Trials in France show that phosphorus can increase the commercial premium >75mm grade of apples by 24%, through increasing apple 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 apple size
Size is a critical characteristic for grading apples. 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. Apples 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 apple size and significant fruit drop.
