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秸秆与地膜覆盖条件下旱作玉米田土壤氮组分生长季动态
引用本文:毛海兰,付鑫,赵丹丹,李蓉蓉,王俊. 秸秆与地膜覆盖条件下旱作玉米田土壤氮组分生长季动态[J]. 水土保持学报, 2018, 32(4): 246-254
作者姓名:毛海兰  付鑫  赵丹丹  李蓉蓉  王俊
作者单位:西北大学城市与环境学院;西北大学陕西省地表系统与环境承载力重点实验室
基金项目:国家自然科学基金面上项目(31570440)
摘    要:研究不同覆盖措施下农田土壤全氮及其活性和半活性组分在作物生长季的动态变化,有助于深入理解农田土壤氮循环过程。基于黄土高原8年春玉米覆盖定位试验,系统分析了土壤全氮、矿质氮、微生物量氮、潜在可矿化氮以及颗粒有机氮在玉米不同生育期的动态特征。试验包括全生育期9 000kg/hm2秸秆覆盖、全生育期地膜覆盖和不覆盖对照3个处理。结果表明:(1)除硝态氮和铵态氮在苗期上升外,秸秆和地膜覆盖下土壤全氮及其组分含量在春玉米生育期基本呈苗期下降、拔节期上升、大喇叭口—抽雄期下降、灌浆和收获期回升的变化趋势;(2)与对照相比,秸秆覆盖提高了大多数生育时期0—40cm土层全氮和硝态氮含量及0—20cm土层铵态氮含量,提高各生育时期0—40cm土层微生物量氮、潜在可矿化氮以及颗粒有机氮含量;(3)地膜覆盖较对照提高大多数生育时期0—40cm土层硝态氮和0—20cm土层铵态氮含量,降低作物生育后期0—20cm土层全氮和0—40cm土层颗粒有机氮含量,降低大多数时期0—40cm土层微生物量氮和10—20cm土层潜在可矿化氮含量;(4)除了地膜覆盖下20—40cm土层颗粒有机氮相对含量在作物不同生育期差异不显著外,秸秆和地膜覆盖下0—40cm土层微生物量氮、潜在可矿化氮、颗粒有机氮对土壤全氮的动态均有重要贡献。总之,黄土高原的春玉米田秸秆覆盖具有明显的提升土壤全氮及其组分含量的作用,有助于培肥地力和土壤固氮;地膜覆盖则降低了作物生育后期土壤全氮及其组分含量,同时显著提高了土壤硝态氮水平,导致农田土壤氮素淋溶风险提高。

关 键 词:秸秆覆盖  地膜覆盖  土壤全氮  微生物量氮  潜在可矿化氮  颗粒有机氮
收稿时间:2018-03-28

Seasonal Dynamics of Soil Nitrogen Fractions in Dryland Spring Maize Field Under Straw and Plastic Film Mulching
MAO Hailan,FU Xin,ZHAO Dandan,LI Rongrong,WANG Jun. Seasonal Dynamics of Soil Nitrogen Fractions in Dryland Spring Maize Field Under Straw and Plastic Film Mulching[J]. Journal of Soil and Water Conservation, 2018, 32(4): 246-254
Authors:MAO Hailan  FU Xin  ZHAO Dandan  LI Rongrong  WANG Jun
Affiliation:1. College of Urban and Environmental Sciences, Northwest University, Xi''an 710127;2. Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, Northwest University, Xi''an 710127
Abstract:Dynamics of soil microbial biomass nitrogen, potentially mineralizable nitrogen and particulate organic nitrogen during crop growing stages are important to understand the nitrogen cycling responding to mulching practices in dryland cropping systems. Based on a long-term mulching experiment in the Losses Plateau, this study investigated the dynamics of soil nitrogen fractions at different crop growth stages under straw and plastic film mulching conditions. Three treatments as straw mulching at a rate of 9 000 kg/hm2 (SM), plastic film mulching (PM) and no mulching (CK) were included. The results showed that:(1) The contents of soil total nitrogen, microbial biomass nitrogen, potentially mineralizable nitrogen, particulate organic nitrogen and mineral nitrogen showed a tendency of decreasing at seedling stage, increasing at jointing stage, decreasing again at belling-heading stage and recovering at filling and harvest stages, except for nitrate nitrogen and ammonium nitrogen which increased at seedling stage. (2) Compared with CK, straw mulching effectively increased the contents of soil total nitrogen and nitrate nitrogen in 0-40 cm soil layer and soil ammonium nitrogen in 0-20 cm soil layer at most growth stages of spring maize, and increased soil microbial biomass nitrogen, potentially mineralizable nitrogen, and particulate organic nitrogen in 0-40 cm soil layer at nearly all growth stages. (3) Compared with CK, plastic film mulching improved soil nitrate nitrogen in 0-40 cm soil layer and ammonium nitrogen in 0-20 cm soil layer at most growth stages of maize, and decreased soil total nitrogen in 0-20 cm soil layer and particulate organic nitrogen in 0-40 cm soil layer at the later growth stages, and decreased microbial biomass nitrogen in 0-40 cm soil layer and potentially mineralizable nitrogen in 10-20 cm soil layer at most stages of maize. (4) Soil microbial biomass nitrogen, potentially mineralizable nitrogen and particulate organic nitrogen under mulching all had an important contribution to the dynamics of total nitrogen, except for the ratio of particulate organic nitrogen to total nitrogen in 20-40 cm layer under plastic film mulching. In conclusion, straw mulching in the Loess Plateau has a significant role in increasing the contents of soil nitrogen and its fractions in spring maize field, which is conducive to improve the soil fertility and nitrogen fixation levels as well as crop production. While plastic film mulching would reduce soil nitrogen fractions at the later growth stages of maize. Higher soil nitrate nitrogen level with plastic film mulching would increase the nitrogen leaching risk in maize field.
Keywords:straw mulching  plastic film mulching  soil total nitrogen  microbial biomass nitrogen  potentially mineralizable nitrogen  particulate organic nitrogen
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