Impact of subsoil water use on wheat yield
Impact of subsoil water use on wheat yield
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DOI：
10.1071/ar06285
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发表时间：
2007-01-01
影响因子：
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通讯作者：
Graham, J. M.
中科院分区：
文献类型：
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作者：
Kirkegaard, J. A.;Lilley, J. M.;Graham, J. M.
储存在土壤剖面深处的水通常被认为对作物产量有价值，因为它在籽粒灌浆期间变得可用，但底土水对籽粒产量的价值尚未在田间分离和量化。我们使用带灌溉的防雨棚来控制小麦作物的供水，这些小麦作物具有不同的底土水，以隔离和量化底土水转化为谷物产量的效率。在中度花后胁迫条件下，花后1.35-1.85m土层增施10.5mm底土水，增产0.62t/ha，增产效率59 kg/ha。额外的产量是由于开花后12-27天的较高同化作用，与籽粒大小的增加有关，而不是与其他产量构成因素有关。在更严重的胁迫下，更早的开始，额外的水使用低于1.25米，伴随着额外的水使用在上层土壤和它是更难以隔离和量化的深层水对粮食产量的好处。从施加胁迫时起，所有层使用的额外水以30-40公斤/公顷转化为谷物。mm，但这增加到60公斤/公顷。开花后用水量为0.5mm。底土水分利用的高效率是通常预期的季节性总用水量的3倍，是以前估计的花后总用水量在类似环境中的两倍。结果表明，相对少量的底土水分对粮食产量是非常有价值的。
Water stored deep in the soil profile is generally considered valuable to crop yield because it becomes available during grain filling, but the value of subsoil water for grain yield has not been isolated and quantified in the field. We used rainout shelters with irrigation to control the water supply to wheat crops that had different amounts of subsoil water available to isolate and quantify the efficiency with which the subsoil water was converted to grain yield. Under moderate post-anthesis stress, 10.5mm of additional subsoil water used in the 1.35-1.85m layer after anthesis increased grain yield by 0.62 t/ha, representing an efficiency of 59 kg/ha. mm. The additional yield resulted from a period of higher assimilation 12-27 days after anthesis and was related to an increase in grain size rather than other yield components. Under more severe stress with earlier onset, extra water use below 1.25m was accompanied by additional water use in upper soil layers and it was more difficult to isolate and quantify the benefit of deep water to grain yield. The additional water used from all layers from the time the stress was imposed was converted to grain at 30-40 kg/ha. mm, but this increased to 60 kg/ha. mm for water used after anthesis. The high efficiency for subsoil water use is 3 times that typically expected for total seasonal water use, and twice that previously estimated for total post-anthesis water use in a similar environment. The results demonstrate that relatively small amounts of subsoil water can be highly valuable to grain yield.