| The North China Plain is one of the major grain producing areas. In recent years, after crop was harvested, long-term successive rotary tillage with straw returning, which has caused topsoil shallowed, bulk density increased in deep layers, nutrient enriched in top layer, soil degradated and other problems, they lead to crop root development poorly, plant premature aging, disease-resistant decreasing. They limit the sustainable agriculture development. In order to solve the above problems, experiment was conducted in Luoyang city, Henan province from2009to2012. Eight treatments were arranged in a split plot design. The whole-plot treatment factor was S (wheat and maize straw retention) and NS(no straw retention).The subplot treatment factor was the tillage mode, including3C (shallow ploughing for three years), DP2C (shallow ploughing for two years and deep ploughing for third year),2DPC(shallow ploughing for one year and deep ploughing for following two years)and3DP(deep ploughing for constant three years).This paper mainly analyzed the spatial and temporal distribution of soil physical property, chemical property, soil enzyme activity in0-40layers and crop yield. The results as follows:1. Effects of soil physical property under different treatmentsAfter straw returning, soil bulk density was reduced by1.65%, total porosity was increased by1.52%and>0.25mm of water stable aggregate content was increased by12.36%in0-20cm layers. Under the condition of no straw returning.Soil moisture content and soil water storage were higher than those in no straw returning, by5.85%and4.93%. After the deep ploughing, total porosity, content of soil water stable aggregates and soil water storage were significantly increased in20-60cm, and soil bulk density was reduced by1.65%.Compared with conventional tillage, soil moisture content and soil water stable of deep ploughing, treatment were significantly improved in early stage of crop growth, which could contribute to the reproductive and vegetative growth of wheat and maize. So the dynamic of soil water content was changed dramatically in the life of wheat and maize. Meanwhile, water consumption in condition of deep ploughing treatment was increased, depth of watert consumption was deepended from20-40to40-80cm.2. Effects of soil chemical property under different treatmentsIn addition to the jointing stage of maize, straw returning could significantly improve alkali-hydrolyzale nitrogen, available phosphorus and potassium contents at the0-40cm layers, averagely increasing by8.9%,5.64%and14.06%respectively. Acidic substances which were produced in straw decomposition process could effectively delay soil pH increased. Compared with the straw returning, effects of deep ploughing on increasing soil nutrients and mitigating soil pH aspects were not obvious. After tillage treatments, nitrogen, phosphorus and potassium were increased by3.16%,3.5%and6.88%, respectively and the pH value merely decreased by0.015%. Under the conditions of straw returning, the nitrogen contents of2DPC and3DP treatments were significantly higher than NS3C, increasing by13.64%and13.48%, available phosphorus of those treatments increased by10.88%and9.82%. Available potassium increased by22.59%and22.54%. Meanwhile, S2DPC, S3DP treatments could reduce the rate of the nutrient content descent, which was conducive to crop growth and filling.3. Effects of the carbon pool of management under different treatmentsStraw returning could enhance the soil carbon sequestration capacity, significantly increasing soil labile organic carbon and total organic carbon contents at0-40cm by10.2%and13.16%.3C and DP2C deals led to labile organic carbon and total organic carbon concentrated in the0-20cm topsoil, while3DP,2DPC treatments significantly increased the contents of soil organic carbon, total organic carbon content and the library of the indicators. The contents of LOC, TOC and CPIM factors increased by7.75%,8.45%and3.54%, which favor the nutrients uniform distribution in the field. Different treatments Carbon Management Index one year anniversary showed that S3DP, S2DPC were higher and NS2CDP was lower, which increased by20.19%and16.5%more than NS3C treatment In short, under the condition of straw returning,every deep plowing once a year help enhance soil capacity carbon sequestration.4. Effects of soil enzymes activity under different treatmentsCompared with no straw returning, invertase activity, urease activity, alkaline phosphatase activity and catalase activity could be significantly increased by19.09%,10.51%,7.27%and8.91%on average in0-40cm layer respectively. In addition, after long-time shallow tillage, these soil enzyme activities under deep ploughing were higher than those under3C in0-40cm layer, being4.93%,4.78%,2.03%and2.42%on average respectively. Under the same condition of straw treatments, soil enzyme index and all soil enzyme activities in0-40cm layer were that2DPCand3DP were higher than3C. These enzyme activities decreased with settlement depth, but these soil enzyme activities under2DPC and3DP were significantly higher than others. It indicated that the treatments of2DPC and3DP under straw retention were contributed to improve soil enzyme activities and evenly distributed in field.5. Effects of the yield and water use efficiency under different treatmentsAfter straw returning, crop grain yield, water use efficiency and precipitation use efficiency were significantly increased by729.39kg/hm2,3.79%and3.93%, respectively. The trend of crop grain yield of different tillage treatments were3DP>2DPC>DP2C>3C. The grain yield of2DPC,3DP and DP2C were higher than3C treatment, increasing by14.92%、14.3%and6%. Meanwhlie, Compare to3C treatment, the grain yield of S3DP and S2DPC treatments which were raised by19.39%and19.83%, were higher than S3C treatment, improving by15.46%and14.64%. What is more, S2DPC and S3DP treatments could enhance the role of improvement on the regulation action of soil water.then water use efficiency were increased. In term of water use efficiency, S2DPC and S3DP treatments were increased by17.93%and17.51%compared with NS3C. The efficiency of precipitation of S2DPC and S3DP treatments were rose by17.6%and16.9%. In condition of economic and ecological benefits, S2DPC treatment was the best mode in this area. |
PDF Full Text Request