Effects Of Straw Returning On Physical And Chemical Properties Of Brown Soil And Growth And Development Of Corn

The experiment for six years in a row used pulverized corn straw to return to the field after the harvest,in order to study the effects of soil physical and chemical properties and as well as the growth and development status of corn by using different quantity of corn straw to return to soil,to explore the dynamic change law of soil physical and chemical properties and the growth and development status of corn,under different amount of corn straw returned to the field,with that to measure and evaluate the effects of different corn straw mulching amount on soil physical and chemical properties and growth status of corn which can provides scientific basis for the popularization and application of corn straw mulching technology.In this experiment,a total of 5 straw mulching treatments were set,namely CK treatment?without straw mulching?,J1 treatment(straw mulching amount of 3000kg·hm^-2),J2treatment(straw mulching amount of 6000kg·hm^-2),J3 treatment(straw mulching amount of9000kg·hm^-2),and J4 treatment(straw mulching amount of 12000kg·hm^-2).The main research results are as follows:1.Corn straw mulching has a great impact on soil bulk density,porosity,soil moisture content and soil hardness.The soil bulk density and hardness showed a trend of decreasing with the increase of returning amount of corn straw,and the soil bulk density and hardness of each treatment increased with the increase of soil depth.Soil porosity showed a trend of increasing with the increase of returning amount of corn straw,and soil porosity of each treatment decreased with the increase of soil depth.In the 0?10cm soil layer,the porosity of corn straw returned to the field by J1,J2,J3 and J4 increased by 8.16%,10.20%,12.24%and14.26%,respectively,compared with CK treatment.When the amount of corn straw returned to the field is too large,reaching more than 9000kg·hm^-2,the field will significantly reduce the soil moisture content.2.Returning corn straw to the field has a great effect on improving the content of soil p H,soil organic matter,soil total nitrogen,soil alkali-hydrolyzed nitrogen,soil available phosphorus,soil available potassium and soil carbon and nitrogen ratio,but has no significant effect on soil electrical conductivity.As a whole,soil p H increased with the increase of the amount of corn straw returned to the field,and the soil p H of each treatment increased with the deepening of soil layer.The contents of soil organic matter,soil total nitrogen,soil alkali-hydrolyzed nitrogen,soil available phosphorus and soil available potassium in soil layer0?40cm under each corn straw mulching treatment were increased compared with the control group,and increased with the increase of corn straw mulching amount.The order of soil carbon and nitrogen ratio in each treatment is J4>J3>J2>J1>CK,that is,the soil carbon and nitrogen ratio increased with the increase of straw mulching amount.3.Returning corn straw to the field also has a great impact on the emergence rate,plant height,stem diameter and yield of corn.Under the conditions of this experiment,with the increase of returning amount of corn straw to the field,the emergence rate of corn gradually decreased.And the plant height,stem diameter and yield of maize showed a parabolic trend with the increase of straw mulching amount,within the range of straw mulching amount0?9000kg·hm^-2,the plant height,stem diameter and yield of corn plants increased with the increase of straw mulching amount,instead,when the amount of corn straw returned to the field exceeded 9000kg·hm^-2,the plant height,stem diameter and yield of corn plants decreased.Comprehensive consideration of the effects on soil physical and chemical properties and the growth and development of corn y using different quantity of corn straw to return to soil,it is more suitable to use straw mulching amount less than 9000kg·hm^-2.Meanwhile,keeping the number of corn straw returned to the field within a relatively small range will be conducive to increasing the convenience of soil turning,land preparation and ridging in the later stage.