Effects of organic manures on yield, fruit quality, nutrients and heavy metals content of Barhy date palm cultivar

Abstract

A field experiment was conducted to investigate the effects of plant residues and/or inorganic manures with or without chemical fertilizers (NPK) on yield, fruit quality and contents of some nutrients and heavy metals of fruit of Barhy date palm cultivar during 2009 to 2010 and 2010 to 2011 in Jouff, Saudi Arabia. The following five treatments were used in this experiment: agricultural waste + mineral fertilizers, agricultural waste + 5% sheep manure, agricultural waste + 10% sheep manure, agricultural waste + 20% sheep manure and agricultural waste + 40% sheep manure. The results indicate that agricultural waste + 40% sheep manure gave the highest initial fruit set and retained fruit, bunch weight, yield fruit weight, flesh weight, flesh thickness, fruit volume, fruit dimensions, total soluble solids, non-reducing sugars and total sugars as compared with the other treatments in the two seasons. Applying agricultural waste + mineral fertilizers showed highest increase in the total acidity and moisture content percentage than the other treatments in both seasons. Moreover, N, P, K and Mn contents in fruit increased significantly with agricultural waste + 40% sheep manure more than those in the other treatments in both seasons. Fe and Zn contents, did not change significantly in both seasons. It could be concluded that the highest yield and better quality of Barhy date palm cultivar were obtained with agricultural waste + 40% sheep manure. Key words: Date palm, organic manure, nutrients, heavy metals, fruit quality.