添加紫云英后2种水稻土的DOC动态特征与差异分析

以福建省2种典型中低产田(红泥砂田和灰黄泥砂田)为研究对象,在15和25℃条件下进行室内模拟淹水培养试验,研究添加等量紫云英后二者的可溶性有机碳(DOC)动态变化特征差异.结果表明:与对照相比,2种温度培养下添加紫云英均显著提高红泥砂田和灰黄泥砂田的DOC含量,2种温度下灰黄泥砂田的DOC含量分别比红泥砂田高29.38%~694.98%和45.40%~471.22%,且二者均呈先增后减、最后趋于稳定的变化趋势;25℃条件下土壤DOC峰值(10 d)较15℃条件下(20d)提前了10 d.可见,中低产水稻土添加紫云英后DOC含量均显著提高,不同肥力水平和培养温度下土壤DOC动态变化规律相似,但其动态特征差异较明显,肥力相对较高的灰黄泥砂田有利于DOC的形成,培养温度升高则加速DOC的形成.

Dynamic characteristics and difference of dissolved organic carbon in two types of paddy soils after Chinese milk-vetch application

Waterlogged incubation experiment was conducted with 2 typical low yield paddy soils, red mud sand and grey yellow sand, at 15 ℃ and 25℃. Changes in dissolved organic carbon (DOC) content after Chinese milk-vetch application were monitored. The results showed that DOC contents in 2 paddy soils applied with Chinese milk vetch increased significantly compared with the control at both 15 ℃ and 25 ℃. DOC contents in grey yellow sand were 29.38%-694.98% (15 ℃) and 45.40%-471.22% (25℃) higher than those in red mud sand. Variation pattern of DOC content for both paddy soils started with dramatic rise and then de-clined gradually, ending up in low levels for latter part of the incubations. DOC level reached the maximum on the 15th day of the experiment when incubated at 25℃, which was 10 d earlier comparing to incubation at 15℃. To summarize, Chinese milk vetch is likely to increase DOC content in waterlogged paddy soil. Change trends of DOC contents in 2 typical paddy soils were similar but grey yellow sand with higher fertility and temperature accelerated DOC formation.