地表覆盖对西北旱地土壤有机氮累积及矿化的影响.pdf

中国农业科学201043(3):507-513ScientiaAgriculturaSinicadoi:10.3864/j.issn.0578-1752.2010.03.009地表覆盖对西北旱地土壤有机氮累积及矿化的影响谢驾阳王朝辉李生秀田霄鸿（西北农林科技大学资源环境学院陕西杨凌712100）摘要：【目的】认识土壤氮素的转化和供应过程是优化作物栽培和氮素养分管理的关键。【方法】本文采用5年田间长期定位试验的土壤研究了地表覆草和覆膜栽培对旱地土壤氮素矿化和供氮能力的影响。【结果】与常规栽培相比地表长期覆草会提高土壤氮素矿化势降低矿化速率；覆膜则会降低土壤氮素矿化势提高矿化速率覆草、覆膜和常规栽培的矿化势分别为25.0—29.7、23.2—25.9、23.3—26.2mg·kg-1。不施氮时覆草和覆膜均能提高土壤有机氮含量增加土壤轻质有机氮含量；施氮后覆草能增加土壤有机氮和轻质有机氮含量但覆膜却降低了土壤有机氮和轻质有机氮含量。施氮240kg·hm-2时地表覆草、覆膜和常规栽培土壤的有机氮含量分别为1.03、0.95和0.96g·kg-1轻质有机氮分别为51、35和37mg·kg-1。【结论】作物生长过程中地表覆草栽培能使土壤将较多的矿质氮转化形成可矿化有机氮；覆膜栽培则不利于土壤的有机氮累积。因此覆草栽培虽增加了土壤氮素供应能力但为实现作物增产需增加氮肥投入或在作物需氮较多的生长阶段补充氮肥覆膜栽培则需要注意配施有机肥。关键词：覆草；覆膜；氮矿化势；轻质有机氮EffectsofDifferentSurfaceMulchingonSoilOrganicNitrogenAccumulationandMineralizationinDrylandofNorthwesternChinaXIEJia-yangWANGZhao-huiLISheng-xiuTIANXiao-hong(CollegeofResourcesandEnvironmentalScienceNorthwestAgriculturalandForestryUniversityYangling712100Shaanxi)Abstract:【Objective】Understandingsoilnitrogentransformationandsupplyingprocessisthekeyforoptimizingcropcultivationandnitrogenmanagements.【Method】Inthispapersoilsweresampledfroma5-year-longfieldexperimenttostudytheeffectsofdifferentsoilsurfacemulchingonsoilorganicnitrogenaccumulationandmineralizationindrylandofnorthwesternChina.【Result】Theresultsshowedthatcomparedtoconventionalcultivationlongtermsurfacemulchingwithstrawincreasedsoilnitrogenmineralizationpotentialbutdecreasedmineralizationrate.Mulchingwithplastic-fil