Land preparation and cultivation

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Sweetpotato grows best and produces smooth, well-shaped storage roots in a well-prepared soil. Good land or soil preparation involves removal or incorporation of crop debris and any vegetation that may compete with the sweetpotato crop, and deep manual or mechanical cultivation.

Cultivation aims to turn over the topsoil and loosen the compacted soil below, to achieve a good tilth for forming the hills or ridges, and provide a soft, uniform medium where storage root growth is not impeded. This can be achieved by thorough plowing and harrowing done a number of times depending on soil condition. Plant mulches, manures or other additives such as lime or gypsum, that have been applied to the surface, are mixed into the soil for greatest effect. Loosening up the soil increases the oxygen content, which favours the development of microorganisms that decompose organic matter. Good land cultivation also helps control weeds.

The use of heavy machinery, such as tractors, for soil preparation may compact the sub-soil producing a hard pan or compaction layer. This problem is greater on clay soils than on sandy soils. A hard pan can impede drainage, causing waterlogging, poor development of beneficial organisms, and poor root growth, which consequently leads to poor plant growth and poor quality storage roots.

Soil should be cultivated when damp but not too wet. Cultivation of dry or very wet soil can break up the soil structure, leading to poor drainage and aeration, surface crusting, cracking allowing entry of weevils, and greater susceptibility to erosion.

After cultivation, the land is usually formed into ridges. Mounds are preferred by farmers working entirely with hand tools. In some areas, broad raised beds are used. On deep, well-drained soil, planting may be done on flat fields.

Ridges are oriented along contours on sloping land, to maximize rain infiltration and minimize erosion. On flat irrigated land, ridges may be oriented East-West for maximum light interception, or any direction for convenience of furrow irrigation. Ridges are typically about 30-45 cm high, but may be higher in wet areas to maximize soil drainage. They are usually between 90 and 120 cm apart.

Further cultivation after crop establishment may be undertaken to control weeds, or to reform ridges (hill up) after fertilizer side dressing or to prevent weevil infestation. However, disturbance of soil in the ridges should be minimized to avoid root damage.



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

Planting material preparation


Soil management

Water management

Vine lifting

Integrated pest management


Postharvest practices

Land preparation using water buffalo  and a plough in the Philippines (F. Villamayor).