不同耕作制度下稻田土壤有机碳垂直分布季节变化及其影响因素——以海南省定安县为例

Seasonal Variations and Influencing Factors of Vertical Distribution of Soil Organic Carbon in Paddy Fields Under Different Cultivation Systems:Take Ding’an County,Hainan Province as Example

【目的】本文研究了不同耕作制度下稻田土壤有机碳在0~30 cm土层中垂直分布的季节变化特征。【方法】选择了海南省定安县4种不同耕作制度下的稻田(一熟制、二熟制、三熟制、撂荒地)为研究对象,对比分析其土壤有机碳和易氧化有机碳在不同季节0~30 cm土层中的垂直分布差异。【结果】研究区二熟制和三熟制稻田在不同季节各个土层中有机碳和易氧化有机碳的含量都高于一熟制和撂荒地。一熟制稻田受土壤理化性质的影响,各个季节土壤有机碳和易氧化有机碳在垂直方向上差异显著。旱季有利于表层易氧化有机碳的累积,雨季有机碳分解速率高,不利于有机碳固存。【结论】一年内不同季度稻田土壤有机碳的垂直分布存在差异,这与土壤自身的理化性质和耕作制度的选择存在一定相关性。

【Objective】The present paper aimed to understand the seasonal variation characteristics of the vertical distribution of soil organic carbon in the 0-30 cm soil layer of different farming systems.【Method】Four paddy fields(one-cropping system,two-cropping system,three-cropping system and abandoned land)in Ding’an county,Hainan province were selected as the research objects,the comparative analysis of the vertical distribution difference of soil organic carbon and easily oxidized organic carbon in the 0-30 cm soil layer in different seasons was conducted.【Result】The contents of organic carbon and easily oxidized organic carbon in the soil layers of the two-cropping and three-cropping rice fields in the study area in both four seasons were higher than those in the one-cropping and abandoned land.One-cropping system rice field was affected by the physical and chemical properties of the soil,and its soil organic carbon and easily oxidized organic carbon had significant vertical differences in different seasons.The dry season was conducive to the accumulation of oxidizable organic carbon in the surface layer,and the high decomposition rate of organic carbon in the rainy season was not conducive to the storage of organic carbon.【Conclusion】There were differences in the vertical distribution of soil organic carbon in paddy fields in different seasons within a year,which was related to the physical and chemical properties of the soil and the choice of farming systems.