Sugar beet (Beta vulgarisL.) response to diammonium phosphate and potassium sulphate under saline–sodic conditions

Abstract

AbstractSalinity and sodicity are prime threats to land resources resulting in huge economic and associated social consequences in several countries. Nutrient deficiencies reduce crop productivity in salt‐affected regions. Soil fertility has not been sustainably managed in salt‐affected arid regions. Few researchers investigated the crop responses to phosphorus and potassium interactions especially in saline–sodic soils. A research study was carried out to explore the effect of diammonium phosphorus (DAP) and potassium sulphate (K2SO4) on sugar beet (Beta vulgarisL.) grown in a saline–sodic field located inKohat district ofPakistan. The crop was irrigated with ground water withECiwvalue of 2.17–3.0 dS/m. Three levels each of K2O (0, 75 and 150 kg/ha) as K2SO4and P2O5(0, 60 and 120 kg/ha) as DAP were applied. The application of P significantly affected fresh beet and shoot yield while K fertilizers had significant effect on fresh beet yield and ratio of beet:shoot, while non‐significant effects on the fresh shoot were observed. The application of K1and K2promoted sugar beet shoot yield by 49.2 and 49.2% at P1and 64.4 and 59.7% at P2, respectively over controls. In comparison with controls, fresh beet yield was increased (%) by 15 and 51, 45 and 84, and 50 and 58 for corresponding K1and K2at P0, P1and P2, respectively. Addition of P1and P2increased beet yield by 37 and 47% over control. The shoot [P] (mmol/kg) were achieved as 55.2, 73.6 and 84.3 at P0, P1and P2, respectively. The shoot [Mg] and [SO4] tended to decrease with increasing P levels, while [SO4] was markedly reduced at P2. The effect of P on leaf [Na] was non‐significant, but increasing levels of K decreased [Na] substantially at P0and P1, but there was no difference in the effect of K level on [Na] at P2. Consequently, K application reduced leaf Na:K ratios. Fresh shoot yield was weakly associated with leaf [P] (R2 = 0.53). The leaf Na:K ratio showed a negative relationship (R2 = 0.90) with leaf [K]. A strongly positive relationship (R2 = 0.75) was observed between leaf [K] and fresh beet yield. The addition of K2SO4also enhanced [SO4] and SO4:P ratios in leaf tissues. The ratio of Na:K in the shoot decreased with increasing K application. These results demonstrated that interactions of K and P could mitigate the adverse effects of salinity and sodicity in soils. This would contribute to the efficient management of soil fertility system in arid‐climate agriculture.