Soil analysis
High yields of top-quality crops require an abundant supply of 16 essential nutrient elements (See below for detailed information). In addition to providing a place for crops to grow, soil is the source for most of the essential nutrients required by the crop. Our soil resource can be compared to a bank where continued withdrawal without repayment cannot continue indefinitely. When nutrients are removed by one crop and not replaced for subsequent crop production, yields will decrease accordingly. Accurate accounting of nutrient removal and replacement, crop production statistics, and soil analysis results will help you manage fertilizer applications.
A soil analysis is used to determine the level of nutrients found in a soil sample. As such, it can only be as accurate as the sample taken in a particular field. The results of a soil analysis provide you with an estimate of the amount of fertilizer nutrients needed to supplement those in the soil. Applying the appropriate type and amount of needed fertilizer will give the you a more reasonable chance to obtain the desired crop yield.
We provide the following soil analysis and services:
- Recommendations for taking soil sample including sampling instructions
- We can provide you with a free sample bag and a freepost bag to send your soil sample to Far North Envirolab Ltd
- After the tests we will provide and recommend the calculated amounts of each individual element as fertilizer
- Advise on how to improve and increase your soil fertility
Analytical Services
Initial general soil test
If your soil has not been analysed in the last five years or you have not done any previous soil analysis, we recommend an initial general soil test.
This package includes
- Soil Type
- Soil density
- Moisture content
- Organic matter
- pH
- Iron
- Phosphorus
- Potassium
- Calcium
- Sodium
- Magnesium
- CEC
- Base Saturation
- total Nitrogen
Soil test 10 parameter including CEC (cation exchange capacity)
If you are commercially working with your soil [stock, horticulture, pasture, etc] and you need annual soil analysis for the correct addition of fertilizers, we recommend this test
This package includes
- Soil density
- Moisture content
- Organic matter
- pH
- Phosphorus
- Potassium
- Calcium
- Sodium
- Magnesium
- CEC
- Base saturation
Basic soil test
If you own a lifestyle block and need to know your soil fertility, the basic soil test is ideal.
This package includes
- pH
- Potassium
- Phosphorous
- Calcium
- Sodium
- Magnesium
- CEC
Soil Respiration Test
We can offer a soil respiration test whereby the carbon dioxide from the soil can be
measured accurately and the active biological activity established. Read more…
pH only for fertility information
If you like to know your soil pH, as indication for the available elements, we can measure it for you
To each soil test you can add individual parameters (some are listed below)
- Soil type, soil moisture, soil density
- Total hardness, carbonate hardness, Acidity
- Total Nitrogen including Ammonia-N, Nitrate-N, Nitrite-N
- Iron, Copper, Manganese, Calcium
- Sulphate sulphur
- Organic matter
- Individual test-parameters not listed above (Molybdenum, Chloride, Selenium, Cobalt, Aluminium etc)
Below some general information on soil testing to provide a knowledge base for our services.
This information is copied from a publication by the New Mexico State University. Please see link at the bottom of the page for more details
Objectives of Soil Analysis
- To provide an index of nutrient availability or supply in a given soil. The soil extract is designed to evaluate a portion of the nutrients from the same “pool” used by the plant.
- To predict the probability of obtaining a profitable response to fertilizer application. Low analysis soils may not always respond to fertilizer applications due to other limiting factors. However, the probability of a response is greater than on a high analysis soil.
- To provide a basis for fertilizer recommendations for a given crop.
- To evaluate the fertility status of the soil and plan a nutrient management program.
The soil analysis along with the information provided in the information sheet, is interpreted and reported in terms of the nutrients needed to supplement those in the soil. With this information, producers can add sufficient nutrients for the correct balance to obtain high yields.
Limiting Factors
Crop yields are determined by a variety of factors including crop variety selection, available moisture, soil fertility, crop adaptation to the area, and the presence of diseases, insects, and weeds. The soil analysis and its interpretation deal only with the fertility level (plant nutrients) of the soil. Recommended fertilizer will provide sufficient nutrients for the best possible yields. Other factors of production or management may still cause low yields, even though nutrients are adequate.
The Soil Analysis Report
After the soil is analyzed, fertility recommendations are made based on amounts of actual nutrients in the soil, not on the amount of any particular fertilizer or mixture. For example, if 100kg of N were recommended, that amount could be supplied by approximately 300 kg of ammonium nitrate (33%N), 220 kg of urea (45%N), or 120 kg of anhydrous ammonia (82%N). Likewise, a recommendation of 60 kg of P205 per acre could be added as 133 kg of 45% triple superphosphate.
| %P=%P205 x0.437 | %K=%K20x0.826 |
| %P205=%Px2.29 | %K20=%Kx1.21 |
Interpretation of the Soil Analysis Report
The soil analysis report contains two parts: characterization and fertility status of the soil, and fertility recommendations. Soil characterization (pH, texture, percent exchangeable sodium, percent organic matter, and salinity expressed as electrical conductivity) is explained in the report. The fertility status is reported as nutrients available to the plant. The second part, fertility recommendation, contains the suggested amounts of fertilizer to apply. These amounts are based on the crop requirements, management practices affecting the crop (as shown in the information sheet), the present fertility level of the soil, and the yield goal desired by the producer. Special notification is given if the tests indicate that a salt or sodium hazard exists or if the information provided shows any other specific problems.
Soil amendments or treatments to reduce a sodium or salt hazard will be recommended if requested. In general, application of gypsum is suggested for reducing a sodium hazard, and leaching is recommended in most cases to lower salt content in the soil. Gypsum or leaching requirements are calculated and reported if requested.
Table 1. Essential nutrient elements.
| Nutrient | Symbol | Form available | Category |
| Carbon | C | CO2, H2O | Non-fertilizer elements supplied through air, water, and soil nutrients |
| Hydrogen | H | H20 | |
| Oxygen | O | CO2 | |
| Nitrogen | N | N03-, NH4+ | Macronutrients required by plants in large amounts |
| Phosphorus | P | PO4= | |
| Potassium | K | K+ | |
| Calcium | Ca | Ca++ | Secondary nutrients required by plants in moderate amounts |
| Magnesium | Mg | Mg++ | |
| Sulfur | S | SO4= | |
| Boron | B | HBO4- | Micronutrients required by plants in small amounts |
| Chlorine | Cl | Cl- | |
| Copper | Cu | Cu++ | |
| Iron | Fe | Fe++, Fe+++ | |
| Manganesse | Mn | Mn++ | |
| Molybdenum | Mo | Mo04= | |
| Zinc | Zn | Zn++ |
further information can be found at:
New Mexico State University website .
Or in the following books
Resource Management Soil
Bryan Davies, Brian Finney, David Eagle
Farming Press
Fertilisers and soil in New Zealand farming
C.During
Practical soil management
Ian Cronforth
Biodynamic Perspectives
Farming and Gardening
New Zealand Biodynamic Association
Edited by Gita Herderson
Down to Earth
Peter Lester
Practical Organics for New Zealand Farmers
Trisha Fisk
Please also see our FAQ section for more information