海南岛儋州橡胶林生态系统氮储量研究

生态系统N储量是由乔木层、林下植被层、凋落物层和土壤层N储量组成的。对海南岛儋州6个龄级(5、10、15、20、25、30 a)的橡胶林进行调查采样,并进行室内测试分析得出N含量,计算得出各个层次的N储量和生态系统总N储量。结果表明:(1)儋州一代和二代橡胶林土壤N含量和储量均随着土壤层次的增加而减少,橡胶林土壤N含量和储量均表现为0～20 cm内一代小于二代,20～40 cm内两代相差不大,40 cm以下一代均明显大于二代;(2)儋州橡胶林生态系统总N储量范围为5.30～8.53 t·hm^-2,平均为6.447 t·hm^-2,其中土壤N储量5.727 t·hm^-2,植物(包括乔木和林下植被)N储量为0.694 t·hm^-2,凋落物N储量0.026 t·hm^-2; 土壤N储量所占比例最大(88.83%),是橡胶林生态系统N储量最主要的组成部分。说明海南岛儋州橡胶林土壤总体处于缺氮状态,有必要增施氮肥或复合肥。

Research on nitrogen reserves of rubber forest ecosystem in Danzhou of Hainan Island

Rubber forest ecosystem are consisted of the arborous layer,the understory layer,litter layer and soil layer. The rubber forest in Danzhou of Hainan Island was divided into six age levels,which were investigated by sampling,the nitrogen content indoor was tested and analyzed,and then nitrogen reserves of each layer and ecosystem could be gained. The results were as follows:(1)The soil N contents and reserves of the first generation and second generation rubber plantation in Danzhou all decreased with the increase of soil layer. Those of the first generation were less than the second in 0-20 cm,and these of the first and second generations were almost the same in 20-40 cm,these of the first generation were significantly more than the second under 40 cm;(2)The range of nitrogen stock of rubber plantation ecosystem in Hainan Danzhou was 5.30-8.53 t·hm^-2,the average was 6.447 t·hm^-2,thereinto,the soil was 5.727 t·hm^-2,the vegetation(include arbor and understory)was 0.694 t·hm^-2,the litter was 0.026 t·hm^-2; the soil's nitrogen stock account for the most,reached to 88.83%,and it was the main part of rubber plantation ecosystem's nitrogen stock. The soil of rubber plantations in Danzhou was under the condition of lacking N collectively,it was necessary to fertilize with N or compound fertility.