SOIL AND TISSUE ANALYSIS IN PREDICTING NUTRIENT NEEDS

Considerations of economy, energy and the environment make it imperative that fertilizers should be used efficiently to ensure high crop yields and to either sustain the available soil nutrient status at the maintenance level or to raise it to the sufficiency level for specific crops.
Scientists who work in perennial tree crop production are less than satisfied with the current effectiveness of the soil (McLean, 1977) and plant (Jones, 1976; Munson, 1977; Summer, 1978) analysis tools available for this purpose.

A great deal has been written about the execution, interpretation and practical application of soil and plant analysis tests for the accurate diagnosis and correction of crop nutrition.
In the case of plants one is dealing with a number of progressively more complex categories of crop nutrition (see under Plant Analysis) armed with knowledge of critical nutrient concentrations (Ulrich, 1976), some information on nutrient ratios (interactions) and very little else.
In the case of soils information about plant-available nutrients will often be available, although this is rare for perennial tree fruit crops and often bears little relationship to foliar analysis information.

Single element deficiencies may be diagnosed and quantitative corrective treatment recommended on the basis of field experimentation and/or experience.
Multiple visually identified deficiencies and situations that lead to suboptimal nutrition with no visible symptoms (single-or multi-element conditions) are much more difficult to deal with and their treatment inevitably involves some degree of ‘hit or miss’.

Treatment follows diagnosis.
To determine economically and accurately the rate(s) of fertilizer(s) to apply in a given situation it is necessary to know:

1. the correlation between the soil test value and the uptake of applied nutrient by a particular tree crop;

2. the calibration relationship between the soil test value and the crop yield responses to varying rates of nutrient applied as fertilizer in the field;

3. the change in soil test value that occurs when known quantities of fertilizer are applied to the soil.

Only the healthy plant can provide a guide to amounts of plant-available nutrient and chemical soil tests can only provide useful information when

Symposium on Mineral Nutrition and Fruit Quality of Temperate Zone Fruit Trees

J.B.D. ROBINSON

https://doi.org/10.17660/ActaHortic.1980.92.59