胶园间种柱花草的生态适宜性及间作效益评价

在幼、中、成龄胶园中进行了柱花草间种的生态适宜性试验。结果表明，仅幼龄胶园可以间种，间种后土壤肥力略有下降，对胶树生长亦有一定影响，但无显著差异，柱花草产量为全光照的46．5％。中、成龄胶园不宜间种柱花草，原因是：（1）中、成龄胶园内光照太弱，上午10：00平均仅为全光照的13％；（2）中、成龄胶园行间整地后橡胶营养根系生长迅速，密布土壤表层，柱花草无法同其竞争；（3）中、成龄胶园柱花草长势弱，易遭受从橡胶树冠落下的雨滴打击，林地湿度较大，炭疽病十分严重易导致衰败。对Wasana的PER和LER评价公式进行了修正，建立了土壤养分均衡率公式，采用了Wasana的IER经济效益评价公式，对幼龄胶园间作柱花草的效益进行了评价。

Ecological Suitability and Benefit Evaluation of Stylosanthes guianensis Intercropped under Rubber Plantations

An ecological suitability experiment of intercropping Stylosanthes guianensis under rubber plantations has been made for two years. The results showed that Stylosanthes guianensis was able to be intercropped only in young rubber plantations and yielded only 46.5% of that in full-lighted conditions. The soil fertility in the intercroppingplantations declined to some extents. The rubber trees grew slower than the control, butthere was no significant difference betWeen them. In premium rubber plantations, weakradiation, strong rubber root system, and prevalence of anthracnose due to wet conditionsresulted in poor growth or death of Stylosanthes guianensis, and hence unsuitability forintercropping.Wasana's general benefit evaluation system (LER and PER) was modified in this paper. A new formula of soil nutrient equivalent ratio (SNER) was put forward. The general benefits and economic benefit of intercropping Stylosanthes guianensis under youngrubber plantations were evaluated by using the modified formula (LER and PER), SNERand Wasana's IER formula, which produced satisfactory results.