The role of grassland crop rotation in piedmont zone of North Ossetia-Alania

The purpose of the study is to identify the effect of grassland crop rotation crops on the physical, agrobiological parameters of soils and on crop productivity in the forest-steppe zone of the Republic of North Ossetia-Alania. Tasks of the experiment: to study the structural and aggregate composition of the soil; to determine the volume mass of the soil under crop rotation crops; to identify the general biological activity of the soil; to identify the effect of crop rotation crops on productivity. The object of the study is the crops of the grassland crop rotation. The research was carried out in the field stationary crop rotation of the NCMPARI VSC RAS in the conditions of the forest-steppe zone of the RNO-A. The soil of the experimental site is represented by leached chernozems on pebbles, where humus ranges from 3.4 to 4.7%. The experiments were carried out in triplicate. The area of the experimental plots is 100 m2 and registration plot is 96m2. It was found that at the beginning of the growing season, the lumpy fraction under crop rotation crops varied from 13.50% to 50.10%, and soil lumps from 0.25 to 10 mm (macrostructure) – from 49.40% to 82.60%, fraction <0.25 mm – from 1.80 to 8.0%. The index of the structural coefficient ranged from 2.22% (corn) to 2.49% (oats + clover). Studies have proven that leached chernozems contain from 45.0 to 66.5% of aggregates that resist the eroding effect of water, so these soils have a good structure. Over the years of research on oats + clover crops (on average 0–30 cm of soil layer), the soil density was 0.95 g/cm3 at the beginning of the growing season, 1.19 g /cm3 during the period of intensive growth, 1.22 g/cm3 at the end of the growing season. This tendency is evident in all crop rotation crops. In our studies, the best indicators for the collection of forage units were the grass links of the crop rotation and amounted to 15.05 t/ha. In the rowed link of the crop rotation they amounted to 13.12 t/ha. In general, the energy value of the grassland link of the crop rotation turned out to be 216.45 MJ more than the tilled one, and amounted to 255.0 MJ/ha.