An integrated approach is developed to assess major crops water productivity (CWP) in relation to water supply across the irrigated areas of Punjab province in central Pakistan during 1982–2015. The role of precipitation (effective rainfall) in term of add on to water supply and impacts on wheat yield is also studied. The water supply from canals displayed a significant declining trend for Rabi season (wheat mainly) during 1996−2015. Crop water productivity for harvestable area (CWP_A) has decreased; however, it has increased in case of production (CWP_P) and yield (CWP_Y). The role of tube wells is analyzed to assess the improved CWP even under decreased canal water supply. Contribution of water supply through effective rainfall showed a significant add on of 7.6 mm to 291.8 mm to water supply and 0.48 kg ha⁻¹ mm⁻¹ to 8.19 kg ha⁻¹ mm⁻¹ towards CWP_Y during the studied 34-year period. The precipitation (effective rainfall) contribute water supply of 10.6 mm (6.64 mm), 23.4 mm (14.6 mm), and 25.5 mm (16.0 mm) for January, February, and March, respectively. Average canal water supply for irrigation is observed to be 254.9 mm against irrigation need of 418.6 mm with a deficit of 39.1%, across irrigated areas. The multiple regression models are developed with seasonal predictive capacity for wheat harvestable area and yields with an explained variability of ~ 81% and ~ 78%, respectively. A decrease in temporal satellite-based weekly composite NDVI profile during 1986, 1992, 1994, 1997, 2002, and 2010 corresponded to El Niño episodes, since negative phases of ENSO are known to cause droughts across Punjab province. The synthesized information calls for a more comprehensive management of declining canal water supply for sustainable major crops water productivity such as wheat which is a staple food crop.

已开发出一种综合方法来评估1982-2015年巴基斯坦中部旁遮普省灌溉地区的主要农作物水分生产率（CWP）。还研究了降水（有效降雨）在增加水供应方面的作用以及对小麦产量的影响。在1996-2015年期间，拉比季（主要是小麦）的运河供水量呈显着下降趋势。收获面积的作物水分生产率（CWP _A）下降；但是，在产量（CWP _P）和产量（CWP _Y）。分析了管井的作用，以评估即使在运河供水减少的情况下改善的CWP。通过有效降雨的供水贡献显着增加了7.6 mm至291.8 mm的供水量，并向CWP _Y增加了0.48 kg ha ^-1 mm ^-1至8.19 kg ha ^-1 mm ^-1在研究的34年期间。降水（有效降雨）分别在1月，2月和3月提供了10.6毫米（6.64毫米），23.4毫米（14.6毫米）和25.5毫米（16.0毫米）的供水。在整个灌溉区中，灌溉的平均运河供水量为254.9毫米，而灌溉需求为418.6毫米，赤字率为39.1％。建立了多元回归模型，其具有小麦可收获区域和产量的季节性预测能力，其解释性分别为〜81％和〜78％。1986年，1992年，1994年，1997年，2002年和2010年期间，基于卫星的时态卫星周综合NDVI分布的减少与厄尔尼诺事件有关，因为已知ENSO的负相位会导致旁遮普省的干旱。