{'fraction_non_alphanumeric': 0.011656441717791411, 'fraction_numerical': 0.009202453987730062, 'mean_word_length': 4.952554744525547, '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}}
Studies of Plough Design and Ploughing Relevant to Conditions in Northern Europe

Although the development of plough design has been on the agenda for hundreds of years, there is still room for improvements. The present study attempts to give an overview of previous work and to identify the areas having most potential for future improvement. The study is based on 165 publications from 1771 to 2001 and covers the main parameters in relation to energy requirement, wear, ploughing result and crop yield. The study concludes that the features of greatest future potential are changes of the ploughing depth and of the shape and surface characteristics of shares and other lower plough body parts. The effects of ploughing depth have been studied in numerous investigations. The results show that the depth should be chosen with regard to soil type and weed infestation. It may often be reduced to 18-20 cm or less without significant reduction of crop yields, but with a considerable reduction of energy demand. The share tips and other lower plough body parts contribute about two thirds of the total draft requirement of the plough bodies, and they may contribute to some extent to plough pan formation. Therefore, the shapes of these parts considerably influence energy requirement, wear and maintenance costs and the resistance to root penetration and water infiltration below the plough layer. Reduction of the draft force requirement by reducing the ploughing depth and improving the shape opens up possibilities for decreases in tractor power and weight, or an increase in work rate through greater working speed or width.