A Multidisciplinary Approach to Optimize Hydrogels for Improving Field Capacity of Agricultural Soils.

Fresh water resources across the world are being over-exploited over the past two decades due to industrial revolution and population explosion in 19th and 20th century. Besides, the climatic changes are expected to further increase the stress on fresh water resources. This stress on water affects irrigated agriculture greatly as it constitutes about 85% of world-wide consumption of water and 40% of food production comes from irrigated lands. So it is indeed a high time to have better water management practices for effective use of available fresh water, especially in agriculture. The objective of this research is to validate the use of Super Absorbing Polymers (SAP) for conservation of water in agriculture. SAPs are polymers that can absorb water several hundred times to its own mass and swell. SAPs swelling capability are affected by environmental changes like temperature, pH and ionic concentrations. The amount of water absorbency of the SAP can be controlled chemically (type and degree of cross-linking between the polymeric chains) and physically (porosity and particle size). Earlier much research has been reported on use of SAPs in soils and as an aid to improve plant growth in lab scale. Amendment of SAPs to the soil increases the water holding capacity, plant available water and decreases hydraulic conductivity of the soil. Further the amendment of SAPs to soil makes plants grow faster, better and less sensitive to water stress. Certain cases have reported that SAPs have no effect on hydraulic properties of the soil. In this research we try to prepare SAPs with salt resistance and mechanical strength and examine the hydraulic properties of the soil amended with SAPs with different application rates, water absorbency and particle size. The outcome of this research is expected to address the contradicting reports of usage of SAP as a soil amendment for water conservation.