Influence of technological measures of growing different species of sainfoin on dynamic of biomass accumulation and its structure

Abstract

Purpose. To establish patterns of formation of high-yielding sainfoin phytocoenoses depending on species and variety, fertilization, and plant mowing height in the conditions of the Right Bank Forest-Steppe of Ukraine. Methods. Experimental studies were carried out during 2016-2018 in fields of Agronomic Experimental Station of the NULES (Pshenychne village, Vasylkiv district of Kyiv region). Weather conditions during the years of the research were quite complex for cultivation of perennial grasses. Rainfall close to normal was observed only in 2016. Three sainfoin species, namely common,Transcaucasian, and Hungarian were studied. Accounting and observation in the experiments were conducted according to conventional methods. Results. On average, in 2016–2018 on non-fertilized areas increase in mowing level of 5 cm to 15 cm caused decrease in height of common sainfoin herbage in the second cutting by almost 7 cm, in height of Transcaucasian and Hungarian sainfoin by 4 cm and 2 cm, respectively, whereas for full mineral fertilization and the inoculation of seeds in common sainfoin by 9 cm, Transcaucasian sainfoin by 4 cm, and Hungarian sainfoin by 2 cm. Thus, an increase in height of mowing affects most negatively on the common sainfoin both on unfertilized plots and at full or phosphate-potassium fertilization. The structure of plant essentially depended on sainfoin species, fertilization, and year of using herbages. The analysis of green mass of herbage sainfoin in flowering phase showed that the least indices of green mass per sample of 10 plants (109–151 g, depending on the sainfoin species) in the first year of using herbage were on unfertilized crops; indices of leaf mass (37–45 g) and stem mass (64–96 g) were the least too. Conclusions. The height of mowing herbage in the first cutting is an important factor in formation of sainfoin herbage height in the following cuttings. When increasing the height of mowing from 5 cm to 15 cm, not only the direct yield of the first cutting is lost, but it negatively affects the productivity of subsequent cuttings. Common sainfoin was the most productive species of three-year study, which regardless of fertilization and year of cultivation formed the highest yield of green mass. On average for three-year study (2016–2018), in common sainfoin mass of leaves, stems, and inflorescence was 28.7 %, 64 %, and 7.3 %, respectively. In Transcaucasian sainfoin these indices were 31.9; 61.5, and 6.6% and in Hungarian sainfoin were 33.9; 59.3, and 6.8%