Rainfall is the key contributor to provide soil moisture for wet season rice (T. Aman) cultivation. Erratic rainfall often causes water shortage resulting negative impact on plant growth and grain yield. The study aimed to determine suitable transplanting window that utilize maximum rainfall for T. Aman rice. Firstly, three years field experiment were conducted in Kushtia, Bangladesh from T. Aman, 2013 to 2015, and then the findings were implemented for another two adjacent locations, Panba and Rajshahi. The field experiment considered six transplanting dates of popular cultivar BR11 (growth duration 145 days) at 7 days interval starting from 10 July to 14 August. The CROPWAT 8.0 model was used to calculate crop water requirement (CWR), effective rainfall and irrigation demand (ID) from collected weather data in each growth phase of rice. In all locations T. Aman rice received enormous rainfall up to vegetative phase resulting no irrigation demand in all three tested years. The early transplanting received more rainfall in reproductive phase than late planting. Thus, Irrigation demand increased at reproductive phase with delay transplanting in moderate drought prone Kushtia, Pabna and Rajshahi. A significant relationship (R2 = 0.71) observed between reproductive phase ID and grain yield, while grain yield responded weakly with the ID at ripening phase. Based on yield performance 10–24 July found suitable transplanting window for BR11 in Kushtia. Considering the relationship between ID and grain yield, 10–17 July and 10–24 July considered the best transplanting window in Pabna and Rajshahi, respectively. Location specific suitable transplanting windows were selected considering minimum ID at reproductive phase and the maximum grain yield. Delay in transplanting demanded more irrigation and reduced grain yield. Whereas, early transplanting utilized maximum rainfall, reduced ID in reproductive stage and ensured desired grain yield.

中文翻译：

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雨育水稻的早期移栽利用降雨将灌溉需求降至最低

降雨是为湿季水稻（T. Aman）种植提供土壤水分的关键因素。不规律的降雨经常导致水资源短缺，从而对植物生长和粮食产量产生负面影响。该研究旨在确定利用最大降雨量种植 T. Aman 水稻的合适移栽窗口。首先，2013 年至 2015 年在孟加拉国库什蒂亚进行了为期三年的田间试验，从 T. Aman 到 2015 年，然后在另外两个相邻的地点 Panba 和 Rajshahi 实施了研究结果。田间试验考虑了从 7 月 10 日到 8 月 14 日以 7 天为间隔的流行品种 BR11（生长持续时间 145 天）的 6 个移栽日期。CROPWAT 8.0 模型用于从水稻每个生长阶段收集的天气数据计算作物需水量 (CWR)、有效降雨量和灌溉需求 (ID)。在所有地点，T. Aman 水稻在生长期之前都收到了大量降雨，导致所有三个测试年份都没有灌溉需求。早栽比晚栽在生殖期获得更多的降雨。因此，中度干旱易发库什蒂亚、帕布纳和拉杰沙希的生殖期灌溉需求增加，移栽延迟。在生殖期 ID 和籽粒产量之间观察到显着关系 (R2 = 0.71)，而籽粒产量对成熟期 ID 的反应较弱。根据产量表现，7 月 10-24 日在库什蒂亚找到了适合 BR11 的移栽窗口。考虑到 ID 与粮食产量之间的关系，7 月 10-17 日和 7 月 10-24 日分别被认为是 Pabna 和 Rajshahi 的最佳移栽窗口。考虑繁殖期的最小 ID 和最大籽粒产量，选择位置特定的合适移栽窗口。延迟移栽需要更多的灌溉和减少粮食产量。而早期移栽利用了最大降雨量，减少了繁殖期的 ID 并确保了理想的粮食产量。 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .