Analysis of Tissue, Soil and Water

Soil Analysis

Soil analysis is used particularly as an indication of potassium and phosphorus requirements and to assess plant-available soil mineral N for nitrogen recommendations. It is also used to assess soil pH, and organic matter levels. A soil test should be taken before planting. Sample the top 30cm, taking 10 or more samples for fields of around 1ha. Bulk the samples. For larger fields, 30 samples is the required minimum.

Water Analysis

In fertigation and hydroponic systems, analysis of your irrigation water is essential for checking water quality and adjusting your fertilizer input, pH and EC accordingly. Irrigation water should be run for several minutes before samples are collected for analysis, in clean bottles, from the point where the water enters the system.

In hydroponic systems, collect sample from several emitters in the line to periodically monitor the applied nutrient solutions. Where recycled irrigation water is used, periodically analyse the run-off solution to make sure there is no buildup of undesirable elements such as Na & Cl, or an imbalance of nutrients in the solution.

Leaf Tissue Analysis

Leaf tissue analysis is important to confirm that the balance between elements within an appropriate fertilizer programme will maximize crop production. It is a highly effective way of monitoring nutrient levels in the crop, particularly under soilless cultivation, allowing the fertilizer programme to be adjusted as required.

Leaf tissue analysis will also confirm most visible deficiency symptoms, reveal hidden deficiencies where visual plant symptoms are not yet present and show excessive nutrient concentrations which may be causing other nutrients to be deficient – e.g. excess K supply creating an imbalance of calcium or magnesium.

Fresh, whole leaves that are free of dust or dirt, disease and pest damage should be taken. Typical practice is to collect a random sample of leaves in the morning, before the day heats up. Collect a minimum of 60 samples taking the youngest fully developed or expanded leaves from the same cultivar. Note: each leaf consists of its 3 leaflets minus the leaf stalk (see photo). Where you suspect a deficiency or issue, perhaps in a specific area of the field, keep samples separate and compare with those of healthier plants. Tables 8 and 9 give interpretative nutrient ranges for leaves from a range of different sources and regions.

While fruit analysis is not commonly used, Table 10 gives an indicative range for macronutrients in fruit. Table 11 gives Yara’s standard recommendation for use of micronutrients for strawberry grown in peat/hydroponics.

The figure above also shows the distribution of selected nutrients within various sections of the fruit. In this trial, the fruit was divided into proximal and distal parts and each of them separated into inner and outer part of fruit. The berry peel was removed and not tested.

All nutrient norm figures are guidelines and could vary according to variety as well as local research. Consult your local Yara agronomist for ways of overcoming deficiencies.