Effects Of Intercropping With Leguminous Crops And Surface Mulching On The Growth Of Crops And Soil Nutrients

Under the great pressure of our huge population, more fertilizer and pesticides are put into agricultural production to pursue higher crop yield, which have caused serious of environmental pollution of soil, water and atmosphere. In order to reduce the use of chemical fertilizer and pesticides in agricultural production, field experiments were carried out in the suburb of Qingpu District, Shanghai. Typical vegetable production base was chosen to carry out three kinds of field experiments:(1) intercropping tomato with legumes;(2) intercropping green pepper / eggplant with legumes or surface mulching,(3) intercropping pakchoi with leguminous green manure to explore better models of common garden stuff which not only reduce production investment, but also increase crop yield under organic agricultural cultivation. It also aims to provide a theoretical basis for the further application of leguminous crops in the development of organic agriculture and provide theoretical evidence for environment-friendly agricultural production in which fertilizer and pesticide pollution is low enough. The results are as follows:(1)Intercropping tomato and leguminous could significantly increase the height of tomato plants. Intercropping tomato and kidney bean increased the yield of tomato by 15.7%. Intercropping tomato and kidney bean increased total N in soil by 16.9%; ammonium N by 14.0%; available P by 26.6% and available K by 23.4%. Likewise, intercropping tomato and Phaseolus vulgaris L. var. humilis Alef. also increased soil nutrients. The leguminous intercroppings could also improve the activities of soil urease, sucrase and phosphatase. Intercropping tomato and kidney bean increased urease, sucrase and phosphatase by 64.6%、26.8% and 25.5% respectively. By contrast, non-leguminous intercropping reduced the yield of tomato and had no significantly effect on soil N and P contents. Consequently, intercropping tomato and kidney bean could reduce the usage of chemical fertilizer and increase the yield of tomato. Leguminous intercropping is a better mode of production in organic tomato cultivation.(2)Intercropping green pepper with kidney bean and green soybean could increase the diameter of green pepper by 37.8% and 32.4%, the weight of single green pepper by 36.5% and 30.8% respectively. Intercropping green pepper with green soybean increased the yield of green pepper 15.7%. Intercropping green pepper with kidney bean and green soybean could increase ammonium N in soil by 28.4% and 20.3%; available P by 24.6% and 20.0%. Likewise, mulching with toothed burclover increased ammonium N by 35.9%; available P by 14.2% and available K by 44.1%.In the mature mid-term of green pepper, intercropping green pepper with kidney bean and green soybean increased soil urease by 29.3% and 30.9%; sucrase by 39.4% and 28.6%; phosphatase by 34.7% and 43.5% respectively. Mulching with toothed burclover increased sucrase and phosphatase by 38.8% and 21.7% respectively. In the later period of green pepper matured, intercropping green pepper with kidney bean and green soybean increased urease by 24.5% and 21.1%; phosphatase by 25.0% and 28.1% respectively.(3)Intercropping eggplant with kidney bean and green soybean could increase the number of eggplant in single plant by 30% and 20%. Intercropping eggplant with kidney bean increased the diameter of eggplant by 17.8%. Intercropping eggplant with kidney bean and green soybean could increase the yiled of eggplant by 21.1% and 18.2%, soluble protein by 24.3% and 18.7%, total soluble sugar by 66.2% and 35.2% respectively. Intercropping eggplant with kidney bean increased soil urease by 27.9%, sucrase by 30.9% and phosphatase by 13.1%. By contrast, mulching with toothed burclover increased sucrase by 36.5%, but showed no significant effect on the yield and the quality of eggplant.(4)The pakchoi plant hight of monoculture is significantly higher than that of intercropping with leguminous green manure. Intercropping pakchoi with chinese milk vetch chould increase total yield of pakchoi by 28.4%; soluble protein by 33.6%; total soluble sugar 73.6%. Likewise, intercropping pakchoi with spring vetch increases total soluble sugar of pakchoi by 62.5%. Intercropping pakchoi with leguminous green manure showed no significant effect on the contents of organic acid and chlorophyll of pakchoi.Intercropping pakchoi with leguminous green manure could improve the activities of soil urease, sucrase and phosphatase campared with pakchoi monoculture. The activities of urease and sucrase were higher than monoculture all through the mature period of pakchoi. The activity of phosphatase was significantly improved in the midanaphase of pakchoi matured. The activity of catalase was not influenced by intecropping. It was found that intercropping pakchoi with chinese milk vetch obtained the highest net income, ￥1280 667-2 after comprehensive analysis of three kinds of cultural patterns. Therefore, chinese milk vetch or spring vetch are recommended choices as leguminous green manure to intercrop with pakchoi for increasing both production and income.(5)All the above four field expriments indicated that the activities of soil enzyme show significant correlation with soil nutrient contents of available N, P and K.(6)Legume intercropping will play an important role in the development of sustainable agriculture in the suburb of Shanghai.