摘要
以稻田免耕长期定位试验站为平台,研究不同耕作方式对紫色水稻土有机碳以及易氧化有机碳剖面分布的影响。结果表明:连续耕作20年后,不同耕作处理稻田剖面(0～60cm)中有机碳含量随着采样深度加深而降低,土壤有机碳含量最高值和最低值分别出现在垄作免耕(稻油)表层(0～10cm)和水旱轮作(稻油)底层(40～60 cm),其中垄作免耕(稻油)处理中0～10 cm和10～20 cm土层有机碳含量和常规平作(中稻)、垄作免耕(中稻)之间差异并不显著,但其20～40cm土层有机碳含量则显著高于其他耕作处理(P<0.05),表明长期耕种20年后,耕层(0～20cm)土壤有机碳含量已趋于平稳;另外,同传统耕作处理相比,长期垄作免耕(稻油)的固碳潜力主要表现在20～40cm土层。常规平作(中稻)和垄作免耕(中稻)处理剖面土壤易氧化有机碳含量均随土层加深而降低,而垄作免耕(稻油)和水旱轮作(稻油)则分别在20～40cm和10～20cm土层出现易氧化有机碳含量增加的现象,表明耕作和轮作方式对土壤有机碳稳定性具有明显的影响。对不同耕作处理稻田土壤有机碳与易氧化有机碳、易氧化有机碳分配比例之间的关系分析,其一元线性回归方程分别为:y=1.990 1x+6.521 4,R=0.881 9,n=16;y=0.270 4 x+7.345 7,R=0.542 2,n=16,表明稻田土壤易氧化有机碳与其有机碳关系密切,可用于表征该区域土壤碳库的变化大小。
Effect of different tillage systems on distribution of soil organic carbon（SOC） and readily oxidation carbon（ROC） in profiles of long term experiment site（since 1990） were studied.The experiment included four tillage treatments： plain-cultivation（rice）,ridge-cultivation without tillage（rice）,ridge-cultivation without tillage（rice-rape） and plain-cultivation（rice-rape）.The results showed that the contents of SOC decreased gradually with the increase of soil profiles（0-60cm） and the highest and lowest SOC concentrations in different soil layers（0-10cm,10-20cm,20-40cm and 40-60cm） of paddy fields were respectively found in ridge-cultivation without tillage（rice-rape） and plain-cultivation（rice-rape） after different cultivation treatments were conducted for 20 years.SOC concentrations in the 0-10 cm and 40-60cm layers had no significantly difference among ridge-cultivation without tillage（rice）,ridge-cultivation without tillage（rice-rape） and plain-cultivation（rice）.But SOC concentration of ridge-cultivation without tillage（rice-rape） in the 20-40cm layer was significantly higher than other cultivation treatments（P0.05）.It was indicated that SOC concentration of surface layer had reached a plateau and accumulation of organic carbon in the 20-40cm layer was much more obvious in paddy fields under ridge-cultivation without tillage（rice-rape） when compared to traditional cultivation treatments.In addition,ROC concentrations decreased gradually with the increase of soil profiles（0-60 cm） under plain-cultivation（rice） and ridge-cultivation without tillage（rice）.But ROC concentrations increased respectively in 20-40cm and 10-20cm layers under ridge-cultivation without tillage（rice-rape） and plain-cultivation（rice-rape）.The results showed that cultivations and rotation systems for SOC stability had obvious effect.The regression equations of SOC and ROC,SOC and ROC/SOC were also developed.They were as follow： SOC= 1.990 1ROC＋ 6.521
出处
《农机化研究》
北大核心
2013年第1期184-188,共5页
Journal of Agricultural Mechanization Research
基金
国家科技支撑计划项目(2008BAB38B02-3-2)
中央高校基本科研业务费专项资金项目(XDJK2011D002)
关键词
有机碳
垄作免耕
易氧化有机碳
土壤剖面
soil organic carbon
ridge-cultivation without tillagesoil
readily oxidation carbon
soil profile
