Investigations into the soils and landforms of pre-European Maori gardens on Banks Peninsula, Canterbury, New Zealand : A dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Resource Studies with Honours in the University of Lincoln

Abstract

Panau Soils (from Panau Pa, Long Lookout Point) overall, exhibit variable physical soil properties, but are not completely dissimilar morphologically, to other related southern Yellow-Grey Earths (Pallic Soils). The morphological and chemical properties of the Panau Pa garden soils (Tahi2 , Toru2 and Wha2), the beachfront soil (Beach) and the penguin soil (Iwa), however, are radically dissimilar in terms of 'soil profile forms' and chemical properties. An unmodified/uncultivated soil (Whitu) from the Panau Pa site showed chemical properties comparable with the Kirikiriwaerea Soils (Yellow-Grey Earths from Menzies Bay Valley). Historically parts of the Panau Pa site (specifically the Panau Pa garden soils, the beach-front soil and the penguin soil) are located on an old penguin rookery, hundreds and possibly thousands of years old. Consequently, soils of these sites have a tendency to be moderately acidic, increasing in acidity with increasing depth. In comparison, the uncultivated soil (Whitu) and basaltic soil (Waru) of Panau Pa, and the Kirikiriwaerea soils, have moderately acidic soils which increased in pH down the profile.

Organic matter for the Panau Soils show very high values - particularly in the Panau garden soil members and the penguin soil member (Iwa) - in the top horizons (Ah). This organic matter remains quite high with increasing depth. The high concentrations of organic matter is reflected in the dark soil colours of these loessial soils. These high organic matter amounts are in all probability penguin derived. In contrast, organic matter for the uncultivated soil (Whitu) and Kirikiriwaerea Soils are much less. Kirikiriwaerea Soils, however, still possess dark soil colours,but this maybe due to the weathering of the predominant basaltic components.

The amounts of total phosphorus (mg%) of the Panau garden soil members, the beach-front soil member (Beach), and the penguin soil member (Iwa), are extremely high in both surface and subsurface horizons. The Panau Pa basalt soil (Waru) also has relatively high total P, increasinq with depth. Conversely, the uncultivated soil (Whitu) from Panau Pa, and the Kirikiriwaerea Soils, have considerably lower amounts of total P. These high total P concentrations is in all probability derived from penguin sources particularly guano. Total P analysis of cemented beach rocks near the Panau Pa beach-front reveal amounts of> 2600 mg%.

In terms of cation exchange properties, Na content is high in both the Panau Soils and the Kirikiriwaerea Soils, understandable considering their close proximity to the sea and susceptibility to sea- and wave-spray. Ca and Mg content for the Panau Soils is medium, with the Panau garden soil members and the penguin soil (Iwa), exhibiting slightly lower Mg values compared to the uncultivated soil (Whitu) and the basalt soil (Waru). In contrast, Kirikiriwaerea Soils have slightly higher Na at subsoil depths, and extremely high ca and Mg content in both surface and subsurface horizons.