An effect of doses of nitrogen and of Rhizotorphin on pea (Pisum sativum l.) productivity in the conditions of podzol heavy-loam soil
The results of field two-factor experiment in the conditions of soddy-podzol heavy-loam soil permitted to determine an effect of increasing doses of nitrogen (factor A) on agro-chemical indicators of soil and grain productivity of pea (Pisum sativum L.). Variety response of the experimental crop was studied during treatment of sowing material with a bacterial preparation of biofertilizer “Rhizotorphin” (factor B). According to the results of agro-chemical analyses a close correlation dependence (r = 0.70-0.99) between the studied nitrogen doses (N30-120) and the amount of its mineral forms (N-NO3 / N-NH4 / Nmin) in soil has been established. Due to the usage of bacterial preparation of biofertilizer “Rhizotorphin” for pea seed inoculation a productivity increase was 4.45 dt/ha at LSD05 = 1.85 dt/ha. The responsiveness of pea plants on applying increasing doses of nitrogen was different that was connected both with biological peculiarities and the variety's ones of the studied crop and with an application of the bacterial preparation for treatment of sowing material as well. The use of “start doses” of nitrogen provided a reliable productivity increase of Pisum sativum for 1.96-6,43 dt/ha-1 at LSD05 = 1.72 dt/ha. Higher nitrogen doses (60-75 kg/ha) conditioned pea productivity decrease for 6.77-6.88 dt/ha. Nitrogen dose of 90 kg/ha promoted emphatic increase of grain productivity up to 23.34-29.59 dt/ha. Further nitrogen doses increase result in reliable productivity decrease. Greater economic indicators had been obtained at seed treatment with bacterial preparation of biofertilizer “Rhizotorphin” and using nitrogen doses (N30-90) - profitability level varied in a range of 26.5…60.0 per cent, with maximum to indicator (60,0%) at using a “start dose” of 30 kg/ha. Minimal prime cost of a ton of pea grain of Agrointel variety was obtained at seed treatment with bacterial preparation and nitrogen application in a dose of 30 kg/ha and comprised 3.750 rouble.