PRECISION FRUIT GROWING: HOW TO COLLECT AND INTERPRET DATA ON SEASONAL VARIATION IN APPLE ORCHARDS

Very little has been published to date on seasonal spatial variability of produc-tion in fruit crops, and most papers refer to data collected post harvest. This work analysed field information recorded within-season (fruit growth rate) and at harvest (crop load, fruit size, fruit ripening) in 2008 in two commercial apple (Malus domestica Borkh.) orchards in the Ferrara province, Italy. In high-quality apple production systems, manual refinement of chemical thinning is a must, but growers lack a methodology for assessing the efficacy of thinning treatments and to assist further management decisions, such as irrigation levels, for example. The within-season data were used to provide assistance in management decisions taken by growers and/or consultants throughout the season. The goal was to assist in improving the efficacy of management to ensure high production while maintaining as high yields as possible. The relationships between the within-season and harvest measurements were analyzed using both traditional and spatial statistical techniques. Maps of crop production/ quality parameters and fruit growth were generated by punctual kriging with a global variogram on a common grid. Within-season monitoring provided more robust estimations of the fruit load per tree than traditional methods, which underestimated fruit load, leading to more appropriate thinning. Monitoring fruit growth rates also provided good estimations of fruit size distribution at harvest and permitted better satisfaction of the target market. Useful information could be obtained by interpretation at the block (orchard) scale, however, a spatial analysis at a sub-block level appeared to offer the opportunity for differential management. The work presented is intended as a proof of concept of this methodology, the satisfactory results from which signal that it may be not far from large-scale adoption.