脲酶/硝化抑制剂双控下红壤性水稻土氮素变化特征

Characteristics of nitrogen changing in red paddy soil under different ratios of NBPT and DMPP to urea

以红壤性水稻土为对象,设置大田试验处理:不施肥(CK)、单施氮肥(U)、氮肥配施0. 5%脲酶抑制剂N-丁基硫代磷酰三胺(NBPT)与1%硝化抑制剂3,4-二甲基吡唑磷酸盐(DMPP)(U+N/D)、氮肥配施1%NBPT与2%DMPP [U+2 (N/D)],研究4种施肥组合下双季稻土壤脲酶、土壤NH+4-N、田面水NH+4-N和NO-3-N的变化特征。结果表明,与CK和U处理相比,各施肥处理在施肥后第1～15 d,土壤脲酶活性、土壤NH+4-N、田面水NH+4-N含量增加,田面水NO-3-N含量无显著变化。与U+2 (N/D)处理相比,早稻中U+N/D处理的脲酶活性显著增加了0. 03～0. 70 mg·g-1,土壤NH+4-N含量显著增加了19. 11～61. 44 mg·kg-1,田面水NH+4-N含量显著增加了34. 48～40. 70 mg·L-1。相关分析表明,土壤NH+4-N与土壤脲酶、田面水NH+4-N均呈显著负相关,田面水NH+4-N与土壤脲酶、田面水NO-3-N均呈显著正相关(P <0. 05)。综上,与其他处理相比,U+N/D处理是在短期内有效提高土壤脲酶活性、土壤NH+4-N和田面水NH+4-N含量的最优处理,合理配施尿素及0. 5%脲酶抑制剂NBPT和1%硝化抑制剂DMPP能够显著提高NH+4-N供水稻吸收,减少氮素损失。

Field experiments were conducted to investigate the variation characteristics of no fertilizer (CK),nitrogen only (U),nitrogen fertilizer with 0.5%urease inhibitor NBPT (N-butyl glucosinolates phosphoryl three amine)and 1% nitrification inhibitor DMPP (3,4-dimethyl pyrazole phosphate)(U +N/D),and nitrogen fertilizer with 1% NBPT and 2% DMPP [U +2(N/D)]under the condition of double paddy field on soil urease,soil NH4^+-N,surface water NH4^+-N and NO3^--N.Results showed that compared with no fertilizer and common urea,for all the fertilizer treatments in 1-15d after fertilization,the content of soil urease activity,soil NH4^+-N and surface water NH4^+-N increased,the conten.t of surface water NO3^--N had no significant change.And compared with U +2(N/D)treatment,the urease activity of U +N/D treatment in early rice significantly increased by 0.03-0.70mg·g^-1,soil NH4^+-N content significantly increased by 19.11- 61.44mg·kg^-1,the surface water NH4^+-N content significantly increased by 34.48-40.70mg·L^-1.Correlation analysis showed that soil NH4^+-N and soil urease,surface water NH4^+-N were significantly negative correlated,surface water NH4^+-N and soil urease,surface water NO3^--N were significantly positive correlated (P <0.05).In conclusion,compared with other treatment,U +N/D treatment was effective in the short term to improve soil urease activity and soiI NH4^+-N and surface water NH4^+-N content.Reasonable urea application with 0.5% of urease inhibitor (NBPT)and 1% of nitrification inhibitons (DMPP)can significantly improve the NH4^+-N absorption for rice,reduce nitrogen loss.