Soybean Growth and Yield Response to Fertilizers: A Comparative Review of Organic and Inorganic Inputs under Kabul Semi‑Arid Conditions

Abstract

Soybean (Glycine max L.) is a globally important crop valued for its high protein and oil content, yet its productivity in Afghanistan remains constrained by poor soil fertility and reliance on chemical fertilizers. This review article synthesizes experimental evidence on the comparative effects of organic inputs (night soil, farm manure) and inorganic fertilizers (diammonium phosphate, urea) on soybean growth and yield under Kabul’s semi‑arid conditions. The purpose of this study is to evaluate sustainable nutrient management strategies that enhance crop productivity while maintaining soil health. Field trials conducted at Kabul University employed a randomized complete block design with five treatments: control, night soil, farm manure, DAP, and urea. Growth parameters such as plant height, branches per plant, leaf number, and pods per plant were measured alongside yield attributes including 100‑seed weight and grain yield. Results demonstrated that organic amendments significantly improved soybean performance compared to chemical fertilizers. Farm manure produced the tallest plants, highest branching, and maximum pods per plant, with grain yield reaching 1725 kg/ha. Night soil accelerated flowering and pod formation while also improving yield (1616 kg/ha). In contrast, urea resulted in the lowest yield (1262 kg/ha), highlighting the limitations of sole reliance on chemical inputs. The findings confirm that organic fertilizers enhance soil structure, microbial activity, and long‑term fertility, making them vital for sustainable soybean production in semi‑arid Kabul. Integrating organic inputs into nutrient management strategies can reduce dependence on chemical fertilizers, improve food security, and support climate‑resilient agriculture in Afghanistan.