有机肥氮替代化肥氮提高玉米产量和氮素吸收利用效率

【目的】有机肥替代部分化肥是实现中国化肥零增长的重要技术途径之一。利用在紫色土上8年定位试验研究有机肥氮连续替代化肥氮玉米生产力和氮素吸收利用效率的变化,为紫色土区合理利用有机养分资源和玉米施肥结构的调整提供科学依据。【方法】本试验为8年定位试验,试验施肥模式有5种:不施氮肥对照(CK)、农民常规施肥(FP)、化肥优化施用(OP)、在化肥优化的基础上有机肥(鸡粪)氮替代50%化肥氮(MF)、有机肥(鸡粪)氮替代100%化肥氮(OM)。试验研究了不同施肥处理下玉米产量、生物量和氮素吸收利用的变化。【结果】有机肥氮替代部分化肥氮能够显著增加玉米籽粒产量和生物量。相比常规施肥(FP)、有机肥氮替代100%化肥氮(OM)和化肥优化施用(OP),有机肥氮替代50%化肥氮处理(MF)的8年玉米籽粒平均增产率分别为13.7%、13.5%和12.5%,地上部生物量增产11.3%、7.0%和8.6%。与对照相比,各施肥模式均降低了玉米产量年度变异系数,提高了可持续指数和收获系数,其中有机肥氮替代50%化肥氮(MF)年度变异最小、可持续指数和收获指数最高。有机肥氮替代部分化肥氮促进了玉米对氮的吸收累积和向籽粒的转运。与化肥优化施(OP)和有机肥氮替代100%化肥氮(OM)处理相比,有机肥氮替代50%的化肥氮处理(MF)籽粒中氮素累积吸收量增加7.0%和29.6%,氮的总表观利用率提高2.5个百分点和26.5个百分点。有机肥氮替代50%化肥氮处理(MF)的氮肥偏生产力、氮收获指数和氮肥贡献率分别比OP提高6.2 kg·kg~(-1)、3.5个百分点和6.3个百分点,比OM提高6.6 kg·kg~(-1)、0.8个百分点和5.8个百分点。不同施肥处理每生产1 t玉米对氮素的需求量存在明显差异,化肥优化(OP)和有机肥氮替代50%的化肥氮(MF)处理生产1 t玉米籽粒对氮素的需求量(9.4 kg和10.8 kg)明显低于FP和OM处理(14.5 kg和12.9 kg),提高了氮素的生产效率。【结论】有机肥氮替代50%化肥氮显著提高了玉米经济产量和生物产量,提高了产量的稳定性和可持续性;促进了玉米对氮素的吸收和向籽粒的转运,提高了氮的利用效率。有机肥氮替代部分化肥氮是西南紫色土地区玉米增产稳产、氮肥增效的合理施肥方式。

Nitrogen of Organic Manure Replacing Chemical Nitrogenous Fertilizer Improve Maize Yield and Nitrogen Uptake and Utilization Efficiency

【Objective】 Replacing chemical fertilizer with organic manure is an important way to achieve fertilizer zero increase in China. Eight years location experiments of replacing chemical fertilizer with organic manure were carried out to study maize productivity and nitrogen uptake and nitrogen utilization efficiency in purple soil, so as to provide scientific evidence about rational utilization organic resources and adjust maize fertilization pattern.【Method】In 8 years location experiments, five different fertilization patterns were designed, including CK (non-N fertilization), FP (farmers’ practice), OP (optimal chemical fertilization), MF (organic manure replacing 50% chemical N) and OM (organic manure replacing 100% chemical N), on the variation of maize yield and biomass and nitrogen uptake and nitrogen utilization efficiency.【Result】Replacing partial chemical with organic manure increased maize yield and biomass significantly. Compared with FP and OM and OP treatments, replacing 50% chemical N with organic manure increased maize yield by 13.7% and 13.5% and 12.5%, respectively; it also increased maize biomass by 11.3% and 7.0% and 8.6%, respectively. Compared to CK, the other four treatments decreased the coefficient of variation (CV) and increased the SYI and HI with the greatest change in MF. Organic manure replacing partial chemical N promoted N uptake in maize, and transferred more N to grain. Compared to OP and OM treatments, replacing 50% chemical N with organic manure increased grain N uptake by 7.0% and 29.6%. RE_N increase 2.5% and 26.5%, respectively. Compare to OP treatment, PFP_N and NHI and FCR_N in MF increased by 6.2 kg·kg^-1 and 3.5% and 6.3%, respectively; Compared to OM treatment, increased by 6.6 kg·kg^-1 and 0.8% and 5.8%, respectively. There was a significant difference in N demand for each ton of grain yield among treatments, with 9.4 and 10.8 kg in OP and MF treatments, respectively, which was less than that in FP and OM treatments (14.5 and 12.9 kg). Therefore, OP and MF could improve the N efficiency for grain production. 【Conclusion】 Replacing 50% chemical N with organic manure significantly increased maize economic yield and biomass, also increased yield stability and sustainability; It promoted N uptake in maize and transferred more N to grain, thus increasing N efficiency. So partial chemical N is replaced by organic manure is a rational fertilization pattern to increase maize yield and improve maize yield stability and improve N efficiency in Southwest China.