Plant succession of natural grasslands under radical improvement in the southern forest-steppe of the Western Siberia
The low fodder productivity of vast areas of natural forage lands in Siberia necessitates their radical improvement. High fodder productivity will strengthen the fodder base of the region, which is important for the developing cattle breeding. The authors carried out an experiment of radical improvement of natural grasslands in order to clarify and develop methods of increasing the productivity of natural grasslands in the southern forest-steppe of Western Siberia. The authors studied the effect of two factors: The first factor - tillage followed by sowing of perennial grasses; The second factor - the effect of organic fertilizers (20 t/ha). By the second year of observations in the variant where soil disking was carried out, only motley grasses were noted. Disking followed by seeding of perennial grasses promoted the development of seeded grasses (80% of the composition of the herbage). The remaining niche of grass stand was occupied by motley grasses. The influence of organic fertilizers in the second year of observations almost does not affect the structure of herbage, only in the variant with the sowing of grasses the distribution of different botanical groups is more uniform. The composition of grass stand changes significantly between the second and sixth years of observations under the influence of tillage and organic fertilizers. The development of cereals and legumes in the herbage in the variant without tillage in the third and subsequent years is noted. By the sixth year of observations in the herbage remain only cereal grass (60%) and mixed grass (40%). Dynamics of herbage structure by years of development on the background of organic fertilizers differs little from the herbage without fertilizers. By the second year of observations, there is no significant influence of fertilizers and tillage on the yield of grasses. In the sixth year of observations (2016) there was a significant influence of organic fertilizers. Even without soil treatment, the yield almost doubled from 0.6 t/ha in the version without fertilizers to 1.1 t/ha of absolutely dry matter in fertilized variants. The greatest increase in yield was noted in the variant with discing, 2.7 times (from 0.6 to 1.6 t/ha); in the variant with grass seeding and discing 1.4 times (from 1.1 to 1.6 t/ha) (absolute dry matter). The effect of tillage on the yield without fertilizer was much less. Consequently, tillage and fertilization contribute to a more uniform distribution of representatives of different botanical groups of grasses in the herbage. The productivity of the natural meadow increases significantly by the sixth year of observations after the improvement.