Effects Of Different Fertilizer Treatments On Yield,Quality And Nutrient Efficiency Of Two Cultivars Of Navel Orange

Field trials have been setup seven years ago with two navel orange cultivars, ?Newhall‘ and ?Cara Cara‘, were conducted for two consecutive years to study the effect of different fertilization treatments on fruit yield, quality and nutrient efficiency, so as to provide reference for fertilization. The main results are as follows:Pand K fertilizers application increased fruit yield and fruit quality of Newhall and Cara Cara navel orange, but fruit yield and quality would decrease when applied too much P and K. Newhall got the best yield when N 0.8 kg,P2O5 0.40 kg and K2 O 0.50 kg were applied to each plant. Cara Cara got the best yield when N 0.8 kg,P2O5 0.20 kg and K2 O 0.50 kg were applied to each plant. With the increasing application rate of P, single fruit weight of two kind navel orange cultivars was decreased. With the increasing application rate of K fertilizer,TA of two cultivars of navel orange fruits was increased while TSS/TA was decreased, and fruit weight was increased firstly and decreased finally. Comprehensive analysis of various quality indexes, fruit quality of P2K2, P1K2 and P2K0 treatments has good performance for two cultivars of navel orange. but P2K3 treatment resulted in poor fruit quality for two cultivars of navel orange. The application of Mg, Fe, Zn improved effectively the yield and quality of Cara Cara. Based on comprehensive consideration of yield and quality, the best treatment for Newhall was N 0.8 kg,P2O5 0.40 kg and K2 O 0.50 kg per tree every year, for Cara Cara was N 0.8 kg, P2O5 0.20 kg and K2 O 0.50 kg per tree every year, and the Fe was suggested to use.The soil available P, K and leaves P, K contents of two cultivars of navel orange were increased significantly by applying P and K respectively. But were not raised anymore while excess of P and K used, while the Ca, Zn absorption and utilization by the navel orange trees were inhibited by excess P, K application.There were differences between the two kinds of navel orange fruit nutrient content, but there‘s no difference in fruit nutrient content among different fertilization treatments. Fruit yield was the decisive factor for navel orange fruit nutrient removal and fertilizer application rate was the key factor for nutrient efficiency, while nutrient efficiency decreased significantly with the increasing fertilizer application rate.