When is the best time to sow winter potatoes? How to manage in the field?

After the late rice harvest, some farmers will begin to use winter fallow fields to grow potatoes, and from February to March the following year, they will harvest and sell potatoes before a large number of potatoes are on the market, which can make a considerable profit. So when is the best time to sow winter potatoes? How to manage in the field?

When is the best time to sow winter potatoes?

The planting time should be carried out immediately after the late rice was cut, and it was the most ideal from late October to early November. Note that if you use rice fields to plant potatoes, it is best to plant in deep ditches and high borders, and it is not appropriate to choose rice fields where the soil is heavy and easy to consolidate. In order to prevent the spread of diseases, avoid continuous cropping with peanuts, tobacco, tomatoes and other eggplant crops.

In addition, the selection of convenient drainage and irrigation, fertile sandy soil, timely early sowing, which is the basis for high yield and high quality.

Second, how to manage winter potatoes in the field?

1. Water management

Potato is a crop that needs more water. Soil water shortage will reduce the absorption rate of N, P, K and other nutrients, and reduce the accumulation of dry matter in tubers. Most of the growth period of winter potato is in the season of drought, little rain and low air humidity, especially in the driest season from February to April every year, which is the most exuberant time for potato growth, and the greatest demand for water, which is also the key period to determine yield. From February to March, it is best to water it once a week. During the whole growth period of potatoes, it is most appropriate for soil moisture to be kept at 60% of the maximum capacity in the field.

2. Nutrient management

The main results are as follows: (1) according to the basic principle of the combination of organic and inorganic, base fertilizer and topdressing, balanced fertilization should be promoted, controlled and protected. In the early stage, the potato should grow as early as possible, be more branched, and fertilize mainly with nitrogen, phosphorus and potassium, and 70% fertilizer should be applied within 60 days after emergence; in the middle stage, the growth of stems and leaves should be controlled, so as to promote the formation and expansion of underground tubers; in the later stage, the leaf color should not turn yellow prematurely, so as to maintain the photosynthetic efficiency of leaves, produce more nutrients for underground tuber expansion, fertilize mainly with potassium and calcium fertilizer, and apply nitrogen fertilizer appropriately. All fertilizers should be applied 30 days before harvest.

(2) the application of organic fertilizer should be applied at the time of sowing, 30-40 tons of fully mature organic fertilizer per hectare, 45% potato special compound fertilizer (13-6-16, plus medium trace elements) or 900 kg per hectare, calcium superphosphate 300 kg, urea 150 kg, potassium sulfate 300 kg.

(3) the application of topdressing fertilizer is mainly nitrogen, phosphorus and potassium fertilizer, but the application time should not be too late, especially in the later stage, in order to avoid excessive growth of stems and leaves and affect tuber expansion and quality. Topdressing is divided into 2-3 times according to the profit of about 250 kg per hectare. The seedlings were fertilized for the first time and poured with water to promote early development and increase the photosynthetic area. The second topdressing during budding can promote the continuous growth of stems and leaves and increase the area of photosynthesis, which is beneficial to the expansion of tubers. Topdressing should be carried out in the afternoon, should avoid fertilizer contact with leaves, such as fertilizer sprinkled immediately after watering to accelerate fertilizer dissolution, taking into account the cleaning of leaves. The potato cubes were sprayed with 800 times Jiamei platinum for 2-3 times during the expansion period.

3. Weeding and ridging in mid-tillage

Potato tuber layer is mainly distributed in the soil layer of 10 cm to 15 cm, which needs loose soil environment. To create a good environment for the healthy growth of the plant and the expansion of the tuber, the weeding is usually done three times in the middle tillage: the first time is carried out before the seedling is closed, with appropriate deep hoe; the second and third times, shallow hoe is needed to prevent the new stolon from being cut off. Combine with weeding, ridging and soil cultivation every time. Timely and early cultivation of soil has no harm to underground roots and stems, while high cultivation of soil is beneficial to water and fertilizer conservation, frost prevention, reduction of green potato, improvement of tuber quality and increase of yield.

4. Pest control

The main results are as follows: (1) in order to obtain higher yield and quality, it is necessary to strictly control insect pests, especially aphids can transmit viruses, and aphids control aphids from emergence. Do not use high toxic, high residue, high biological enrichment, high three (teratogenic, carcinogenic, mutagenic) pesticides and their mixtures prohibited by the state.

(2) pest control aphids can be controlled with 2.5% bifenthrin EC or 10% imidacloprid wettable powder. The underground pests such as mole cricket and ground tiger can be trapped and killed by chlorpyrifos, and Liriomyza huidobrensis and Pieris rapae can be controlled by Liriomyza huidobrensis and Pieris rapae.

(3) the disease control of planting potato in winter is mild, but the main diseases of potato in winter, such as bacterial wilt, late blight and leaf roll virus, should be sprayed in time, and the diseased plants should be pulled out in time. In the areas with serious incidence of late blight, metalaxyl mancozeb, Ruidui, Yinfari and other pesticides are used to control late blight, and the control effect can be achieved after 2-3 times of spraying.