Effect of Irrigation levels, Mulching and Kaolin on Yield and Fruit Quality of Washington Navel Orange Trees Grown in Clay Soil

Abstract

A field experiment was carried out during 2019 and 2020 seasons at El-Riad, Kafr El-Sheikh governorate, to study the effect of irrigation levels, mulching and antitranspiration on yield and fruit quality of Washington navel orange trees. Eighteen combination treatments consist of three irrigation levels of 100, 75 and 50% ETc, two mulching types viz, black polyethylene and rice straw beside bare soil as control; and spraying with two kaolin concentrations 0.0 and 3% were arranged in a randomized complete block design with three replicates. Results indicated that irrigation levels at 100 and 75% ETc significantly enhanced and increased fruit set %, yield kg/tree or ton/feddan, fruit quality, yield efficiency kg/m 3 of canopy volume, water use efficiency kg/m 3 water and reduce fruit drop %. In addition, soil mulching with black polyethylene or rice straw was significantly increased all studied parameters compared to bare soil. Moreover, foliar application of kaolin at 3% was more effective in most cases compared to spraying with tap water. Overall, the combination of irrigation at 75% ETc with black polyethylene or rice straw mulch combined with spraying kaolin at 3% showed the best results of fruit set, less fruit drop, total yield, and fruit quality and increased water use efficiency. Furthermore, this combination saved about 25% of the total used water without negative effect on tree yield and fruit quality.