Technical and economic evaluation of the effect of kaolin foliar application time on some physiological, quantitative and qualitative characteristics of figs (Ficus carica cv. Sabz) in rainfed conditions

Drought and heat stress are intensified by the decrease in soil moisture in rainfed fig orchards during droughts, and it is necessary to provide a suitable method to increase the tolerance of trees and the quantity and quality of fruit. Using kaolin at the right time is a way to maintain rainfed trees in drought conditions. In order to investigate the effect of kaolin application time on some characteristics of figs, an experiment was conducted in the form of a randomized complete block design with four replications at the Estahban fig research station for technical evaluation during ۲۰۱۶–۲۰۱۸ and economic evaluation in ۲۰۲۴. Experimental treatments included foliar spraying with kaolin (late May or mid-July), water spraying (late May or mid-July), and control. The results showed that ۵% kaolin foliar spraying at the end of May had increasing effects on the leaf width and the number of syconia in the shoot. Also, spraying kaolin at the end of May improved many physiological characteristics in heat stress, so that with the use of this substance, the intensity of photosynthesis, relative water content of leaves, stomatal conductance and temperature of fig leaves improved to ۶. ۱ μMco۲.m-۲. S-۱, ۷۳.۷%, ۰.۰۸ mM. m-۲. S-۱ and ۲۶.۹ oC changed, respectively. The amount of carotenoid pigments, chlorophylls a, b and the total of fig leaves with ۵% kaolin at the end of May were higher than leaves without kaolin coating. Although the use of kaolin at the end of May had no effect on the quality of dried fig fruits, it increased the quantity of fruits and yielded up to ۸۲۷ g.m-۳ of tree crown. Therefore, a ۵% kaolin foliar application in late May is recommended to reduce heat stress and drought effects and increase fig yield in rainfed orchards. Also, the economic analysis of the results showed that this treatment has the highest net income and investment return rate.

کلیدواژه ها:

Anti-transpirants ، Drought ، Heat stress ، photosynthesis ، Spraying time ، Syconium ، تنش گرمایی ، خشکسالی ، زمان محلول پاشی ، ضدتعرق ، فتوسنتز ، گل آذین