Purpose. To determine the long-term effect of a complex of factors (anthropogenic and natural) on the productivity of sugar beet for a significant period and the level of pest reproduction. Study of short crop rotations.
Methods. Field, laboratory, statistical.
Results. The uneven distribution of precipitation during the sugar beet growing season has differently affected the efficiency of fertilizer systems and, as a consequence, the growth, development of plants and the yield of root crops. Yield of sugar beets at constant sowing on average for five years was dynamic, but its highest productivity, regardless of the fertilizer system, was in the first years of research, from 29.7 to 39.1 t/ha (on average for 1978–1982). Further cultivation in monoculture has led to yield reduction. The highest yield of sugar per hectare was also observed in the first five years, and varied in different fertilizer treatments from 4.67 to 6.22 t/ha. The lowest yield was in 1988–1992 and 1998–2002, 2.71 to 4.42 t/ha and 2.23 to 4.53 t/ha, respectively. Sugar beet yield in crop rotation was influenced by both forecrop and aftercrop. On average, during the years of research (2011–2019), the highest yield (43.0 t/ha) was obtained in the three-field crop rotation winter wheat — spring barley — sugar beet, while the lowest (41.8 t/ha) in the crop rotation sunflower — winter wheat — sugar beet, slightly higher in the four-field crop rotation soybean — winter wheat — sugar beet — corn (42.3 t/ha). The yield of sugar during continuous sowing, on average during the study period, was 3.5–5.1 t/ha, while in crop rotation it was 7.7–8.3 t/ha. According to the results of the survey of crops in the cotyledon phase, it was found that in unchanged sowing the density of common beet weevil (Bothynoderes punctiventris Germ) is quite high, 8.8 beetles/m2 (average for 2006–2008) and exceeds the harmfulness threshold (0.2–0.3 beetless/m2) several times. At this density, the damage to plant seedlings was significant.
Conclusions. The yield of sugar beet is influenced by both natural and anthropogenic factors. Of the anthropogenic, in addition to fertilizers, it is important to adhere to scientifically sound crop rotation. Long-term stationary studies have shown that the cultivation of sugar beet in monoculture leads to a gradual and stable decrease in yield and, consequently, the yield of sugar per hectare. The use of mineral and organic fertilizers helps to increase yields, but not significantly. In addition to weather conditions, the yield of sugar beet in crop rotation is influenced by forecrop and aftercrop. In the studied crop rotations, the lowest yield was obtained in the crop rotation where the forecrop of beets was sunflower, and the largest yield was obtained with legumes. Observance of crop rotation affects the phytosanitary condition of sowing; therefore, in monoculture, the density of common beet weevil is much higher than threshold, which leads to additional costs.
Efficiency of grain production in crop rotations of the dry steppe of the Lower Volga region
