秸秆还田替代化肥对黄土旱塬小麦产量及水肥利用的影响

Effects of Straw Returning Instead of Fertilizer on Wheat Yield and Water and Fertilizer Utilization in Loess Dryland

为研究不同秸秆还田量替代部分化肥后对黄土高原冬小麦产量、水肥利用效率和硝态氮积累特征的影响。于2018—2021年在晋南黄土旱塬冬小麦种植区,设置秸秆不还田(S0)、秸秆半量还田(S1/2)、秸秆全量还田(S1)、秸秆2倍量还田(S2)4个还田量处理,研究不同秸秆还田量替代化肥对冬小麦产量形成、水肥利用效率及土壤硝态氮残留的影响。结果表明:在黄土旱塬麦区,秸秆还田替代8.3%~31.9%N和15.7%~63.2%P_(2)O_(5)的基础上,冬小麦产量总体随秸秆还田量增加而增加,且在降水丰沛年份,增加秸秆还田量可产生更大的产量效应。3年试验总体表明,S2处理冬小麦平均产量分别较S0、S1/2和S1处理分别高17.5%(P<0.05),10.4%(P<0.05),4.3%。连续3年秸秆还田均提高了冬小麦穗数,S2处理冬小麦平均单位面积穗数分别较S0、S1/2和S1处理高17.1%(P<0.05),12.3%(P<0.05),3.6%,不同处理间穗粒数和千粒重差异不显著。播前2 m土壤贮水量总体随着还田量的增加而增加,试验期间S2处理平均贮水量较S0提高8.3%(P<0.05)。冬小麦生育期耗水量也表现为随着还田量的增加而增加,S2处理平均耗水量较S0处理增加了10.0%(P<0.05)。不同处理间水分生产效率差异不显著,平均为14.9 kg/(hm^(2)·mm)。在秸秆还田替代部分化肥基础上,旱塬冬小麦肥料利用效率随着秸秆还田量的增加而增加,其中,S2处理平均氮肥偏生产力(PFP_(N))、氮肥农学效率(AE_(N))、氮肥当季回收率(RE_(N))和磷肥偏生产力(PFP_(P))较S0处理分别提高66.4%,155.8%,113.5%,105.2%。连续3年秸秆不还田使0—2 m土壤硝态氮残留量较2018年播前提高100.6%,并随水向下淋溶在深层土壤中累积,而秸秆还田处理2 m土层硝态氮累积量均低于2018年播前,S2处理2 m土壤硝态氮残留量最低,为244.8 kg/hm^(2)。综合考虑,晋南黄土旱塬麦区,在秸秆还田替代8.3%~31.9%N和15.7%~63.2%P_(2)O_(5)基地上,可增加播前土壤底墒,降低肥料残留,并提高肥料利用效率,进而提高冬小麦产量,其中,以2倍秸秆还田量(平均为7477 kg/hm^(2))产生的产量和水肥效应最佳。研究结果可为推进旱作麦区面源污染防控和冬小麦高产高效绿色生产提供理论依据。

In order to determine the effects of different straw returning amounts instead of some chemical fertilizers on yield,water and fertilizer use efficiency and nitrate accumulation characteristics of winter wheat,from^(2)018 to 2021,an experiment including four treatments,which were no straw returning(S0),half of straw returning(S1/2),total straw returning(S1)and two times straw returning(S2),was conducted in the Winter wheat planting region in loess dryland of southern Shanxi to study the effects of different straw returning amounts instead of some chemical fertilizers on yield formation of winter wheat,water and fertilizer use efficiency and soil nitrate-N residue.The results showed that on the basis of straw instead of 8.3%~31.9% N and 15.7%~63.2% P_(2)O_(5) in winter wheat growing region of loess dryland,the yield of winter wheat generally increased with the increasing of straw returning amount,and in wet year,increasing the amount of straw returning could produce greater yield effect.The 3-year experiment showed that the average yield of winter wheat in the treatment of S2 was 17.5%(P<0.05),10.4%(P<0.05)and 4.3% higher than that in S0,S1/2 and S1 treatment,respectively.The spike number per hectare of winter wheat was increased by returning straw to the field for three consecutive years.The average spike number of winter wheat in S2 treatment was higher 17.1%(P<0.05),12.3%(P<0.05)and 3.6% higher than that in S0,S1/2 and S1 treatment,respectively,but there was no significant difference in Kernels number per spik and thousand kernel weight among different treatments.The 0-2 m soil water storage before seeding gradually increased with the increasing of straw returning amount to the field,and during the experiment,the average soil storage of S2 was 8.3% higher than that of S0 treatment(P<0.05).Water consumption also increased with the increasing of straw returning amount,and the average water consumption of S2 was 10.0%(P<0.05)higher than that of S0 treatment.There was no significant difference in water production efficiency among different treatments,with an average of 14.9 kg/(hm^(2)·mm).Based on straw returning instead of partial fertilizer,the fertilizer use efficiency of winter wheat in loess dryland increased with the increasing of straw increasing amount,and the average nitrogen partial fertilizer productivity of N(PEP_(N)),agronomic efficiencies of N(AE_(N)),current recovery efficiencies of N(RE_(N))and partial fertilizer productivity of P(PEP_(P))of S2 treatment were 66.4%,155.8%,113.5% and 105.2% higher than those of S0 treatment,respectively.After three consecutive years of no straw returning,the soil nitrate-N residue of 2 m soil layer increased by 100.6% compared with that pre-sowing in 2018,and nitrate nitrogen accumulated in deep soil layer with downward leaching of water.The accumulation of nitrate nitrogen in 2 m soil layer of straw returning treatment was lower than that pre-sowing in 2018,and the residue of nitrate nitrogen in 2 m soil treated with S2 was the lowest,244.8 kg/hm^(2).Comprehensively considered,in the wheat planting region of loess Dryland in southern Shanxi,straw instead of 8.3%~31.9% N and 15.7%~63.2% P_(2)O_(5) could increase soil moisture before sowing,reduce fertilizer residue,improve fertilizer use efficiency and obtain remarkable yield.Among the different treatments,the yield and water and fertilizer effect in the S2 treatment(average straw returning amount 7477 kg/hm^(2))were the best.The results could provide theoretical basis for the prevention and control of non-point source pollution and the high-yield and high-efficiency green production of winter wheat in the dryland of wheat area.