Effect Of Straw Returning Mode On Soil Water Retention And Fertilizer Supply Capacity And Maize Growth And Development

Straw returning to the field with different tillage and fertilization is an effective measure to improve soil fertility and promote sustainable development of agriculture.However,in the practice of agricultural production,the straw mulching technology in different areas still needs to be further improved.The split zone design was adopted,and the main zone was straw returning mode,which was divided into three treatments:no-tillage mulching returning（N）,deep pine crushing returning（P）and rotary crushing returning（R）.The secondary area was divided into three treatments with different nitrogen application amounts,namely:conventional phosphorus and potassium treatment+straw rotting agent,no nitrogen application（T1）;Conventional nitrogen application+straw rotting agent（T2）;80%conventional nitrogen application+straw rotting agent（T3）;Nitrogen fertilizer is urea,phosphate fertilizer is superphosphate,potash fertilizer is potassium chloride.The conventional nitrogen application was 240 kg·hm^-2,80%.The conventional nitrogen application was 192kg·hm^-2.All treatments had the same amount of phosphorus and potash fertilizer,P₂O₅ and K₂O were 74 and 89 kg·hm^-2 respectively.The application amount of straw rotting agent is 200 kg·hm^-2.The plot covers an area of 68.4 m² with 12 ridges and a length of 10 meters.A total of 9 treatments were performed,and each treatment was repeated 3 times.Through the combination of different returning methods and different fertilizing methods,a suitable returning scheme of corn stalk in southern Liaoning was found.Based on the soil and climate conditions in the maize producing areas in southern Liaoning province,the results are as follows:water use efficiency no-tillage treatment;Rotary tillage treatment;Deep tillage treatment.The maximum WUE of NT treatment reached 18.4.The WUE was significantly different under different fertilizer treatments,which showed as 100%nitrogen treatment;80%nitrogen treatment;Nitrogen free treatment.The surface water content of rotary tillage and deep pine is not as good as that of no-tillage during the first few growing periods,and no-tillage is more favorable for soil surface water storage due to less disturbance and straw mulching.With the growth and development,the tillage of deep pine is beneficial to water infiltration,thus improving the storage capacity of the middle and lower layers of soil.The seedling emergence rate of no-tillage treatment reached99.3%,which was 0.8%and 1.1%higher than rotary tillage treatment and deep tillage treatment.No-till treatment;Rotary tillage treatment;The yield of no-tillage treatment was 7.9%higher than that of rotary tillage treatment and deep tillage treatment.The yield of 100%nitrogen increased by 6.3%compared with 80%nitrogen.A The surface water content of rotary tillage and deep pine is not as good as that of no-tillage during the first few growing periods,and no-tillage is more favorable for soil surface water storage due to less disturbance and straw mulching.With the growth and development,the tillage of deep pine is beneficial to water infiltration,thus improving the storage capacity of the middle and lower layers of soil.Under the condition of straw returning and different tillage conditions,the treatment of higher nitrogen fertilizer amount can better promote the growth and yield of upper part of corn field in the whole growth period,and the nitrogen supply of topsoil is in a synchronous state with the growth and development characteristics of corn in each growth period.Although the treatment with 20%nitrogen reduction（80%nitrogen application rate）achieved higher productivity and agronomic efficiency of nitrogen application,its yield was reduced.Therefore,the nitrogen application rate should be determined according to the actual situation under the straw returning condition,and it is not advisable to reduce nitrogen blindly.