INFLUENCE OF FERTILIZERS APPLICATION ON YIELD AND FRUIT CHARACTERISTICS OF “KHENAZI” AND “LULU” DATE PALM CULTIVARS (Phoenix dactylifera L.) GROWING IN SANDY SOILS

Abstract

The present study was conducted during three consecutive years 2011, 2012 and 2013 at a private orchard located in Al- Hello at Ajman Emirate (UAE). The varieties used were Khenazi and Lulu date palm cultivars grown in sandy soil. This is done to study the effects of nitrogen (46% urea), phosphorus (48% P2O5), potassium (50 %K2SO4), granular sulphur (90%) and organic manure fertilization treatments on quantitative and qualitative characteristics of Khenazi and Lulu date palm cultivars. Soil content of N, P, K, Ca, Mg, Na, S, Fe, Mn, Zn, Cu, pH and Ece were determined before application of treatments. A mixture of nutrient elements 100g was applied for each tree except the control. Treatments applied in a trench method alone or in combination were N1600g urea, N2, 1000g urea, P, 800g, K, 1200g, N1+P+S, N2+P+S, N1+K+S, N2+K+S, 50 kg organic manure and the control (untreated). The results showed that, on Khenazi date palm, fertilizers treatments significantly affected fruit weight, flesh weight, fruit length and fruit width, fruit volume and flesh to seed ratio. Among all fertilizer applications the highest flesh to seed ratio and fruit length were obtained from N1+K+S. Moisture % decreased and TSS% increased by all fertilizers treatments, however, the lowest moisture % and highest TSS % were obtained from N1+K+S. The longer leaves obtained from N2, N1+P+S, N1+K+S and N2+K+S, whereas, all tested fertilizers treatments produced broad leaves. Application of different fertilization treatments significantly affected fruit number per strand and fruit number per bunch. The treatment N1+K+S gave the highest number of fruits per strand and bunch. Moreover, fertilization treatments significantly affected bunch weight and yield per palm except that 600g urea (N1) did not affect bunch weight in the three years of study. The study revealed that fertilizers alone or in combination improved fruit content of N, P, K, Ca, Mg, Fe, Cu, Mn and Zn, but among all fertilizers treatments, combined N1+K+S recorded the highest Fe, Mn and Zn in the fruit. The results obtained indicated that leaf N, P, K, Ca, Mg, Fe, Cu, Mn and Zn were affected by fertilizers treatments alone or in combination, but combined N1+K+S increased leaf Fe, Mn and Zn more than other fertilizers treatments. Regarding Lulu cultivar, the results indicated that all studied fertilizers treatments increased fruit traits of fruit weight, flesh weight, flesh to seed ratio, fruit length, fruit width, fruit volume and TSS%, but combined N2+K+S increased fruit weight, flesh weight, flesh to seed ratio and VI decreased moisture content compared to all fertilizers treatments. All tested fertilization treatments significantly increased leaf length and leaf width, fruit maturation%, fruit set %, number of fruits per strand, and number of fruit per bunch. Meanwhile, fertilizer treatment of combined N2+K+S gave the heaviest bunch weight and yield production per palm compared to all fertilizers treatments. The results indicated that the application of fertilizers alone or in combination significantly improved fruit content of N, P, K, Ca, Mg, Fe, Mn, Zn, Cu. The highest fruit Mg, Fe and Mn was achieved by combined N2+K+S. Likewise leaf nutrients content of N, P, K, Ca, Mg, Fe, Cu, Mn and Zn were affected by fertilizers treatments alone or in combination. However, combined N2+K+S were better than all fertilizers treatments in leaf Mg, Fe, Mn content. Therefore, application of combined N1+K+S was more efficient for Khenazi cultivar and combined N2+K+S for Lulu cultivar. Both fertilizers treatments, N1+K+S and N2+K+S, were suitable under the prevailing conditions.