Avocado root distribution in fine and coarse-textured soils under drip and microsprinkler irrigation
Avocado root distribution in fine and coarse-textured soils under drip and microsprinkler irrigation
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DOI：
10.1016/j.agwat.2008.02.005
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发表时间：
2008-07
影响因子：
6.7
通讯作者：
Eduardo Salgado;R. Cautín
中科院分区：
文献类型：
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作者：
Eduardo Salgado;R. Cautín
果园中常见的灌溉计划问题是用于监测活跃根区土壤水分含量的仪器的正确位置。鉴于田间土壤的高度空间变异性，以及果园内和树木周围根系分布和频率的季节性变化，土壤水测量的准确性和代表性可能会受到强烈影响。因此，对果园进行充分的土壤水监测需要在较长时间内评估给定位置的活性根的变化和位置。我们检查了嫁接到“Mexicola”幼苗砧木上的 12 年生“Hass”鳄梨（Persea americana Mill.）树的根系，这些树在智利中部的滴灌或微喷灌系统下生长在细质或粗质土壤中。春、夏、秋三季在树行内挖长3m、深0.75m的沟渠，统计树壁上发现的活跃根系（白色，直径≤2mm）。在我们研究的三个生长季节中，季节对根分布的影响最显着，因为秋季根频率约占累积平均值的一半。此外，秋季微喷头下根部最集中的位置在细土和粗土之间存在明显差异，细土位于距离树干约 200 厘米，深度为 50-60 厘米，而粗土则位于距离树干 30 厘米以内，在土壤的前 25 厘米内。细土中的树木比粗土中的树木多出 25%，滴灌比微喷灌产生的根多约 30%，尽管这两个数字主要是由于细土和滴灌组合中的根数较多。总体而言，我们发现对于所有组合，距树干第一米内的根部频率最高，但灌溉类型之间存在一些差异。在半干旱地区的整个生长季节，树根的数量和根系活动最大的区域的位置都会发生一些变化，这些变化会根据季节性土壤温度、土壤质地和灌溉类型而变化。
A common irrigation-scheduling problem in orchards is the proper location of instruments for monitoring soil water content within the active root zone. Given the high spatial variability of soils in the field, and seasonal changes in root distribution and frequency, both within the orchard and around the trees, the accuracy and representativeness of soil water measurements can be strongly affected. Adequate soil water monitoring in orchards thus requires assessment of the variability and location of the active roots in a given location over an extended period of time. We examined the root systems of 12-year-old ‘Hass’ avocado (Persea americana Mill.) trees grafted on ‘Mexicola’ seedling rootstocks, growing in fine or coarse-textured soils, under either drip or microsprinkler irrigation systems in Central Chile. We dug 3m long and 0.75m deep trenches within the tree rows in spring, summer and autumn, and counted the active roots (white, diameter ≤2mm) found on the walls. Over the three growing seasons of our study, season had the most significant effect on root distribution, as autumn root frequencies accounted for about half of the cumulative average. Also, the location of the highest concentration of roots under microsprinklers in autumn clearly differed between the fine soils, at about 200cm from the trunk and 50–60cm deep, and coarse soils, where they were found within 30cm from the trunk, and within the first 25cm of soil. Trees in fine soil had 25% more roots than those in coarse soil, and drip irrigation produced about 30% more roots than microsprinkler, although both of these figures are mainly due to the high number of roots found in the fine soil-drip irrigation combination. Overall, we found the highest root frequency within the first meter from the tree trunk, for all combinations, with some differences between irrigation types. Throughout the growing season in semi-arid regions, some changes in both the quantity of tree roots and the location of the zones of the greatest root activity should be expected, which will vary according to the seasonal soil temperatures, soil texture, and type of irrigation used.