Soils are tested to measure the soil quality & mineral nutrients.
About this Testing
Why Test Soils
Soil analysis is a valuable tool to monitor the levels of soil nutrients available to the pasture or crop. Most New Zealand pastoral soils are deficient in phosphorus, sulphur and to a lesser extent potassium and some trace elements can also be deficient. Soil testing takes the guess work out of nutrient management and allows cost effective fertiliser programmes to be produced,targeting fertiliser applications where they are most required to meet the owner's objectives.
Measure whether soil nutrient levels are high enough to sustain the desired level of plant growth.
Indicate the existence of any deficiency, excess or imbalance of major nutrients.
Provide a scientific basis on which to assess fertilizer and lime requirements of crops, pasture and turf.
The Organic Soil Profile measures the soil quality, testing the soil organic matter, available nitrogen, total nitrogen and carbon:nitrogen ratio.
What Tests to Order
For Horticultural and Cropping Soils: a Basic Soil Profile, sulphate-S and available N test are usually recommended.
For Pastoral Soils: a Basic Soil Profile and sulphate-S test are usually recommended. Where reactive phosphate rock (RPR) fertiliser has been used, also include the Resin P test.
Other soil tests include: organic sulphur, the Organic Soil Profile for soil quality, aluminium, boron, the EDTA and Mehlich 3 trace metal tests and more.
Appropriate sampling methods must be used for the results to be meaningful and do not collect soil samples within three months of applying fertiliser or lime. Aim for a representative sample size of 500g per sample and sampling at the same time of year in the same way will give better nutrient monitoring.
For Tree Crop soil samples: collect two 15 cm soil cores from the root zone of ten trees from two diagonal lines through the sample area. Remove leaf litter material before sampling.
For Row Crops like Kiwifruit or Grapes: take 20 soil cores from the plants root zone across the sample area. Remove leaf litter before sampling.
For Vegetable or other Field Crops: collect twenty 15 cm soil cores across the sample area. Using a single or double diagonal sample line can be helpful.
For Pastoral Farming: collect twenty 7.5 cm soil cores using a single or double diagonal sampling line. Avoid dung and urine spots and other non typical soil areas.
Soil and plant sampling instructions are available on a plant species basis in our Crop Guides.
Complimentary Soil and Plant Test Kits for submitting samples are available from the laboratory. These sample kits contain instructions, an analysis request form, sampling bags and courier bag to send in the samples.