长期施肥下红壤性水稻土有机碳储量变化特

研究了1982—2012年长期不同施肥下红壤性水稻土土壤有机碳含量变化、固碳趋势及外源碳输入对土壤固碳的贡献.结果表明： 施肥能提高土壤有机碳含量，连续30年不同施肥后，各施肥处理土壤有机碳含量趋于稳定，有机无机配施的土壤有机碳含量为21.02～21.24 g·kg^-1，增加速率为0.41～0.59 g·kg^-1·a^-1，单施化肥的土壤有机碳含量为15.48 g·kg^-1.各有机无机肥配施处理土壤的平均有机碳储量为43.61～48.43 t C·hm^-2，历年平均土壤有机碳储量显著大于单施化肥处理.土壤固碳速率与年均投入碳量呈显著指数正相关.本试验条件下，每年需要增加外源有机碳为0.12 t C·hm^-2才能维持土壤有机碳的平衡.

Variation characteristics of soil carbon sequestration under long-term different fertilization in red paddy soil.

The objective of this study was to clarify the changes of soil organic carbon （SOC） content, the saturation capacity of soil carbon sequestration and its cooperation with carbon input (crop source and organic fertilizer source carbon) under long term (1982-2012) different fertilization in red paddy soil. The results showed that fertilization could increase SOC content. The SOC content of all the fertilization treatments demonstrated a trend of stabilization after applying fertilizer for 30 years. The SOC content in the treatments applying organic manure with mineral fertilizers was between 21.02 and 21.24 g·kg^-1, and the increase rate ranged from 0.41 to 0.59 g·kg^-1·a^-1. The SOC content in the treatments applying mineral fertilizers only was 15.48 g·kg^-1. The average soil carbon sequestration in the treatments that applied organic manure with mineral fertilizers ranged from 43.61 to 48.43 t C·hm^-2, and the average SOC storage over the years in these treatments was significantly greater than those applying mineral fertilizers only. There was an exponentially positive correlation between C sequestration efficiency and annual average organic C input. It must input exogenous organic carbon at least at 0.12 t C·hm^-2·a^-1 to maintain the balance of soil organic carbon under the experimental conditions.