玉米秸秆还田配施氮肥对土壤酶活、土壤养分及秸秆腐解率的影响

Effects of Nitrogen Fertilizer on Soil Enzymatic Activity, Soil Nutrients and Decomposition Rate of Maize Straw

通过田间试验研究玉米秸秆与氮肥配施对土壤养分、土壤酶活及秸秆腐解率的影响,以5年不施氮肥和施氮300 kg/hm^2耕层土壤为背景,在长期氮肥定位试验区进行试验。结果表明,秸秆还田配施氮肥能够增加土壤脲酶、土壤过氧化氢酶和土壤蔗糖酶活性。玉米出苗期至成熟期,不施氮处理和施氮处理土壤脲酶活性范围分别为13.53~14.21 U/mL和11.80~15.67 U/mL,在灌浆期差异达到显著水平;土壤过氧化氢酶活性范围分别为48.57~55.92 U/mL和50.69~59.34 U/mL,在灌浆期差异达显著水平;蔗糖酶活性范围为36.90~51.85 U/mL和46.40~58.22 U/mL,在3个时期差异均达显著水平。秸秆还田配施适量的氮肥对铵态氮质量分数的影响不显著,但增加硝态氮和速效氮质量分数,不施氮处理和施氮处理硝态氮和速效氮质量分数平均值分别为10.39、18.45 ug/kg和126.43、145.39 mg/kg。

The experiment was carried out in the long-term nitrogen fertilizer location test area, with no nitrogen fertilizer applied for five years and 300 kg/ha surface soil applied for nitrogen as the background. The results showed that the activities of soil urease, soil Catalase and soil invertase could be increased by returning to straw with nitrogen fertilizer. As results, the activities of soil urease, soil catalase and soil sucrase were increased by straw combined with nitrogen fertilizer. From seedling stage to maturity stage of maize, urease activity ranges of soil without and under nitrogen treatment were 13.53-14.21 U/mL and 11.80-15.67 U/mL, respectively. The activity range of soil catalase was 48.57-55.92 U/mL and 50.69-59.34 U/mL, respectively. The range of sucrase active was 36.90-51.85 U/mL and 46.40-58.22 U/mL, with significant differences in all three stages. The effects of straw mulching and the application of appropriate nitrogen fertilizer on the mass fraction of ammonium nitrogen were not significant,but the mass fraction of nitrate nitrogen and rapidly available nitrogen could be increased. The average mass fraction of nitrate nitrogen and rapidly available nitrogen under no nitrogen treatment and nitrogen treatment were 10.39 ug/kg, 18.45 ug/kg, 126.43 mg/kg, and 145.39 mg/kg.