Fertility management in arboriculture

How to increase the level of organic matter in the soil, agroforestry, etc...

Fertility management in arboricultureHow to increase the level of organic matter in the soil, agroforestry, etc...

1. Arboriculture
2. Fertility management in arboriculture

As with most agricultural production, reasoned fertilisation is the key to reconciling optimum production and environmental performance in arboriculture.

This portal provides a general overview of the fertilisation of fruit trees, as well as a range of practices to enhance soil fertility.

Controlling fertilisation

Fertilisation of fruit trees can be managed by estimating their needs.

Requirements vary according to species, soil and climate, as well as production levels. By way of example, the following table sets out the requirements for various fruit trees, based on an estimate from the arboriculture technical bulletin, PFI PACA.

Contribution in Kg of the element / year / ha for a yield of 1 T / ha	Nitrogen N	Phosphorus P2O5	Potassium K2O	Magnesium MgO
Apple	1,2 à 1,6	1,65	2,0 à 2,5	0,75
Pear	1,5 à 2,0	1,65	2,0 à 2,5	0,75
Earlypeach	1,7 à 2,3	1,65	2,0 à 2,5	0,6
Late peach	2,5 à 3,0	1,65	2,0 à 2,5	0,6
Plum	3,0 à 4,0	1,0	4,0 à 5,0	1,25
Apricot	3,0 à 4,0	1,0	5,0 à 6,0	1,25
Cherry	4,0 à 5,3	0,75	5,3 à 6,65	1,65

Nevertheless, estimating the fertiliser values to be applied to the orchard as a function of the desired (or obtained) yield may prove insufficient. This reasoning only provides an order of magnitude and should ideally be supplemented by various analyses in order to take more factors into account, and thus achieve optimum fertilisation.

Soil analysis

In arboriculture, soil analyses are generally carried out at regular intervals (every 5 to 10 years) in the superficial horizons. This is to determine the nutrient content (P, K, Mg) and physico-chemical characteristics (pH, OM content, RedOx, resistivity, etc.) in the first few decimetres of the soil, i.e. the zone mainly explored by the roots. On the other hand, for more "structural" indicators (granulometry, cation exchange capacity, etc.) samples can be taken at greater depths, particularly before planting..

Visual observations and leaf analysis

The attention paid to the orchard and leaf analyses are not a sufficient source of information to determine fertilisation practices on their own, but they can complement the reasoning. In fact, the observation of any deficiency symptoms on the leaves (discolouration) cannot be corrected in the current season, but does provide an avenue for improvement in subsequent seasons. In the same way, leaf analysis results are difficult to compare with suitable benchmarks, as they are highly variable due to a number of factors : phenological stage, climate, variety, season. They must therefore be repeated over several years before providing sufficiently accurate information..

Soil cover

Generally speaking, soil fertility can be improved by plant cover. Grass cover or green manures can offer the soil protection against erosion, improve structure, protect against nitrate leaching, maintain organic matter, etc..

Whether established or spontaneous, plant cover can be maintained with a wide range of tools and practices : this is the case, for example, with the sandwich method, where the soil is worked only in a strip on each side of the row.

Similarly, mulching is a weed management practice that has a positive impact on soil fertility.

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