Detailed explanation of high-efficiency sweet potato cultivation techniques, key points easy to understand at a glance
Sweet potato is a high-yielding and stable-yielding crop. It has the characteristics of wide adaptability, strong stress resistance, drought tolerance and barren tolerance, and few pests and diseases. When planted in places with better water and fertilizer conditions, the yield per mu can generally reach 2000-3000 kg for spring sweet potatoes. However, due to differences in natural conditions and cultivation levels, the yield per unit area is also very uneven. In order to give full play to the yield-increasing potential of sweet potatoes and achieve high quality and high yield, the following opinions on high-yield sweet potato cultivation techniques are specially proposed.
Seedbed seedling raising
Promoting germination and raising seedlings is an important part of the entire off-season cultivation. The seedling raising time should be appropriately advanced to mid-February, when seed potatoes are moved into a protected seedbed for seedling raising. The seedbed uses double-layer film protection. The seed potatoes are arranged neatly. After covering with a layer of fine soil, a layer of plastic film is laid flat, and then a layer of film is covered over an arched frame to increase the seedbed ground temperature. Holes should be punched in the flat plastic film in time to guide seedlings out, so as to avoid burning tender seedlings at high temperatures on sunny days. In the first month of the seedbed, spray water once every 7 days. After 1 month, spray water and fertilizer plus Xinguozhimu twice a week to prevent pathogen infection and protect the seedlings' healthy growth. (When the plant height reaches 15 cm) cut a batch every 7-10 days. From the first cutting, spray water and fertilizer twice a week, with the concentration appropriately increased, to ensure nutrient supply for regenerated seedlings.
Apply sufficient base fertilizer
Choose loam soil and select sandy plots. In early spring, combined with plowing, apply 2-3 tons of farmyard manure, 15 kg of urea, and 20 kg of phosphate fertilizer per mu.
Plastic film mulching
Plastic film mulching can increase temperature and preserve soil moisture. At the same time, it can improve the physical and chemical properties of the soil and increase the diurnal temperature difference in the soil. For sweet potato planting, generally a high-ridge mulching method with two rows planted in a staggered manner can be used. The whole ridge spacing is 60 cm, the mulching width is 50 cm, the small row spacing is 40 cm, plants are staggered between rows, the plant spacing is 33 cm, and about 4000 plants are left per mu. The ridge height should be moderate. If the planting period is too dry, flat mulching and flat planting can be used to facilitate seedling growth.
Plant early at the right time
Plant early at the right time and maintain reasonable close planting: mid-April is the suitable period for seedling planting. At this time, the temperature in early spring generally warms up and is basically stable. The suitable planting period is when the 10 cm ground temperature reaches above 15°C after the late frost ends, and planting can begin. In the previous winter or early that year, plow and sun-bleach the soil in advance, and when planting, form ridges and prepare beds again. The bed width is 50 cm. In early and mid-April, according to the seedling emergence speed of the seedbed, cut seedlings successively for planting. Use the line flat planting method to increase the number of nodes of sweet potato seedlings inserted into the soil, thereby increasing the number of tubers set. Plant 3500-4000 plants per mu, with a plant spacing of about 33 cm. The planting time should not exceed April 20, otherwise the harvest time will be delayed, which will affect the transplanting season of continuous cropping late rice.
Planting early at the right time is the key to increasing sweet potato yield. Under suitable conditions, the earlier the planting, the longer the growth period, the earlier and more tubers are set, the longer the tuberous roots expand, and the higher the yield and better the quality. If planting is too late, the growth period is shortened, sweet potatoes are fewer and smaller, and the yield is low and the quality is poor. The suitable planting period is when the 10 cm ground temperature reaches above 15°C after the late frost ends (around mid-April). With plastic film mulching, planting can be appropriately advanced and can begin. In order to improve planting quality and ensure strong seedlings, when planting, remove “old hard seedlings” and weak or diseased seedlings, and select strong seedlings for planting. When planting, it is best to grade large and small seedlings and plant them separately so that they grow evenly. To prevent sweet potato black spot disease, use a 50% thiophanate-methyl 1000-fold solution to soak the base of the seedlings for 2-3 cun for 10 minutes. Sweet potatoes should strive for shallow planting on the basis of ensuring survival. The planting depth is generally 5-6 cm. When planting, soil should be firmed tightly, and the depth should be consistent, so that the leaves are exposed above the ground and do not stick to mud when watering. The seedling heads should be upright. The seedlings should not be exposed too long, so as to prevent strong winds from whipping the seedlings and affecting survival.
Field management
1. Management during the rooting and seedling recovery stage
The rooting and seedling recovery stage lasts from the growth of new roots after planting to the beginning of tuberous root formation, about 1 month. After sweet potatoes are planted, check and replant seedlings in time to ensure a full stand. After planting, if there is severe drought, water in time to promote seedling recovery and facilitate rooting and survival. Generally, after planting, water once, and thereafter cultivate once every 10-15 days to loosen the soil, raise temperature, and eliminate weeds. Spray Xinguozhimu at the appropriate time to promote rapid plant growth and help root formation.
2. Management during the branching and tuber-setting stage
30-40 days after planting, as the temperature rises, stem and leaf growth accelerates, and tuberous roots continue to form and expand. Water and fertilizer management should be strengthened in time. If drought occurs, apply 5-8 jin of urea per mu with irrigation water. After watering, cultivate and loosen the soil early to preserve moisture.
3. Management during the stage of vigorous stem and leaf growth and tuberous root expansion
From the first half of July to late August, during this period the stems and leaves grow vigorously and the tuberous roots expand, and the leaf area index reaches its maximum. Generally during this period, it is necessary to achieve promotion within control and control within promotion. This period coincides with the rainy season, with high temperatures and rapid plant growth. To prevent excessive vegetative growth, use 50 PPM paclobutrazol solution plus Diguo Zhuangtiling and spray evenly in the field, preferably so that the leaf surface is covered with the solution without dripping. This can promote fruit development and make sweet potatoes high-quality and high-yield. During this period, the underground tuberous roots expand rapidly. If summer drought occurs, watering is needed, but the water amount should not be too large. To promote tuber expansion, use one bag (12) g of expansion agent per mu mixed with 15 kg of water, spray once every 7-10 days, for two consecutive sprays.