Effects Of Topsoil Regulation And Returning Organic Materials Into Soil On Spatiotemporal Distribution Of Water And Nitrogen In Soil-wheat System

With long-term tillage and chemical fertilizer application in China, problems of soil compaction,topsoil shallowing and nutrient imbalance in farmland become more and more outstanding to us.From2010to2011, experiments of deep ploughing and returning organic materials into soil wereapplied with Aikang58of wheat as materials in Zhaojing town, Huojia County, Henan province.During different growth stages of wheat, contents of moisture and of nitrogen in0to50cm topsoiland different parts of wheat plant were studied detailedly, and utilization rates of water and nitrogenwith topsoil regulation and returning organic materials into soil were discussed further, creating avirtuous circle of nutrient in farmland and keeping sustainable development of agriculturalproduction. The conclusions were as follows:1. To the moisture in soil-wheat system, by the measure of deep ploughing, the plough layerwas broken, the water content of the subsoil was improved and the water content in up-ground ofwheat plant was increased in the early growth stages, while the water content in up-ground of wheatplant was increased by the measure of shallow plowing in the late growth stages. Compared withshallow plowing, the water content of root in0to50cm topsoil was increased significantly with deepploughing in the early growth stage, but the difference between deep ploughing and shallow plowingwas not significant in the late growth stage. The measure of returning organic fertilizer into soil tookadvantage of improving the moisture contents in0to50cm soil, and the measure of returning cornstraw into soil took advantage of promoting the moisture contents in30to40cm soil. So organicfertilizer and corm straw were very important to the improvement of water content in up-groundwheat plant, without significant impact on the water content of wheat root in0to50cm soil.2. To the nitrogen in soil-wheat system, content of nitrate nitrogen in0to50cm soil andnitrogen in different parts of wheat plant with shallow plowing was higher than that with deepploughing. And the contents of nitrogen in0to50cm soil and wheat plant were improved in somedegree by the measure of returning organic fertilizer into soil, with different changes in differentparts of wheat plant by returning organic fertilizer into soil during different growth stages. 3. To the development of wheat plant, there was no obviously effect of topsoil regulation on theheight of wheat plant. Population of wheat, leaf age and number of lateral root were improved bydeep ploughing in the late growth stage, which enhancing the growth potential of the wheat in thelate growth stage and promoting the ability of grain filling. Number of lateral root was increasedsignificantly by the returning corn straw into soil in the early growth stage of wheat, whichfacilitating strong seedlings in the early growth stage. And the measure of retuining organic fertilizerinto soil took advantage of extending the growth period and increasing the relative content ofchlorophyll in leaves, as well as the dry matter of grains in filling stage. On the other hand, theamount of roots in0to50cm soil was improved significantly by deep plowing, that in0to30cmsoil was promoted evidently by organic fertilizer, and that in30to50cm soil was increased byreturning corn straw into soil, which expanding the distribution scope and improving the ability ofabsorption water of plant roots. Furthermore, the biological yield of wheat in maturity stage wasimproved by shallow plowing and returning organic fertilizer into soil.4. With regression analysis, there was quadratic regression relation between content of water inleaves and in spike stalks and glumes of wheat plant (y) and the days after blossom (x), and therewas cubic relation between content of water in internodes of wheat plant (y) and the days afterblossom (x). To nitrogen content of wheat plant, there was liner regression relation between contentof nitrogen in leaves, spike stalks and glumes, uppermost internodes,2nd and3rd from uppermostinternodes (y) and the days after flowering (x), and there was cubic relation between content ofnitrogen in4th and5th from uppermost internodes (y) and the days after flowering (x). Additionally,the higher water content in wheat plant was, the higher nitrogen content in plant was.