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为探明渭北旱塬不同秸秆覆盖量对春玉米田土壤活性有机碳(LOC)、碳库管理指数(CMI)和作物产量的影响,于2007—2010年在陕西合阳县旱农试验站进行定位试验,以不覆盖为对照(CK),设置了3个水平秸秆覆盖量处理:4 500 kg/hm2(S1)、9 000 kg/hm2(S2)和13 500 kg/hm2(S3)。结果表明,0～20 cm土层,与CK相比,S1、S2和S3总有机碳(TOC)质量分数分别提高5.08%、14.12%和28.03%(P<0.05);活性有机碳(LOC)分别显著提高19.20%、44.02%和23.50%(P<0.05);碳库管理指数(CMI)分别显著提高20.94%、46.86%和50.21%(P<0.05)。春玉米产量分别与LOC和CMI显著相关(P<0.05),而与TOC则无显著相关性。研究表明,LOC和CMI较TOC更能灵敏、客观地反映渭北旱塬不同量秸秆覆盖还田对土壤碳库质量的影响,且秸秆覆盖量以9 000 kg/hm2为宜。
In order to explore the effects of different straw mulching amount on soil active organic carbon (LOC), carbon stock management index (CMI) and crop yield in the spring maize field in Shaanxi Province, from 2007 to 2010, Positioning experiments were conducted to investigate the effect of straw mulching on CK (CK). Three CK levels were established: 4 500 kg / hm2 (S1), 9 000 kg / hm2 (S2) and 13 500 kg / hm2 (S3). The results showed that the contents of total organic carbon (TOC) in S1, S2 and S3 increased by 5.08%, 14.12% and 28.03%, respectively, compared with CK in 0-20 cm soil layer (P <0.05) (P <0.05). The carbon stock management index (CMI) increased by 20.94%, 46.86% and 50.21% (P <0.05), respectively, significantly increased by 19.20%, 44.02% and 23.50%, respectively. Spring maize yield was significantly correlated with LOC and CMI (P <0.05), but not with TOC. The results showed that LOC and CMI were more sensitive and objective than TOC objectively to reflect the effect of different amount of straw mulching on soil carbon pool quality in Weibei dry land, and the amount of straw mulching was 9 000 kg / hm2.