Analysis of direct and indirect effect of nitrogen fertilizers on Oka floodplain meadow egetation | Анализ прямого и опосредованного действия азотных удобрений на растительность лугов Окской поймы
2010
Kurkin, K.A., The V.R. Vilyams All-Russia Research and Development Inst. of Forages, Moscow Region (Russian Federation)
The observation of meadow vegetation and study of the influence on it of nitrogen fertilizer were carried out in the Ryazan Region. There was studied the effect of direct and indirect influence of fertilizers on self-sown seedlings, as well as on the dynamics of floodplain meadow vegetation after draining and irrigating. On flood meadows under one- and two-cut utilization, with the application of ammonium saltpeter at the rate of N100 and more during the season, available seedlings and species of ground-level layer perish because of self-poisoning due to shading. On short-flood meadows with the irrigation under five-cut utilization and with the application of increased amounts of nitrogen for aftergrowing (the total rate - N405), the participation of semi-high grasses in the yield during the 2 year is increased from 20 up to 60% but during the 4 year is declined to 30%. With three-cut utilization schedule (with the same soil fertility) the participation of semi-high grasses is increased up to 75% by the 4th year. The behavior of each semi-high grass species shows its bio-ecological peculiarities. Different regimes of nitrogen additions were studied in Oka floodplain meadows. When more than 100 kg/ha nitrogen were added as ammonium nitrate, seedlings and low plants died due to deep shade and nitrate toxicity. High nitrogen addition (N405) and frequent cutting (5 times) led to mean height grass dominance. Grass response to nitrogen regime was species-specific. As a consequence of topdressing, the intensive growth of grasses starts creating thereby shading which inhibits wakening buds in a tillering node. After plant formation sleeping buds start growing, in short grasses embryonic leaves and growth cones preserve, and in the high grasses both generative and long vegetative shoots die. Semi-high grasses are intermediate. Long preservation of high portion of semi-high grasses in plant stand is possible only with 3-cut utilization
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