Effects Of Conservation Tillage Measures On Crop Yield And Soil Fertility In The Loess Plateau

Loess Plateau is an traditional dryland farming area in China, traditional farming methods of topsoil disturbance is large, long-term frequent plowing the soil, resulting in declining soil fertility and crop yields low and unstable and lead to deterioration of the ecological environment. Conservation tillage is an important means to complish the sustainable development of agriculture which can control soil erosion, the agricultural ecological environment, improve the water use efficiency and increase crop yield in dryland.The test use the conservation tillage location field experiments of Changwu agro-ecological experimental station which was set up in the typical areas of Weibei dryland, study the yield s,water use efficiency, crop nutrient uptake and soil fertility changes pring maize and winter wheat under different conservation tillage. The main results are as follows:1. The effect of conservation tillage measures on winter wheat yield, water use efficiency and nutrient absorption was remarkable.(1)The yield-increasing effect of wheat cover measures was significantly. The yield of winter wheat no covering which was the lowest was 4666 kg/hm2. The yield-increasing effect of whole film coverage all the year round was the most significant, higher than the yeild of no covering with 15.4%. The yield under the dual mulching of plastic film and straw all the year round increased by 8.1%. Plastic film mulching and the dual mulching during summer fallow period increased by 5.4% and 5.0%, respectively.(2) The whole-film mulching throughout the year can significantly improve water storage within 0~200cm soil layer, increasing 17.3 mm than that of no covering; covering measures all can significantly improve the water use efficiency of winter wheat. The amplification of the whole-film mulching throughout the year was the largest,increasing by11.3%. The amplification of film mulching during summer fallow period was the smallest,increasing by 7.5%.(3) Covering measures can significantly increase N, P and K nutrient accumulation amount of winter wheat. N accumulation amount of the whole-film mulching throughout the year was the highest, increasing 26.5% than that of no covering. P accumulation amount of the dual mulching throughout the year was the highest, increasing by 27.8%. K accumulation amount of the whole-film mulching throughout the year was the highest, increasing by25.8%.2. The effect of conservation tillage measures on spring maize yield, water use efficiency and nutrient uptake was remarkable.(1) Under the traditional farming conditions, the yield-increasing effect of the dual mulching of plastic film and straw was significantly, increasing 98.8% than that of no covering. The straw mulching increased by 36%. The amplification of film mulching was the smallest, increasing by 9.7%. Under no-tillage conditions, the yield of the dual mulching was3.3 times higher than that of no covering. Plastic film mulching increased by 2.2 times, and the straw mulching increased by 21.9%.(2) Under the traditional farming conditions, the dual mulching compared with no covering could the most significantly improve the water use efficiency, increasing by 89.3%.The straw mulching comed second, increasing by 31.8%. The amplification of film mulching was the smallest, increasing by 1.8% and the difference was not significant; Under no-tillage conditions, in the aspect of water use efficiency of spring maize, the amplification of the dual mulching was the largest, being 2.8 times higher than that of no covering. The amplification of film mulching comed second, increasing 1.8 times. The amplification of the straw mulching was the smallest, increasing 22.4%.(3) Under the traditional farming conditions, nitrogen and phosphorus nutrient accumulation of spring maize which no covering was the lowest. Nitrogen nutrient accumulation of the straw mulching was the highest. Phosphorus nutrient accumulation of the dual mulching was the highest. Under no-tillage conditions, covering measures all could increase N, P and K nutrient accumulation amount of spring maize in different degrees.