Plants diagnostics of nitrogen nutrition of flax

Field experiments with fiber-flax varieties Zaryanka, the Alpha and the Lada was carried out on soddy-podzolic soil under Northern part of the Nonchernozem zone. As a result of 5 years of research studied the influence of increasing doses of nitrogen fertilizer on the dynamics of mineral nitrogen in the soil, total nitrogen content of the flax plant. The mathematical model of flax straw yield has been developed. It was revealed that the increase of productive moisture reserves in the soil from 30 to 40 mm in a layer of 0–40 cm in the phase of “herringbone”–the beginning of rapid growth, increased productivity of flax straw varieties Alpha on 2.8 t ha^–1. The simultaneous increase in the total nitrogen content of the flax plants in the phase of “herringbone” on the 0.1% increment crop yield increase up to 3.0 t ha^–1.