Dry season vegetable production is challenging due to water scarcity, a drawback on sustaining year‐round crop production. Biochar improves soil moisture and nutrient retention and may be used to improve vegetable water productivity. We examined the combined effect of rice straw biochar and irrigation on yield, water productivity, and phosphorus (P) uptake of okra (Abelmoschus esculentus L.) grown on a sandy clay loam soil in the dry season. Biochar was applied at 0, 5, 10 Mg ha⁻¹, and 10 Mg ha⁻¹ biochar fortified with P [10 Mg ha⁻¹_(P)] under full irrigation (FI) and deficit irrigation (DI) and replicated in each growing season for three years. Under DI, the 10 Mg ha⁻¹ and 10 Mg ha⁻¹_(P) biochar treatments significantly (p < .05) increased okra fresh fruit yield (Y_FF) by 67 and 82% but had no impact on total aboveground biomass yield (Y_TBM) in the first growing season. Biochar at 5 Mg ha⁻¹ had no impact on okra yield. Okra yield was higher under biochar fortified with P compared to the traditional method of applying P alone, e.g. 30 Mg ha⁻¹_(P) produced significantly higher Y_TBM than 30 Mg ha⁻¹ under DI. Biochar had no impact on P uptake in the first growing season. Estimated okra water use was 224 and 193 mm under FI and DI. Yield reduction under DI compared to FI was only 8%. Amid water scarcity, a minimum of 10 Mg ha⁻¹ rice straw biochar under DI is therefore recommended for farmers in the area.

中文翻译：

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稻草生物炭和灌溉对黄秋葵产量和水分生产率的影响

由于缺水，旱季蔬菜生产具有挑战性，这是维持全年作物生产的一个不利条件。生物炭可改善土壤水分和养分保留能力，可用于提高蔬菜水生产率。我们研究了稻草生物炭和灌溉对旱季在砂质壤土上生长的秋葵（Abelmoschus esculentus L.）的产量，水分生产率和磷（P）吸收的综合影响。在完全灌溉（FI）和亏缺灌溉（DI）下，分别以0、5、10 Mg ha ^-1和10 Mg ha ^-1的生物炭施用P [10 Mg ha ^-1 _（P） ]强化的生物炭，并分别重复生长期三年。在DI下，10 Mg ha ^-1和10 Mg ha^-1 _（P）生物炭处理显着（p <.05）使秋葵新鲜水果产量（Y _FF）分别增加67％和82％，但在第一个生长季节对地上总生物量产量（Y _TBM）没有影响。5 Mg ha ^-1的生物炭对秋葵的产量没有影响。与单独施用磷的传统方法相比，用磷强化的生物炭在秋葵中的产量更高，例如，在DI下30 Mg ha ^-1 _（P）产生的Y _TBM明显高于30 Mg ha ^-1。生物炭在第一个生长季节对磷的吸收没有影响。在FI和DI下，秋葵的用水量估计为224和193 mm。与FI相比，DI下的产量降低仅为8％。在缺水的情况下，至少10 Mg公顷因此，建议该地区的农民在DI下使用^-1稻草生物炭。