摘要
水分亏缺是干旱、半干旱区作物生产的最主要限制因子 .在我国西北半干旱区 ,随着集水生态农业的发展 ,实施在作物生育期对其进行关键性的有限灌溉 ,这就使得更多的土地具有种植价值了 .用一个度量作物不同生长阶段水分亏缺的灵敏度指标值λi 来确定灌溉关键期 .对一个给定的作物 ,在不同的生长阶段 ,λi 的值是不同的 ,λi的值越大 ,生长阶段对水分越灵敏 ,水分亏缺对产量造成的危害越大 ,从而越需要保持水分平衡 .在西北半干旱区甘肃省定西农业试验站 ,经过两年冬小麦种植试验 ,建立了冬小麦产量 -耗水量 Jensen模型 ,该模型表明拔节期以后 ,λi 值明显增大 ,至抽穗期达最大 ,这说明从拔节期开始 ,该地冬小麦进入灌溉关键期 ,抽穗期是灌溉的最关键时期 .一个理论方法应用到有限灌溉试验田 ,确定了灌溉水减少与经济效益的关系 ,结果表明在作物生育期 ,一些水分减少是可能的 .用 Nairizi和 Rydzewski的方法计算出的 λi 值确定出的最大允许水分亏缺是不合理的高 ,它们计算 λi 值的方法在半干旱区是不适用的 ,用我们建立的模型计算出的最大允许水分亏缺比较合理 ,在效益成本比为1 .5时 ,冬小麦允许的水分亏缺是 1 2 .4 % 。
Water deficit is the most important limiting factor for crop production in the arid and semi arid regions in China.It is fact that crops are partially irrigated in key growing stage in Northwest of China along with the development of rainwater catchment technology.This results in that more land can become productive by using partial irrigation at strategic times during the growing season.The determination of critical irrigation time may be accomplished by using a sensitivity index ( λ i ) that is the sensitivity of a crop to water stress during the i th stage of growth.The value of λ i for a given crop is different at the various stages of growth.A more sensitive growth stage has a higher value of λ i ,and the water deficit has more serious harm to crop,therefore the supply of water is more important at this stage.The field experiment was carried out in Dingxi agricultural test station of Gansu province from September in 2001 to July in 2003 and winter wheat ( Triticum aestivum L.) used as tested crop.The Jensen model of winter wheat yield water consumption was established by using two years experimental data.The model showed that the value of λ i significantly increased after stem elongation and reached the maximum at heading.This indicated that it was irrigation key stage of winter wheat after stem elongation,the heading was the most critical moment of irrigation.A theoretical procedure was applied to determine the savings in water and the economic benefit derived from partial irrigation,using a water stress sensitivity index for winter wheat in the region.The results indicated that some water reduction is possible.The suggested maximum allowable water reduction was unreasonably high for the sensitivity index ( λ i ) calculated by Nairizi and Rvdzewskis method.Their index is not applicable in semi arid areas.However,the field derived λ i of our model resulted in a reasonable water reduction close to the field applied water reduction to achieve a corresponding relative yield.The water reduction of 12.4% was allowed for winter wheat at a benefit to cost ratio (B/C) of 1.5.
出处
《西北植物学报》
CAS
CSCD
2004年第3期412-417,共6页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家重大基础研究前期专项 2 0 0 2 CCA0 0 3 0 0
教育部科技重点项目 0 1172
博士点基金项目 2 0 0 2 0 73 0 0 17
关键词
冬小麦
水分胁迫
灵敏度指标
灌溉水减少率
经济效益
winter wheat
water stress
sensitivity index
water reduction rate
economic benefit
