化学氮肥配施有机肥对陇中旱作春小麦氮素利用效率和土壤养分含量的影响

Effects of Combined Application of Nitrogen and Organic Fertilizers on Nitrogen Use Efficiency and Soil Nutrients of Dryland Spring Wheat in Central Gansu

【目的】为评价化学氮肥配施有机肥对陇中黄土高原半干旱区春小麦氮素利用及土壤肥力效应的影响。【方法】在陇中黄土高原旱作区由黄土母质发育而来的黄绵土麦田上进行连续5 a的田间定位试验,以陇中旱作春小麦(Triticum aestivum L.)为研究对象。以不施氮肥(CK)为对照,在等氮条件下分析和比较了单施化学氮肥(N,尿素228.2kg hm^(-2))、单施有机肥(M,有机肥21.0 t hm^(-2))和化学氮肥配施有机肥(NM,尿素114.1 kg hm^(-2)和有机肥10.5 t hm^(-2))对春小麦氮素积累量、氮素利用效率和土壤养分含量的影响。【结果】(1)等氮量条件下,NM处理对各生育期春小麦氮素积累具有显著的提升作用,与处理N相比NM处理下成熟期春小麦氮素积累量提高了15.89%,全生育期氮素吸收速率平均提高了15.67%。与处理N相比NM处理下春小麦花前氮素转运量、转运率和花后氮素积累量分别提高了24.72%、4.45%和21.95%。NM处理较N处理春小麦氮肥偏生产力、氮素回收率和氮肥农学利用效率和氮素收获指数分别提高了20.50%、16.35%、24.14%和2.07%。(2)在定位试验开展5 a后,NM处理土壤有机碳和全氮含量较N处理提高了11.09%和13.40%,而不施氮肥导致土壤有机碳和全氮较耕作前下降达13.88%和11.63%。除分蘖期外各处理下土壤无机氮含量均表现为NM>N>M>CK,各处理间差异性显著(P<0.05)。与N处理相比在小麦整个生育期NM处理下土壤无机氮含量平均提高了9.66%。(3)NM处理较其他处理提高了春小麦产量和生物量,优化了小麦产量构成因素。NM处理的春小麦产量达到了2787.13 kg hm^(-2),比常规施肥处理N提高了17.89%,具有显著的增产效应。通过通径分析发现每公顷有效穗数和千粒重的提高是促进小麦增产的重要原因。【结论】在等氮条件下采用化学氮肥配施有机肥的方式可以培肥土壤、提高土壤氮素有效性,在化肥减施下实现春小麦氮素利用效率和产量的同步提高,是陇中旱作区春小麦生产中值得推广的施肥方式。

[Objective]The paper aims to evaluate the effect of combined application of nitrogen(N)and organic fertilizer on N utilization and soil fertility of spring wheat in the semi-arid area of Loess Plateau in central Gansu.[Method]A five-year field experiment was conducted on the wheat field of loessial soil developed from the loess parent material in the dry farming area of the Loess Plateau in Central Gansu.The dry farming spring wheat(Triticum aestivum L.)in Central Gansu was used as the research object,and the treatments included:no N fertilizer(CK)as the control,a single application of chemical N fertilizer(N,urea 228.2 kg hm^(-2)),a single application of organic fertilizer(M,organic fertilizer 21.0 t hm^(-2))and chemical N fertilizer combined with organic fertilizer(NM,urea 114.1 kg hm^(-2) and organic fertilizer 10.5 t hm^(-2)).The N accumulation,N use efficiency of spring wheat and soil nutrition content were determined under equal N conditions.[Result]①Compared with N treatment,the N accumulation of spring wheat in the mature stage was increased by 15.89%,and the average N absorption rate in the whole growth stage was increased by 15.67%.The N transport amount,transport rate,and N accumulation after anthesis of spring wheat under NM treatment increased by 24.72%,4.45% and 21.95%,respectively.The partial N productivity,N recovery rate,N agronomic utilization efficiency,and N harvest index of spring wheat in NM treatment were increased by 20.50%,16.35%,24.14%,and 2.07%,respectively.②The contents of soil organic carbon and total N in NM treatment were 7.90% and 5.86% higher than those in N treatment.Except for tillering stage,the content of soil inorganic N under each treatment was NM>N>M>CK,and there was a significant difference among the treatments(P<0.05).Compared with N treatment,the content of soil inorganic N increased by 9.66% under NM treatment in the whole growth period of wheat.②The yield of spring wheat treated with NM was optimized,and the yield of spring wheat was higher than these of other biological factors.The yield of spring wheat under NM treatment reached 2787.13 kg hm^(-2),which was 17.89% higher than that of conventional fertilization treatment(N).Through path analysis,it was found that the increase of effective panicles per hectare and 1000 grain weight was an important reason to promote wheat yield.[Conclusion]In conclusion,under the condition of equal N amount,chemical N fertilizer combined with organic fertilizer can fertilize the soil and improve the soil N availability.In addition,simultaneous improvement of N use efficiency and yield of spring wheat under reduced fertilizer application.Thus,it is a fertilizer application method worthy of popularization in the spring wheat production in the dry farming area of central Gansu.