HYDROGEL APPLICATION AS A WAY FORWARD FOR FOOD SECURITY IN THE RAIN FED AREAS OF PAKISTAN: A FOUR-YEAR FIELD EVALUATION OF SOIL MOISTURE RETENTION, WHEAT PRODUCTIVITY AND SOIL FERTILITY IN THE POTOHAR PLATEAU

Abstract

Recurrent drought and highly variable rainfall constrain wheat productivity across the rain fed Potohar Plateau, where erratic soil moisture availability is the limit on cereal crop yields and leading cause of food security. Superabsorbent polymer can absorb and slowly release large volumes of water. This study evaluated a soil applied hydrogel at three rates (5.0, 7.5 and 10.0 kg ha⁻¹) against a control (without hydrogel) in a randomized complete block design with 3 replications for four consecutive rain-fed wheat seasons (2021 to 2024) on sandy loam texture soil at tehsil Jand district Attock of the Potohar Plateau, Pakistan. Soil moisture was monitored stage wise across five phenological phases, soil chemical properties (pH, electrical conductivity, available P₂O₅ and K₂O, and organic matter) were measured at two depths before sowing and after harvest. Crop growth, root behavior, grain and straw yield were recorded. Hydrogel consistently raised stage wise soil moisture relative to the control in every year, with the largest gains during the moisture sensitive flowering to maturity window. Mean grain yield increased by approximately 12.7 % at 5.0 kg ha⁻¹, 27.6 % at 7.5 kg ha⁻¹ and 26.4 % at 10.0 kg ha⁻¹ relative to the control. The relative yield advantage of hydrogel was greatest in the driest season (2024 averaged over years, depths and sampling stages, hydrogel increased plant available phosphorus by 16.7 to 24.3 %, potassium by 20.5 to 23.0 % and leaving soil pH essentially unchanged. The 7.5 kg ha⁻¹ rate delivered the highest average productivity at a lower quantifiable and environmental cost than 10.0 kg ha⁻¹. We interpret hydrogel as a one component of integrated rainwater and soil fertility management for barani wheat. Therefore, this study suggests inclusion of hydrogels to store and retain water in rainfed areas which ultimately resulted in increase of yield and nutrients availability.