Increasing apple yield
Plant nutrients are essential building blocks of crops. In order to obtain high apple yields it is important to achieve the right balance of fruit number on the tree. High yields are obtained on freely drained soils where water is not limiting.
Tree density, orchard orientation and spacing are critical to ensure crops make best use of environmental conditions so that yield potentials are reached.
Thorough soil preparation prior to planting and maintenance of optimum pH ensures good rooting and that nutrients are readily available.
Pruning and crop thinning are critical if growers are to produce an optimum number of evenly sized fruit.
The use of fungicides and insecticides will reduce the incidence of yield and quality sapping diseases and pests.
All crop nutrients must be available to the crop at the required rate and balance.
Crop Nutrition and Pome Fruit Yield
Nitrogen, calcium and potassium are required in greatest quantities by pome fruit crops.
Nitrogen is critical to maximize early season tree, leaf and fruit growth. Typical removal in apple fruit is around 0.6kg of N per ton of fruit annually.
Large amounts of calcium are needed within the tree to support crop production. Most of this is taken up during early periods of growth. Only a small proportion of calcium finds its way into the fruit. As a result, annual crop removal is less than 0.1 kg/t of fruit.
Maximum potassium uptake occurs during the fruit filling stage, and is later than the peak of nitrogen and calcium. It is a key driver to maximize fruit yield and weight with on average 1.4kg removed per tonne of apple crop harvested.
Relatively low levels of phosphorus are used by pome fruit crops and uptake occurs readily throughout the season. Soil supplies can commonly meet needs, however during peak periods of demand, fertigation, foliar, or fruit applications may be necessary.
Magnesium is important to maintain good growth, but removal is low at less than 0.1kg/t of fruit.
It must be ensured that boron, iron, manganese, molybdenum and zinc are also not limiting.
Crop nutrition is essential
- Nitrogen and potassium are key elements in boosting shoot and leaf growth, maximizing flowering, fruit set and fill, as well as yield potential.
- Phosphorus is important for early growth and rooting, and then again for producing a large number of healthy flowers clusters, and good fruit size.
- Calcium is needed to ensure healthy leaf development and canopy growth, thereby providing for a firm platform for high yields.
- Magnesium and manganese also ensure good photosynthetic activity, maintaining productive growth and strong fruit retention on the tree.
- Poor availability of any micronutrient will restrict yield. Boron is particularly important at flowering to maximize flower number and fruit set. Zinc is also important for bud development and flowering.
