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在南非亚热带德兰士瓦东北部的 Levubu,土样采用重量分析法测定,以获得夏秋冬春威廉士香蕉的水分利用系数(Et/Eo)。采样在成龄蕉园中进行(种植密度1666株/公顷);灌溉系统为株冠下的喷水器,在连续灌溉前后采集重复土样.50cm 土层剖面的总水分损失(Et)与采样之间的总蒸发损失(Eo)有关。在有效水分耗损54%的条件下,Et/Eo 的季节性变化从冬季的0.57至夏季的1.01。总水分损失的垂直分布大致是:10cm 土层为40%,而30cm 土层为80%.这表明,香蕉根系具有一种浅的水分抽礅模式。根系观察室的研究表明,20cm 深度的最低土温与威廉士香蕉新根生长量呈高度相关性(R~2=84%;p<0.001)。在亚热带地区的冬季,Et/Eo 的降低,也许可用土温低引致根系生长差及水分抽取潜力来解释。对以上结果的讨论与蕉园灌溉措施有关.Et=香蕉园植株蒸腾作用及土壤蒸发作用的水分损失(mm);Eo=A 级蒸发皿的蒸发量;Et/Eo=蒸发蒸腾比率或作物水分利用系数;LAI=叶面积系数。
In Levubu, Northeastern Transvaal, South Africa, the soil samples were gravimetrically measured to obtain the water use efficiency (Et / Eo) of the banana in summer, Sampling was carried out in adult banana plantations (planting density of 1666 plants per hectare). The irrigation system was a sprinkler under the canopy, and the repeated soil samples were taken before and after continuous irrigation.The total water loss (Et) and sampling Between the total evaporation loss (Eo). Seasonal changes in Et / Eo ranged from 0.57 in winter to 1.01 in summer at 54% effective moisture depletion. The vertical distribution of total water loss is roughly 40% for the 10 cm soil layer and 80% for the 30 cm soil layer, indicating that the banana root system has a shallow water pumping pattern. Studies in the Root Observation Room showed that the lowest soil temperature at 20 cm was highly correlated with the growth of new roots of Williams banana (R ~ 2 = 84%; p <0.001). In the subtropical winter, the reduction in Et / Eo may be explained by the low soil temperature that can lead to poor root growth and water extraction potential. Discussion of the above results is related to banana irrigation Et = water loss from banana plant transpiration and soil evaporation (mm); Eo = evaporation from pan A; Et / Eo = evapotranspiration or crop moisture Utilization factor; LAI = Leaf area factor.