Measures for increasing yield of sweet potato tuber root expansion period

The sweet potato root enlargement period is the late growth stage of sweet potato, which is the key period for the formation of yield. In this period, the rainfall is less, the temperature difference between day and night is large, the growth of sweet potato stems and leaves is weakened, the leaves are yellow and fall off, and the nutrients are concentrated to the roots. In management, we must continue to protect stems and leaves, maintain normal physiological functions, and promote rapid expansion of roots.

The root expansion period of the cracked fat red sweet potato is generally started from the end of August, and cracks appear due to the enlargement of the roots. At this time, the crack fertilizer should be applied to prevent premature senescence of the stems and leaves and accelerate the expansion of the potato pieces. It is mainly applied with nitrogen and potassium fertilizer. Generally, it is leached with 3%~5% potassium sulphate or 15%~20% ash ash in late August, and 1% potassium dihydrogen phosphate solution can also be used. 150 kg. Or apply 4~5 kg of ammonium sulfate per acre, and 500 kg of water; or use 200~250 kg of human excrement, 600~750 kg of water, and apply it through the ridge. It can also spray 150-200 kilograms of grass ash water per acre. For the late maturing and premature aging plots, 2% nitrogen, phosphorus and potassium mixture can be applied.

It is strictly forbidden to turn over the vines to damage the stems and leaves, affect photosynthesis, reduce the accumulation of nutrients, and increase the weight gain of potato tubers. Generally, the yield is reduced by 20%~25%, and the high is over 30%. Therefore, sweet potatoes should not be vinened throughout the growth period. For the growing sweet potato field, it is better to use the method of vine tip or light vine to control the growth, inhibit the formation of fiber roots, avoid the consumption of nutrients by fiber roots, improve the photosynthetic capacity of leaves, and promote the expansion of potato chips.

Drought-proof drainage encounters dry weather in the late stage of sweet potato growth. The conditional areas should be watered by furrows, fertilize water, promote stem and leaf growth, enlarge photosynthetic area, increase photosynthetic products, and facilitate root enlargement. However, it is not advisable to water the water within 20 days before harvest to avoid reducing the storage stability of sweet potato roots. If you encounter autumn sputum, you should clear the ditch and drain in time to prevent the potato pieces from being stained, and form hard heart rot and lead to reduced production.

In the late growth stage of foliar fertilizer, the ability of roots to absorb fertilizer is weakened, and foliar spray fertilizer can ensure the nutrients needed for root enlargement. Generally, hilly slopes or fields with premature aging should be sprayed with 0.5% urea solution; those with prosperous leaves should be sprayed with 0.2% potassium sulphate or 5% ash ash; general fields can be sprayed 0.4%~0.5% mixture of urea and potassium dihydrogen phosphate. 75~100 kg of spray fertilizer per acre. The spraying time generally starts from mid-August, and is sprayed once every 7~10 days, and sprayed a total of 2~3 times. The spraying time should be carried out before the sunny evening, and it should be sprayed after the spraying.

Inflated sweet potato is a compound growth regulator that promotes root development, increases the number of potatoes per plant, promotes the growth of above-ground stems and leaves, enhances photosynthesis, improves the proportion of large and medium-sized potato tubers, and accelerates potato tubers. Inflated, it can increase production by about 10%. In the end of August, after filtering 1 kg of swelled with 20 kg of water, the leaf surface is sprayed at a walking speed, and it is usually sprayed twice.