不同有机肥与化肥配施对氮素利用率和土壤肥力的影响

Effect of different organic manures combined with chemical fertilizer on nitrogen use efficiency and soil fertility

【目的】不同类型畜禽粪便有机肥在成分和性质上存在明显差异,本文研究了华北地区主要有机肥与化肥以不同比例配施后,对作物氮素吸收利用及土壤养分的影响,以期为本地区有机肥的科学利用提供理论依据和数据支撑。【方法】在华北平原冬小麦–夏玉米种植区进行田间试验。以推荐养分施用量(每季作物N 225kg/hm^2)为基础,设置了1个常规单施化肥处理(CF),12个鸡粪、猪粪和牛粪氮分别与化肥氮配比处理(有机肥氮素占比25%、50%、75%、100%),化肥及3种有机肥的加倍单施处理,同时设1个不施肥处理为对照,共18个处理。分析了作物的氮素吸收量、氮素利用效率,测定了0-20、20-40 cm土层土壤氮、磷、钾含量。【结果】常规施肥量下,单施鸡粪、猪粪、牛粪处理的氮素收获指数(NHI)均与化肥处理相当,平均为79.06%;单施牛粪处理的氮素生理利用率(NPE)为64.42 kg/kg,显著高于化肥处理;而单施鸡粪、猪粪处理的NPE与化肥处理相当,平均为55.14 kg/kg。与常规施肥量相比,加倍施用鸡粪、猪粪和化肥处理的显著降低NHI值和NPE值,而加倍牛粪处理的NHI与NPE值没有降低。牛粪、鸡粪、猪粪与化肥配施的处理间NHI与NPE值均未表现出显著性差异,且与单施化肥的处理相当。常规施氮量下,单施猪粪、鸡粪处理的氮素偏生产力(PFP)和回收率(NRE)接近,均值为分别39.67 kg/kg和41.85%,达到了单施化肥处理的水平,而牛粪处理的氮素PFP以及NRE仅为29.08 kg/kg和15.6%,显著低于化肥、鸡粪和猪粪处理。与常规施氮量相比,加倍施用牛粪、鸡粪、猪粪和化肥处理的氮素的PFP值平均降低了49.1%,氮肥NRE值平均降低了23.2%。牛粪、鸡粪、猪粪与化肥各配施比例处理的氮素PFP和NRE值均达到了单施化肥的水平。与单施化肥相比,单施有机肥以及有机无机配施没有明显提高土壤全氮含量,但显著提高有效磷和速效钾含量,单施鸡粪、猪粪处理土壤表层有效磷含量分别是单施化肥处理的5.82和7.06倍。【结论】推荐施肥量下,鸡粪或猪粪单独施用或配施少量化肥氮,牛粪配施75%左右的化肥氮可实现与化肥相当的氮素利用效率,同时提升土壤肥力。在实际生产中应根据有机肥特性调节有机肥与化肥配施比例,实现有机肥的科学利用。

【Objectives】There are obvious differences in composition and properties among different organic manures. The objectives of this study were to discuss the effect of different organic manures combined with chemical fertilizer on nitrogen use efficiency and soil nutrients and provide a theoretical basis for efficiently using different organic manures by optimizing fertilization techniques.【Methods】Eighteen fertilizer treatments included in this field experiment were:one chemical fertilizer treatment(farmer's N rate, N 225 kg/hm^2 per season);twelve treatments of organic manures(chicken manure, pig manure and cow manure) with chemical fertilizers(ratios of manure N in the total N input were 25%, 50%, 75% and 100%);four double farmer's rate treatments of three manures(chicken manure, pig manure and cow manure) and chemical fertilizer applied singly;one without any fertilizer treatment. The effects of different fertilization systems on nitrogen uptake,nitrogen use efficiency and soil fertility of crops were studied and discussed.【Results】Under farmer's N rate(225 kg/hm^2), applying chicken manure or pig manure alone had similar nitrogen harvest index(NHI) and physiological efficiency(NPE) as treatments applying chemical fertilizer alone, NHI and NPE values of treatments applying cattle manure were 79.06% kg/kg and 64.42 kg/kg. Compared with famer's N rate, the double rate of chicken manure, pig manure or chemical fertilizer decreased crops' NHI and NPE significantly,while the double rate of cattle manure did not decrease crops' NHI and NPE. The difference among various ratios of chicken manure and chemical fertilizer, pig manure and chemical fertilizer, cattle manure and chemical fertilizer was not significant. Under farmer's N rate(225 kg/hm^2), applying chicken manure or pig manure alone had similar partial factor productivity(PFP) and recovery efficiency(NRE) as treatments applying chemical fertilizer alone. PFP average and NRE average of treatments applying chicken and pig manure were39.66 kg/kg and 41.85% respectively, however, PFP and NRE of treatment applying cattle manure were 29.1 kg/kg and 15.6%. Compared with famer's N rate, the double rate of cattle manure, chicken manure, pig manure or chemical fertilizer decreased crops' PFP and NRE by average of 49.1% and 23.2%, respectively. Moreover,all treatments combining cattle manure, chicken manure or pig manure with chemical fertilizer also had similar PFP and NRE as treatments applying chemical fertilizer alone. Applying organic manure alone or combining organic manure with chemical fertilizer could not increase soil total N content. High level of P and K content in organic manure resulted in more soil available K and P than treatments applying chemical fertilizer alone.Available P of treatments receiving chicken or pig manure was 5.82 or 7.06 times that of treatment receiving chemical fertilizer alone.【Conclusions】Under the recommended fertilization rate, chicken manure or pig manure should not be applied or combined with a small amount of nitrogen fertilizer, and cow manure with about75% nitrogen fertilizer could achieve the same nitrogen use efficiency as chemical fertilizer, while improving soil fertility. In actual production, the proportion of manure and chemical fertilizer should be adjusted according to the characteristics of manure, so as to realize the scientific utilization of manure.