施用生物有机肥对黄瓜连作土壤有机碳库和酶活性的持续影响

采用田间定位试验和室内培养试验相结合的方法,研究了一次性施用生物有机肥对黄瓜连作土壤有机碳组分、有机碳矿化和酶活性的持续效应.结果表明: 连续种植4季黄瓜过程中,与对照处理(CK)相比,施用生物有机肥可明显增加黄瓜连作土壤总有机碳、活性碳库、缓效碳库和惰性碳库的有机碳含量,且随着黄瓜连作季数的增加,土壤惰性碳库比例逐渐增加;连续种植4季黄瓜后,施用生物有机肥处理中土壤有机碳累计矿化量和日均矿化量与CK相比分别增加了17.3%～31.0%和7.8%～43.0%,且在同一季黄瓜成熟期,施用生物有机肥还能提高黄瓜连作的土壤脲酶、过氧化氢酶、蔗糖酶和磷酸酶(中性)的活性,增幅分别为10.5%～62.1%、4.8%～25.5%、3.9%～21.4%和4.6%～66.4%.相关分析和通径分析结果表明,黄瓜连作过程中4种酶的活性与土壤有机碳各组分动态变化均呈显著相关,且黄瓜连作过程中土壤脲酶和蔗糖酶活性是影响有机碳矿化的主要生物酶.施用生物有机肥可提高黄瓜连作过程中土壤有机碳各组分含量和酶活性,增加土壤惰性碳库比例、有机碳累计矿化量和矿化速率,从而增强土壤固碳能力.

Long-term effects of bio-organic fertilizer application on soil organic carbon pool and enzyme activity of cucumber continuous cropping.

The combination of field trial and indoor incubation experiment were conducted to examine the long-term effects of one-time application of bio-organic fertilizer on soil organic carbon (C) components, organic C mineralization, and enzyme activity in cucumber continuous cropping. Compared with CK, bio-organic fertilizer application significantly increased the content of soil organic C, activated C pool, slow-release C pool and inert C pool during four continuous cucumber planting seasons. With the increases of the number of consecutive crops, the proportion of soil inert carbon gradually increased. After four continuous seasons of cucumber planting, the cumulative and daily mineralization rate of soil organic C in the bio-organic fertilizer treatment increased by 17.3%-31.0% and 7.8%-43.0%, respectively. In the stage of cucumber ripening, bio-organic fertilizer application increased the activities of continuous soil urease, catalase, sucrose and neutral phosphatase by 10.5%-62.1%, 4.8%-25.5%, 3.9%-21.4% and 4.6%-66.4%. The activities of those four enzymes increased with the increases of the application amount of organic fertilizer. Results from the correlation and path analysis showed that the activity of the four enzymes were significantly correlated with the dynamics of organic carbon components in soil cucumber continuous cropping process. Soil urease and invertase activities significantly affected organic carbon mineralization during the continuous cropping process of cucumber. Application of bio-organic fertilizer could increase soil organic carbon content and enzyme activity, improve inert carbon ratio of soil organic carbon pools, cumulative and mineralization rate of organic carbon in continuous cropping process, thereby enhance soil carbon sequestration capacity.