不同耕作方式对玉米田土壤有机碳含量的影响

Effects of different tillage methods on soil organic carbon content in a summer maize field

在华北夏玉米生产体系中,采用田间试验,研究了撂荒、翻耕、免耕和旋耕4种耕作方式下,玉米4个生育期（苗期、拔节期、灌浆期、成熟期）耕层（0~20 cm）土壤总有机碳质量分数、活性有机碳质量分数和碳库管理指数的变化。结果表明：在观测期间,玉米不同生育期（0~20 cm）土层有机碳质量分数和活性有机碳质量分数均呈明显的动态变化,就3种耕作方式来讲,土壤总有机碳和活性有机碳均表现为免耕最高,翻耕和旋耕次之;成熟期免耕、旋耕、翻耕3种处理的土壤碳库管理指数比撂荒分别提高了47.38%、30.43%、27.00%;土壤活性有机碳与总有机碳、碳库管理指数均存在显著相关关系,玉米产量与土壤总有机碳质量分数存在显著相关性,与土壤活性有机碳质量分数和土壤碳库管理指数无明显相关性。综合考虑以上因素,免耕有利于提高土壤有机碳质量分数和土壤碳库管理指数,改善土壤质量,提高土壤肥力。

As an essential indicator of soil quality, soil organic carbon （SOC） and its carbon pool management index （CPMI） had an important role in determining the reasonableness of tillage method. The field experiment was conducted to study the change of different tillage methods （abandoned, conventional, no-tillage, rotary） in SOC, active organic carbon （LOC） and CPMI in four growing stages （seedling, jointing, filling, maturing） under a summer maize cropping system in North China. The results showed that there were obvious changes in the SOC and LOC in 0-20 cm soil layer during the experiment period of summer maize, treatment with no-tillage had higher SOC content and LOC content than conventional and rotary tillage. No-tillage, rotary and conventional tillage increased CPMI in comparison with abandoned by 47.38%, 30.43%, 27.00% respectively in soil at maturing stage. The content of LOC in soil was significantly positively correlated with the content of SOC and CPMI. The corn grain yield was significantly positively correlated with the content of SOC, no significantly correlated with the content of LOC and CPMI. In conclusion, no-tillage method can both increase SOC content and improve CPMI, favoring soil quality melioration and soil fertility improvement.