| Through research on the application technology of returning straw to the field and controlling the loss of urea under field conditions,the goals of increasing crop yield,high-efficiency utilization of nitrogen fertilizer and soil fertility in the process of crop production in the wheat and jade rotation system in mortar black soil area are realized.Test 1,the effect of returning straw to the field and controlling loss of urea on the physical and chemical properties of mortar black soil and wheat yield under the condition of reduced nitrogenField experiments were conducted under a wheat/maize rotation system in a typical mortar black soil area of ??southern Henan Province to explore the application effects of returning straw to the field and controlling loss of urea on wheat production under reduced nitrogen conditions.In the field experiment,straws were returned to the field as the main treatment,and different nitrogen fertilizers were used as side treatments,including: no nitrogen fertilizer(CK),ordinary urea 100%(general N100),ordinary urea 70%(general N70),and control loss of nitrogen fertilizer 70%(Control N70).The results show that,compared with the nitrogen reduction treatment under the condition of not returning to the field,the soil bulk density under the condition of normal N70 and N70 control was significantly reduced by 12.3% and 17.9%,and the total nitrogen content of the soil was significantly increased by 25.0% and 27.3%.There is no significant difference between nitrogen reduction treatment and full urea treatment(general N100).Returning straw to the field improves soil bulk density,total N and organic matter content,while the effects of different nitrogen fertilizers on the above indicators are not significant.The nitrogen use efficiency(NRE)of wheat in the N70 control treatment was the highest,but there was no significant difference from the general N100 and general N70 treatments.Under the condition of returning to the field,the highest yield of N70 treated wheat was 7391.59 kg/ha,which was 13.9% higher than that of normal N100 without returning to the field.In summary,returning straw to the field has a greater effect on the physical and chemical properties and yield of mortar black soil,and the application of loss-controlling nitrogen fertilizer under the condition of reducing nitrogen by 30% shows a certain yield increase advantage.Taking into account that continuous nitrogen reduction will increase the loss of production reduction,in the later experiments,the focus is on setting the ratio of controlled loss of urea to replace ordinary urea under equal nitrogen conditions,and explore the best replacement ratio,in order to play a role in the wheat and jade rotation system in the black soil area of ??mortar The greatest effect of losing control of urea.Test2,two,the effect of straw returning to field and urea replacement under equal nitrogen conditions on the physical and chemical properties and yield of Shajiang black soilOn the basis of the first year of experiment,set up field positioning experiment,with straw returning to the field and straw not returning to the field as the main factors,there are no nitrogen fertilizer(CK),4 equal nitrogen fertilizer treatments: ordinary urea(U100),control loss Urea(CLF100),70% control loss urea+30% normal urea(CLF70)and 40% control loss urea+60% normal urea(CLF40),continuous positioning for multi-season experiments,to study whether straw is returned to the field and different control loss The effect and mechanism of the replacement ratio of urea on the physical and chemical properties of mortar black soil,crop yield,nitrogen fertilizer utilization,etc.,are recommended as the application technology method for controlling loss of urea in mortar black soil area.The results show: 1.Returning straw to the field significantly increases the water content of mortar black soil and reduces the soil bulk density.Returning straw to the field and applying nitrogen fertilizer significantly reduces the soil p H.Compared with not returning to the field,the water content of CLF70 treatment increased by 18.42% under the conditions of returning to the field in 2018 corn season;the water content of U100 treatment in 2019 wheat and corn season increased significantly by 31.82% and 31.16%;the water content of CK treatment in 2020 wheat season A significant increase of 21.73%.After returning the straw to the field,the soil bulk density of the corn season in 2018 and2019 was significantly reduced by 0.87% to 9.17% and 3.85% to 9.42%.In the 2018 corn season,the p H value of each treatment under the conditions of returning to the field was significantly lower than that of the non-returning treatment by 0.44 to 0.91;in the 2020 corn season,the p H value of the soil in the treatment of straw returning to the field was reduced by 0.40 to 0.97 compared with that of non-returning.Compared with the treatment of field return in 2018,the treatment of field return in 2020 significantly reduced the p H value of 0.32~0.42;except for the 2019 corn season,the p H value of the soil in the maturity period of each season was the highest in the CK treatment.Returning straw to the field can significantly increase the organic matter content,total nitrogen content,and available nutrient content of mortar black soil.2.Whether the straw is returned to the field or not,the yield effects of different nitrogen fertilizer ratios are different.Compared with non-returning,the output of U100 treatment in the 2019 and 2020 wheat seasons after straw returning to the field increased significantly by 11.97% and 26.37% respectively;under the condition of returning straw to the field,the highest CLF70 treatment in the 2018 corn season was 9854.98 kg/ha.Compared with U100 treatment,the yield was significantly increased by 4.65%;the highest yield of CLF70 treatment in the 2020 wheat season was 7487.03 kg/ha,which was significantly increased by 8.71% and 9.88% compared with U100 and CLF100treatments;except for the 2020 wheat season,the three application controls for each season There was no significant change in crop yield under the treatment of urea loss under the condition of returning straw to the field.Under the condition of not returning to the field,compared with U100 treatment,CLF70 and CLF40 treatments significantly increased the crop yields of the 19-year wheat season,20-year wheat and corn seasons.The highest yield of CLF40 treatment in the 2019 wheat season was 8951.14 kg/ha,which was higher than that of U100.Treatment significantly increased by 10.45%;the maximum yield of CLF40 treatment in 2020 corn season was 9891.30 kg/ha,which was significantly increased by 10.16% and 7.79% compared with U100 and CLF100 treatments.Except for the 20-year corn season,the three applications in other seasons were out of control.The yield of urea-treated crops did not change significantly under the condition of not returning straw to the field.Under the condition of not returning to the field,the replacement of loss-controlled urea can significantly improve the nitrogen use efficiency of wheat.In the 2019 wheat season,2020 wheat and corn season,the CLF70 treatment and CLF40 treatment under the condition of not returning to the field significantly increased the crop nitrogen utilization by 42.10% and 45.50%,33.75% and 40.34%,12.42% and 26.81% compared with the U100 treatment.In the 2018 corn season,2019 wheat season,and 2020 corn season,under the condition of returning straw to the field,the nitrogen fertilizer utilization rate of the crop nitrogen fertilizer was significantly reduced by 17.12%~21.98%,45.66%~47.10% compared with that of the non-returning urea treatment.18.32%~29.95%.3.In order to further understand the difference in the effects of the application of controlled-release urea under different conditions of returning straw to the field,and to reveal the mechanism of the controlled-release nitrogen fertilizer in nutrient transformation,in 2020,samples of wheat and maize growth stages will be sampled to detect nutrient dynamics,focusing on different growth stages.Period of nitrate nitrogen content and nitrification potential are tested.Under the condition of returning straw to the field,the loss-controlled urea substitution treatment reduced the soil nitrate nitrogen content in the early stage of corn growth compared with the corresponding U100 treatment.The soil nitrate nitrogen content of the CLF70 and CLF40 treatments at the corn jointing stage in 2020 was 33.44 mg/kg,31.12 mg /kg,significantly reduced by21.08% and 26.55% compared with U100 treatment;in 2020,the nitrate nitrogen content of CLF100 and CLF40 treatments in corn at the big bell-mouth stage was 21.42 mg/kg and 22.50 mg/kg,which were significantly lower than U100 treatment by 20.49%,16.48%.Under the condition of not returning to the field,the loss-controlled urea substitution treatment increased the soil nitrate nitrogen content than the corresponding U100 treatment.The CLF70 treatment increased the soil nitrate nitrogen content of 19.39mg/kg at the corn bell mouth stage in 2020,which was significantly higher than that of the U100 treatment.20.49%;CLF40 treatment in the 2020 wheat maturity period,2020 corn bell mouth period,and filling period of the soil nitrate nitrogen content is 17.87mg/kg,21.16 mg/kg,22.63 mg/kg,which is significantly higher than U100 treatment by 40.82%,74.73%,31.04%.In the early stage of maize growth,the nitrification potential of the soil under the control of loss-controlled urea substitution treatment is inhibited.Under the condition of not returning to the field,the nitrification potential of CLF100,CLF70,CLF40 at the jointing stage of corn in 2020 is reduced by 9.85%,12.88%,and 8.33% compared with U100 treatment..Under the condition of returning straw to the field,the nitrification potential of each treatment was low.The returning of straw to the field significantly inhibited the nitrification potential of the soil.The nitrification rate of U100 treatment was significantly lower than that of the treatment without returning to the field by 64.10% and65.08% in the wheat filling stage and corn jointing stage..In summary,combined with factors such as yield,nitrogen utilization,nitrogen conversion,soil nutrient and cost,in the mortar black soil area,if the straw is returned to the field,it is not recommended to use loss-of-control urea;under the condition of not returning to the field,it is recommended to use loss-of-control urea and The ratio of ordinary urea is 4:6. |
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