长期施用有机肥对草甸碱土碳库管理指数的影响

基于1995年在黑龙江省大庆市肇州县进行的长期定位试验，研究了长期施用有机肥对草甸碱土活性有机质和碳库管理指数的影响。采用3种浓度的KMnO₄(33，167，333mmol/L)氧化法测定了土壤高活性有机质、中活性有机质和活性有机质3部分含量。结果表明，长期施用有机肥能增加草甸碱土活性有机质各组分含量和碳库管理指数。活性有机质各组分含量和碳库管理指数在施用有机肥1~5a的处理间均呈上升的变化趋势，并与玉米产量趋势相一致，在施用有机肥第5a时，均达到最高值，施用有机肥5~16a的处理间，均呈现逐渐下降趋势，最终趋于稳定。中活性有机质和活性有机质与总有机质均达到极显著性正相关，而高活性有机质与总有机质无显著性相关，活性有机质各组分与碳库管理指数也均达到极显著性正相关。研究表明，总有机质不能很好地评价草甸碱土的土壤肥力，而中活性有机质、活性有机质和碳库管理指数能更为客观地反映草甸碱土的土壤肥力，可作为草甸碱土改良的良好评价指标。

Effects of Long-term Application of Organic Manure on Carbon Management Index in Meadow Alkaline Soil

Based on a long-term experiment in Zhaozhou County,Daqing City,Heilongjiang Province in 1995,the effects of long-term application of organic manure on labile organic matter(LOM) and carbon manage- ment index(CMI)were studied,which supplies evaluation indicators for improving meadow alkaline soil.Highly labile organic matter(HLOM),middle labile organic matter(MLOM) and LOM were determined using oxidation method at 3 KMnO₄,concentrations(33,167 and 333 mmol/L).Results from the experiment indicated that LOM concentrations and CMIs were significantly increased by long-term application of organic manure in meadow alkaline soil.Each component of LOM concentrations and CMIs were increased by applicanon of organic manure,and were consistent with crop yield increasing,respectively.After the 5 years of application of organic manure,each component of LOM concentrations and CMIs reached the highest values,respectively.But each component of LOM concentrations and CMIs were gradually decreased and finally stabilized.There were significant positive correlations among MLOM and LOM and total organic matter(TOM),but no correlation between HLOM and TOM.There was also highly significant positive correlation between each component of LOM and CMIs.The study indicates that TOM cannot be used as a good indicafor of soil fertility in meadow alkaline soil.MLOM,LOM and CMI objectively reflect soil fertility in meadow alkaline soil and thus may be used as indicators for improving the soil.