Soil mapping, compilation and land evaluation of Motueka, Riwaka and Moutere Valleys : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Natural Resource Management, Massey University, Palmerston North

Abstract

The development of a soil map of the Motueka area, along with the supporting documents was completed during this study. This was achieved by the verification of an old poorly documented paper soil map. Primary Solutions Ltd initiated this project, but Tasman District Council provided the funding and assistance during this project. The project was developed as it was realized that there was significant potential for the map to be expanded and therefore better utilized. Validation of the original map was done by auger observations during extensive fieldwork. It was found that the paper map provided a reasonably accurate portrayal of textural distinctions, but lacked definition for drainage classes. Some reclassification of the map was therefore undertaken, and two new soil series were developed (the Ferrer and Motueka) to compliment the existing seven series (Riwaka, Umukuri, Sherry, Maori, Hau, Braeburn and Tahunanui). Some areas of the Ferrer series still exist within the Riwaka series as they could not be extracted due to the timeframe of this study. Soil physical and chemical analysis was also carried out on four of the most extensive and intensively used soils (Riwaka, Umukuri, Sherry and Ferrer). The Umukuri soil had the most suitable results from the tested physical factors, while the Riwaka came out as the poorest. The Riwaka was the most chemically fertile soil, while the Sherry was the least fertile. Current land use in the study area (a total of 4355 ha) is dominated by apples (30% or 1261 ha) and pasture (28% or 1207 ha) Other horticultural crops with significant areas in the study area are kiwifruit (499 ha), hops (218 ha) and blackcurrants (87 ha). There is limited potential for expansion of the more intensive land uses onto pasture, as the pasture is generally located on stony or wet soils making them unsuitable for horticulture. Land evaluation results demonstrated that all the sampled soils generally were well suited to hop, blackcurrant and kiwifruit. The Umukuri soil however was rated the most suitable, while the Sherry rated the poorest.