ABSTRACT

Improvement of efficiencies of N fertilizer and irrigation water is needed for large-scale market-oriented rice cultivation without puddling practice as in American continents. Effects of reductions of N fertilizer and irrigation water on grain yield of drill-seeded rice on zero-leveled fields were quantified across five N levels (220, 180 [two sources with 5 or 3 splits], 140, and 0 kg N ha⁻¹) and three irrigation strategies (irrigating every 3, 6, or 8 days; W1, W2, and W3, respectively) in dry and wet seasons during an El Niño event in Central Colombia. Reducing the N application rate from 180 kg N ha⁻¹ to 140 kg N ha⁻¹ (22% reduction) did not reduce yield in either season in spite of slightly reduced N uptake, owing to increased N use efficiency in all irrigation strategies. Three split of N fertilizer with slow release urea (180 kg N ha⁻¹) and with basal organic amendment did not reduce yield compared with the conventional 5 split method. Yield in dry season reduced under the 2 water-saving strategies (W2, W3) almost proportionally to the reduced water supply (irrigation + rainfall) by flowering. In wet season, yield in mild water saving (W2, with 26% water saving) was similar to conventional irrigation management (W1), leading to its highest water productivity. Physiological parameters (e.g. stomatal conductance, total N uptake) were greater in wet season than in dry season. This study showed potential reduction of N fertilizer and conditions of climate for water-saving in drill-seeded rice production in Colombia.

摘要

以市场为导向的大规模水稻种植需要提高氮肥和灌溉水的效率，而无需像美洲大陆那样进行水坑作业。在五个氮水平（220、180 [5 或 3 分裂的两个来源]、140 和 0 kg N ha ^{- 1} ) 和三种灌溉策略（每 3、6 或 8 天灌溉一次；分别为 W1、W2 和 W3）在哥伦比亚中部厄尔尼诺事件期间的旱季和雨季。将施氮量从 180 kg N ha ^{-1 降低}到 140 kg N ha ^-1（减少 22%）尽管 N 吸收略有减少，但在任何一个季节都没有降低产量，这是由于所有灌溉策略中的 N 使用效率提高了。三分氮肥加缓释尿素（180 kg N ha ^-1) 并且与传统的 5 分割方法相比，使用基础有机改良剂不会降低产量。两种节水策略（W2、W3）下旱季产量的降低几乎与开花导致的供水减少（灌溉+降雨）成正比。在雨季，轻度节水（W2，节水 26%）的产量与常规灌溉管理（W1）相似，导致其最高的水生产率。生理参数（如气孔导度、总氮吸收）在湿季大于旱季。该研究表明，在哥伦比亚的钻籽水稻生产中，氮肥的潜在减少和气候条件有利于节水。