黄土高原旱地不同种植模式土壤碳特征评价  

Evaluation on soil carbon contents under different cropping systems on dryland in Loess Plateau

作　　者：李小涵[1,2,3] 王朝辉[1,3] 郝明德[1,2] 李生秀[1] 

机构地区：[1]西北农林科技大学资源环境学院,杨凌712100 [2]中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,杨凌712100 [3]农业部黄土高原农业资源与环境修复重点开放实验室,杨凌712100

出　　处：《农业工程学报》2010年第S2期325-330,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：农业公益性行业科研专项(200803029);现代农业产业技术体系建设专项;国家自然科学基金项目(30871596和40671107)

摘　　要：增强农田土壤碳固持能力、增加碳贮量是减少温室效应气体排放,提高土壤生产力的重要措施。利用黄土高原23a的定位试验,分层采集休闲、苜蓿连作、玉米连作、小麦连作、豌豆-小麦-小麦-糜子(豆禾)及玉米-小麦-小麦-糜子(禾谷)轮作条件下0～40cm土层的土样,研究了作物种类和种植模式对土壤不同形态碳的影响。结果表明:与休闲相比,不同作物长期连作或轮作显著提高0～40cm土层各种形态碳的质量分数,总碳提高35%～74%,有机碳提高47%～139%,无机碳提高20%～26%,轻质有机碳提高的幅度最大,是休闲的3～11倍。不同种植模式之间,0～15cm的各土层中,土壤总碳、有机碳、轻质有机碳均是苜蓿连作质量分数最高,其次是禾谷或豆禾轮作,玉米或小麦连作较低。无机碳却不同,苜蓿连作仅使0～5cm土层的无机碳增加。随土层深度增加,土壤总碳、有机碳和轻质有机碳均是苜蓿连作下降幅度最大。可见,长期苜蓿连作是增加旱地土壤碳的一种有效措施,特别是有机碳和轻质有机碳,但主要表现在15cm以上的表层土壤。与连作相比,轮作增加土壤碳的作用较强,且不同轮作之间并无显著差异。Enhancement of the carbon sequestration capacity and carbon storage of crop land soil is one of the key measures to reduce the greenhouse gas emission and increase the soil productivity.Soil samples were taken from the 0～40 cm soil layers in the plots of fallow,monocroppings of maize,wheat and alfalfa,and rotations of pea-wheat-wheat-millet and maize-wheat-wheat-millet in a 23 year long-term field experiment.Effects of different crops and cropping systems on different carbon forms were studied in dryland soil.Results showed that compared to fallow,soil carbon contents of monocropping or rotation of different crops all increased,with total carbon increased by 35%～74%,organic carbon increased by 47%～139%,inorganic carbon increased by 20%～26%,and light fraction organic carbon increased by 3～11 times.Over different cropping systems,the alfalfa monocropping had the highest contents of total carbon,organic carbon and light fraction organic carbon in 0～15 cm soil layers,then was the rotation of the cereals-millet and the pea-cereals,and the monocropping of maize and wheat had the lowest contents of these carbon forms.However,alfalfa monocropping only increased the inorganic carbon contents in the 0～5 cm soil layer.With the increase of soil layer depth,the contents of total carbon,organic carbon and light fraction organic carbon were all observed to decrease,and the greatest decrease occurred in the alfalfa monocropping.This indicated that long term monocropping of alfalfa was an effective measure to increase soil carbon in dryland soil,especially for the organic carbon and the light fraction organic carbon.However,this increase effects are found only in the layers above 15 cm soil depth.Rotations show greater potential in increasing soil carbon than monocropping of different crops,while no significant difference is observed between the two different rotations.

关 键 词：轮作 碳 土壤 旱地 连作 

分 类 号：S344[农业科学—作物栽培与耕作技术] S154[农业科学—农艺学]