南亚热带土壤温度动态变化特征及其意义

Dynamic Changes of Soil Temperature in the South Subtropical Region and the Significance

根据定位系统观测资料，阐述了南亚热带山地常绿森林区、丘陵旱作区和平原水稻区多种土壤的温度变化与气温的关系。观测研究结果表明：低山常绿森林区温度的三维空间差异比丘陵区、平原区大，丘陵区又比平原区大；南亚热带林区的气温、地表温、30cm土温比中亚热带的高，比热带的低：南亚热带林区的谷地气温高于针叶林、混交林和阔叶林，谷地地表温低于针叶林而高于混交林和阔叶林，谷地20m土温低于针叶林、混交林而高于阔叶林；在气温一致的丘陵区栽植植物不同，其地表温、土温略有差异；在平原水稻土区，年气温、地表温、20cm土温差异不大，但30cm以下土温渐显差异；不同地貌单元的气温、地表温和土温的年际差异、年平均温度、各月及0～12～24时的温度动态变化各具特征。根据气温与植物生长的关系，拟把气温＞22℃的4～10月称热季、气温＜22℃的1～3月及11～12月称作凉季。可因地制宜，根据气温和土温的变化特征与土壤水分和作物生长的关系，采取措施调节温度，以利于作物生长。

Based on the systematic Observational data,this paper deals with the dynamic changes of soil temperature under evergreen forest, upland of hills and rice production region on the plain of the Pearl River Delta; and discusses the effects of atmosphere temperature on the changes of the soil. Results showed that the difference in three dimension of temperature under ever-green forest region was larger than that in hills and plain region. It was found that the atmosphere temperature of the valley part of the south subtropical forest region was higher than that under coniferous, mixed or broad-leave forest;the surface temperature of the valley part is lower than that under coniferous forest but higher than that under mixed or broad-leave forest; the temperature of 20cm depth of soil layer of valley part was lower than that under coniferous and broad-leave forests but higher than that under broad-leave one. In the hills region with the same atmosphere temperature,there was still a slight difference in temperature of surface and soil layer due to differences in cultivated plants; while on the plain region almost no difference in annual atmosphere temperature, surface temperature and temperature in 20cm depth of soil layer was found. It indicated that there was clear difference in the temperature of atmosphere, soil surface and soil layer and its dynamic changes under different geomorphologic regions. Based on the research results, it is suggested that a year can be divided into two seasons, namely hot season with averege temperature >22℃ and cold season with average temperature <22℃; effective measures should be taken to regulate the soil temperature in order to satisfy the needs of normal growth of plants.