Influence of fertilization systems on productivity formation of grains and legumes in short-rotation cultivations

Abstract

The yield and quality indicators of a pea, soybean grain, and water-physical and nutritional condition of the soil under these crops in different types of crop rotations under intensive and alternative fertilizer systems were studied. The maximum yield of pea grain 2.51–2.64 t/ha and soybean 2.13–2.25 t/ha was obtained under conditions of direct N₄₅R₄₅K₄₅ use for peas and soybeans and plowing once per rotation of 40 t/ha of manure, which exceeded control indicators by 29.0–29.2 and 35.2–36.4 %. Higher yields were formed by pea plants in grain crop rotation with 50 percent saturation of grain ears. In the crop rotation, saturated with 75 % of ears, pea yield was lower by 0.13 t/ha. The best precursor for soybeans was spring barley, after which the unfertilized variant yielded 3.5 % higher than after buckwheat and 4.3–5.3 % when using organo-mineral fertilizer systems. Peas and soybeans have the highest weight of 1000 grains (237–244 g and 172.5–
176.3 g), grain nature (779–789 g/l), protein content (18.86–19.70 and 37.7–38.6 %) and fat (19.0–19.7 %) were obtained on the variant of manure aftereffect (40 t/ha) and direct application of fertilizers to crops in the norm N₄₅Р₄₅К₄₅. Grain of lower quality was obtained under control (without fertilizers). Depending on the predecessor and the type of crop rotation, the percentage of protein in peas and soybeans was 18.48–18.53 and 35.7–36.1 %, fat – 18.0–18.7 %.

The reserves of productive moisture in the arable layer of the soil for the period of germination of legumes were sufficient for the growth and development of plants and depending on the structure of crop rotation and predecessors were: under peas – 26.5–28.0 mm, soybeans – 30.4–31.8 mm. These indicators increased with the depth of sampling and in the layer of 20–40 cm were: under peas – 31.4–
33.2 mm, soybeans – 36.0–37.8 mm. Fertilizer systems provided a higher level of moisture accumulation. Compared to the control on the options with alternative fertilization system, the value of soil moisture was higher by 1.8–2.4 %, intensive – by 6.0–6.4 % under peas, and by 3.0–3.8 % and 6.5–7.0 % under soybeans. With the passage of subsequent phases of vegetation, the values of soil moisture changed depending on precipitation, the intensity of its use by crops, and different levels of fertilizer.

The density of soil structure under legumes of crop rotations increased during their growing season and was lowest in the initial stages of development. In particular, for the period of germination layers 0–10 cm under the pea, its values varied from 1.10 to 1.18 g/cm³, in the horizon 10–20 cm and 20–30, respectively, 1.19–1.28 g/cm³ and 1.26–1.37 g/cm³. Under soybean crops, respectively, by horizons: 1.12–1.17, 1.17–1.22, 1.21–1.26 g/cm³. The use of intensive (manure + mineral fertilizers) and alternative (green mass of post-harvest radish oil + by-products of the predecessor + mineral fertilizers) fertilizer systems restrained the compaction process and provided the soil layer 0–10 cm lower by 3.4–1.7 % of the soil mass after spring barley and by 2.6–1.74 % after buckwheat in comparison with the control without fertilizer.

The nutrient regime of the soil in pea and soybean crops depended on the fertilizer systems, the type of crop rotation, and the predecessor. The highest content of alkaline hydrolysis nitrogen in both pea and soybean crops (11.97–12.08 and 11.64–11.75 mg/100 g of soil), mobile phosphorus (12.97–13.13 and 12.71–
12.86 mg/100 g of soil) and exchangeable potassium (11.57–11.67 and 11.45–
11.63 mg/100 g of soil) in the arable layer were in the germination phase on the option of using 40 t/ha of manure in crop rotation and direct application under these cultures of mineral fertilizers in a dose of N₄₅R₄₅K₄₅.