Yellow Maize Crop Response to Potassium and Boron Fertilization under Upper Egypt Conditions.

Abstract

Potassium (K) and boron (B) are essential nutrients for plant growth, yield and quality, for their roles as enzymes activities and for sugars and carbohydrate transport as well as the synergetic relationship between them. In addition, plants that are large consumers of K require B levels greater than 20 ppm in the tissue to accomplish this. Also, to achieve or maintain maximal maize yields, supplemental K and B fertilization is often required, particularly on soils testing low for native available soil K and B. So, two field experiments were carried out during the two successive summer growing seasons of 2015 and 2016 at Kom Ombo Agriculture Research Station, Aswan Governorate (Latitude 24° 47' 21.40 N, Longitude 32° 92' 47.5 E), to evaluate the response of maize crop (Zea maize L. c.v yellow single hybrid 168) to K and B fertilization. Treatments were carried out in a split plot design with three replicates; the main plots were assigned for 6 rates of K fertilizer: K1 (control: without K fertilization), K2 (24 kg K2O fed-1), K3 (36 kg K2O fed-1), K4 (48 kg K2O fed-1), K5 (foliar applied 2% K2O) and K6 (24 kg K2O fed-1+ foliar applied 2% K2O), and the split plots were devoted to three treatments of foliar applied B (B0: without B, B1: 25 mg B L-1 and B2: 50 mg B L-1). Results demonstrated the importance of potassium and boron fertilization for maize crop yield and its quality under the present conditions. Results showed that addition of K fertilizer rates as soil and/or foliar with boron increased maize grain yield, its components and quality. N, P, K and B concentrations and uptake in both stalk and grain were also significantly increased. Yet, interactions among K fertilization rates and foliar applied B significantly increased grain and stalk yields as well as grain contents of carbohydrate and oil. The highest grain and stalk yields (3700 and 5369 kg fed-1, respectively) were recorded by the interaction of K4×B2 without significant differences between it and the yields recorded by the interactions of K3×B2 or K6×B2. N, P, K and B concentrations or uptake in grain and stalk increased with interaction between K and B, but these increases were only significant for K and B. On the other hand, economic evaluation of the studied treatments illustrated that the treatments of K6 (24 kg K2O fed-1+foliar applied 2% K2O) and K3 (36 kg K2O fed-1) with foliar applied 50 mg B L-1 were the most profitable since they achieved the optimum maize grain yield under this study conditions.