Sharing High-Yield Planting Experience for Autumn Potatoes

Mr. Zhang Chaohu from Jinghe Subdistrict Office, Tengzhou, Shandong, achieved a high yield of 1500 kg/mu with his autumn potatoes this year. His experience is as follows.

1. Seed potatoes: This spring he used virus-free Dutch No. 5 potatoes shipped from Northeast China to plant a spring potato crop, harvested in early June. From these he selected small tubers grown from vigorous plants with no symptoms of viral infection, and used whole tubers as seed. To prevent disease infection, the seed potatoes were not cut into pieces, and mechanical damage was avoided as much as possible. To promote rapid sprouting of the seed potatoes, 12 days before sowing, they were sprouted using a gibberellin glycerol solution (also called GG solution). The gibberellin concentration was 50-100×10-6. When preparing it from a 1000×10-6 gibberellin stock solution, the ratio of water to glycerol used to dilute the stock solution was 4:1. To disinfect pathogenic fungi on the surface of the seed potatoes, 600-fold mancozeb fungicide was also added. The seed potatoes were soaked for 15 minutes, then removed and piled in a ventilated, cool, rain-sheltered place, with each pile of seed potatoes about 30 kg. The piles were covered with moist fine soil, then with straw mats to preserve moisture. After 7-10 days, when the sprouts had grown to 2-3 cm, the potato piles could be opened, the seed potatoes picked out, and the sprouts exposed to light for greening and hardening for 1-2 days before sowing. Those with sprouts not long enough were kept piled for further sprouting. Sprouts longer than 2 cm were best; those shorter than 1 cm affected yield.

2. Sowing: Sowing was done in early August. Before sowing, the cultivation land was first loosened with a rotary tiller, then a soil conditioner, Mian Shen Geng, was sprayed at 200 g/mu to promote loosening and aeration of the soil 30-50 cm deep, which benefits future tuber expansion and deep root penetration and enhances absorption capacity. The planting density was greater than for spring cropping. Row spacing was 60 cm, plant spacing 20 cm, maintaining 5000 plants per mu and 9000-10000 stems. Before sowing, 100 kg/mu of commercial organic fertilizer and 100 kg/mu of potassium sulfate-type compound fertilizer were applied. A 3-cm shallow furrow was opened according to the row spacing, the seed fertilizer was applied, and the fertilizer and soil were mixed evenly. After the seed potatoes were sown, they were covered with 14 cm of soil to form large ridges. Ridge cultivation has the advantage of allowing irrigation in drought and drainage in waterlogging. After sowing, water immediately, and do not let the water stop until emergence, to keep the ridge soil cool and moist. In prolonged drought without rain, watering also has a cooling effect.

3. Field management: The growing period of autumn potatoes is relatively short. Before late September, the sunshine is longer and the temperature higher, which favors stem and leaf growth. In the later period, sunshine is shorter and the temperature lower, which favors tuber growth and makes stems and leaves less prone to excessive growth. Therefore, in management he took measures to promote vine growth as early as possible. After emergence and before the rosette stage, topdressing was applied twice consecutively, each time 10 kg/mu of compound fertilizer. With each watering, one intertillage was done, keeping the soil alternately dry and moist and the ridge soil loose and air-permeable. Combined with intertillage, the ridges were widened and thickened so that the longitudinal section of the ridge was concave-shaped. This ridge shape places the tubers in a soft soil layer during the tuber-setting period, which favors expansion. Before late September, timely promotion of stems and leaves was achieved through frequent watering and topdressing. Natural brassinolide Yishuofeng 481 was sprayed to promote growth and development. During the tuber-setting period, the temperature gradually decreased and soil evaporation declined; as long as the ridge soil remained moist, the furrows were not watered when dry.

4. Harvest: The first frost in early November only kills the top stems and leaves, so there is no need to harvest in a hurry. Harvest in mid-November.