Water use, competition, and crop production in low rainfall, alley farming systems of south-eastern Australia
Water use, competition, and crop production in low rainfall, alley farming systems of south-eastern Australia
复制标题
澳大利亚东南部低降雨量巷道耕作系统中的用水、竞争和作物生产
DOI：
10.1071/ar03049
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
M. Portelli
中科院分区：
文献类型：
--
作者：
M. Unkovich;K. Blott;A. Knight;I. Mock;A. Rab;M. Portelli
一年生作物在多年生灌木或乔木带之间的小巷中种植了3 - 4年，分布在澳大利亚东南部低降雨量（<450 mm）的3个地点。在两个降雨量较低的地点（Pallamana和Walpeup），距灌木带2-5 m范围内的作物产量随着时间的推移显著下降，在种植的最后一年，超过9 m的作物产量下降了45%。在第三个较湿润的地点（Bridgewater），直到研究的最后一年，当树木生长速度增加时，树木带附近的作物谷物产量的减少才显着减少（11米以上12%）。一旦多年生植物下面的土壤剖面干涸，作物产量的减少与灌木或乔木带与作物之间对水分的竞争加剧有关。在所有3个样地，在建立年，木本多年生植物的水分利用估计值都低于一年生作物，但在此之后，巷子耕作系统的水分利用估计值在不同样地之间存在差异。在Pallamana，多年生灌木在建立后的第二个夏天使用了大量储存的土壤水分，随后主要依赖于降雨以及它们可以从邻近作物下面清除的水分。在Walpeup立地建立年份之后，多年生灌木下的用水量最初比一年生作物下多67 mm，到最后一年下降到仅多24 mm。在布里奇沃特的树木下，用水量持续增加，到最后一年比邻近的一年生作物下多243毫米。尽管在Walpeup和Pallamana，灌丛带比相邻的作物系统使用更多的水，但这主要是由于利用了储存的土壤水分，而且灌丛带仅占土地面积的7-18%，因此与传统作物单一栽培相比，灌丛带的总用水量增加很小，而且在补给控制方面，这小于作物产量损失的面积。在较为湿润的布里奇沃特地区，与传统的一年生种植系统相比，巷弄农业似乎正在消耗越来越多的水。总的来说，这些数据支持了之前的研究结果，即在降雨量较低的环境中（<350毫米），巷子耕作可能会受到作物和多年生植物之间对水的竞争的困扰。
Annual crops were grown in alleys between belts of perennial shrubs or trees over 3–4 years at 3 sites across low rainfall (<450 mm) south-eastern Australia. At the two lower rainfall sites (Pallamana and Walpeup), crop grain yields within 2–5 m of shrub belts declined significantly with time, with a reduction equivalent to 45% over 9 m in the final year of cropping. At the third, wetter site (Bridgewater), the reduction in crop grain yields adjacent to tree belts was not significant until the final year of the study (12% over 11 m) when the tree growth rates had increased. The reductions in crop yield were associated with increased competition for water between the shrub or tree belts and the crops once the soil profile immediately below the perennials had dried. At all 3 sites during the establishment year, estimates of water use under the woody perennials were less than under annual crops, but after this, trends in estimates of water use of alley farming systems varied between sites. At Pallamana the perennial shrubs used a large amount of stored soil water in the second summer after establishment, and subsequently were predominantly dependent on rainfall plus what they could scavenge from beneath the adjacent crop. After the establishment year at the Walpeup site, water use under the perennial shrubs was initially 67 mm greater than under the annual crop, declining to be only 24 mm greater in the final year. Under the trees at Bridgewater, water use consistently increased to be 243 mm greater than under the adjacent annual crop by the final year. Although the shrub belts used more water than adjacent crop systems at Walpeup and Pallamana, this was mostly due to the use of stored soil water, and since the belts occupied only 7–18% of the land area, increases in total water use of these alley farming systems compared with conventional crop monocultures were quite small, and in terms of the extent of recharge control this was less than the area of crop yield loss. At the wetter, Bridgewater site, alley farming appeared to be using an increasing amount of water compared with conventional annual cropping systems. Overall, the data support previous work that indicates that in lower rainfall environments (<350 mm), alley farming is likely to be dogged by competition for water between crops and perennials.