轮作草地土壤碳蓄积与矿化动态特征  

Dynamic Characteristics of Soil Carbon Accumulation and Mineralization in Rotational Pasture

作　　者：林栋[1,2] 张德罡 McCulley Rebecca L.[2] 周生伟 LIN Dong;ZHANG De-gang;McCulley Rebecca L.;ZHOU Sheng-wei(College of Grassland Science,Gansu Agricultural University,Lanzhou,Gansu Province 730070,China;Department of Plant and Soil Sciences,University of Kentucky,Lexington,KY 40546-0091,USA;College of Science,Gansu Agricultural University,Lanzhou,Gansu Province 730070,China)

机构地区：[1]甘肃农业大学草业学院,甘肃兰州730070 [2]美国肯塔基大学植物与土壤科学系,肯塔基列克星敦40546-0091 [3]甘肃农业大学理学院,甘肃兰州730070

出　　处：《草地学报》2019年第4期1037-1043,共7页Acta Agrestia Sinica

基　　金：科技部重点研发项目(2016YFC0501900);美国农业部食品与农业孵化项目(1010357);甘肃省高校科研项目(2016A-031)资助

摘　　要：为探明作物-草地轮作系统中草地土壤碳(Carbon,C)蓄积与矿化动态特征,本试验以温带气候区有机农牧场低投入蔬菜生产后的5年草地轮作土壤为研究对象,测定不同轮作年限和季节土壤有机碳(Soil Organic Carbon,SOC)及其颗粒有机碳(Particulate Organic Carbon,POC)和非颗粒有机碳(non-Particulate Organic Carbon,n-POC)组分含量,并对土壤C矿化潜力进行分析。结果表明,草地轮作年限显著影响SOC含量(P<0.01),季节对草地SOC含量无显著影响;SOC含量从草地建植初期的17.31 g·kg^-1增加到第5年的20.88 g·kg^-1,且接近永久性草地SOC含量;POC敏感指示土壤有机C库变化动态,草地生长年限显著影响土壤POC和n-POC组分变化(P<0.01),草地建植5年POC含量增加了53.5%,n-POC含量增加17.6%,春季草地土壤n-POC含量显著高于夏季和冬季;草地轮作4年后土壤C矿化率显著升高,并接近永久性草地水平;秋季草地土壤在71 d的培养期内平均C矿化速率为5.9μg·g^-1·d^-1,显著低于其他季节。草地轮作增强了土壤C矿化潜力,提高了土壤C循环强度和有机C有效性,同时延长了SOC半衰期,对增加土壤C库容量和稳定性具有重要作用。In order to explore the dynamic characteristics of soil carbon(C)accumulation and mineralization in crop-pasture rotation system,the changes of soil organic carbon(SOC),particulate organic C(POC)and non-particulate organic C(n-POC)concentrations and the potential soil C mineralization(CM)in a five-year vegetable-pasture rotational agroecosystem in a low-input organic farm in temperate climate area were studied.The results showed that pasture rotational year significantly affected SOC content(P<0.01),but season did not.SOC content increased over 5 years in pasture rotation from 17.31 to 20.88 g kg^-1 soil,and was close to that in the permanent pasture.POC content sensitively indicated the change of SOC pool.Time for pasture growing significantly affected SOC fractions(P<0.01),and POC and n-POC increased by 53.5%and 17.6%after 5 years pasture growing.Season did not affect SOC and POC contents.However,n-POC content was significantly affected by season,and it was 18%higher in spring than summer and winter.The soil CM rate significantly increased after 4-year rotation and was close to the average level of permanent pasture.The average soil CM rate in autumn was 5.9μg·g^-1·d^-1 in 71-day incubation period,which was significantly lower than those in other seasons.Because the pasture rotation enhanced soil CM potential,promoted C cycling rate and SOC availability,and delayed half-life time of SOC,it played an important role in the capacity increasing and stabilization of soil C pool.

关 键 词：碳蓄积 颗粒有机碳 碳矿化 轮作草地 

分 类 号：S812.2[农业科学—草业科学]