基于净初级生产力的海南天然橡胶产胶潜力研究

以CASA模型为基础,建立基于MODIS数据的天然橡胶林净初级生产力遥感估算模型,利用2009年生长季（4月-12月）250m分辨率的MODIS数据和气象站点的气象数据估算了阳江农场天然橡胶的生长季净初级生产力（NPP）。并通过天然橡胶的干物质分配率计算了阳江农场天然橡胶的产胶潜力,最后以地面实际橡胶干胶产量的时间序列、空间序列与估算的天然橡胶林产胶潜力进行了相关分析。结果表明,阳江农场天然橡胶产胶潜力空间差异显著,且在时间变化上具有明显的季节性规律;产胶潜力与实际干胶产量存在明显的线性关系,表明本研究所采用的天然橡胶林净初级生产力估算模型、产胶潜力估算模型可行。2009年阳江农场全场的产胶潜力为5573t,比实际年干胶产量4572t高出22%,阳江农场干胶产量仍有很大的提升空间。

A Study on Potential Productivity of Natural Rubber in Hainan Province Based on a Net Primary Production Model

The contradictions between the supply and requirement of natural rubber are currently becoming increasingly acute. Hainan Province has become the largest producer of natural rubber. Yangjiang Farm, one of the largest farms in the Hainan State Farms, is located in north-central Hainan Island. The land area and natural rubber plant area of the farm are 14 367 hm² and 5 190 hm², respectively, with the harvested area being 4934 hm². Yangjiang Farm was chosen for this study of the pilot area with an annual output of natural rubber about 4500 t. Based on the Carnegie Ames Stanford Approach (CASA), a net primary productivity model for natural rubber using Moderate Resolution Imaging Spectroradiometer (MODIS) data was developed. This model accounts for effects of temperature and differences in surface water vapor pressure. On the basis of this, the NPP of natural rubber in Yangjiang Farm was calculated using MODIS data of 250 m×250 m spatial resolution in combination with weather station-based meteorological variables from April through December in 2009. Then, the potential productivity of natural rubber in Yangjiang Farm was calculated through the NPP and distribution of dry matter. In general, for the entire farm, the spatial distribution of the potential productivity of natural rubber was affected primarily by hydrothermal conditions and rubber strain, showing marked geographical differences. Meanwhile, seasonal changes in the potential productivity of natural rubber corresponded to the biological characteristics and changes in phenology of natural rubber. Compared the estimates with the final yield by methods of time series and spatial series, a conclusion was drawn that there was an evident linear relation between them. Results show that the two models appear to be essentially feasible. The potential productivity of natural rubber in Yangjiang Farm was 5573 t in 2009, 22% higher than the final yield of 4572 t. This suggests that there is large potential for further increasing the rubber production in Yangjiang Farm. This study would be of importance to increase the production of natural rubber and income of rubber farmers and to protect the environment.