Browse by author
Lookup NU author(s): Dr Robert Shiel
Full text for this publication is not currently held within this repository. Alternative links are provided below where available.
People in the Southern Highlands of Papua New Guinea cultivate some land semi-continuously within a regime of shifting cultivation; the staple crop is sweet potato (Ipomoea batatas). The fertility of Tropepts, variably affected by falls of volcanic ash, was investigated to give further understanding of how subsistence farmers avoid the soil constraints that commonly prompt abandonment. While organic matter, N and K all decrease significantly with time under cultivation, they do not reach critical levels. Phosphorus also decreases significantly ol;er time, although contents are small throughout. Other nutrients show no significant variation with period of use or abandonment. These findings comply with the diversity of crops cultivated early in the life of 'gardens': followed by sweet potato, cultivated as a virtual monocrop in long established 'gardens'. If continues yielding adequately regardless of decrease in nutrient availabilities, notably because nutrient ratios remain favourable for tuberisation and because of sweet potato's tolerance of small phosphorus concentrations. It appears that burning of vegetation significantly increases available minerals and helps maintain a supply which is adequate for longterm sweet potato monoculture. Similar situations are postulated for other areas of less-weathered soils within the tropics.
Author(s): Sillitoe P, Shiel RS
Publication type: Article
Publication status: Published
Journal: Soil Use and Management
Year: 1999
Volume: 15
Issue: 1
Pages: 49-55
Print publication date: 01/03/1999
ISSN (print): 0266-0032
ISSN (electronic): 1475-2743
Publisher: Wiley-Blackwell Publishing Ltd.
URL: http://dx.doi.org/10.1111/j.1475-2743.1999.tb00063.x
DOI: 10.1111/j.1475-2743.1999.tb00063.x
Altmetrics provided by Altmetric
