Water Competition of Intercropped Pearl Millet with Cowpeaunder Drought and Soil Compaction Stresses
Water Competition of Intercropped Pearl Millet with Cowpeaunder Drought and Soil Compaction Stresses
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DOI：
10.1626/pps.9.123
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发表时间：
2006-01
影响因子：
2.5
通讯作者：
W. Zegada‐Lizarazu;Yasuhiro Izumi;M. Iijima
中科院分区：
文献类型：
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作者：
W. Zegada‐Lizarazu;Yasuhiro Izumi;M. Iijima
摘要珍珠粟与豇豆间作是半干旱地区常见的一种作物。在有限的水分环境下，间作植物之间对土壤水分的竞争可能很强。此外，由于重型机械的使用，土壤压实问题日益严重，可能加剧对有限资源的竞争，特别是对表土的竞争。在2004年日本夏季进行了两个田间试验，以评估在干旱和土壤压实条件下间作珍珠粟的水分竞争能力。为此目的，植物水源确定的氢稳定同位素（氘）技术。植物水分关系和生物量生产也进行了评价。根据木质部汁液中氘浓度值，珍珠粟与豇豆的竞争改变了水分来源。珍珠粟被迫更多地依赖最近供应的（灌溉/降雨）水。与此相反，豇豆的水源是不变的植物竞争。当植物遭受干旱时，珍珠粟的蒸腾速率因竞争而降低其单作潜力的40%，而豇豆则不是。此外，间作珍珠粟，在干旱和土壤压实，表现出较低的叶水势和生物量比各自的单作同行。豇豆有较高的竞争比在湿，干，压实处理，而珍珠粟在松散的条件下更具竞争力。总之，在干旱和土壤紧实条件下，水分竞争限制了间作珍珠粟的水分利用，迫使珍珠粟转向最近供应的水分。与此相反，豇豆在这些压力条件下没有表现出任何显着的变化。
Abstract Intercropping pearl millet with cowpea is a common practice in semiarid areas. Under limited water environments, competition for soil water between intercropped plants may be strong. Furthermore, the increasing soil compaction problems, due to the use of heavy machinery, may intensify competition for limited resources, particularly in the topsoil. Two field trials were conducted to evaluate the water competition ability of intercropped pearl millet when subjected to drought and soil compaction during the 2004 Japanese summer. For this purpose plant water sources were determined by the hydrogen stable isotope (deuterium) technique. Plant water relations and biomass production were also evaluated. According to the deuterium concentration values in xylem sap, pearl millet water sources were changed by the competition with cowpea. Pearl millet was forced to rely more on recently supplied (irrigation/rainfall) water. In contrast, the water sources of cowpea were unchanged by plant competition. When plants were subjected to drought, the transpiration rate of pearl millet was reduced by 40 % of its monocropped potential by competition, but that of cowpea was not. Moreover, intercropped pearl millet, under drought and soil compaction, showed lower leaf water potential and biomass than their respective monocropped counterparts. Cowpea had a higher competitive ratio under wet, dry, and compaction treatments, while pearl millet was more competitive under loose conditions. In conclusion, under drought and soil compaction, water competition restricted the water use of intercropped pearl millet, forcing pearl millet to shift to the recently supplied water. In contrast, cowpea did not show any significant changes under these stress conditions.