Due to declining water resources allocated to agriculture and rapid population growth, it is important to use water efficiently and increase crop water productivity (CWP). Deficit irrigation is considered an important strategy to achieve this goal. For this purpose, field experiments were conducted at the research farm of the Agriculture Faculty on Kabul University campus for two continuous years (2018-2019). The experiment consisted of four treatments, including full irrigation (ET100), 80% (ET80), 60% (ET60), and 40% (ET40) arranged in a randomized complete block design with three replications. Compared to ET100 and ET80, the ET60 and ET40 treatments significantly (P<0.05) reduced the duration of flowering and pod formation. The bean crop also showed best performance in plant height, number of leaves per plant, leaf area, leaf area index, number of pods per plant, number of seeds per pod, length of pod, 100-seed weight, and total grain yield in the ET100 and ET80 treatments. Moreover, significantly greater values of crop water productivity (CWP) and lower value of Ky were observed in ET80 compared to ET100, ET60 and ET40. Overall, the experiment results showed that regulated deficit irrigation can effectively increase water productivity. Supplying only 80% instead of full water requirement can result in a higher common bean CWP. This is of particular importance in water-scarce areas, where the water saved based on this practice can be used to irrigate additional acreage.

The excess application of chemical fertilizer contributes to environmental pollution. Therefore, this study aims to explore the integrated use of animal manure and chemical fertilizer to identify a more sustainable and environmentally friendly alternative to nitrogen fertilizer. Two experiments were conducted in 2018 and 2019 at Kabul University, Afghanistan, using an LD04-13265 soybean variety. The integration of animal manure and chemical fertilizer was categorized into six treatments: (1) control (no fertilizer), (2) animal manure low dose (AMLD), (3) animal manure high dose (AMHD), (4) chemical fertilizer (CF), (5) CF 50% + AMLD, and (6) CF 75% + AMLD. The results revealed that AMHD and its integration with 75% chemical fertilizer greatly influenced the vegetative growth of soybean plants in experiments I and II. The number of pods per plant and pod length significantly (p < 0.05) increased under the CF 75% + AMLD treatment. In experiment I, soybean yield increased the most with the CF treatment, followed by CF 75% + AMLD. In contrast, in experiment II, the highest yield per hectare was observed in the CF 75% + AMLD treatment, followed by CF. The CF 75% + AMLD treatment significantly increased the SPAD value in both experiments. Consequently, a strong relationship was observed between the SPAD value and yield (r = 0.74) in experiment I and between SPAD and pod length (r = 0.82) in experiment II. Incorporating animal manure with chemical fertilizer significantly impacted soybean growth and yield, offering a potential possibility for reducing reliance on nitrogen fertilizer application to mitigate environmental pollution.