耕作模式对土壤生物活性与养分有效性及冬小麦产量的影响

Effects of Tillage Patterns on Soil Biological Activity,Availability of Soil Nutrients and Grain Yield of Winter Wheat

为探讨长期玉米秸秆还田下不同耕作模式对土壤生化性状及冬小麦产量的影响,从2011年10月至2016年6月连续5个冬小麦生长季进行田间定位试验。设4个耕作处理,分别是连续旋耕秸秆不还田(RT)、连续旋耕秸秆还田(RS)、连续深耕秸秆还田(DS)及前2年旋耕秸秆还田第3年深耕秸秆还田(TS)。与RT相比,连续5年秸秆还田显著提高0~10、10~20和20~30 cm土层土壤有机碳、无机氮、速效磷、速效钾含量;土壤脲酶、蛋白酶、硝酸还原酶和蔗糖酶活性及土壤微生物多样性分别提高23.1%~59.3%、13.2%~40.7%、14.1%~28.8%、10.9%~19.5%和31.9%~42.5%。秸秆还田使各土层变形菌门、硝化螺旋菌门及放线菌门的相对丰度显著提高,而酸杆菌门相对丰度则显著降低。与DS及TS相比,RS显著提高0~10 cm土层土壤养分状况及生物活性,10~30 cm土层则显著降低。连续旋耕至第3年,无论秸秆还田与否,小麦均表现减产;DS与TS处理则表现持续增产,平均年增产3.2%和3.9%。本研究表明在黄淮海东部地区,秸秆还田条件下,2年旋耕后接1年深耕的耕作模式有助于改善耕层土壤质量和提高冬小麦生产力。

To determine the effects of different tillage practices on soil biochemical properties and grain yield of winter wheatunder continuous maize straw return,we conducted a five-year field experiment from October2011to June2016.Four treatmentswere compared,which were continuously rotary tillage with total maize straw removed(RT),continuously rotary tillage withmaize straw return(RS),continuously deep-plowing tillage with maize straw return(DS),and two-year rotary tillage followed byone-year deep-plowing tillage with maize straw return(TS).Compared with RT,treatments with straw return significantly improvedthe soil fertility in the0–10,10–20,and20–30cm depths,increasing contents of soil organic carbon,mineral nitrogen,available phosphorus and available potassium.In addition,the activities of urease,protease,nitratase,and invertase,as well as soilmicrobial diversity in the0–30cm depth increased by23.1%–59.3%,13.2%–40.7%,14.1%–28.8%,10.9%–19.5%,and31.9%–42.5%,respectively.Straw return resulted in significant increases in relative abundances of Proteobacteria,Nitrospirae,and Actinobacteria and significant decrease in that of Acidobacteria.In the three treatments with straw return,vertical distributionof soil fertility was affected by tillage practice.For example,the soil fertility and bioactivity in the0–10cm depth were significantlyhigher in RS than in DS and TS,whereas those in the10–30cm depth were significantly lower in RS than in DS and TS.Consecutively rotary tillage for three years resulted in yield decrease of wheat,whether straw returned to the field or not.In contrast,DS and TS with deep-plowing practice showed continuous yield increase during the five years with the average annual increaseof3.2%and3.9%,respectively.The present study indicates that under straw return condition,two-year rotary tillage followedby one-year deep-plowing tillage is a promising pattern in the eastern part of Huang–Huai–Hai Plain to improve soil qualityand wheat productivity.