METHOD OF DETERMINING OPTIMUM DOSE OF FIRST NITRIC FERTILISER FOR WINTER CEREALS Russian patent published in 2017 - IPC A01C21/00 A01G7/00 

FIELD: agriculture.

SUBSTANCE: invention relates to agriculture, specifically to technology of cultivating winter cereals. Method involves determining time of beginning of spring vegetation (VNVV) of winter cereals, collecting soil samples from 0–20 cm layer and vegetable samples with account sites of field in period of beginning of spring vegetation of plants, counting in all living stems with length > 10 mm, determining density agrophytocenosis (AFC), making a decision on value of planned yield. Additionally, extraction of soil samples from 20–40 cm layer, in which level of phosphorus and potassium modes of AFC is determined from content in soil movable phosphorus (P₂O₅) and exchange potassium (K₂O), in soil samples from 0–20 cm layer, determining level of nitric AFC mode from content of nitrogen of exchange of ammonium (N-NH₄), and determining optimum dose of first nitric fertiliser for winter cereals,calculated by formula:

where dn = x_n-K_n (difference between value of each factor and value of its constant), x is a factor, K is a constant of factor (average annual level of factor), Y is optimum dose of first nitric fertiliser, kg nitrogen in rate of application/ha, x₁ is nitrogen content of exchange of ammonium (N-NH₄) in soil, mg/kg, x₂ is movable content of phosphorus (P₂O₅) in soil, mg/kg, x₃ is content of exchange potassium (K₂O) in soil, mg/kg, x₄ is density AFC, stems/m², x₅ is planned productivity, centner/ha.

EFFECT: method provides more accurate determination of optimum dose of first nitric fertiliser for winter cereals with due allowance for yield.

5 cl, 2 tbl, 1 ex