Ask the Experts

Grace

Dear Grace 

Plants such as macadamia, avocado, tree tomato, and apples flourish in deep and well-drained soils. Adequate drainage helps prevent the development of fungal diseases and root rot.

Before planting, it is important to perform a soil test to understand the soil fertility, drainage, texture, and other soil properties. The drainage should be moulded before planting.

A pH range of between 5.5 to 7.5

Fruit trees are easily affected by the alkalinity, acidity, and salinity of the soil. Plants perform best at a pH range of between 5.5 to 7.5. After the soil is tested, a professional will determine whether the soil is suitable for the crop you want to grow or not.

 After assessing soil health and pH, professionals and agronomists will help you devise the best technique to adjust the soil pH and to maintain ideal soil conditions in the orchard. Some soil-improvement techniques that can be used include:

• Increasing the organic matter with manure, crop rotation, cover crops, and adding compost manure.

• Applying nitrogen-based fertilisers, especially during the early and vegetative stages.

• Adding lime to the soil to neutralise the soil pH.

Get your soil tested

When the soil has attained the optimum conditions for fruit and vegetable production, achieving a healthier fruit season becomes easier. It is not possible to fully understand the soil conditions by just looking, smelling, or feeling it.

Commercial fruit farmers, especially those that practice large-scale production, invest in regular soil testing to ensure that they achieve optimum performance and production.

Integrating regular soil testing with regenerative and sustainable soil practices will minimise the costs of amending the soil and the need for fertilisers.

It is important to understand your soil throughout the plant’s growing season. Before planting, soil testing will help you understand the nutrients which are present and absent in the soil.

This will help both smallholder and large-scale growers to devise effective manuring and fertiliser application programmes.

Besides, it will help farmers determine whether the pH is suitable for fruit production or it needs to be adjusted. Also, soil testing will help the growers to understand the soil’s ability to resist diseases and any soil-borne diseases that are likely to occur.

Organic- friendly soil fumigation

Soil fumigation is an important practice to prevent soil-borne and bacterial diseases in plants such as apples, citrus, macadamia, grapes, and avocado.

After testing and treating your soil, the next step is to select the most suitable variety.

Varieties

The growing conditions of different varieties vary. Apart from the climatic conditions and geographical location, the choice of the varieties selected is also influenced by the geographical location and soil properties. It’s recommended to understand the soil requirements before planting fruit seedlings.

Answered by an Oxfarm consultant

Tips to consider when fertilizing

I have planted apples on  10 acres. The fruit is promising, I need some tips on fertiliser application.

Peter 

Dear Peter

Nutrient deficiencies can greatly affect the performance and productivity of apple trees. When practicing organic farming, most of the fertilisers used are organic, although small amounts of chemical fertilisers are important. Apple trees require various micronutrients in high levels at different growth stages such as Calcium, Nitrogen, Potassium, Phosphorus, Sulphur, and Magnesium. Besides, they require small traces of micronutrients like Molybdenum, Iron, Cobalt, Silicon, Copper, Zinc, Manganese, Sodium, Boron, and Chloride. Nitrogen is required in large amounts in the early stages and when the trees are growing vigorously. During the flowering and fruiting stage, NPK formulations with a high potassium percentage should be applied or sprayed.

Some indications of nutrient deficiencies in apple plants include:

• Slightly red leaves indicate lack of nitrogen.

• Yellow and green patches on fruits is an indication of potassium deficiency.

• Corky areas on apple fruits indicate boron deficiency.

• Curling backward of leaves is an indication of phosphorus deficiency.

• Deformed fruits.

The amount of fertilisers required by apple trees varies depending on the soil fertility, manure applied, and the growth stage. Several things can happen when incorrect amounts of fertilisers are applied. 

For instance, excessive application of fertilisers makes the plants concentrate on producing a lot of shoots and leaves instead of fruits.

Failing to use fertilisers or applying extremely little fertilisers can lead to nutrient deficiencies, stunted growth, and poor health. Besides, the plants under-perform and their ability to fight pests and diseases reduces.

Know when to apply

• Fertilisers should be applied three times per year.

• The first application should be done before flowering.

• The second application should be made after flowering.

• The third application should be done a month later

However, in the early growth stages, and during vegetative growth, fertilisers can be applied at different times of the year depending on the nutrients required. Fertilisers should, however, be applied at controlled rates. Manure and other organic products should be applied regularly to keep the soil healthy and fertile.

Mulching, especially young plants, minimises the growth of weeds, enhances the soil texture, increases the organic matter, minimises water loss through evaporation, and increases soil micro-organisms.

Answered by an Oxfarm consultant