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Soil testing for optimising apple crop protential

 

Soil testing is the single most important tool available for making decisions on applying fertiliser and lime in a profitable and responsible way. Using soil testing and soil nutrition management, growers can maintain or increase yields, improve crop quality and spend fertiliser budgets more efficiently.

Although apples are often considered a moderate feeding crop, new growing styles, dwarfing root stocks and plantings in less fertile regions have changed how soil nutrition should be viewed. Such agronomic changes require a more thorough understanding of soils and their nutrient capacities. This is particularly relevant now with growers seeking high quality returns in today’s competitive markets.

It is generally accepted that a plant’s genetic potential is limited by the nutrient in the shortest supply. Although this concept was popularised over 150 years ago the “law of minimum” still applies to many of the challenges that growers face today. Until it is known which nutrient factor is holding back potential, it cannot be addressed.

A robust soil testing regime is the first step to building knowledge of what is occurring under our feet. So where should a grower start? One soil test or ten? One test covering a ten-hectare block will not provide sufficient information for an informed decision to be made. Conversely, 50 tests on the same block will confuse growers into inactivity.

Consulting traditional regional soil maps or NDVI maps will help to ascertain the appropriate number of samples to represent the soil types and variability within a block. Knowledge of soil types will also assist in making decisions on testing frequency. Your Farmlands Technical Advisor can advise on suitable sites for testing and facilitate collecting, submitting, and analysis of your samples.

Soil test results provide important information about nutrient status, eliminate guesswork and allow growers to work with known factors. While the test results provide the basis for applying nutrients, it must be understood that soil attributes will often be variable.

Knowledge of individual blocks is extremely important when analysing soil test results. It is important to consider trends in test results over time and to be aware that only the area where tree feeder roots are present is sampled. Apple tree roots often extend well below the sampling depth, so overall tree health and performance should also be considered when making fertiliser decisions. Previous and expected crop loads, drainage, vigour, leaf test results, seasonal weather, post-harvest fruit storability, soil condition and previous soil test results should also all be considered.

To be truly successful in interpreting soil test results a knowledge of soil science is essential (e.g. understanding soil nutrients, the interactions they have with one another and what this means for the potential of apple trees). Taking the time to learn more about the soil types on their blocks is critically important for growers. Getting up close and personal by digging holes and inspecting soil profiles and properties is certainly a great way to learn more.

Farmlands Technical Advisors who work with apple growers are trained to interpret soil test results and recommend the best course of action to growers.

 

For more information please contact your local Farmlands Technical Advisor.

Article supplied by Andy Davis, Technical Leader – Pip and Stone Fruit, Farmlands Co-operative