Hydrogel Polymer: A Water Conservation Practice For Drought Prone Agriculture

Abstract

The most crucial sector of the world economy is agriculture [1]. Nearly 1.3 billion people (About 40% of world) relying on agriculture. Drought has a dire impact on agriculture. Drought disrupts plant growth, resulting in a decrease in crop quantity and quality [2]. Application of water directly to the crop surface is a frequent irrigation method; however, it does not solve the drought problem [3]. Further, a large amount of water is wasted due to evaporation or runoff, and plants take in too little water, resulting in lower yields [4]. Sprinklers are an alternative method to reduce water waste but necessitate the purchase of costly equipment that most farmers cannot afford [5]. With a limited supply of freshwater and arable land, and an expected increase in global population of 9 billion by 2050, and 11.2 billion by 2100, [6], Food production must be tripled to provide enough food by increasing the yields of various crops both vertically and horizontally, and to reduce the gap between food crop production and consumption. There is a growing focus on producing enough food to feed each of us using every technology available. The need for water is constantly increasing in the current global ecological and economic scenario, yet the availability of clean water is decreasing [7]. Drought impact on farming is a worldwide issue that has prompted experts to seek novel solutions [8]. Drought cannot be stopped, but due to the growing availability of technological innovation, it can be forecasted. In some cases, hydrogel polymers having good water absorption capacity and retention capabilities even at high temperatures are one of the interim solutions [9]. Hydrogels improve soil physical properties by increasing water retention capacity, increasing infiltration and reducing irrigation frequency [10]. Cross linked polyacrylates or polyacrylamides are the most common hydrogel polymers employed in agriculture so far [11]. The inside of a hydrogel polymer is filled with water and buildup with a network of polymer chains. [12]. These structures may absorb and store rain water [13]. Using hydrogel polymers in soil allows water to be released slowly into the soil, allowing plant roots to absorb water more slowly, thus meeting their needs over a longer period of time [14]. Hydrogel polymers act as soil amendments to provide a suitable environment around plants when the root zone soil dries up, improving the efficiency of irrigation water and prolonging the duration of irrigation are both important in the field of agriculture. The dosage of hydrogel polymer must be adjusted according to the soil conditions [15].Based on sources, Hydrogel polymer may be natural or synthetic. Synthetic polymer hydrogels are not biodegradable, which hurts the environment [16]. Natural polymers (agarose, alginate, and chitosan) can be used to alleviate the problem of hydrogel structure deterioration. Irrigation using biopolymer hydrogels could be a solution to the current drought situation [17]. In the agricultural industry, hydrogel polymers are used for a variety of purposes, including water retention, seed coating, soil erosion reduction, food additives, tissue culture, and structural components (covers for agricultural products) [18]. According to previous studies, applying low concentrations of superabsorbent polymers (SAPs) to soil for physical properties such as aeration reduces the rate of agglomeration and association between soil particles [19], Therefore, the application of hydrogels may be the best technology to improve water and fertilizer efficiency in arid regions [20]. In this review, we discuss the role of hydrogel polymers in agriculture.