Effects of sulphur and zinc applications on growth and nutrition of bread wheat in calcareous clay loam soil

Abstract

The objective of this study was to evaluate the effects of sulphur (S) and zinc (Zn) on soil pH and electrical conductivity (EC), nitrogen (N), S, iron (Fe), Zn, N:S ratio; and straw and grain dry weight of wheat grown in a calcareous clay loam soil. For this purpose, a pot experiment was conducted in greenhouse conditions. Sulphur was applied at 0, 10, 50, 250 mg Skg^-1 (as CaSO₄.2H₂O) and zinc at 0, 5 mg Znkg^-1 (as ZnSO₄.7H₂O) to the soil. The soil pH decreased by S alone. The soil EC increased due to increase in sulphur with zinc. The straw S concentration increased by sulphur alone. In the 250 mg Skg^-1 application to soil, the straw S concentration increased by 28.13% when compared with 0 mg Skg^-1 treatment. The concentrations of grain S and Fe, straw Zn, straw and grain N and N:S ratios were not significantly affected by sulphur and zinc. The grain Zn concentration was significantly increased by sulphur with zinc. In the 250 mg Skg^-1 with 5 mg Znkg^-1 application to the soil, the grain Zn concentration increased 38.47% when compared with no sulphur and zinc treatment to soil. The zinc treatment led to a significantly reduced straw Fe concentration. The straw dry weight was significantly affected by sulphur alone and it increased from 2.53 to 3.86%. The grain dry weight was significantly affected by zinc alone and it decreased by 12.18%. But, the grain zinc concentration increased 25% by increasing the zinc. The results suggest that application of sulphur and zinc could be a good approach for the nutrition of wheat plants. However, the generated salinity was high for sulphur applications, which means that plants might be faced high salinity problems. Also, with the application of high sulphur to plants, it should be considered that an N:S imbalance can occur. On the other hand, N:S imbalance can occur in crops grown in high N fertility in especially, S-deficient soils. Therefore, the levels of electrical conductivity, pH, texture, CaCO₃, organic matter, sulphur and nitrogen of soils and cultivated plant species should be taken into consideration when recommending sulphur and zinc application to soils.

Key words: Sulphur, zinc, soil pH, soil salinity, calcareous soil, wheat, N, Fe, Zn, N:S ratio.