Weeds in slash‐and‐burn rice fields in northern Laos
Weeds in slash‐and‐burn rice fields in northern Laos
复制标题
老挝北部刀耕火种稻田杂草丛生
DOI：
10.1046/j.1365-3180.1996.d01-6.x
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发表时间：
1996
期刊：
影响因子：
1.7
通讯作者：
B. Keobulapha
中科院分区：
文献类型：
--
作者：
W. Roder;S. Phengchanh;B. Keobulapha
总结
老挝北方刀耕火种的农民认为杂草、降雨不足和鼠害是高地最重要的制约因素。生产140-190天/公顷的人工投入用于除草，导致劳动生产率低。飞机草（Chromolaenaodorata（L.）King和罗宾逊，胜红蓟，鸭跖草属，海金沙（Lygodium flexuosum（L.）开关：和黄麻属（Corchorus spp.）在1930年代引进的Chromoiaena odorata已成为主要的休闲物种，并被大多数农民认为是理想的休闲植物。1950年代、1970年代和1992年报告的平均休耕期分别为38年、20年和5年。在过去的几十年里，休耕期的减少使除草需求明显增加。水稻收获后，水稻茎、草本植物和树木的地下生物量在1991年分别为168、67和60 gm-2，1992年分别为115、43和24 gm-2。每隔14天除草并不增加水稻产量。
Summary
Slash-and-burn farmers in northern Laos consider weeds, insufficient rainfall and rodent damage as the most important constraints to upland rice (Oryza sativa L.) production. Labour inputs of 140-190 days ha-1 for weed control result in low labour productivity. Average weed cover observed in rice fields was 5.6, 4.1, 2.1, 1.7, 0.7 and 0.7 cm m-1 (transect) for Chromolaena odorata (L.) King and Robinson, Ageratum conyzoides L., Commelina spp., Lygodium flexuosum (L.) Sw., Panicum trichoides Sw. and Corchorus spp, respectively. Chromoiaena odorata, which was introduced in the 1930s, has become the main fallow species and is considered a desirable fallow plant by most farmers. Average fallow periods reported for the 1950s, 1970s and 1992 were 38, 20 and 5 years respectively. Reduced fallow periods in the last decades have re-suited in a marked increase in weeding requirements. Above-ground biomass for rice stem, herbaceous plants and trees after rice harvest was 168, 67 and 60gm-2 in 1991 and 115, 43 and 24 gm-2 in 1992. Weeding at 14-day intervals did not increase rice grain yield.