RESPONSIVENESS OF POTATO VARIETIES TO BALANCED MINERAL FERTILIZER APPLICATION RATES

Abstract

The effectiveness of applying balanced rates of mineral fertilisers for potatoes was studied in the forest-steppe zone of the Southern Urals, taking into account potato varieties and agronomic practices. It was established that the crucial factor affecting the formation of planned tuber yields is the level of mineral nutrition, which accounted for 67% of the yield variation in 2019, 40% in 2020, 45% in 2021, and 39% under the conditions of 2022. For comparison, the planting density determined the variation by 8.4%, 41.5%, 37.2%, and 23.2%, respectively, and the genotype accounted for 15.2%, 10.9%, 14.3%, and 13.2% of the total tuber yield variation. In 2022, single irrigation of potatoes determined 20.4% of this parameter's variance. The fertiliser rate calculated to achieve the planned yield of 40 t/ha led to an average increase in tuber yield for the Zakhar variety by 8.16 t/ha, Kashtak by 9.08 t/ha, Amulet by 7.76 t/ha, and Cavalier by 9.75 t/ha. The fertiliser rate calculated for a 60 t/ha yield increased by 13.56, 12.92, 14.71, and 18.33 t/ha, respectively. The target tuber yield of 40 t/ha was achieved by the Zakhar (39.8 t/ha) and Kashtak (41.8 t/ha) varieties in 2019 (correlation coefficient 0.91), Amulet (39.1 t/ha) in 2020 (correlation coefficient 0.85) with a planting scheme of 75 x 19 cm, Cavalier (38.7 t/ha) in 2021 (correlation coefficient 0.39), and Amulet (41.8 t/ha) in 2022 with a planting scheme of 75 x 14 cm. The planned yield of 60 t/ha was achieved by the studied varieties only in 2022 with single irrigation (300 m3/ha) and a dense planting scheme (75 x 14 cm) for Amulet (60.9 t/ha) and Cavalier (58.4 t/ha), also with a planting scheme of 75 x 19 cm. The formation of planned potato yields in the forest steppe of the Chelyabinsk region can be ensured by cultivating adaptive varieties of local selection (Zakhar, Kashtak, Amulet, and Cavalier) and regulating the water regime through critical irrigation. In 2022, potato irrigation increased the average yield by 11.1 t/ha for Cavalier, 10.7 t/ha for Kashtak, 10.6 t/ ha for Zakhar, and 10.1 t/ha for Amulet compared to the rain-fed variant, thereby increasing the profitability of mineral fertilisers with an additional tuber yield by 1.5 to 2 times.