玉米秸秆配施氮肥还田对土壤酶活、土壤养分及腐解率的影响
【研究目的】在黑龙江省玉米连作区，设置不施氮和施氮300kg··hm-2两个处理，研究氮肥对玉米生长期内还田玉米秸秆腐解率的影响及对土壤养分、土壤酶活的影响。【结果】秸秆配施氮肥还田增加了土壤土壤脲酶、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13.53U/ml~14.21U/ml和11.80U/ml~15.67U/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48.57U/ml~55.92U/ml和50.69U/ml~59.34U/ml，在灌浆期差异达到显著水平；蔗糖酶活性范围为36.90 U/ml~51.85 U/ml和46.40 U/ml~58.22 U/ml，在三个时期差异均达到显著水平；秸秆还田配施适量的氮肥对铵态氮质量分数的影响并不显著，但能够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10.39ug/kg、18.45ug/kg和126.43mg/kg、145.39mg/kg；玉米的整个生育期，施氮处理玉米秸秆腐解率均高于不施氮处理，150d后秸秆腐解率差异达到显著水平，不施氮处理和施氮处理秸秆腐解率分别为65.29%和67.81%。
英文摘要:
[Objective] In the continuous cropping area of maize in heilongjiang province, two treatments of no-nitrogen application and 300kg· hm-2 nitrogen application were set up to study the effect of nitrogen fertilizer on the decomposition rate of returned corn straw during the growth period of maize and the effect on soil nutrients and soil enzyme activity. [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 13.53U/ml~14.21U/ml and 11.80U/ml~15.67U/ml, respectively. The activity range of soil catalase was 48.57U/ml~55.92U/ml and 50.69U/ml~59.34U/ml, respectively. The range of sucrase activity was 36.90 U/ml~51.85 U/ml and 46.40 U/ml~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 10.39ug/kg, 18.45ug/kg, 126.43mg/kg and 145.39mg/kg, respectively. During the whole growth period of corn, the decomposition rate of corn straw under nitrogen treatment was higher than that without nitrogen treatment. After 150d, the difference in the decomposition rate of corn straw reached a significant level. The decomposition rate of corn straw without nitrogen treatment and under nitrogen treatment was 65.29% and 67.81%, respectively.
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