The following are the crop details for sweet potato.
Scientific Name: Ipomoea batatas
Species: I. batatas
Local Names: Viazi vitamu (Swahili); Makwasi (Kikamba, Kenya); Mapwoni (Luhya, Kenya)
Sweet potato is a herbaceous perennial in the Convolvulaceae family that is grown for its edible storage roots.
The sweet potato plant is a creeping, branching vine with lobed, heart-shaped leaves and white or lavender flowers. The plant has tubers, which are enlarged roots that serve as an energy store for the plant.
The tubers vary in shape and color and can be red, yellow, brown, white, or purple. Sweet potato vines can grow 4m (13 ft) long and are typically grown annually, harvested after one growing season.
Sweet potatoes, also known as yams or Spanish potatoes, are native to Central America.
Sweet potato tubers are consumed raw as a vegetable or processed into flour or starch. The leaves can be eaten raw or cooked.
Farmers plant several kinds of varieties based on yield, performance, maturity, culinary value, and pest tolerance. Since the varieties have different essential characteristics, this strategy reduces the risk of failure.
The following are the sweet potato varieties grown in Kenya
Suitable for most areas in the country. Red skin color, cream flesh. Popular high yielding variety.
General Information and Agronomic Aspects
Sweet potatoes are perennial vines that have only one growing season.
It is widely grown on a small scale throughout East Africa, primarily in subsistence farming, and is currently gaining popularity alongside other indigenous foods.
The roots are consumed alone or in combination with other foods such as milk, porridge, soups, or meat. Young leaves are used as vegetables.
Sweet potato vines are a valuable and nutritious fodder crop, particularly during the dry season. Some varieties are particularly well suited to this, producing an abundance of tops.
Two types of cultivars are commonly recognized among the vast array of cultivars grown. The most common types, grown throughout the tropics, are white, red, or purple, though yellow-fleshed varieties are gaining popularity in Africa and Asia.
The Orange-fleshed varieties have higher sugar and vitamin A content and lower dry matter content. East African nutritionists advocate the use of yellow-fleshed sweet potato varieties to combat widespread vitamin A deficiency, which reduces children's resistance to infectious diseases and contributes to infant mortality.
Young leafy shoots are high in protein (approximately 20% of dry weight) and a good source of b-carotene, thiamine (vitamin B1), riboflavin (B2), folic acid, and ascorbic acid.
Sweet potato is a sun-loving crop, but it can tolerate 30-50% less direct sunlight. During the growing season, it grows best with a well-distributed annual rainfall of 600-1600 mm.
Dry weather encourages the formation and growth of storage roots. Sweet potato is drought tolerant, but it cannot withstand long periods of drought; if drought occurs around the time of planting or root initiation, the yield is significantly reduced.
The most important management practice for managing water supply in rain-fed crops is probably maintaining soil organic matter.
Organic matter added to the soil will allow it to hold more water and stay moist for longer. Plant mulches applied to the soil's surface also help to reduce surface evaporation and maintain an even soil temperature.
They also prevent soil crusting and improve rainwater infiltration. Weeding is also important because weeds compete with the crop for water and cause the soil to dry out faster. Weeds that have been uprooted can be left on the soil as mulch.
Where irrigation is available, a number of factors should be considered in irrigation management:
The goal is to maintain as consistent soil moisture levels as possible. Larger water applications are generally preferred over smaller, more frequent irrigations.
Water should be applied in sufficient quantities to wet the root zone without causing deep drainage or run-off. Overwatering, in addition to being wasteful of water, can cause significant loss of soil nutrients (leaching) while contaminating groundwater and streams with nutrients that may be directly toxic to people or promote algal growth and eutrophication. Soils with a light texture (sandy) require more frequent irrigation than soils with a high clay or organic matter content.
Light-textured soils require less water to wet and are more susceptible to leaching and run-off losses.
The crop's water requirements will be significantly higher in clear, hot, and/or windy weather than in cloudy, overcast weather. Microorganisms.
Following cultivation, the land is typically prepared into ridges. Farmers who work entirely with hand tools prefer mounds. Broad-raised beds are used in some areas. Planting on flat fields is possible in deep, well-drained soil.
Ridges on sloping land should be oriented along contours to maximize rainwater infiltration and minimize erosion. Ridges are typically 30-45 cm high, but in wet areas, they may be higher to maximize soil drainage. They are typically 90–1120 cm part.
Sweet potatoes can be planted at any time if there is no critical dry season. Planting early in the rainy season is best in regions with a critical dry season. If the rainy season is long and wet, it is usually planted near the end.
Sweet potato planting material is obtained from either vine cuttings, which is the most common source, or storage roots.
Plant cuttings should be planted at approximately 15 x 20 cm spacing if planting material is to be kept in a multiplication plot before planting the next crop. After 45 days, new growth may be ready for cutting.
Use of stem cuttings:
Farmers obtain mature crop cuttings before or shortly after harvesting storage roots. The cuttings are either used to establish a maintenance field or planted directly into the next sweet potato crop.
The following factors influence yield when using stem cuttings: Choosing 'clean' planting material is critical. This includes removing any insects, soil, or signs of virus or fungal disease from the cuttings.
In general, the apical (tip) portion of the vine is superior to the middle or basal portions. This portion has been shown to establish faster than other portions and is less likely to be infested with sweet potato weevils and fungal pathogens.
For cultivars with long vines, the second or third cut is sufficient. If vine growth has been so rapid that the stem has not matured in the apical portion, the second cutting may be superior to the tip portion.
The number of nodes is more important than the length of the cut. The average size is 20-40 cm, with 5-8 nodes. Field conditions may influence the relationship between cutting length and crop development.
Farmers should experiment to see what length works best for their specific situation. Usually, one-third to two-thirds of the cutting is buried.
A minimum of 2-3 nodes, but up to approximately 8 nodes, are placed beneath the soil. The time between cutting and planting may affect yield depending on the storage conditions for the cuttings.
Storing cuttings in humid conditions for one to two days may encourage node rooting. Longer storage may be detrimental to the establishment due to the depletion of the cuttings' energy reserves.
To reduce losses, remove the leaves from the lower portion of the cutting and store bundles of cuttings in a cool, shady, wind-free location wrapped in a wet cloth or sack. If roots form during storage, they must be carefully planted to avoid root damage.
Use of storage roots: Storage roots are used while there are inadequate stem cuttings available or when pest and disease infestation is so severe that only a few healthy vines remain.
Since the sprouts can be harvested mechanically from the seedbed, they can also be used in highly mechanized production. Healthy storage roots should be selected from high-yielding plants.
The roots are densely planted in a seedbed far from different candy potato crops. To help retain moisture, the roots are covered with about 3 cm of soil, and the bed is covered with straw. When the sprouts have grown effectively, they are cut near their base and planted in the field.
To increase the number of cuttings, remove the sprout tips when they are about 20 cm long to promote branching.
Rapid seed multiplication: Rapid multiplication can be used when a large number of cuttings are required. Although sweet potato growers have not fully acknowledged the value of this practice, it may be the simplest way to produce a large number of planting materials.
The following steps are involved in this method: 30 cm cuttings are taken from established plants or sprouted storage roots. These are then cut into single-node cuttings with the attached leaf. The vine's tip is discarded.
A seedbed is produced by mixing loose, humus-rich soil with ash. Plant the single-node cuttings densely, with the stem section buried and the leaf upright. The seedbed is watered on a regular basis and kept moist, especially during the first week of the establishment. When the seedlings have developed enough roots, they should be transplanted into the field after about 2 weeks.
To avoid damaging the roots, they should be carefully removed from the seedbed. To avoid excessive evaporation and wilting, transplanting should be done in the late afternoon. Degeneration of planting material When the sweet potato is vegetatively propagated for several generations, yield decline is common.
This is usually due to a virus buildup, many of which have no obvious symptoms. This frequently gives the impression that a new variety (carrying few viruses) yields significantly higher than traditional varieties, when in fact it may not be any better after a year or two of virus accumulation. Heat treatment and meristem culture (from research institutions) can be used to remove viruses.
Depending on the severity of the original virus infestation, this process typically results in a yield increase of 20 to 200% for both vines and roots. The higher yield may be maintained in the field for several years before the virus load has built up.
After forming ridges or mounds, sweet potato cuttings are planted by burying the lower portion in the top of the ridge or mound. A hole can be dug with a stick or by hand, and soil should be gently pressed around the inserted cutting. The stem is typically positioned at an angle.
According to some workers, cuttings oriented across the ridge yield more than those oriented along the ridge. Ridge spacing in ridge planting systems is typically 90-120 cm, while row spacing is 20-30 cm (3-5 plants per meter). Higher plant density generally results in a lower yield per plant but a higher yield per hectare. With short growing seasons, close spacing is used, and wider spacing may be preferred where the market prefers larger storage roots.
The size and spacing of mounds are determined by soil conditions. They can be planted 75-200 cm apart and with several cuttings per mound. Although some farmers plant two cuttings at each mound, there is little evidence that this is beneficial. Single cuttings are said to produce a higher proportion of large storage roots.
Weed infestation is a problem in the first two months of growth and requires adequate control to ensure high yield. Following that, the vines' vigorous growth effectively covers the ground and smothers weeds. Manual weeding is commonly used in the tropics. Sweet potato responds well to fertilization, especially if the land has been cropped continuously. However, fertilizer is rarely used in the tropics.
To improve soil fertility, manure or good compost should be added. This is a common practice among smallholders and traditional farmers. Around the world, sweet potato is used in a wide range of cropping systems. Rotating sweet potato with other crops such as rice, legumes, and maize is beneficial for disease, pest, and weed control.
The harvesting season for sweet potato storage roots is not well defined; it varies depending on the cultivar, cultural practices, and climate. In tropical countries where sweet potatoes are grown for domestic consumption, 'progressive harvesting' (piece-meal harvesting) is common practice. To avoid weevil damage, it is generally recommended to harvest within 4 months. Manual harvesting with implements such as a stick, spade, or hoe is common in the tropics.