Cultivation experience of High yield of Spring Sweet Potato

Sweet potato is a root crop, which has the characteristics of high yield, stable yield, wide adaptability, strong stress resistance, rich nutrition and wide use. In the adjustment of planting structure, it has become a hot crop. How can we achieve high yield of sweet potatoes?

1) according to the experiment of balanced fertilization and ridging planting, it is necessary to absorb N 4-5kg P _ 2O _ 5o when 4-5kg P _ 2O _ 5o is 3-4kg and K _ 2O is 7-8kg to produce 1000kg tuber, so it is an important condition for high yield of sweet potato to apply sufficient fertilizer and mix with whole fertilizer. Fertilization should achieve fast fertilizer effect and early seedling development in the early stage, stable fertilizer effect in the middle stage, strong but not prosperous in the middle stage, and long fertilizer effect in the later stage and not early senescence of the plant. In high-yield fields, organic fertilizer 4000kg, urea 10kg, diammonium phosphate 20kg and potassium sulfate 25kg should be applied per mu. The method of fertilization should be applied with strips when ridging.

The high-yield soil of sweet potato is characterized by loose structure, large porosity, good air permeability, sufficient oxygen supply, water permeability and waterlogging. Combined with deep ploughing and ridging cultivation, the physical and chemical properties of soil can be improved. The ridge protruding the ground is not only conducive to drainage in the rainy season, but also due to the decomposition of organic matter, and it can absorb heat quickly during the day, increase the ground temperature, dissipate heat quickly at night, and have a large temperature difference between day and night, which is beneficial to the growth of sweet potato and the accumulation of nutrients by root system. When setting up ridges, it is necessary to achieve fat ridges, narrow and deep ridges, flat ridges, solid ridges, no big hills and hard hearts. The distance between ridges and 70cm is about.

2) the root tuber of sweet potato with strong seedlings was planted early and selected as vegetative vegetative body, and there was no obvious mature stage. Generally, the growth stopped when the air temperature was lower than 15 ℃, and the ground temperature dropped to 16 ℃-18 ℃. Early planting in an appropriate period can prolong the growth period and form the root tuber early, which can not only make use of the air temperature before the rainy season to make the root expand rapidly, but also store the photosynthate formed by the stem and leaf in the inflated root in the high temperature and rainy season. to promote the coordinated growth of underground and upper parts. According to the meteorological data for many years, the planting time of spring potato in our city is around May 1. The experiment shows that the root expansion period of April 28 is 7 days longer than that of May 10, and the yield is increased by about 10% per mu, and the tuber is neat and of high quality.

In order to improve the survival rate, early development and rapid growth of seedlings, the seedlings should choose the first batch of strong seedlings collected in the seedling bed, the first batch of seedlings have strong stems, exuberant leaves and developed roots. The gallbladder should be fully refined. Generally, the seedlings are exposed to the sun for 3-5 days in the seedling bed before planting, so that the leaves of the seedlings are dark green and the leaves become thicker. For example, after pinching off a section of the seedling, there is white milk flowing out from the cross section. This kind of seedling has high survival rate, fast growth and high yield. Do not choose unrefined seedlings, black root potato seedlings, sprouted potato seedlings.

3) in time to lift the vine, top and pick the heart into the rainy season, sweet potato stems and leaves grow luxuriantly, node roots are easy to breed and disperse nutrients, which is not conducive to the transport of photosynthate to the root tuber. In order to prevent this phenomenon, in the past, turning vines was often used to reduce soil moisture, increase soil temperature and prevent root nodes from happening. According to the experiment, it takes a lot of work and reduces the yield of sweet potato, mainly because the stems and leaves are seriously damaged after turning the vine, breaking the best distribution of light energy in the leaves, the photosynthetic rate is reduced by 30%, the respiration intensity is increased by 19%, and the yield is reduced by about 10%. Turning the vine into lifting the vine in production avoids the damage of stems and leaves, does not destroy the distribution of leaves, and is conducive to high yield. But the vine should not be too much, generally 1-2 times, the time ends before the end of August.

Topping and heart-picking of sweet potato can control the length and growth of the main stem, promote the growth of lateral buds and grow fast. The specific method is that after the sweet potato is planted, when the length of the main stem is 12 nodes, the top growing point of the main stem is removed to promote the occurrence of branching. When the branch grows to 12 nodes, the branch growth point will be removed. In this way, the contradiction between the above ground part and the underground part can be coordinated, which is beneficial to the expansion of the root tuber.

IV) Chemical control, fertilizer and water skillfully chasing too much fertilizer and water in the potato field, especially too much N, often cause stem and leaf growth, affect the expansion of root tubers and reduce yield. In practice, spraying plant growth inhibitors such as paclobutrazol or ketamine in potato fields can play a role in promoting up and down control. In general, it is sprayed for the first time before the rainy season in early July, and then every 10-15 days, even 3-4 times. Each mu was sprayed with 50-100g paclobutrazol or 7-15g protamine, and 50-75kg of water was sprayed evenly. The dosage of medicinal drugs should be flexibly used according to the growth of stems and leaves, rainfall, variety characteristics, soil fertility and so on.

On the basis of sufficient base fertilizer, the topdressing of sweet potato is mainly crack fertilizer and foliar fertilizer. There are urea 4-5kg, superphosphate leaching solution 10kg, potassium sulfate 3kg per mu of crack-chasing fertilizer, and water 150-200kg is mixed into nutrient solution. When cracks generally begin in the field, crack-by-crack irrigation should be carried out one by one on a cloudy or sunny afternoon, and uniform topdressing is required. Foliar fertilizer spraying is determined according to plant growth, the weak growth and signs of premature senescence are mainly spraying N, combined with P, K fertilizer, using 100kg to add water 0.5kg urea, 0.2kg potassium dihydrogen phosphate, stirring and spraying evenly. If the growth is strong, the main spraying P, K fertilizer can be sprayed with 0.2% potassium dihydrogen phosphate aqueous solution. In late August, a packet of sweet potato expander was used to dissolve and filter with water 20kg, and then the plant leaves were evenly sprayed twice with an interval of about 10 days. In case of autumn drought, timely irrigation can prevent premature senescence, prolong the functional period of leaves and increase the rate of root expansion. Generally, after watering in the first ten days of September, the leaf area coefficient is 0.6 higher than that of watering, and the yield is increased by 24.2% per mu. Sweet potato likes abundant moisture, and the amount of irrigation should not be too large, about 40m3 per mu. And pay attention to do not step on the potato ridge after irrigation, so as not to affect the soil permeability.