Abstract
The article gives an assessment of one of the promising and valuable oilseeds – mustard, the cultivation of which is provided for by the program of diversification of grain production in Kazakhstan, in particular, crop production. It was revealed that the conditions of mineral nutrition of mustard in the steppe zone of Northern Kazakhstan have not been studied. Therefore, field experiments were conducted to study the optimization of mustard mineral nutrition conditions. A 14-variant scheme is presented for creating different levels of phosphorus and nitrogen in the soil in order to determine the quantitative relationship between the level of nutrients in the soil and the productivity of mustard varieties. During all the years of the study, mustard developed in conditions of phosphorus deficiency in the soil, average nitrogen supply and increased potassium only. The application of nitrogen-phosphorus fertilizers contributed to an increase in the nitrogen content of nitrates and mobile phosphorus in the soil by 2-3 times and was determined by the amount of fertilizers applied. The productivity of mustard on a naturally non-windy background was low, it depended on the dose of fertilizers, soil moisture, and the initial content of nutrients. This explains the ambiguous reaction of mustard to the application of the same types, doses and combinations of fertilizers.