东北冷凉风沙区不同保护性耕作措施对玉米耕层土壤肥力水平的影响

以东北冷凉风沙区普遍采用的玉米垄作保护性耕作方式为研究对象,通过定点试验(2004～2007年),研究不同保护性耕作措施对玉米耕层土壤肥力水平的影响.研究结果表明:不同保护性耕作措施下的土壤微生物数最均大于传统耕作(CK),其中留茬覆盖(B2)>留茬(B1)>火茬(B3).灭茬方式(B3)的土壤脲酶活性最高,留茬覆盖(B2)处理前期土壤脲酶活性较低,但后期增长迅速.留茬覆盖(B2)措施对土壤碱性磷酸酶活性的影响最显著.不同保护性耕作措施土壤有机质含量均高于传统耕作(CK),其中留茬覆盖(B2)比对照高1.58%,但差异不显著.同一种保护性耕作措施下土壤有机质含量都表现出随覆盖年限的延长而提高的趋势,留茬覆盖(B2)方式的有机质含量增加明显,2007年比2004年增加0.18g·kg~(-1).年际间不同保护性耕作措施下的土壤碱解氮、速效磷和速效钾的含量均高于传统耕作(CK),且随着保护性耕作方式实施年限延长,同一种保护性耕作措施下的土壤碱解氮和速效磷的含量呈现增加趋势,其中留茬覆盖(B2)的增幅最大,2007年比2004年分别增加35.3%和32.7%.

Effect of Different Conservation Tillage Measures on Maize Topsoil Fertility in Cold,Windy and Sandy Areas in Northeast China

The conservation tillage pattems under ridge plowing were carried out in cold, windy and sandy areas of Northeast China. The influence of different conservation tillage measures on maize topsoil fertility, ineludind soil microorganism numbers, enzyme activity, organic matter content and soil nutrients was studied from 2004 to 2007. The results showed that the number of soil microorganisms under conventional tillage were lowest, mulch (B2)> residue stubble (B1)>stubble ploughing (B3).Soil urease activity of stubble ploughing (B3)was highest. Mulch (B2) had low soil urease activity at early stage, but increased rapidly at late stage.The influence of no-tillage with mulch on activity of soil phosphatase was very significant. Soil organic matter content of different conservation tillage were higher than conventional tillage (CK), Where mulch (B2) higher than the conventional tillage 1.58％, but the difference was not significant. Soil organic matter content under the same type of conservation tillage measure increased with the Period covered. Organic matter content of no-tillage with mulch (B2) were increased significantly, 2007 than 2004 0.18g·kg~(-1).Soil nitrogen, available phosphorus and potassium contents of conservation tillage measure Inter-years were higher than the control tillage (CK), and with the trend of the longer prolong cultivation duration, the more increased Alkalihydr.N and Available P under the same conservation tillage measure, Mulch (B2) had the biggest and alkalihydrolysis N and available P increase, 35.3％ and 32.7％.