Сергей Михайлович Авдеев In the studies carried out in 2004–2005 at the structural subdivision of Russian State Agrarian University – Moscow Timiryazev Agricultural Academy (Field Station), accumulation of NPK in the roots was observed. It was revealed that the underground mass of agrophytocenoses consisting of legume and cereal component mowed twice significantly outstripped the variants mowed three times during the growing season. The maximum underground mass was recorded in the third year of use. It was 8.70–10.7 t/ha in the variant with the variegated alfalfa Lugovaya 67. Dynamics of increase of underground mass in agrophytocenoses with meadow clover in 2004 and 2005 were close – 2.49–3.72 and 2.68–3.70 t/ha. At the same time the underground mass of variants with clover was characterized by the high content of nitrogen. Thus, the highest N content in agrophytocenoses with clover was observed for the varieties Mars (1.89%) and Ranniy 2 (1.82%), while agrophytocenoses with alfalfa had values of 1.75% and 1.65% (the varieties Lada and Lugovaya 67, respectively). The highest phosphorus content was observed in the variants where the legume component is represented by alfalfa Lugovaya 67 (0.48%) and Vega 87 (0.42%). At the same time among clover-grass agrophytocenoses it was 0.38% (the variety Ranniy 2). The maximum content of К2О was observed in the underground mass of alfalfa Lugovaya 67 (0.87%) and clover Trio (0.84%). The lowest relative content of potassium (0.64%) was recorded in the agrophytocenosis, where the legume component is represented by alfalfa (the variety Vernal). As a result of the conducted research, the advantage of alfalfa varieties over clover varieties was noted in terms of the relative content of the studied elements. At the same time, the maximum values were observed in agrophytocenosis (cereals + alfalfa) of the variety Lugovaya 67. Among the variants (cereals + clover), the maximum values for the accumulation of studied elements were characterized by the variety Ranniy 2.
Научная статья 
кострец безостый