腐植酸氮肥对玉米产量、氮肥利用及氮肥损失的影响

【目的】 通过研究新型腐植酸氮肥对玉米产量、氮肥吸收利用和分配及氮肥在土壤中分布以及损失的影响，为促进新型肥料的应用，减少环境污染，提高作物产量提供理论依据。 【方法】 采用固定装置，应用同位素示踪技术进行田间试验。试验共设 4 个处理:CK1 (不施氮肥)、CK2 (普通尿素 N 225 kg/hm2)、HA1 (脲基活化腐植酸氮肥 N 225 kg/hm2)、HA2 (常规掺混腐植酸氮肥 N 225 kg/hm2)。采集玉米播种前、施肥前和收获后 0—20 cm、20—40 cm、40—60 cm 土壤样品，采用静态箱体内置硼酸吸收池法测定氨挥发，氧化亚氮通过静态箱体收集、真空瓶贮存后气相色谱仪测定。玉米成熟后采集地上部植株样品，将营养器官与籽粒分离，计产并测定产量构成指标。 【结果】 籽粒中氮素 34.6%～36.2% 来自肥料，营养器官中氮素 14.6%～17.4% 来自肥料。CK2、HA1 和 HA2 处理的氮肥利用率分别为 25.1%、30.9%、28.5%，氮肥损失率分别为 38.1%、19.8%、27.2%。与 CK2 相比:1) 施用 HA1 能提高玉米产量；2) HA1 和 HA2 处理的氮素吸收总量分别增加 25.8 和 16.3 kg/hm2，氮肥利用率分别提高 5.8 个百分点和 3.4 个百分点，氮肥损失率分别减少 18.3 个百分点和 10.9 个百分点；3) HA1 和 HA2 处理 0—60 cm 土壤氮素残留率分别增加 12.5 个百分点和 7.5 个百分点；4) 施用腐植酸氮肥明显提高 0—20、20—40 cm 土壤铵态氮和硝态氮含量。 【结论】 腐植酸氮肥能显著提高玉米产量和氮肥利用率，促进玉米对土壤氮素的吸收利用，显著增加 0—20 cm 土壤氮素残留量和 0—40 cm 土壤无机态氮含量，减缓氮素向深层土壤迁移，从而减少淋溶损失。腐植酸氮肥能改善氮素在土壤中的分布，满足作物根系需肥特性；腐植酸氮肥能显著降低氧化亚氮产生量和其它途径的氮素损失，从而减少氮素损失量。其中，脲基活化腐植酸氮肥作用效果更加明显。

Effects of humic acid nitrogen fertilization on corn yield,nitrogen utilization and nitrogen loss

Objective]In order to promote application of the new type fertilizers, increase crop yield and reduce environmental pollution, the research explored effects of humic acid nitrogen fertilizer on corn yield, nitrogen absorption and utilization, and nitrogen distribution and loss in soil.Methods]The nitrogen isotope tracer technique was used to study the effects of humic acid nitrogen on the nitrogen utilization. Experimental plot soil was circled by specific device. The tested N fertilization treatments were: 1) CK1 (N 0 kg/hm2), 2) CK2 (urea N 225 kg/hm2), 3) HA1 (activated humic acid fertilizer, N 225 kg/hm2), and 4) HA2 (ordinary humic acid nitrogen N 225 kg/hm2). Soil samples in different layers of soil (0–20 cm, 20–40 cm and 40–60 cm) were collected by using earth drilling before planting corn, before fertilization and after the harvest. Ammonia volatilization nitrogen was measured by the static body mothed, and N2O was measured by static body collecting, vacuum flask cold storage and gas chromatograph determining. After the harvest, vegetative organs and grains were separated. After drying, corn production and vegetative organs’ weights were calculated. The vegetative organs and grain were mechanically ground by ball milling ready for measuring.Results]In grains, the nitrogen amounts from the fertilizers occupied 34.6%–36.2%, and in vegetative organs they occupied 14.6%–17.4%. The utilization rates of common urea and the activated humic acid fertilizer and conventional mixing humic acid fertilizers were 25.1%, 30.9% and 28.5%, respectively, and the loss rates of the nitrogen fertilizers were 38.1%, 19.8% and 27.2%, respectively. The results of application of the activated humic acid fertilizer and conventional mixing humic acid fertilizers compared with common urea were: 1) Maize yields were increased significantly; 2)The total N absorption amounts were increased by 25.8 kg/hm2and 16.3 kg/hm2, respectively;3) The nitrogen utilization rates were increased by 5.8 and 3.4 percentage points, respectively; 4) The nitrogen loss rates were reduced by 18.3 and 10.9 percentage points, respectively; 5) The soil nitrogen retention rates at the 0-60cm depth were increased by 12.5 and 7.5 percentage points; 6) The soil ammonium nitrogen and nitrate nitrogen contents were significantly improved in 0–20 cm and 20–40 cm.Conclusions]Humic acid nitrogen fertilizer could significantly improve the utilization rate of nitrogen fertilizer and maize yield, and significantly increase the N residue in soil at 0–20 cm depth. Humic acid nitrogen fertilizer could increase the inorganic nitrogen contents in soil of 0–40 cm, and retard N moving to deeper layer thereby reduce the nitrogen leaching loss. Application of humic acid fertilizer can improve the distribution of nitrogen in the soil thereby can be better adapted to crop root fertilizer demand characteristics. Humic acid nitrogen fertilizer could significantly reduce N2O loss and other loss thereby reduce the nitrogen loss. The activated humic acid fertilizer was better than the conventional humic acid fertilizer.