Submitted by admin on April 23, 2009 - 00:44
Lime, Fertilisers, and Trace Elements
The fertiliser, trace elements, and lime needs of New Zealand soils can be summarised in a simplified form by dividing (most, but not all) soils into four classes. The two larger classes are derived from so-called sedimentary rocks – greywacke (cemented hard sandstones and mudstones), schist (typically found in Otago), and softer mudstones and sandstones. The latter form the basis of many hill-country soils of the North Island. The class of soils with higher mineral fertility occurs in the drier districts (12–25 in. mean annual rainfall). But it also includes the young soils of river flats and the best of the steep hill country in rainier districts. The class with lower mineral fertility occurs in the wetter districts. The other two classes of soils are derived from volcanic ash. They are confined to the North Island. One class is derived from rhyolitic (pumice) ash erupted during the last 2,000 years. Soils derived from these more recent pumice showers are rather low in available trace elements. The other class of soils is derived from older pumice showers and from andesitic ash. Its supply of trace elements generally appears adequate, but phosphorus fixation is high.
The fertiliser elements needed on these four classes of soils and the prevalence of these needs are indicated in the table below.
| Lime and Fertiliser Elements Needed on Soils Derived from Sedimentary Rocks | |
| Young Soils and Soils in Drier Districts (Less Leached Soils | Older Soils and Higher Rain-fall Districts (Leached Soils) |
| Needed for Plants | Needed for Plants |
| Nitrogen* | Nitrogen* |
| Limestone* | Limestone* |
| Phosphorus† | Phosphorus* |
| Potassium‡ | Potassium* |
| Sulphur* | Sulphur* |
| Manganese‡ | Magnesium‡ (orchards, etc.) |
| Boron‡ | Molybdenum* |
| Zinc‡(stone fruit only) | Boron† |
| Copper‡ | Selenium† |
| Needed for Animals | |
| Selenium† | Needed for Animal |
| Copper‡ | Selenium† |
| (Due to molybdenum excess) | Cobalt‡ |
| Lime and Fertiliser Elements Needed on Soils Derived from Volcanic Ash | |
| Soils Derived from Younger Rhyolitic Pumice | Soils Derived from Andesitic Ash and Older Pumice |
| Needed for Plants | Needed for Plants |
| Nitrogen* | Nitrogen* |
| Phosphorus* | Phosphorus* |
| Potassium* | Potassium* |
| Sulphur† | Limestone‡ |
| Boron* | |
| Magnesium‡ | |
| Copper‡ | |
| Needed for Animals | Needed for Animals |
| Cobalt* | Cobalt‡ |
| Selenium† | |
| Copper† | |
| (Mainly due to excess molybdenum) | |
*Widespread or severe deficiency.
†Moderately widespread or widespread, but moderate deficiency.
‡Sporadic deficiency.
by Cornelius During, B.AGR.SC., formerly Farm Advisory Service, Department of Agriculture, Wellington.
