秸秆还田对石灰性土壤Zn扩散迁移及形态转化的影响  

Effect of Straw Return on Diffusion, Translocation and Transformation of Zinc in Calcareous Soil

作　　者：陈艳龙 贾舟 师江澜 刘珂 王少霞 田霄鸿 CHEN Yanlong;JIA Zhou;SHI Jianglan;LIU Ke;WANG Shaoxia;TIAN Xiaohong(College of Natural Resources and Environment, Northwest A＆F University, Key Laboratory of Plant Nutrition and the Agri- Environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China)

机构地区：[1]西北农林科技大学资源环境学院农业部西北植物营养与农业环境重点实验室,陕西杨凌712100

出　　处：《土壤学报》2018年第3期721-733,共13页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(41371288;31662233);国家科技支撑计划项目(2012BAD14B11)共同资助~~

摘　　要：有机碳(特别是活性组分)通过络合、螯合等作用对土壤锌(Zn)的迁移转化起重要作用。目前,作物秸秆还田已经代替传统有机肥,成为中国提高粮田土壤有机碳含量及质量的最主要措施。基于此,采用半扩散池装置通过室内模拟试验探究了秸秆还田对石灰性土壤有效Zn(二乙三胺五乙酸浸提态Zn,即DTPA-Zn)扩散迁移及Zn形态转化的影响,以期为提高石灰性土壤Zn有效性及移动性,进而改善作物对Zn的吸收利用提供科学依据。结果表明,单独秸秆还田显著提高了土壤有机碳及活性碳组分(如溶解性有机碳(DOC)和富里酸(FA))含量,但对土壤DTPA-Zn的扩散迁移及Zn形态转化影响甚微。单施Zn肥通过提高松结有机态Zn(Lom-Zn)含量及其在全Zn中的分布,显著改善了土壤DTPA-Zn含量及扩散迁移能力;但是,其扩散的DTPA-Zn却主要被限制在非施肥区15 mm以内(45 d),这可能与外源Zn在石灰性土壤上的无效化有关。当秸秆还田与Zn配施时,土壤DTPA-Zn和各形态Zn含量与单施Zn肥相似,但DTPA-Zn的最远扩散距离可达非施肥区20 mm(45 d)处,且累积扩散量和扩散比率均高于单独施Zn。秸秆还田配施Zn肥施肥区土壤活性碳组分(DOC和FA)含量的提升,有效地抑制了外源Zn向无效态组分(残渣态)转化,进而提高了土壤DTPA-Zn的含量及扩散迁移能力。可见,在秸秆还田条件下,土壤施Zn是一种有效提升石灰性土壤有效Zn含量同时兼顾Zn扩散迁移能力的重要措施。【Objective】Zinc（Zn）deficiency in humans caused by inadequate dietary intake is a nutritional problem, which affects approximately two billion people all over the world. It is well known that low zinc（Zn）availability in soil is an important reason for low Zn content of cereal grain, consequently resulting in Zn malnutrition in humans who rely mainly on cereals as staple food. Organic carbon in soil, especially its labile fraction, plays a decisive role in Zn translocation and transformation through changing soil chemical properties（i.e. pH and carbonate）and complexing and chelating Zn, of which the latter is one of the most important factors controlling solubility and mobility of Zn in the plant-soil system. Nowadays in China, the major approach to improvement of quantity and quality of soil organic carbon in cereal cropland is to incorporate crop straw, instead of the traditional organic manure and compost. When straw is incorporated, changing soil labile organic fractions, soil Zn responds correspondingly in diffusive translocation and transformation, of which the mechanism is still unclear in calcareous soils. 【Method】 In view of the above-mentioned scientific issue, an incubation experiment was carried out in greenhouse, using the half-cell device to evaluate effect of crop straw return on Zn availability（diethylenetriamine penta–acetic extractable Zn, i.e. DTPA-Zn） Zn diffusion and Zn transformation in calcareous soil. The soil treated with ground maize straw（0, 15 g kg^（-1） soil）and/or Zn SO4·7 H2 O（0, 20 mg Zn kg^（-1） soil） was placed in the 10-mm central compartment of the device, leaving the lateral compartments packed with untreated soil. After 45 days of incubation, the soils in the central cell and lateral compartments were collected with a frozen microtome for analysis of soil DTPA-Zn, total Zn, Zn fractions, soil organic carbon and its fractions（i.e. dissolved organic carbon and its SUVA254, humic substances, and fulvic and humic acids）【Result】Straw

关 键 词：土壤DTPA-Zn 扩散池 Zn分组 腐殖质 活性有机碳 

分 类 号：S158.5[农业科学—土壤学]