硫膜和树脂膜控释尿素对土壤硝态氮含量及氮素平衡和氮素利用率的影响

Effects of sulfur-and polymer-coated controlled release urea fertilizers on spatial-temporal variations of soil NO_3^- -N and nitrogen balance and nitrogen use efficiency

【目的】控释尿素已被证明对于提高氮素利用率、减少氮素损失和增产有积极意义,且不同包膜的控释尿素由于包膜材料的不同,对于氮素的释放和供应强度有所不同。本文在黄淮海区域采用玉米田间试验,探讨硫膜和树脂膜控释尿素在氮素供应和减少氮素损失等方面的效应,以期为黄淮海区域夏玉米在高温多雨的种植条件下两种控释尿素的选择和应用提供依据。【方法】以硫膜和树脂膜控释尿素为研究对象,采用田间试验研究0—100 cm土壤剖面中的硝态氮含量,玉米整个生育期的土壤氮素平衡和玉米产量以及氮素利用率。【结果】与相同施氮量的普通尿素相比,硫膜和树脂膜控释尿素均具有"前控后保"的特性,使玉米苗期0—100 cm土层的土壤硝态氮含量降低了11.7%~56.7%和28.8%~68.2%,玉米灌浆期和收获期0—40 cm土层的硝态氮含量分别提高了16.3%~46.7%、0.5%~60.7%;两种控释尿素均能有效降低玉米整个生育期土壤残留的无机氮量、氮素表观损失量和盈余量,降幅分别为12.0%~18.4%、13.2%~66.4%和15.6%~30.9%,使玉米产量提高14.6%~37.5%,氮素利用率提高12.3~20.8个百分点。在N 210 kg/hm2、N 300 kg/hm2两种施氮量条件下,与相同施氮量的硫膜控释尿素相比,树脂膜控释尿素处理的玉米苗期0—60 cm土层的硝态氮含量降低了26.4%~39.1%,灌浆期0—40 cm土层和收获期0—20 cm土层的硝态氮含量分别提高了10%~21.8%和9.6%~16.4%,土壤残留无机氮量、氮素表观损失量和盈余量分别降低了2.3%~6.0%、44.6%~61.3%和17.0%~17.7%,玉米产量提高了6.8%~8.3%,氮素利用率提高了7.1~8.4个百分点,说明树脂膜控释尿素的效果优于硫膜控释尿素。树脂膜控释尿素和硫膜控释尿素在施氮量N 300 kg/hm2时均比N 210 kg/hm2条件下玉米整个生育期不同土层的硝态氮含量提高了1.2%~90.9%和2.0%~56.7%,玉米整个生育期土壤残留无机氮量、氮素表观损失量和盈余量分别提高了42.1%~47.6%、66.2%~137.9%、52.5%~53.8%,玉米产量和氮素利用率分别提高了20.8%和22.5%、6.5和5.2个百分点,施氮量N 300 kg/hm2优于N 210 kg/hm2。【结论】树脂膜控释尿素在减少夏玉米农田土壤剖面硝态氮残留、维持土壤氮素平衡和提高氮素利用率等方面的效果优于硫膜控释尿素和普通尿素。综合考虑保证土壤氮素供应、减少氮素损失、提高玉米产量及氮素利用率等因素,在黄淮海区域高温多雨气候条件下种植夏玉米,以施氮量N 300 kg/hm2的树脂膜控释尿素或者硫膜和树脂膜控释尿素二者配合施用效果最佳。

【Objectives】Controlled release urea has been proven to have positive significance to increase nitrogen use efficiency,reduce nitrogen loss and increase production. Different controlled release urea coated with different materials has different N release rate and N supply intensity. A field experiment was conducted in a maize farmland in Huang- Huai- Hai area to study the effects of sulfur- and polymer- coated controlled release urea on regulation N supply intensity and reducing nitrogen loss. This study is aimed to provide guidance on sulfur- and polymer- coated controlled release urea application in Huang- Huai- Hai maize zone under the condition of high temperature and rainy.【Methods】The field experiment was conducted to study the effects of sulfur- and polymer- coated controlled release urea on the 0-100 cm spatial- temporal variations of soil NO-3- N,nitrogen balance and nitrogen fertilizer use efficiency.【Results】Compared with common urea of the same N application rate,the sulfur- and polymer- coated controlled release urea has the characteristics of controlled N- supply in the beginning and sufficient N- supply in later days. The sulfur- and polymer- coated controlled release urea reduces soil NO-3- N content of 0- 100 cm soil layer by 11. 7%- 56. 7% and 28. 8%- 68. 2% respectively during maize seedling stage,increases soil NO-3- N content of 0-40 cm depth at maize filling and harvesting stages by 16. 3%-46. 7%,0. 5%-60. 7%,respectively. The sulfur- and polymer- coated controlled release urea reduces the soil residual nitrogen content by 12. 0%-18. 4%,nitrogen apparent loss by 13. 2%-66. 4% and the nitrogen surplus by15. 6%-30. 9% in the whole maize growth stage,respectively. The maize yield and the utilization rate of nitrogen were increased by 14. 6%-37. 5% and 12. 3-20. 8 percentage points,respectively. Compared with sulfur- coated controlled release urea of the same N application rate 210 kg / ha or 300 kg / ha,polymer- coated controlled release urea reduces the soil NO-3- N content of 0-60 cm depth by 26. 4%-39. 1% during maize seedling period,brings up the soil NO-3- N content of 0- 40 cm at maize filling stage by 10%- 21. 8% and that of 0- 20 cm at maize harvesting stage by 9. 6%-16. 4%,respectively. Polymer- coated controlled release urea reduces the soil residual nitrogen content by 2. 3%-6. 0%,nitrogen apparent loss by 44. 6%-61. 3% and nitrogen surplus by 17. 0%-17.7% than those of sulfur- coated controlled release urea with the same N application rate,respectively. Polymer-coated controlled release urea improves the maize yield and the utilization rate of nitrogen by 6. 8%- 8. 3% and 7.1-8. 4 percentage points more than those of sulfur- coated controlled release urea with the same N application rate,respectively. Over all,polymer- coated controlled release urea is better than sulfur- coated controlled release urea in reducing the soil residual nitrogen content,and maintaining the soil nitrogen balance and improving nitrogen fertilizer use efficiency. The N application rate 300 kg / ha of the polymer- coated controlled release urea or the sulfur- coated controlled release urea increases the soil NO-3- N content of 0-100 cm depth during maize growing stages by 1. 2%- 90. 9%,2. 0%- 56. 7% respectively and increases the soil residual nitrogen content,nitrogen apparent loss and nitrogen surplus by 42. 1%- 47. 6%,66. 2%- 137. 9% and 52. 5%- 53. 8% respectively. The300 kg / ha application rate also improves the maize yield and the utilization rate of nitrogen by 20. 8% and 22. 5%,6. 5 and 5. 2 percentage points more than that of the N application rate of 210 kg / ha respectively. The effects of the N application rate 300 kg / ha of the polymer- or the sulfur- coated controlled release urea are better than those of the N application rate 210 kg / ha.【Conclusions】Polymer- coated controlled release urea in reducing soil profile nitrate nitrogen residual,maintaining soil nitrogen balance and improving the utilization rate of nitrogen in summer maize farmland is better than sulfur- coated controlled release urea and common urea. In the context of sufficient N supply,reduced nitrogen loss,improved maize yield and nitrogen utilization efficiency,the application of the polymer- coated controlled release urea or combining with sulfur- coated controlled release urea at N application rate of 300 kg / ha is the best recommended nitrogen fertilization management practice for Huang- Huai- Hai summer maize zone which is under the condition of high temperature and rainy climate.