Residual Silicon and Phosphorus Improved the Growth, Yield, Nutrient Uptake and Soil Enzyme Activities of Wheat

Silicon (Si) is known as a beneficial or quasi-essential element particularly for graminaceous crops, as Si increases photosynthetic efficiency, increased resistance to biotic and abiotic stress, aluminium toxicity, heavy metal toxicity, dry matter accumulation and enhances resistance to lodging and drought. The combined application of phosphorus (P) and Si has a significant impact on the growth and yield of various crops. While the residual effect of Si and P application on growth, yield and soil biological activity in wheat were not ascertained. Therefore, the present study was conducted to evaluate the residual effect of Si and P on the wheat crop. The four levels of Si (0, 40, 80, and 120 kg Si ha–1) and P (0, 30, 60, and 90 kg P2O5 ha–1) were applied to the preceding aerobic rice crop and their effect was evaluated in succeeding wheat crop after two years of application. The results demonstrated a significant effect of Si and P on wheat growth, yield, nutrient uptake, and soil enzyme activities. The residual effect of 120 kg Si and 90 kg P2O5 ha–1 significantly improved the grain yield of the succeeding wheat crop by 24–45%. Further, the residual Si and P remarkably improved Si, N, P, and K concentration in wheat grain by 35, 13.2, 45, and 56 %, respectively, over control. Similarly, an increase in the microbial biomass carbon, dehydrogenase, fluorescein diacetate, and alkaline phosphatase activity by 17.2, 33.5, 12.4, and 37.5%, respectively were observed in the residual application of 120 kg Si and 90 kg P2O5 ha–1 over control. Therefore, the inclusion of Si and P could have great potential to improve soil enzyme activities and productivity of the wheat crop.