Evaluation Effects of Sustainable Deficit Irrigation and Organic Mulch on apple cv. “Granny Smith” Water Productivity and Yield at harvest

Water is one of the most important restrictive factors in the production of agricultural products worldwide. The aim of this research is to study the effects of different levels of irrigation and organic mulch on yield, water productivity, fresh weight, dry matter percentage, hardness, soluble solid content, titratable acid, and chlorophyll index of Granny Smith apple fruit at harvest. For this purpose, factorial experiment was performed in a randomized complete block design with three replications in 2019. Irrigation treatment were applied at supply levels of 100, 75 and 50 percents of tree water requirement (ETc) and organic mulch to thicknesses of zero, 4, 8 and 12 cm. The results showed that the highest average of fresh weights of fruit were allocated to 75 and 100 percent water supply levels and organic mulch treatment at thicknesses of 8, 4 and 12 cm had a significant positive difference in fresh weight of fruit compared to the control, respectively. The average yield of mulched trees was 11.52 percent more than control trees, the highest yield was obtained in treated trees with 8 cm of mulch. Fruit SSC and the firmness of fruit were improved at 50 percent irrigation. The interaction of 8 cm mulch treatment with 75 percent irrigation had the most amount of fruit acid. Both chlorophyll a, b and total decreased with increasing drought stress and improved with the application of mulch treatments .In addition, interaction of both experimental treatments, increased water productivity and benefit per drop unit area.