Yield and Nutrient Contents of Wheat, and Changes in Selected Soil Properties after 23 Years of Phosphorus Fertilizer Application

Effective nutrient and fertilizer management practices play a pivotal role in sustaining agriculture and mitigating the effects of climate change. These practices have a direct influence on soil fertility and crop productivity. This study investigated the long-term impacts of different phosphorus (P) fertilizer doses (0, 50, 100, and 200 kg P2O5 ha-1) on biomass yield and grain nutrient levels of wheat crops as well as on selected soil properties. The experiment was established in 1998 at the Research Center of Cukurova University in Adana, Southern Turkey. The wheat seeds were sown in October 2020 and harvested in May 2021. The experimental design was a randomized complete block, comprising 12 plots and replicated three times. Soil samples were collected at depths of 0-15 cm and 15-30 cm and subsequently analyzed for total carbon, organic carbon (OC), total nitrogen (TN), and the number of mycorrhizal spores. At harvest, wheat plant samples were collected for evaluating total dry biomass, grain yield and concentrations of potassium (K), zinc (Zn), total carbon (C), and total nitrogen (N) in the grain. The result showed that there was a linear increase in the total dry biomass of wheat, however, grain yield started to decline at P200. The wheat grain nutrient concentrations did not differ significantly across P doses, except for higher concentrations of Zn and K at P50 and higher values of grain C and N at P100. However, there was a linear decrease in Zn concentration as the applied P dose increased. The soil OC and soil TN at 0-5 cm were significantly changed relative to the control. The highest levels of soil OC and TN were observed at P100. The number of mycorrhizal spores did not significantly change with the P dose, but a decreasing trend was observed at higher doses. In conclusion, based on the observed parameters of wheat grain yield, total biomass production, grain nutrient concentrations, and soil OC storage, the application of 100 kg P2O5 ha-1 outperforms other P doses. However, the agronomic efficiencies, soil nutrient balance, and environmental effects of the applied P dose require more research.