion and decay. Some are free-living, whereas others form symbiotic associations with plants (see nitrogen fixation). Another method by which atmospheric nitrogen is fixed is by lightning, which causes nitrogen and oxygen to combine. The oxides so produced dissolve in rain to form nitrous and nitric acids in the soil these acids combine with mineral salts to form nitrites and nitrates. This is an insignificant process when compared with microbial nitrogen fixation. When plants and animals die, the organic nitrogen they contain is converted back into nitrate in the process termed nitrification. Apart from uptake by plants, nitrate may also be lost from the soil by denitrifica-tion and by leaching. The use of nitrogen fertilizers in agriculture and the...

Sequestration Rucksacks And The Cadmium Paradox Some Environmental Implications

As pointed out by Lave et al. (1995), a large-scale introduction of technologies such as EVs that make use of toxic elements such as lead could increase the environmental loading of the metal. However, it is worth noting that this will only be the case if an increased mining of the metal is induced or if recovery and recycling are not more efficient than at present. As shown by Socolow and Thomas (1997) and Karlsson (1999), there is a potential that lead flows can be sufficiently closed within a battery production, use and recycling system. Large batteries and PV systems could be examples of applications where a controlled use of toxic metals is possible. They could then be used as a tech-nospheric 'attractor' for toxic metals. A high demand for the metals would raise metal prices and discourage dissipative uses or even stimulate recovery of hazardous metals from various by-flows, such as cadmium from phosphate fertilizers, vanadium from petroleum refining, lithium from geothermal...

Environmental Controls Of Denitrification

For decades after its discovery as an important microbial process, denitrifica-tion was assumed to be important only in aquatic and wetland ecosystems. It was not until the advent of whole-ecosystem N budgets and the use of 15N to trace the fate of fertilizer N in the 1950s that denitrification was found to be important in unsaturated soils. These studies suggested the importance of denitrification in fertilized agricultural soils, and with the development of the acetylene block technique in the 1970s the importance of denitrification in even forest and grassland soils was confirmed. Acetylene selectively inhibits nitrous oxide reductase (nos see Fig. 13.7), allowing the assessment of N2 production by following N2O accumulation in a soil core or monolith treated with acetylene. Unlike N2, small changes in N2O concentration are easily detected in air. In addition to O2, denitrification is also regulated by soil C and NO . C is important because most denitrifiers are heterotrophs and...

D x xTdxdt dxdtTx xTJ JTx

A large input of nutrients will therefore cause a perturbation to grow before it decays, and the larger the input the faster the growth and the greater the magnitude of growth. Thus, fertilizer input to a lake from runoff could result in very large departures from equilibrium even if the system remains stable and eventually converges asymptotically to equilibrium. Similarly, we can also solve for a critical decay rate that also determines when perturbations will be amplified

Ecological Engineering for Eutrophication Management in Coastal Zones

Upwelling zones, which receive infusions of nutrients from deep ocean waters, support some of the most pro ductive marine ecosystems. However, anthropogenic eutrophication of estuaries and coastal zones has been a growing problem since the latter half of the twentieth century. The main drivers for this have been the increas ing proportion of the population moving to the coastal zones, an increase in the burning of fossil fuels, the increase in the use of synthetic fertilizers and the increase in consumption of animal protein, due to the intensive rearing of poultry and pork. Other contributing factors have been the draining of wetlands and the clear ing of riparian vegetation. The result of these human activities has been a very large increase of the inputs of certain plant nutrients, particularly nitrogen and phos phorus, into aquatic ecosystems. Whereas phosphorus is often the limiting nutrient in freshwater systems, nitrogen is most often the naturally limiting nutrient in...

Oceanic crust See crust


P Merino C Gonzalez Murua A Del Prado S Menndez M Pinto1 and J M Estavillo2

Agricultural activities are significant producers of nitrous oxide (N2O) emission to the atmosphere (Johnson et al., 2007 Ugalde et al., 2007). That is, about 58 of total anthropogenic N2O emissions are caused by agriculture (IPCC, 2007). The main cause of agricultural increases in N2O is the application of N fertilizers and animal manures. Nitrous oxide is a long-lived greenhouse gas in the atmosphere with 296 times the global warming potential of CO2. Denitrification is credited as the primary producer of N2O (Johnson et al., 2005), which is generally favoured in poorly aerated soils with high NO3-concentrations (Van Groeningen et al., 2005). Currently, about 32 of the agricultural land in the EU is used for grassland production (Eurostat, 2005). The response of grassland to fertilizer N is greater than that of most other crops due both to its long growing season and to being harvested as vegetative growth (Whitehead, 1995). In the Basque Country, around 36 of agricultural land is...

Box 82 The benefits of symbiotic nitrogen fixation

Dissolved organic nitrogen is brought to the soil in precipitation (collecting nitrogen as it runs over the foliage and drips to the ground as throughfall) and is also created in soils by a complex mix of processes. Some of these involve organisms and extracellular enzymes breaking up proteins and peptides in the soil organic matter. Soil microbial biomass typically turns over several times a year producing a pool of nitrogen that is rapidly degraded and reused. But it is now realized that a significant portion of the more complex organic nitrogen is created in soils by a set of chemical reactions not requiring living organisms (and so is abiotic). Recent evidence that abiotic immobilization of inorganic nitrogen into organic forms may be an important process challenges the previously widely held view that microbial processes are the dominant pathways for nitrogen immobilization in soils (see Davidson et al., 2003). The most likely way this happens is...

Phytoplankton Blooms in the Black

Many of the Europe's largest rivers, including the Danube, the Dnister, and the Dnipro (also called Dnieper), dump freshwater into the sea. The sea's only source of salty water, on the other hand, is the narrow Bosporus Strait, which connects it to the Mediterranean Sea through the Sea of Marmara. The salty water is denser than the freshwater, and so it sinks to the bottom, leaving a layer of relatively freshwater on top. The density barrier between salt- and freshwater is great enough that the two layers do not mix. As a result, when freshwater enters the sea from rivers, it only mixes with the relatively fresh water in the top 150 m of the sea. This means that fertilizers and runoff carried in the river water remain concentrated at the top of the sea where they nourish the tiny plants (phytoplankton) that grow on or near the surface (see Figure 8). swept over broad stretches of farmland. The floods likely washed sediment, fertilizers, and animal waste into the Danube and the Black...

Perspectives For Sustainable Heavymetal Management In Agrosystems

Long-term strategies focus on reducing inputs to soils. This results in the steady state being reached with lower total accumulation and lower output rates. Input reduction can be achieved by reducing the amount of heavy metals in source material (quality) and by reducing the amount of fertilizer or manure added to the soil (quantity). This kind of input reduction could be aimed at by decreasing application (for example, by educating farmers on how to use nutrient and heavy-metal balances) or by changing the production system (for example, to a mixed farming system).

Nitrogen Pollution in a Global Perspective

Which converts inert nitrogen into nitrogen oxides. Human activities, however, now have by far the highest contribution to global nitrogen fixation. These include the synthesis of fertilizers, fuel combustion, and industrial nitrogen fixation. As a result of such activities, the anthropogenic inputs of NOj, and NHX to ecosystems have increased tenfold in 100 years, and at present account for the majority (65 ) of the total global nitrogen budget. Estimates for the current global anthropogenic nitrogen fixation of 140TgNyr_1 show that 15 originates from fuel combustion, 24 stems from the cultivation of rice and nitrogen fixating crops for food production, and 61 comes from the production of fertilizers via the chemical conversion of N2 to NH3 (the Haber-Bosch process). Of the different regions in the world, North America (28.4TgNyr_1), Europe and the former Soviet Union (26.5TgNyr_1), and Asia (68.9 TgNyr-1) fix the majority of global reactive nitrogen. The production of food (which...

Conclusions And Recommendations

Heavy-metal balances on a national scale provide valuable information for economic analyses. Generic balance studies indicate that legislation limiting metal emissions by industry and using fertilizers with low metal content may be very important. Whereas policies based on direct economic instruments or generic regulations often ignore farm characteristics and individual management options, field-scale and farm-gate balances give farmers specific feedback on effective options for better heavy-metal management. Farmgate balances show the total contaminating potential, whereas field-scale balances enable a direct link with criteria for the protection of soil and other environmental criteria. Although data from long-term field experiments are needed to study the long-term environmental consequences of applying fertilizers and soil conditioners, they may not give sufficient information because variation in data collection may hamper the reliability of data and it may be difficult to...

Long Term Global and Regional Trends in the Nitrogen Cycle

In the terrestrial ecosystem, globally, nitrogen production is generally driven by the use of fertilizers for intensive agriculture, with cultivation and combustion contributing approximately 38 to all anthropogenic sources. However, this is not evenly distributed across the world regions. Asia produces almost half the world's nitrogen fertilizers, followed by Europe then North America (Table 2). Africa, Latin America, and Oceania combined contribute less than 12 of global nitrogen production. World region Fertilizer N-fertilizer 105 x 109 kgNyr 1 by 2030. North America doubled its N production between 1961 and 1997, with most of the increase occurring during the 1960s and 1970s. Although the largest increase was in use of inorganic N fertilizer, emissions of NOx from fossil fuel combustion also increased substantially. By 1997, even though N fixation had increased, fertilizer use and NOx emissions had increased more rapidly and two-thirds ofreactive N inputs were denitrified or...

Land Use Controls to Reduce N Enrichment to Surface Waters

The popular misconception that the nitrate problem is caused by farmers applying too much nitrate fertilizer is too simplistic. Nevertheless, there is now little doubt that the high concentrations of nitrate in freshwaters noted in recent years have mainly resulted from runoff from agricultural land and that the progressive intensification of agricultural practices, with increasing reliance on the use of nitrogenous fertilizer, has contributed significantly to this problem. Since 1945, agriculture in the industrialized world has become much more intensive. Fields are ploughed more frequently more land is devoted to arable crops, most of which demand large amounts of fertilizer grassland too receives large applications of fertilizer to ensure a high-quality silage for winter feed stocking densities in general are higher leading to increased inputs of manure on grassland and problems of disposal of stored slurry cattle often have direct access to water courses resulting in soil and bank...

The Soil Sulfur Cycle

Similar to the soil N cycle, and unlike P, these elements undergo chemical and microbially mediated transformations leading to volatilization. Not only is the biosphere a repository for highly mobile forms of S, but several key reactions of the cycle are accelerated by, and sometimes completely controlled by, microbiological activity. The soil microbial biomass acts as the driving force behind mineralization-immobilization and oxidation-reduction transformations. The primary input of S to soil occurs during the weathering of soils, which releases sulfate into the available pool. Other inputs include plant residue inputs, S fertilizer, pesticides, and irrigation water. Atmospheric deposition can be a significant input of S in areas affected by atmospheric pollution due to combustion of fossil fuels. Losses of S from the soil system include plant uptake and harvesting of residues, long-term fixation into minerals, leaching of soluble sulfate, and gaseous losses of volatile forms of S.

Integrated nutrient management

African soils are eroding and losing nutrients fast. The losses of nitrogen per hectare often exceed the amounts a prosperous western farmer would put on his land each year. The losses far exceed the replenishment African farmers can afford. They pay some of the highest fertilizer prices in the world whether in US dollars or grain equivalents (Mwangi, 1997). Prices in western Kenya are 400 ton of urea, in contrast to 90 ton in Europe (Sanchez, 2002). On average and many use none at all African farmers use fertilizer at only 10 kg ha, whereas European farmers use over 200 kg ha. This means that Africans must make as much use as possible of organic sources of nutrients, and apply them in an integrated fashion with inorganic fertilizers. One route is through highly integrated crop livestock systems, where soil structure and nutrients benefit both from livestock manure and the nitrogen-fixing capacity of forage crops. Careful ecological management of crop livestock systems can create...

Increasing the fertility of the seas

If fish farming in enclosed bodies of seawater presents difficulties, why not simply raise the productivity of the open sea by enriching the surface waters over wide areas by the addition of plant nutrients We spread fertilizers on the land to promote the growth of crops why not spread them on the sea To produce any appreciable increase in concentration of plant nutrients in the open sea would require enormous quantities of fertilizer, and the costs would be tremendous. It would be an extremely wasteful process because so small a proportion of the nutrients absorbed by phytoplankton eventually becomes incorporated in fish flesh. Any additional plant growth obtained as a result of fertilization would contribute very largely to the production of unwanted organisms. Calculations of the increase of yield from sea fisheries that might be obtained by large-scale fertilization of seawater do not stand up to comparison with those known to be obtained from the use of equal quantities of...

Futuro Forestal SA balancing nature and business wwwfuturoforestalcom

In the first 5 years after planting, there is almost constant supervision and manual weeding. After a year the trees are pruned at the beginning and the end of every rainy season. Two applications of organic fertilizer per year are given to the seedlings until they grow with satisfactory vigor. From the fifth year on, when the canopy of the trees starts closing, the intensity of the management is reduced.

Food Consumption and Human Wastes

Application of human excreta as organic fertilizer is common both in Asia and in Europe, but less prevalent elsewhere in the world. The nutrient linkage between farmers and croplands has been relatively stable, but the human wastes in urban areas are less recycled than in rural areas. For instance, less than 30 of human wastes in urban areas were recycled for agricultural uses in the late 1990s in China. This percentage dramatically decreased from 90 in 1980. In contrast, about 94 of human wastes in rural areas were returned to croplands in the 1990s. In European countries, the recycling rate of urban sewage averaged about 50 over the 1990s. Globally, it could be appropriate to assume that about 20 of urban human wastes and about 70 of rural human wastes are recycled at present. Therefore, recycled human wastes amount to 1.5 MMT Pyr- . Adding the quantities of the phosphorus recycled as crop residues, animal manures, and human wastes, the total organic fertilizers applied to croplands...

Phosphate Balance in Cropland

The national phosphorus balance varies significantly from one country to another, due to differences in the use of mineral fertilizers and manure, and differences in animal husbandry practices. Broadly speaking, in developing countries, soils tend to be deficient in phosphorus, while in developed countries the phosphorus content of the soils is adequate or even excessive. Taking into account applications of mineral fertilizers and manure, the balance for some West European countries is positive, particularly in the Netherlands where it exceeds 39 kgPha-1 each year. For the majority of Western European countries, the phosphorus balance ranges from 8.7 to 17.5 kg P ha- annually. China, one of the largest agricultural systems in transition, also achieved a positive balance around 1980 at the national level, in parallel with increasing application of synthetic fertilizers. In 2000, the national surplus of phosphorus in Chinese soils was estimated at an average of 16 kg P ha- . Synthetic...

Climate Change and Agriculture

The rising costs of fossil fuels (the current dip in prices notwithstanding) needed to irrigate more land, produce more fertilizer, and move more food around the globe will add further pressure to an already charged situation. These costs are beginning to influence decisions about the allocation of land Fertilizer production 410

Some Facts From The History Of Conservation

Certain conservation practices developed in early civilizations. Some species of animals were protected by religious taboos religious sanctions prevented destruction of forest groves and sacred mountains. The use of organic fertilizer to maintain soil fertility is found among many more recent primitive peoples and has had a long history in Western Agriculture. The Bible is filled with various injunctions governing the use of land and resources that have a conservation function.