Articles

Effects of Different Rates of Potassium Application on Growth and Yield of Soybean

Soybean is an important legume crop valued for its high protein and oil content, but its productivity is often limited by poor soil fertility and environmental stresses. This study aimed to determine the optimum potassium application rate for improving soybean growth and yield under the agroecological conditions of Kabul, Afghanistan. A field experiment was conducted during the 2025 growing season at the Research Farm of the Faculty of Agriculture, Kabul University, using a randomized complete block design with five potassium levels (0, 25, 50, 75, and 100 kg ha⁻¹) and three replications. Standard agronomic practices were applied uniformly throughout the experiment. Data were collected on plant height, branches per plant, pods per plant, total seeds per plant, 100-seed weight, and grain yield, and analysed using STAR software with the least significant difference test at the 5% probability level. Potassium application had no significant effect on vegetative growth traits, including plant height and number of branches per plant. However, it significantly improved yield components and grain yield. The application of 75 kg K ha⁻¹ produced the highest number of pods per plant, greatest 100-seed weight, and maximum grain yield, whereas increasing the rate to 100 kg K ha⁻¹ resulted in reduced yield. The findings indicate that potassium application enhances soybean productivity primarily through improved yield components rather than vegetative growth. It is concluded that 75 kg K ha⁻¹ is the optimum potassium rate for maximizing soybean yield under the agroecological conditions of Kabul, Afghanistan.

Optimization of Seed Rate for Chickpea Variety FLIP-94 under the Climatic Conditions of Kabul

Chickpea (Cicer arietinum L.) is a vital pulse crop in semi-arid regions, yet its productivity is often constrained by poor agronomic practices, particularly seed rate management (Bhatt et al., 2022; Rahimi et al., 2024). A field experiment was conducted in Kabul, Afghanistan, to evaluate the effect of five seed rates (65, 75, 85, 95, and 105 kg/ha) on growth and yield performance under semi-arid conditions. The trial was laid out in a Randomized Complete Block Design (RCBD) with three replications. Results demonstrated significant differences (p ≤ 0.05) among treatments for plant height, leaf area, pods per plant, seeds per pod, 100 seed weight, and yield, while the number of branches per plant showed no significant variation. The optimum seed rate was identified as 85 kg/ha, which produced taller plants (33.2 cm), higher pod numbers (25–32 pods/plant), heavier seeds (31 g per 100 seeds), and improved yield (0.465 kg/m²). Excessive seed rates (105 kg/ha) reduced yield due to overcrowding, intra specific competition, and depletion of limited soil moisture, resulting in smaller seeds (25 g per 100 seeds) and fewer pods (20.7 pods/plant). These findings highlight the critical role of optimized seed rate management in enhancing chickpea productivity under Kabul’s challenging climatic conditions, where short growing seasons, spring frost, and terminal drought are major constraints (Jettner et al., 2019; Siddique et al., 2022). The study provides evidence based recommendations for local farmers to replace traditional broadcast sowing with optimized seed rates, thereby improving food security and income generation in Afghanistan (FAO, 2026; Merga & Haji, 2019).

Effect of Different Levels of Diammonium Phosphate (DAP) Fertilizer on Growth and Yield of Chickpea (Cicer arietinum L.) Variety Flip 94

Chickpea (Cicer arietinum L.) is an important pulse crop valued for its nutritional quality and role in sustainable agriculture. However, productivity is often constrained by low soil fertility and poor nutrient management, particularly phosphorus deficiency. A field experiment was conducted during the 2025 growing season at the Research Farm of the Faculty of Agriculture, Kabul University, Afghanistan, to evaluate the effect of different levels of diammonium phosphate (DAP) fertilizer on growth and yield of chickpea variety Flip 94. The experiment was arranged in a Randomized Complete Block Design (RCBD) with five DAP levels (0, 50, 100, 150, and 200 kg ha⁻¹) and three replications. Results showed that DAP application significantly influenced all growth and yield parameters, while replication effects were non-significant. Treatment 3 (100 kg ha⁻¹ DAP) consistently performed best, recording the highest plant height (34.23 cm), number of branches per plant (4.92), number of pods per plant (37.47), grains per pod (1.93), and grain yield (5.52 t ha⁻¹). In contrast, the control treatment recorded the lowest values for all studied traits. The improved performance under optimal DAP application is attributed to enhanced nutrient availability, better root development, increased nodulation, and improved photosynthetic efficiency, which collectively supported stronger vegetative growth and reproductive development. In conclusion, application of DAP fertilizer significantly improves chickpea growth and yield under Kabul agro-climatic conditions. Treatment 3 (100 kg ha⁻¹ DAP) was identified as the most effective dose for maximizing productivity of chickpea variety Flip 94.