Improvement of Winter Wheat Mineral Nutrition on Calcareous Common Chernozems

Potassium omission plot in winter wheat was initiated in the fall 2012. It is a one-season demonstration experiment in winter wheat conducted on farmer’s field (Egorlyk District, Rostov Oblast, Southern Russia) in one replication. Two fertilizer treatments are studied: N54P52 (farmer practice) and N54P52 + K40. Plot size is 19.5 ha. Winter wheat is grown after sunflower. The variability of soil fertility parameters is also studied in this project, including nitrate N, Olsen P, exchangeable K, P and K extracted using a routine extraction with (NH₄)₂CO₃ solution.