Applications of Natural Polysaccharide Polymers to Overcome Water Scarcity on the Yield and Quality of Tomato Fruits

Abstract

As a result of water resource crisis, water-saving agriculture is necessary for sustainable development. Natural polysaccharide polymer is gaining great acceptance over synthetic polymers as controlled-release systems due to it is safe for the environment, cost effectiveness, easy availability, and biodegradability. This study is designed to evaluate the potential of natural polymers (cellulose, starch and cellulose/starch composite) to overcome scarcity of water on tomato (Solanum lycopersicum). Two different agricultural solid residues (rice straw and potato peels) were used to prepare of natural polymers. Polymer efficiency to water-saving and controlled release sencor herbicide was studied. Greenhouse experiment was conducted during 2017/2018. Four treatments; without polymer as a control and with different polymers (cellulose, starch and cellulose/starch composite) under three different level of irrigation (100, 75, and 50% FC) were used. Data indicated that the maximum swelling ratio of different polymer were in the fowling order, cellulose/starch (6.21 g/g) > Cellulose (4.80 g/g) > Starch (3.01 g/g). The results from the pot experiment showed that the addition of natural polymers to the soil have a positive effect to conserve water and increase the proportion of soil moisture compared to control. The highest increase was recorded at cellulose/starch polymer, this increase reached to 2.7-, 2.2- and 2.1 fold for 100, 75 and 50% FC that control. Natural polymers application with different water stress condition have positively affected on yield and quality of tomatoes especially when polymers were use under full irrigation. The increase of yield was recorded when applied different polymers (cellulose, starch and cellulose/starch) under full irrigation (100% FC), this increase reached to 13.7, 14.7 and 20.5% compared to without polymers and 2.2, 3.8 and 5.4% under irrigation scarcity (75% FC) compared to control without polymers (100% FC). Irrigation scarcity increased proline and phenol content and decrease total chlorophyll. Vitamin C, total soluble solids, pH, lycopene and juice content improved significantly with applies of natural polymers. The use of natural polymers under water scarcity improved the water use efficiency (WUE) of tomatoes.