METHOD FOR DIAGNOSING LEVEL OF TOTAL NITROGEN IN LEAVES OF WINTER WHEAT PLANTS Russian patent published in 2025 - IPC A01G7/00 A01G22/20 

FIELD: agriculture.

SUBSTANCE: method comprises dividing planting area into four test sections: in first section no fertilizer is applied, in second section fertilizer N₉₀P₆₀ is applied, and for main soil treatment – ammophos 115 kg/ha N₁₄P₆₀, top dressing is carried out in spring with ammonium nitrate in tillering phase 110 kg/ha N₃₈ and in stem elongation phase 110 kg/ha N₃₈.At third section applied are fertilizers N₁₀₂P₅₄K₈₆, and under main soil treatment is introduced 375 kg/ha NPK N₅₃P₅₃K₈₆, top dressing is carried out in spring with ammonium nitrate in tillering phase 71 kg/ha N_24.5 and in stem elongation phase 71 kg/ha N_24.5.At fourth section applied are fertilizers N₁₁₆P₆₀K₉₇, as well as for main soil treatment are introduced 425 kg/ha NPK N₆₀P₆₀K₉₇, top dressing is carried out in spring with ammonium nitrate in tillering phase 81 kg/ha N₂₈ and in stem elongation phase 81 kg/ha N₂₈.Vegetation indices of chlorophyll a and chlorophyll b are determined in a differentiated manner during the phases of spring tillering, stem elongation, earing of winter wheat with the help of a spectroradiometer instrument in the field conditions: PSSR_a = R₈₀₀/R₆₇₅ and PSSRA_b =R₈₀₀/R₆₅₀ from lamina of upper leaves of 25 plants. For this purpose passage of section is carried out along maximum diagonal, starting from sowing border. Sampling of plants is performed in 25 points along the field diagonal; from each test section one sheaf is collected, and the sheaves are composed of whole plants by cutting them with scissors at the soil surface. Total nitrogen content is determined in plant leaves (%) by phases and versions of mineral nutrition in laboratory conditions by titrimetric method. Content of nitrogen in the initial sample is calculated based on the titration results, and the value of total nitrogen is defined as total content of organic nitrogen, ammonia and ammonium salts in the selected samples. Ratio is calculated PSSR_a to PSSR_b, further, performing the correlation analysis to determine the degree of dependence of the PSSR_a/PSSR_b ratio and the content of total nitrogen in the plant leaves. If the correlation coefficient PSSR_a/PSSR_b and content of total nitrogen is higher than 0.5 with a reliability level of 0.95%, then vegetation indices are compared with the level of content of total nitrogen: with values of PSSR_a/PSSR_b in spring tillering phase 1.070-1.095 – optimum, in stem elongation phase 1.071-1.097 – low, in earing phase 1.019-1.034 – very low.

EFFECT: method increases objectivity and accuracy of determining level of total nitrogen in plant leaves.

1 cl, 5 dwg