Trials in France show that phosphorus can increase the commercial premium >75mm grade of apples by 24%, through increasing pome fruit size. Thus, it is particularly important to ensure supplies are not limiting in the period 6 weeks post-flowering. Often this is best achieved by using supplementary foliar phosphate.
Increasing pome fruit size
Size is a critical characteristic for grading pome fruits. A minimal size, determined by the diameter of the equatorial section, is required on all grades. An evenly shaped and sized fruit is desired for the fresh market and also for canning. Pome fruit size is greatly influenced by pruning and thinning practices and also by crop nutrition.
Crop Nutrition and Apple Size
Phosphorus
Magnesium
Lack of magnesium results in reduced photosynthesis leading to smaller leaves that are lighter in colour, poor flowering, reduced pome fruit size and significant fruit drop.
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Increasing pome fruit yield
Plant nutrients are essential building blocks of crops. In order to obtain high pome fruit yields it is important to achieve the right balance of fruit number on the tree.
Improving pome fruit colouration
Colour of the skin is a very appealing pome fruit quality to consumers. Therefore, growers generally seek to improve fruit colouration. Crop nutrition can help to achieve the desired appearance.
Avoiding pome fruit sunscald/sunburn
Sunscald or sunburn in pome fruit accounts for yellow or flushed areas on the fruit skin due to direct sun damage often following a period of cooler, cloudy weather. In severe instances, the scald damage turns dark while the fruit is still on the tree,...
Minimising incidence of pome fruit rots and diseases
Many disease-causing pathogens (fungi, bacteria, viruses and nematodes) attack pome fruit trees.
