Фотосинтетическая деятельность смешанных посевов трав, их продуктивность и влияние на плодородие дерново-подзолистой почвы в условиях Верхневолжья

Abstract

The results of long-term research on the photosynthetic activity of mixed crops of perennial grasses are presented, their productivity and the effect on the fertility of potentially poor soddy-podzolic soils are studied. It was found that in herbage based on clover, the maximum area (68.8 thousand m2/ha) and the photosynthetic potential of leaves (718 thousand m2/ha × day) on the control were formed by mixed crops of clover and festulolium, and against the background of mineral nutrition – mixtures clover with timothy (68.4 thousand m2/ha and 718) and festulolium (66.6 thousand m2/ha and 704 thousand m2/ha × day). In mixed crops with alfalfa mixtures with timothy and ryegrass, they had the highest leaf area – 57.9 and 57.5 thousand m2/ha and FP of 620 and 611 thousand m2/ha × day, respectively. A high leaf surface index was found in clover herbage with festulolium in control (6.88), timothy (6.84) and festulolium (6.66) against the background of mineral nutrition. Grass mixtures of alfalfa in productivity exceeded clover ones, the most productive on both backgrounds in terms of the yield of fodder units and protein collection turned out to be a grass mixture of alfalfa with festulolium – 7.19 in the control and 8.53 thousand / ha of fodder units when applying mineral fertilizers, 1069 and 1194 kg/ha of protein, respectively, sugar – festulolium on the control and festulolium and ryegrass on the background of mineral nutrition. The smallest amount of stubble-root residues (SRR) – 7.99, 8.32 in the control and 11.9, 14.5 t/ha against the background of mineral nutrition, respectively, accumulated grass stands of meadow clover with ryegrass and fescue due to a weak root system. The application of mineral fertilizers increased the amount of SRR in clover mixtures more strongly (by 55% on average) than in alfalfa (only by 26%), although in terms of the total amount of accumulated bio-residues, mixed crops of alfalfa exceeded clover crops – their maximum amount is 13.7 and 12.6 t/hectares on the control and 17.2, and 15.8 t/ha against the background of mineral nutrition accumulated mixtures of alfalfa with timothy and festulolium. Herbal mixtures with alfalfa accumulated more symbiotic nitrogen – from 54 to 58 kg/ha on the control and 56–74 kg/ha on the background of mineral nutrition. Mineral fertilizers significantly affected the symbiotic activity of only clover grass stands, increasing the amount of nitrogen fixed by them by 56%, and their effect on alfalfa mixtures was insignificant.