Relationships between soil, fallow period, weeds and rice yield in slash-and-burn systems of Laos
Relationships between soil, fallow period, weeds and rice yield in slash-and-burn systems of Laos
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DOI：
10.1007/bf00017672
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发表时间：
1995-09
期刊：
影响因子：
4.9
通讯作者：
W. Roder;S. Phengchanh;B. Keoboulapha
中科院分区：
文献类型：
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作者：
W. Roder;S. Phengchanh;B. Keoboulapha
休耕期缩短加速了土壤肥力的下降，预计这将是老挝北方刀耕火种水稻生产系统的主要制约因素。本文阐述了休闲期、土壤肥力参数、杂草与水稻产量的关系。农民不认为土壤贫瘠是限制产量的主要因素。在所观测的土壤参数中，只有土壤有机质与水稻产量呈显著正相关（r= 0.42，p <0.01）。休闲时间与水稻产量无相关性，休闲时间与有机质含量的相关性很弱（r= 0.16，p <0.01）。水稻产量与胜红蓟和曲叶海金沙密度呈负相关。种植期间的土壤流失量为300-29.300千克/公顷。同期0- 3cm土层有机质、全氮、速效磷和速效钾含量分别下降了11%、12%、17%和17%，0-25 cm土层全氮损失量估计为400 kg ha−1。土壤物理性质、水分胁迫和速效氮是影响水稻产量的主要因素。进一步将土壤特性与水稻产量联系起来的尝试应包括在种植季节进行重复测量和对土壤物理特性的观察。
Decline in soil fertility accelerated by shorter fallow periods was expected to be a major constraint in slash-and-burn rice production systems in northern Laos. In this paper we describe relationships between fallow period, soil fertility parameters, weeds and rice yield. Soil infertility is not perceived a major yield constraint by the farmers. Of the various soil parameters observed only soil organic matter showed consistent association with rice yield (r=0.42,p<0.01). Fallow period and rice yield showed no association and the relationship between fallow and organic matter was very weak (r=0.16,p<0.01). Rice yield was negatively related to densities ofAgeratum conyzoidesandLygodium flexuosum. Soil loss during the cropping period ranged from 300–29.300 kg ha−1. For the same period organic matter, total N, available P and available K content in the top 0–3 cm decreased by 11,12,17, and 17%, respectively, and loss of total N for the soil depth of 0–25 cm was estimated at 400 kg ha−1. Soil physical properties, moisture stress and available N are the most likely detriments to rice yields. Further attempts to relate soil properties to rice yield should include repeated measurements during the cropping season and observations on soil physical properties.