Effects Of Straw Strip Returning To Field On Root Distribution Of Maize,Soil Physical And Chemical Properties

In order to investigate the effects of different straw strip returning on yield formation,soil moisture,soil nitrogen and root spatial distribution of Spring Maize in Northeast China.Field simulation experiment was carried out during 2015-2016 in Tieling City,Liaoning Province.The experiment was carried out with straw strip returning(straw strip-rotary tillage and ditch-buried returning)and conventional straw returning.3D-Monolith method was used to sample and measure soil and root.The effects of different straw strip returning on soil structure,water and nitrogen distribution and root characteristics were studied.1.The results show that straw strip returning can improve the seedling rate,improve soil structure,increase the content of available nutrients in 0-40 cm soil layer,have a significant increasing yeild.Compared with without straw returning,the seedling emergence rate of straw strip returning decreased by 1.8%,the average annual yeild was increased by 12.4%.The straw strip returning was significantly higher than that of conventional straw returning to field.Compared with conventional straw returning,The seedling emergence rate of straw strip returning increased significantly.The soil bulk density of plough layer was decreased by 8.6%and 6.4%,before sowing and after harvest respectively.The available N and available K were increased by 10.2%and 13.9%in 10～20 cm soil layer,respectively.2.Straw strip returning could optimize the structure of soil plough layer,and effectively improve the spatial distribution of soil water and nitrogen.The soil moisture content of straw strip returning was in the spatial distribution of the content of low content near the center of the plant and high content around the plant.The water content of the soil in the center of plant was significantly reduced,and there was a significant water depletion area.The content of total nitrogen in soil was in the distribution state of high content near the center of the plant,low content of the surrounding plants,and affected by the fertilization process.The soil water content and total nitrogen content of the deep soil layer(30～60 cm)were significantly increased by straw strip returning.3.The relative index of maize roots was significantly higher than that of no straw strip returning,promoting and increasing root growth and distribution density in 0～60 cm soil layer.Straw stalk rotation and returning to field treatment increased the root distribution density of 0-30 cm plough layer.The soil density of root system in 20～40 cm soil layer was increased by ditch-buried returning.4.The dry matter and yeild of straw strip returning was higher than that of no straw returning.Water production efficiency of the dry matter under Interlacing straw strip returning was higher in spring maize silking stage,water production efficiency of grain yield was higher in mature stage.5.After straw returned to the field with the change of distance,there was no significant difference between spring maize yield,but the spatial distribution characteristics of soil nitrogen and maize roots were significantly changed.The distribution of soil water and nitrogen in the row of straw returned to the space,and the distribution of the content of the two sides of the center of the plant was more symmetrical.traw returning to the field showed the distribution of "the content of the two sides of the center of the plant is asymmetric".Long term experiments were conducted to study the effect of the change of the distance of straw returning to field on Yield.