{'fraction_non_alphanumeric': 0.02085561497326203, 'fraction_numerical': 0.008556149732620321, 'mean_word_length': 4.8105590062111805, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Contrasting Concepts in Soil Test Interpretation: Sufficiency Levels of Available Nutrients Versus Basic Cation Saturation Ratios

Concepts in soil test interpretation differ greatly. All of them are based on valid principles. Any given one seems to work well under specific conditions, but insufficient research has been done to make one concept applicable to all conditions. The two concepts most widely used are: i) sufficiency levels of available nutrients (SLAN) and ii) basic cation saturation ratios (BCSR). Both concepts recognize that there is a fraction of a given plant nutrient measured by soil tests which is readily available to plants, and that the level of available nutrient measured may range from low to high in a given soil. The SLAN concept, is based on a general mathematical expression of the law of diminishing returns where increases in yield of a crop per unit of available nutrient decreases as the level of available nutrient approaches sufficiency. As originally conceived, this expression was thought to apply to all crops and to all soil conditions, but early work showed it had to be adjusted for different crops (Bray, 1958). Likewise, the BCSR concept which holds that for most crops there is a best ratio of basic cations on the soil cation exchange capacity (CEC), is found not to be as simple as originally thought. Marked shifts from large usage of the SLAN concept to much greater usage of the BCSR concept as bases for recommending fertilizer and lime have occurred in recent years. In 1960, a total of 1.25 million samples were tested in the north-central region of the U.S. of which university laboratories tested two-thirds and nonuniversity laboratories tested the remainder. By the end of the 1960's a total of 2 million samples were tested in the same region, with university laboratories testing only one-fifth of the total