Impact of clipping height and application of mineral fertilizers on the productivity of flood plain meadows in the Far North

The aim of the research is to determine the influence of elements of the system for the use of natural hayfields on the structure of phytocenosis and productivity of the meadow. The object of the research is the grass of reclaimed short-flood plain meadow of medium level in the flood plain of Kuya. The natural grass of the experimental site is small, cut and low. The vegetation of meadows is multi-herbage cereal. The field work procedure includes 2 factors: clipping height and application of mineral fertilizers. The reference example does not involve the application of mineral fertilizers, and the clipping height is 4-6 cm. The mineral fertilizers (N45P45K45) were applied on growing grass in spring. The work was carried out according to the research methodology which included the following records and observations: phenological observations; the role of sod-forming process; soil and agrochemical studies; consideration of herbal productivity. Test site soil: alluvial, sod cultivated, medium loamy. The density of the soil solid phase corresponds to 2.55g/cm3. The soil is highly acidic (pHwater - 5.41, pHsalt - 4.16), highly provided with mobile phosphorus (226 mg/kg of soil), the content of water-soluble potassium is 75 mg/kg of soil, and humus content is 1.04% (very low). The grass of the experimental site is thin and low, mainly there are cereals (60%) and forbs (38%). The best alternative for haymaking is the height of 4-6 cm, and when applying fertilizers, the mass of grass increases with respective growth of productivity, and a small share of the forbs remains. The best productivity results were obtained due to the application of mineral fertilizers at the low cut (4-6 cm) of grass, also this option provides an increase of above-ground mass productivity over root mass productivity, the ratio is 1:0,6 (this option ensures the highest productivity and minimal loss).