Alternate wetting and drying (AWD) irrigation can save water while maintaining rice yields, but in some countries its adoption by farmers remains limited. Key knowledge gaps include the effect of AWD on early vegetative vigor and its relationship with yield; the effects of AWD on yield and water use efficiency of local cultivars used by smallholder farmers; and the socio‐economic factors influencing current irrigation scheduling. To address these questions, an on‐farm field trial of dry‐season (chaite) rice, comparing two locally important cultivars (Hardinath‐1 and CH‐45) under AWD imposed from 1 week after transplanting to flowering and continuous flooding (CF), was carried out in Agyauli in the central Terai region of Nepal, and triangulated with social research methods exploring the rationale for current irrigation scheduling and perceptions of AWD. Although AWD plots received on average 57% less irrigation water than CF plots, yields did not significantly differ between irrigation treatments, indicating that AWD could considerably enhance crop water use efficiency in this region. In the earlier flowering, more vigorous CH‐45, there were no treatment differences in any yield component while in the later flowering Hardinath‐1, an 11% decrease in filled grain number was compensated by a 14% increase in the percentage of effective tillers per hill. Although leaf elongation rate on the main tiller did not differ between treatments, tillering and green fraction (a measure of canopy closure) were significantly higher under AWD. Surveys established that most local farmers are already using a local adaptation of AWD to modify irrigation volumes, in some cases in response to a limited and unreliable water supply. However, farmers have few direct incentives to reduce overall water use under current water governance, and formal AWD practices are therefore unlikely to be adopted despite their viability as a water‐saving irrigation technique.

中文翻译：

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尽管灌溉量减少了一半，但交替进行的湿润和干燥灌溉仍能维持水稻产量，但目前尼泊尔小农低地稻农不太可能采用。

交替的干湿灌溉可以节省水，同时保持稻米的产量，但是在某些国家，农民采用它的方式仍然有限。关键的知识差距包括AWD对早期营养活力的影响及其与产量的关系；AWD对小农户使用的当地品种的产量和水分利用效率的影响；以及影响当前灌溉计划的社会经济因素。为了解决这些问题，旱季的农场田间试验（chaite）在尼泊尔中部Terai地区的Agyauli进行了水稻比较，比较了两个本地重要的栽培品种（Hardinath-1和CH‐45）在移植后1周与开花和连续淹水（CF）实施AWD后的关系，并与社会研究方法探索当前灌溉计划的基本原理和对AWD的认识。尽管AWD地块的灌溉水量平均比CF地块少57％，但在不同的灌溉方式之间单产没有显着差异，这表明AWD可以大大提高该地区的农作物用水效率。在较早开花的，较旺盛的CH‐45中，任何产量成分均无处理差异，而在较晚开花的Hardinath-1，填充谷物数量减少11％，而每丘有效耕作机百分比增加14％，可以弥补这一不足。尽管不同处理之间主耕分leaf的叶片伸长率没有差异，但在AWD下，分till和生绿分数（衡量冠层封闭性）明显更高。调查表明，大多数本地农民已经在使用AWD的本地版本来修改灌溉量，在某些情况下，这是对有限和不可靠供水的回应。但是，在当前的水治理下，农民几乎没有直接的诱因来减少总体用水量，因此尽管有作为节水灌溉技术的可行性，但正式的AWD实践不太可能被采用。在AWD下，分和绿色部分（衡量冠层关闭的程度）明显更高。调查表明，大多数本地农民已经在使用AWD的本地版本来修改灌溉量，在某些情况下，这是对有限和不可靠供水的回应。但是，在当前的水治理下，农民几乎没有直接的诱因来减少总体用水量，因此尽管有作为节水灌溉技术的可行性，但正式的AWD实践不太可能被采用。在AWD下，分和绿色部分（衡量冠层关闭的程度）明显更高。调查表明，大多数本地农民已经在使用AWD的本地版本来修改灌溉量，在某些情况下，这是对有限和不可靠供水的回应。但是，在当前的水治理下，农民几乎没有直接的诱因来减少总体用水量，因此尽管有作为节水灌溉技术的可行性，但正式的AWD实践不太可能被采用。