[Application effect of high efficiency and stability urea added with biochemical inhibitors and humic acid in loess]

We carried out pot experiment to investigate nitrogen transformation characteristics, yield increasing effect, and apparent utilization rate of nitrogen fertilizer in loess soils by combining chemi-cal inhibitor and biostimulant humic acid to investigate the application effect and provide a theoretical basis for new type highly efficient and stable urea in loess soil. In this study, blank (CK) and urea (N) were set as controls, and humic acid alone (F), N-butyl thiophosphate-triamine (NBPT), 3,4-dimethyl-pyrazolate phosphate (DMPP), 2-chloro-6-trimethyl-pyridine (CP) and humic acid were respectively combined with three biochemical inhibitors to urea. The results showed that compared with N treatment, F, NBPT+F, DMPP+F, CP+F treatments significantly increased maize yield, chlorophyll content, leaf area index and nitrogen uptake, and had obvious effects on soil available nitrogen contents. The addition of humic acid increased chlorophyll content of maize leaves in all cases compared to the application of biochemical inhibitors alone. Compared with CP treatment, CP+F treatment could significantly increase nitrogen uptake, chlorophyll content, and nitrogen adsorption efficiency of maize. Addition of humic acid with NBPT increased nitrification inhibition rate by 10.7% compared with NBPT alone, but decreased yield, leaf area index, nitrogen uptake, nitrogen use efficiency. Compared with DMPP treatment, DMPP+F treatment significantly reduced maize yield, leaf area index, nitrogen uptake, nitrogen use efficiency and nitrification inhibition rate. Considering maize yield, plant N uptake, N fertilizer uptake rate and soil ammonium N and nitrate N contents, the addition of humic acid and CP is recommended for urea application in loess areas to enhance urea performance, yield, and fertilizer utilization.采用田间盆栽试验,研究生化抑制剂与生物刺激素腐植酸结合制成的高效稳定性增效尿素肥料在黄土中的氮素转化特征、增产效果和氮素肥料表观利用率,以探明其施用效果,为开发适宜黄土施用的新型增效尿素肥料提供理论依据。本研究以不施氮肥(CK)和施尿素氮肥(N)为对照,在尿素中分别添加腐植酸(F)、N-丁基硫代磷酰三胺(NBPT)、3,4-二甲基吡唑磷酸盐(DMPP)和2-氯-6-三甲基吡啶(CP),以及腐植酸与3种生化抑制剂分别组合(NBPT+F、DMPP+F、CP+F)。结果表明: 与N处理相比,F、NBPT+F、DMPP+F和CP+F处理均能显著提高玉米的产量、叶片叶绿素含量、叶面积指数和植株吸氮量,对土壤铵态氮和硝态氮含量也有显著影响。与单独施用生化抑制剂相比,添加腐植酸可提高玉米叶片叶绿素含量。与CP相比,CP+F玉米的植株吸氮量、叶绿素含量、氮肥吸收利用率均显著提高;与NBPT相比,NBPT+F硝化抑制率提高10.7%,但玉米产量、叶面积指数、植株吸氮量和氮肥利用率等均有所降低;与DMPP相比,DMPP+F显著降低了玉米产量、叶面积指数、植株吸氮量、氮肥利用率和硝化抑制率等。综合玉米产量、植株吸氮量、氮肥吸收利用率以及土壤铵态氮、硝态氮含量等指标,在黄土地区施用尿素肥料时,建议添加腐植酸和CP以提升尿素性能,从而提高产量和肥料利用率。.