[Effect of nitragin on alfalfa yield in the chernozem-poor zone of northen Siberia].

The presence of nitragin in soil on which lucerne was cultivated increased the yield of green biomass as well as the content in it of protein, essential amino acids, nitrogen-less extractive substances and ash, and decreased the content of cellulose. Nitragin increased the yield of green biomass by 44--51% in the absence of spontaneous nodule bacteria in soil and by 10--19% in their presence; the content of protein in the crop increased respectively 2.1--2.4 and 1.4--1.8 times. The most active strains of the lucerne nodule bacteria were 435a, 441a and a "local" one; the least active strain was 422a.