Introduction:

Water scarcity and high cost of agricultural inputs are problems that can be alleviated by the application of technologies that increase crop yields and improve the fruit quality. Plant nutrition is essential to reach both, high yields and good quality. Also, plant nutrition can improve the response of fruits to different storage technologies. The aim of the study was to evaluate the effect of macronutrient application by fertigation on apple crop yield and the quality of fruits at harvest and after a storage period in controlled atmosphere (CA).

Methodology:

The study was conducted in the orchard “La Semilla”, a facility that belongs to the Faculty of Agrotechnological Sciences, Autonomous University of Chihuahua, Mexico during the 2014 production cycle. ‘Golden Delicious’ /MM111 trees planted in 1990 were used as experimental units and arranged in a factorial Taguchi L25 design, with five factors (the minerals evauated) and 5 levels (doses in kg ha-1) for each factor: Nitrogen (0, 60, 120, 180 and 240), phosphorus (0 , 24, 48, 72 and 96), potassium (0, 20, 40, 60 and 80), calcium (0, 48, 96, 144, 192) and magnesium (0, 10, 20, 30 and 40) and 5 replicates for each treatment. Quality attributes (color, firmness, total soluble solids-TSS, titratable acidity-TA and ratio TSS/AT) were determined at harvest (125 days after full bloom) and after a 5 months storage period in controlled atmosphere plus a 7 day period at room temperature to simulate shelf life. Results were analyzed by the method maximal response surfaces.

Results:

Calcium, in a proportion 1:1 with nitrogen, was a relevant mineral to improve quality and this effect was more evident after the storage period in CA than at harvest. Nitrogen had a direct effect on firmness, TSS, TA and TSS/TA ratio at harvest and it has also and influence on color and TA in storage. Phosphorus had a greater effect on fruit firmness during storage than at harvest while potassium affected color at harvest and TA during storage. Magnesium had a moderate effect on TA at harvest and during the storage of apples.

Conclusion:

The recommended dose for high yields, good quality of fruits and a good conservation capacity in CA of apples was 138N-45P-40K-110Ca-20Mg.

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