免耕条件下秸秆还田与施肥对小麦-玉米轮作系统土壤养分和酶活性的影响

摘要

为研究免耕条件下秸秆还田与施肥对小麦-玉米轮作系统土壤养分和酶活性的影响,于西北农林科技大学校内试验地进行试验,设3个秸秆还田水平:秸秆全量还田、秸秆半量还田、秸秆不还田,施肥和不施肥2个施肥水平,共6个处理,以秸秆不还田+不施肥作为对照,研究秸秆还田与施肥对小麦-玉米轮作系统一年内两季不同作物收获期0～40 cm土层土壤养分含量和土壤酶活性的影响.结果表明,冬小麦和夏玉米收获期土壤不论是0～20 cm还是20～40 cm土层,秸秆全量还田+施肥和秸秆半量还田+施肥处理相比秸秆不还田+不施肥均能增加土壤有机碳、碱解氮、速效磷和速效钾的含量,并且高于秸秆还田+不施肥处理;秸秆全量还田+施肥处理下的冬小麦土壤脲酶、碱性磷酸酶、过氧化氢酶和蔗糖酶的活性比秸秆不还田+不施肥处理的0～20 cm土层分别提高92.34％,87.91％,4.94％,62.41％;对于夏玉米而言,秸秆全量还田+施肥相比秸秆不还田+不施肥处理的0～20 cm土层提高了土壤脲酶、碱性磷酸酶、蔗糖酶和过氧化氢酶,分别提高了68.54％,49.11％,149.84％,10.38％.可见,土壤脲酶、碱性磷酸酶、过氧化氢酶和蔗糖酶在秸秆全量还田+施肥的处理下活性最高,并且土壤脲酶与全氮和碱解氮相关性最好,碱性磷酸酶与全氮、速效钾和速效磷的相关性比较好,过氧化氢酶与速效钾和速效磷的相关性比较好,蔗糖酶与有机碳的相关性比较好,且均呈正相关.以上结果表明,秸秆还田配施化肥可以提高土壤质量.%In order to study the effects of straw returning and fertilizing on soil nutrient and enzyme activities in wheat-maize rotation system under no-tillage conditions, the experiment was carried out at the experimental ground of Northwest A & F University. Three straws were returned:the amount of straw returned to the field, half of the straw returned to the field and the straw was not returned to the field, fertilizing and non-fertilizing of these two fer-tilization levels, a total of 6 treatments. Effects of straw returning and fertilizing on soil nutrient content and soil en-zyme activities in 0-40 cm soil layer of two crops at different harvesting stages within one year of wheat-maize rota-tion system were studied using straw no return and no fertilizing as control. The results showed that the total amount of straw returning+fertilizing and half of straw returning + fertilizing could increase the soil organic carbon, avail-able nitrogen, available phosphorus and available potassium of winter wheat and summer maize compared with straw no returning and no fertilizing, no matter in 0-20 cm or 20-40 cm soil layers, and higher than that of straw retur-ning + no fertilizing;The activities of soil urease, alkaline phosphatase, catalase and invertase of the winter wheat in total amount of straw returning and fertilizing were increased by 92 . 34％,87 . 91％,4 . 94％,62 . 41％ than straw no returning + no fertilizing treatment of 0 -20 cm soil layer. For the summer maize, straw returning full amount+fertilizing than straw no returning + no fertilizing treatment of 0-20 cm soil layer could improve the soil urease, alkaline phosphatase, invertase and catalase,respectively increased by 68. 54％, 49. 11％, 149. 84％, 10. 38％. It was found that soil urease, alkaline phosphatase, catalase and invertase had the highest activity in the treatment of the total amount of straw returning and fertilizing, and the soil urease had the best correlation with total nitrogen and available nitrogen, alkaline phosphatase had the best correlation with total nitrogen, available potassi-um and available phosphorus, catalase had the best correlation with available potassium and available phosphorus, invertase had the best correlation with organic carbon, and all of them were positively correlated. The above results showed that the application of straw and fertilizer could improve the soil quality.