Rice is widely grown in rainfed lowlands during the wet season in the Mekong region. Limited nutrient availability is a common constraint on crop yield, and the optimal rate of fertilizer application depends on the soil type. The objective of our study was to evaluate rice productivity and the economic feasibility of various nutrient management regimes in Cambodia. We conducted field experiments on three soil types (Prey Khmer, Prateah Lang, and Toul Samroung, equivalent to Psamments, Plinthustalfs, and Endoaqualfs, respectively) in four provinces (Battambang, Kampong Thom, Pursat, and Siem Reap) during the 2016 and 2017 wet seasons to compare nine (2016) and seven (2017) N–P–K combinations. Grain yield ranged from 0.9 to 4.8 t ha−1 in 2016 and from 1.0 to 5.2 t ha−1 in 2017, depending on soil type and nutrient management. The Prey Khmer soil contained around 80% sand, and rice yield responded most weakly to nutrient management. The moderate fertilizer input in the current soil-specific recommendation was effective on this soil type. However, on more fertile soils with a higher clay content and a higher cation-exchange capacity (Toul Samroung and Prateah Lang), an additional 20 kg N ha−1 combined with adding 15 kg ha−1 of P2O5 or 20 kg ha−1 of K2O significantly increased yield and economic return. Although P and K use during Cambodia’s wet season is uncommon, our results demonstrate the importance of these nutrients in improving the country’s rice production.

中文翻译：

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磷和钾在柬埔寨湿季稻土壤特定养分管理中的重要性

在湄公河地区的雨季，水稻广泛种植在雨养低地。有限的养分可用性是作物产量的常见限制因素，施肥的最佳施用率取决于土壤类型。我们研究的目的是评估水稻生产力和柬埔寨各种养分管理制度的经济可行性。我们在 2016 年和 2017 年期间在四个省份（马德望、磅同、菩萨和暹粒）对三种土壤类型（Prey Khmer、Prateah Lang 和 Toul Samroung，分别相当于 Psamments、Plinthustalfs 和 Endoaqualfs）进行了田间试验雨季比较九（2016）和七（2017）N-P-K组合。粮食产量为 0.9 至 4.8 吨公顷-12016 年，从 1.0 到 5.2 吨公顷-12017 年，取决于土壤类型和养分管理。猎物高棉土壤含有约 80% 的沙子，水稻产量对养分管理的反应最弱。当前针对特定土壤的建议中的适度施肥对这种土壤类型有效。然而，在粘土含量较高和阳离子交换能力较高的肥沃土壤上（Toul Samroung 和 Prateah Lang），需要额外增加 20 kg N ha-1再加上 15 公斤公顷-1P的2○5或 20 公斤公顷-1的 K2O显着提高产量和经济效益。尽管在柬埔寨雨季使用磷和钾的情况并不常见，但我们的研究结果证明了这些营养素在提高该国水稻产量方面的重要性。