How to grow autumn sweet potatoes for high yield? Early planting is the key

Practice has proved that the yield of sweet potato is closely related to the growth of stems and leaves. Sweet potato is a warm-loving crop, and the hot and humid July to September is the golden season for cultivating autumn sweet potatoes. High-yield experience from various places has proved that timely early planting, extending the effective growth period, and increasing the effective accumulated temperature are one of the important measures for achieving high yield in autumn sweet potatoes.

According to planting-period trials, during the growth period of autumn sweet potatoes, the effective accumulated temperature is closely related to yield. For sweet potatoes planted from early July to early September, the yields at different growth periods are as follows: with a growth period of 65 to 70 days and an effective accumulated temperature of 650 to 800°C, the tuber yield per mu is about 750 to 900 kg; with a growth period of 100 to 120 days and an effective accumulated temperature of 800 to 1100°C, the tuber yield per mu is 2000 to 2500 kg; with a growth period of 150 days and an effective accumulated temperature of 1200 to 1500°C, the yield per mu can reach 4000 to 5000 kg. This shows that early planting can extend the effective growth period, increase the effective accumulated temperature, and greatly increase the yield.

1. Selection of planting time.

During the growth process of autumn sweet potatoes, the temperature goes from high to low, rainfall goes from abundant to scarce, and sunlight goes from strong to weak. The hot and humid weather from July to September is conducive to the growth of aboveground stems and leaves in the early stage of autumn sweet potatoes, forming a relatively ideal leaf area and laying a good foundation for the production and accumulation of nutrients in the middle and late stages. For autumn sweet potatoes planted in mid- and late September, because the temperature gradually decreases and rainfall is scarce, plant growth is slow, which is very unfavorable to aboveground growth; however, with little rainfall, relatively sufficient sunlight, and a large temperature difference between day and night, the plants consume less and accumulate more. Therefore, seizing the favorable hot and humid weather and planting early in good time so that the aboveground stems and leaves grow early and quickly, branch early, and form a good green leaf area can lay a good foundation for high yield.

2. Management measures.

Early planting and late planting face different climatic and environmental conditions. In cultivation and management measures, corresponding measures should be taken according to the growth characteristics of autumn sweet potatoes and the patterns of climate change.

1. Select high-yield improved varieties tolerant to high temperature and high humidity, such as Guangshu 62, Zhoushu No. 13, Chaoshu No. 1, and other varieties.

2. Use tuber seedlings for propagation, renew and rejuvenate the planting material, eliminate old and weak seedlings, do not use old and weak seedlings as planting material, and select tender, strong seedlings from the first and second sections for planting.

3. Plant at a reasonable density; early planting should be slightly sparser, with about 3200 seedlings per mu. Use the horizontal planting method, eliminate the slanted insertion method, and increase the number of tubers formed. From 8 to 10 days before cutting seedlings for planting, pinch off the growing tips of the sweet potato seedlings to promote branching, and select the first section of tender, strong seedlings that have begun to branch for planting.

4. Apply more organic fertilizer. Do not apply chemical nitrogen fertilizer before tuber formation; apply phosphorus and potassium fertilizer in combination, especially more potassium fertilizer, to prevent excessive vegetative growth of stems and seedlings in the early stage. In the middle and late stages, apply tuber-setting fertilizer and tuber-strengthening fertilizer well to promote tuber root expansion and prevent premature senescence of stems and leaves.

5. In the early growth stage of autumn sweet potatoes there is more rain, so drains should be cleared in time to remove waterlogged water, and intertillage and soil loosening should be noted to keep the sweet potato field dry and well aerated. In the late stage rainfall is scarce, so attention should be paid to irrigation with “horse-racing water” or watering.

6. Timely control of diseases, insects, and rodents, and carry out hilling several times to prevent the ridge soil from cracking and to stop small weevils from invading and damaging the tuber roots. In areas with sweet potato blast, attention should be paid to spraying chemicals for prevention to prevent the occurrence and damage of sweet potato blast.