Zinc and potassium application influence biomass yield, electrical conductivity, proline, chlorophyll and soluble protein content of maize in coastal saline soil
摘要
Agricultural production in coastal saline soils have been severely constrained by the lack of fresh water. Brackish water can be utilized efficiently as an alternative irrigation source for crop production with appropriate potassium and zinc fertilization. A greenhouse pot experiment was carried out with two sources of irrigation water (SW0-normal water- EC:0.5 dS/m, SW1- saline water irrigation- EC: 8 dS/m), three doses of K (K0- control, K1- 90 kg/ha and K2- 120 kg/ha) and three types of Zn fertilizers (Zn0- control, Zn1- soil application of zinc sulphate- 5 kg/ha and Zn2- soil application of nano zinc- 2.5 kg/ha) to assess the interaction effect of salinity, potassium and zinc on biomass yield, nutrient uptake, content of proline, chlorophyll a and b and soluble protein of maize. The biomass yield and proline content increased significantly with brackish water irrigation whereas, the content of chlorophyll a and b, soluble protein and K+/Na+ ratio were decreased. Application of K2 significantly increased the proline content (38%), soluble protein (10%), K uptake (27%) and Zn uptake (35%). It reduced the adverse effect of salinity by lowering ECe and Na uptake. Addition of Zn2 significantly increased proline content (22%), uptake of K (30%), Ca (35%), Zn (51%) and K+/Na+ ratio (53%) with decreasing in Na uptake (68%) over Zn0. Combined application of higher dose of potassium and nano-Zn performed better than their individual application with higher biomass yield and plant parameters. Hence, K2Zn2 fertilizer dose is recommended for sustainable maize production in saline soils.