Quantity of mineral elements in plants not the constant. Thus, the chemical compound of agricultural plants depends on their security mineral substances. The quantity of nutritious elements in a plant depends on soil-climatic conditions of territory, stages of development of grown up cultures, agricultural technicians, processings, degrees of security of soils nutrients, norms of fertilizers and other problems. Long-term researches show, that depending on an irrigation, norms of fertilizers and stages of development of plants, the quantity of nutritious elements at the mixed crops stubbles cultures differs in different bodies of plants. Are studied and analysed influence of norms of mineral and integrally-mineral fertilizers, proceeding from quantity various vegetative irrigation, on quantity of nutritious elements on stages of development of superficial weight of plants at mixed (corn and a soya) crops in stubbles plantings. Proceeding from quantity various vegetative irrigation and applications of various norms of fertilizers, from stage-bystage the analysis of nutrients in the mixed crops of plants it is visible, that the general NPK is observed on the highest phase stooling. From results of the analysis of samples of the plants taken at all stages, joint application of organic and mineral fertilizers in optimum norm becomes known, that, does not become the accumulation reason in considerable quantities of nutritious elements at the mixed crops of plants.