HBRC > What We Do > Land > Soils of Hawke's Bay

New Soil Order classification	PUMICE For a soil to be classified a Pumice soil, it must have at least 60cm of volcanic material aged from 3500 to 700 years B.P., from Ruapehu, Ngauruhoe, Kaharoa, Taupo, and Waimihia eruptive phases.
Old Soil Group classification	Yellow brown pumice.
Common names associated with this Soil Order	Taupo, Waikoau, Tutira, Puketitiri, Te Pohue, Titiokura, Kaweka type, Gisborne, Mohaka, Waihua, Tuai, Hangaroa, Tiniroto, Ruakituri, Mahia, Pakarae, Kakenui.
Physical characteristics	Naturally low fertility with low nutrient reserves, particularly potassium, magnesium, sulphur, phosphorous, nitrogen, and calcium. Trace elements are likely to be deficient - such as copper, cobalt, boron, and selenium. Naturally low levels of organic matter. These may increase following farming activity; care must be taken to maintain this build-up. Low clay content (<10%) - if present, it is allophane clay. If the Waimihia and Taupo material is not present, but other ashes are, the (clay) allophane level increases, as does the phosphorous retention ability of the soil. Generally coarse in texture, sandier if coarse, but grading to silty sand where ashes dominate, structurally weak. Highly susceptible to erosion. Low bulk density - can handle compaction. Naturally low pH, can be very acidic.
Drainage and moisture availability	Well drained, very high macroporosity. However, there is a high available water content, ranging from 20-30% of soil volume. Rapid drainage of excessive water but is still capable of storing large amounts of water for plants. Well-aerated soil. Where compaction occurs, drainage may be impeded. (Can be identified by mottling in the upper profiles). North and west facing slopes are more drought-prone.
Rooting depth	Excellent. Soils are consistently deeper than 60cm. Allows trees to tap the deeper nutrient reserves and moisture zones. As slopes steepen, the soils become shallower and less suitable for planting.

Taupo sandy loam
Source: Simon Stokes

Puketitiri sandy loam
Source: Simon Stokes

Pumice