BY ROBYN PARKES
In 1924, Mr Rigg of the Cawthron Institute, after completing a study of the soils of Waimea West, spoke in awe of the “Māori gravels”.
This consisted of an area of soil approximately 1000 acres in extent, which was specially prepared for kumara growing by Māori during their occupation of Waimea West.
Well-defined areas of this soil occurred both sides of the Waimea River, extending on the west side of the river for several miles from the Waimea bridge to the vicinity of Brightwater.
In the preparation as kumara pits the land was dug, and large quantities of sand and fine gravel were removed.
This was spread over a loamy soil which was the natural topsoil of Waimea West.
During the spreading of the material or at a subsequent date, large gravels were removed, leaving sand and fine gravel of very uniform particles.
The formation of this soil was thought to have extended over a long period, for a good depth was finally gained by repeated spreading of sand on the land.
Rigg made a point of raising the fact that, when it was remembered that the work was performed by hand labour and that 1400 tons of sand and gravel were spread on every acre of land, a good idea could be obtained of the magnitude of the work undertaken by the Māori population.
The soil was dark in colour and was valued for its fertility by the settler farmers of the land.
Other sandy soils in the vicinity did not possess the same properties.
An examination of the gravel soil made by members of the Cawthron Institute staff in the chemical laboratory revealed the fact that the dark colour of the soil was due to the presence of charcoal, with amounts of phosphate and potash being unusually high.
This, they felt, was due to Māori using large quantities of wood or other vegetable matter on the surface of the land.
Together with lime compounds the combination was highly beneficial for the growth of kumara.
The soil remained one of the richest soils in the district and showed the knowledge and skills of Māori concerning agriculture, and how they could obtain maximum results from the soil.
The pits were still very visible at this time, and the enormous extent of the work carried out by Māori before colonisation was clear to see.
The pits were from three to six or seven feet deep. Four layers of soil were found in each pit, being: layer 1 – fine gravelly sand, layer 2 – loam, layer 3 – fine sand, layer 4 - coarse sand.
A final examination determined that, “The soil which the Māori made, from the point of view of texture, drainage, and underlying loam, met exactly the specifications of American experts for the sweet potato crop and the Māori gravel showed that the ancient Māori had fulfilled to the letter all conditions essential for obtaining maximum results from the soil.”
