会同退耕还林不同造林模式下土壤有机碳分布特征

Distribution Characteristics of Soil Organic Carbon in Huitong as Affected By Different Afforestation Models for Conversion of Cropland to Forestland

对会同县退耕还林工程5种造林模式(马尾松林、樟树林、杜英樟树林、杜英+乐山含笑林、乐山含笑+红花木莲林)下土壤密度、含水量、吸湿水、有机碳含量及碳储量进行了比较分析.结果表明:不同造林模式下土壤密度、含水量、吸湿水、有机碳含量存在显著差异,土壤有机碳含量随着土壤深度的增加而减少,土壤碳储量表现为乐山含笑+红花木莲林(119.483 t/hm2)>杜英樟树林(104.792 t/hm2)>杜英+乐山含笑林(104.547 t/hm2)>樟树林(97.983 t/hm2)>马尾松林(74.497 t/hm2).混交林模式比单一树种模式更有利于增加土壤有机碳含量及改善土壤结构,乐山含笑+红花木莲林在增加碳储量、改善土壤结构方面具有较大的潜力.

This paper made a characteristic study, in Huitong, Hunan Province, of the soil particle density, soil water content, soil hydroscopic water and soil carbon storage of different plantations afforested by different models for conversion of cropland to forestland. The results show that many differences of soil particle density, soil water content, soil hydroscopic water and soil carbon storage exist under the models. The soil organic carbon contents decrease with the increase of soil depth. The storage comparison results of organic carbon at the same depth show that the organic carbon storage of Michelia chapensis and Manglietia insignis （Wall.） B1. forest is the highest and that of Pinus massoniana forest is the lowest. The calculated results of soil organic carbon reserve go as follows： the soil organic carbon reserve of Michelia chapensis and Manglietia insignis （Wall.） B1. forest is 119. 483 t/hm^2, that of Elaeocarpus sylvestris （Lout.） Poir and Cinnamomum camphora 104. 792 t/hm^2, that of Elaeocarpus sylvestris （Lout.） Poir and Michelia chapensis 104. 547 t/hm^2, that of Cinnamomum camphora 97. 983 t/hm^2, and that of Pinus massoniana 74. 497 t/hm^2. According to the above statistics, the paper concludes that afforestation of mixed forest is an effective measure for increasing soil organic carbon accumulation, forest of Michelia chapensis and Manglietia insignis （Wall.） B1. being the best example.