The effect of application of potassium, magnesium and sulphur on wheat and barley grain yield and protein content

The objective of our experiment was to study the effect of mineral fertilizers, rich mainly in the K, Mg and S content, and compare their effect on grain yield and protein content of winter wheat and winter barley with fertilizer treatments without these elements. The analyzed fertilizer treatments were 1) Control, 2) mineral nitrogen treatment (N), 3) mineral nitrogen with phosphorus (NP), 4) NP with potassium, magnesium, and sulphur (NP+KMgS), and 5) NP with magnesium, sulphur and minor part of manganese (4%) and zinc (1%) (NP+MgSMnZn). The experiment was established in Lukavec experimental station (the Czech Republic) in 2013 and lasted until 2017. The crop rotation consisted of four arable crops: winter wheat, winter barley, rapeseed, and potatoes, but only winter wheat and winter barley are analyzed in this paper (grain yields and crude protein content). In comparison with the Control, the application of mineral fertilizers significantly increased grain yield and protein content of both kinds of cereal. Comparing mineral fertilizers, no significant differences were recorded between N, NP, NP+KMgS and NP+MgSMnZn treatments, showing that nitrogen was the most limiting factor affecting yield and protein content, and initial concentrations of K and Mg were suitable and capable to cover cereal’s demands. However, application of fertilizers has increased the K and Mg soil content and thus prevents the soil from the element’s deficiency, which does not has to be recognized in the early stages by visual observation of arable plants. The effect of the year was also significant as two out of four seasons were characterized by high temperatures and drought.