Abstract Afghanistan has an arid to semi-arid climate where irrigated agriculture largely depends on scarce irrigation water supplies from snowmelt from the high raised mountains. Under growing water scarcity, farmers not only need to use the available water more wisely but have to develop alternative options for coping water scarcity. Deficit irrigation schedule can be one of the options to mitigate the adverse impacts of water scarcity on crop production. In the current study, FAO’s crop water productivity model (AquaCrop) was calibrated and validated with field data in Kabul River Basin (KRB) for wheat crop to simulate four different water scarcity scenarios (S-A: business-as-usual scenario, S-B: refilling the soil profile to field capacity upon 50 % water depletion, S-C: refilling the soil profile upon 100 % depletion and S-D: refilling the soil profile upon 130 % depletion occurrence) for resultant yield, water productivity (WP) and biomass production. Two wheat fields, namely A and B were monitored intensively for soil moisture content, meteorological situation, irrigation application and post-harvest data. Results show that the measured WP was 1.4 kg m−3 ETa and 1.5 kg m−3 ETa whereas, the actual (measured) water use efficiency (WUE) was 0.58 kg m−3 and 0.66 kg m−3 for Field A and Field B, respectively. The WP of the scenarios S-A, S-B, S-C and S-D was 2.0-2.1 kg m−3 ETa (for plot B and A), 2.5 kg m−3 ETa, 2.74 kg m−3 ETa and 2.8 kg m−3 ETa respectively. Similarly, yield under these scenarios was 6.4 ton ha−1, 8.7 ton ha−1, 7.4 ton ha−1and 6.7 ton ha−1 respectively while the above ground biomass was 21.3 ton ha−1, 21.8 ton ha−1, 19 ton ha−1 and 18.3 ton ha−1 respectively. As a consequence, WP could increase by 92.8 %, 78 % and 95 % in S-B, S-C and S-D, respectively with reference to the measured WP. The optimized scenarios developed in this study can provide guidelines for policy makers and farming communities to mitigate the adverse impact of water scarcity through such innovative interventions.

中文翻译：

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阿富汗喀布尔河流域下游不同灌溉优化策略下冬小麦AquaCrop模型的评价

摘要 阿富汗属于干旱至半干旱气候，灌溉农业在很大程度上依赖于来自高山融雪的稀缺灌溉水供应。在日益严重的缺水情况下，农民不仅需要更明智地使用可用水，而且必须开发替代方案来应对缺水问题。赤字灌溉计划可能是减轻水资源短缺对作物生产不利影响的选择之一。在当前的研究中，粮农组织的作物用水生产力模型 (AquaCrop) 使用喀布尔河流域 (KRB) 小麦作物的田间数据进行校准和验证，以模拟四种不同的缺水情景（SA：照常情景，SB：补充土壤剖面与田间持水量在 50% 水分耗竭时的关系，SC：在 100% 水分耗竭时重新填充土壤剖面，SD：130 % 枯竭发生时重新填充土壤剖面）以获得产量、水生产力 (WP) 和生物量产量。对两个麦田，即 A 和 B 进行了土壤水分含量、气象状况、灌溉应用和收获后数据的集中监测。结果表明，实测 WP 为 1.4 kg m-3 ETa 和 1.5 kg m-3 ETa 而实际（实测）用水效率 (WUE) 为 0.58 kg m-3 和 0.66 kg m-3 的田地 A 和田地B、分别。SA、SB、SC 和 SD 情景的 WP 分别为 2.0-2.1 kg m-3 ETa（对于图 B 和 A）、2.5 kg m-3 ETa、2.74 kg m-3 ETa 和 2.8 kg m-3 ETa . 同样，这些情景下的产量分别为 6.4 吨 ha-1、8.7 吨 ha-1、7.4 吨 ha-1 和 6.7 吨 ha-1，而地上生物量分别为 21.3 吨 ha-1、21.8 吨 ha-1、19 吨ha−1 和 18。分别为 3 吨 ha−1。因此，参考测量的 WP，SB、SC 和 SD 的 WP 可以分别增加 92.8%、78% 和 95%。本研究中开发的优化情景可为政策制定者和农业社区提供指导，以通过此类创新干预措施减轻水资源短缺的不利影响。