To the question of tissue diagnosis of crops nutrition in precision farming system

Using differentiated way of introduction of min-eral fertilizers provides cultivation of grain crops taking into account fertility of each elementary site of a field. The system of diagnostics of nutrition is necessary for increasing efficiency of this way and timely response to security of crops with nutrients. Using of traditional diagnostics of food has certain restrictions as they were developed usually for vegetable cultures. Studying of possibility of using vegetable diagnostics based on extraction of ni-trates and water-soluble mineral phosphates from vegetating parts of spring-sown wheat at differenti-ated way of application of fertilizers was the re-search objective. The experiments were made in a forest-steppe zone of Trans-Urals in the field with spatial heterogeneity which is strongly expressed in fertility. It was established that at differentiated way of application of fertilizers on planned productivity the content of nitrates increased in spring-sown wheat with 6.73 to 34.63 mg/%. It was revealed that differentiated application of fertilizers on the planned productivity of 3.0 and 4.0 t/hectare pro-moted the reduction of the content of nitrates to 8.78 and 19.68 mg/ % respectively. The content of nitrates in spring-sown wheat in the period of its tillering is not interconnected with the content of nitrate nitrogen in arable layer, i.e. the coefficient of correlation was minimum (-0.14). It was established that correlation communication between the content of nitrates in the soil in the period of tillering and productivity of spring-sown wheat was missing, i.e. the coefficient of correlation made 0.17 units. Aver-age degree of dependence was found between the content of nitrates in leaves of spring-sown wheat and productivity (k = 0.63 units). Using of traditional diagnostics of plants nutrition basing on nitrates extraction and water-soluble mineral phosphates is not acceptable for using on grain crops as they do not reflect a real condition of security of cultures with nutrients.