Vine lifting and harvesting

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Vine lifting

Many sweetpotato varieties are characterized by a growth habit of long vines creeping over the soil surface. If the soil is moist and the stem touches it, roots may grow from the nodes. Storage roots may also form at these nodes, but they are usually small and not marketable.

The principle behind vine lifting is that the water and nutrients supplied to these roots are therefore wasted, and will reduce the yield of marketable roots. This waste can be prevented by lifting the vines so that any roots growing at the nodes break or dry out. Vines should not be turned over because this may cause rotting of the leaves in contact with the soil.

In practice, the benefit of vine lifting varies with the cultivar and weather conditions. Cultivars with more upright, bushy habit generally donít need lifting, and some trailing types donít root readily at the nodes. Lifting of these varieties may be necessary only in prolonged humid conditions.

Lifting is commonly practiced once or twice during a wet season crop, and often not at all during the dry season. Experiments done by Indonesian farmers have found that lifting more than once in the season only benefited yield in very moist conditions. Vine lifting during any season should, therefore, not be a routine practice, but should be undertaken only after root growth on stem nodes has been observed. Farmers should look out for root formation on vines during routine field observations, and then decide whether the labour investment in vine lifting is worthwhile or not.

Vine harvesting

For many sweetpotato growers, the vines are a valuable source of fodder for livestock. Vines may be harvested several times during the second half of the growing season. However, harvesting of vines generally reduces the yield of storage roots to some extent. The impact on storage root harvest may depend on the amount of vine removed, the variety, the soil fertility and weather conditions. Simple experiments can be conducted by farmers to determine the amount of vine harvesting that provides an optimum balance of vine and storage root yield.

Vine harvesting usually begins at 30-45 days after planting, when the beds are covered by vines. Two or three of the longest vines per plant are taken, leaving about 15 cm length. Subsequently, vines may be harvested every 10-15 days, taking 2-4 vines per plant

References

Rasco, E.T., Jr. and Amante, V. 2000. Sweetpotato in Tropical Asia. SAPPRAD-PCARRD. 230 p.

 

van de Fliert, E. and Braun, A. 1999. Farmer field school for integrated crop management  of sweetpotato. Field guides and technical manual. International Potato Center. Lima, Peru. 266 p.

 

Contributed by: Vilma Amante and Jane O'Sullivan

Land preparation

Planting material preparation

Planting

Soil management

Water management

Integrated pest management

Harvesting

Postharvest practices


Vine lifting in the Philippines (F. Villamayor).