Chitosan application for organic and safe vegetable production
Chitosan produced from local shrimp-shell waste was tested to determine its general applicability for organic and safe vegetable production. Three model crops were used representing the three major groups of vegetables: fruit type harvested at the mature green or early ripening stage (tomato); young fruit type (cucumber) and leafy type (leaf mustard). In the tomato trials, 10 and 20 mL of 1% locally produced chitosan per 10 L water were compared with the same rate of application using a commercial chitosan imported from Thailand. In the cucumber trials, only the locally produced chitosan was used, at 10 or 20 mL of 1% solution per 10 L water and compared with chemical nitrogen fertilizer and foliar fertilizer at the recommended rate. In the leaf mustard trials, the locally produced chitosan only was also used at 10, 20 and 30 mL of 1% solution per 10 L water. The chitosan solution was sprayed onto the leaves to runoff starting 20 days after transplanting for tomato and cucumber and after 1 week from transplanting for leaf mustard; subsequent sprays were done every 4-5 days. Untreated plants served as controls. The local chitosan was more effective than the imported chitosan at the same rate of application of 20 mL of 1% solution per 10 L water in inducing early flowering and increasing plant height and fruit yield of tomato. The local chitosan-treated plants yielded about 38 t ha-1, while those treated with the imported plants yielded 32 t ha-1. The lower concentration of 10 mL of 1% solution of local or imported chitosan was less effective, but still increased the yield significantly compared with the control. In cucumber, chitosan similarly increased fruit weight and length; 10 mL of 1% chitosan per 10 L water was sufficient to achieve this effect. This effect was better than that of chemical fertilizer treatments. In leaf mustard, chitosan significantly increased plant height and yield, and a rate of application of 20 mL of 1% solution per 10 L water was found to be the optimum level. The results seemed to indicate that the locally produced chitosan can be used to improve growth and yield of different types of vegetables in Cambodia.
Tong, S., Eng, K., Yen, S.O., Kem, R., Buntong, B., Kong, T. and Acedo, A.L. (2017). Chitosan application for organic and safe vegetable production. Acta Hortic. 1179, 15-18
value addition, preharvest spray, fruit vegetables, leafy vegetables