稻麦轮作下不同还田模式对土壤酶活性的影响研究

Effect of Different Residue Covering Mode on Soil Enzyme Activity Under Rice-wheat Rotation

在成都平原区研究不同还田模式对土壤酶活性的影响,旨在阐明稻麦轮作下不同还田模式与土壤酶活性的关系,并探索成都平原最佳还田模式,为种植业废弃物的农业资源化利用提供科学依据。在为期1年的田间定位试验中,按照秸秆直接还田、食用菌生产转化后菌渣还田两种主要模式、设置秸秆全量还田(100%SR)、菌渣低量还田(50%FR)、菌渣全量还田(100%FR)、菌渣高量还田(250%FR)和常规化肥(对照为CF)五种施肥处理,并按生育期测定不同处理下土壤酶活性和土壤养分,分析其相关性。结果表明,成都平原稻麦轮作条件下秸秆还田和菌渣还田均能够提高土壤酶活性,且表现为高量菌渣还田优于低量菌渣还田,全量菌渣还田优于全量秸秆还田;从作物整个生育期来看,土壤脱氢酶、脲酶、蔗糖酶和中性磷酸酶活性均呈现先增后减的单峰变化;土壤脱氢酶和中性磷酸酶活性表现为成熟期低于生长初期,脲酶和蔗糖酶则相反。相关性分析表明,土壤脱氢酶、脲酶、蔗糖酶和中性磷酸活性与土壤养分的相关性较好,能够反映当季土壤的肥力状况,是评价土壤管理的良好指标。

The soil enzyme is a key criterion for evaluating different residue covering approaches, as it is an important indicator of soil quali- ty and function. The objectives of this study are （ 1 ）to study the activities of dehydrogenation, urease, invertase and neutral phosphatase in different plant growing stages; （2）to determine the relationship between different landspreading mode and soil enzyme activity under rice- wheat rotation; and （ 3 ）to provide the best approach for recycling of agriculture waste. The field experiment designed five treatments accord- ing to applied nitrogen （N） quantities, i.e., 256 N kg＂ hm-2（CF） from urea, 256 N kg-hm-2（100%SR） from straw, and I28 （50%FR）, 256 （100%FR） and 384（150%FR） N kg＇hm-2 from mushroom residue. The results showed that application of straw and mushroom residues could increase soil enzyme activities of dehydrogenation, urease, invertase and neutral phosphatase, and soil enzyme activities were higher at 100%SR than at 100%SR. Soil enzyme activity of urease, invertase and neutral phosphatase was observed higher in the period of jointing and heading as compared to those in tilling and mature. Moreover, the enzyme activity had closely related with the soil fertility factors for various residue covering practices, particularly for the relationship between soil organic matter and available nutrient. Thus, we concluded that indicators of soil enzyme activities were reliable for efficiency assessment of residue covering practices.