Impact of local conditions and machine management on grape harvest quality

Since its inception approximately 50 years ago, the grape harvester has been one of the machines responsible for the expansion of viticulture in the world. In Spain, harvesters were introduced in the 1990s (there are now approximately 3,000 machines there as of 2017), while they were introduced in Brazil in 2010. Harvest mechanization requires specific crop adaption and new work features that deserve to be analysed from their very beginnings. The aim of this study was to evaluate the management of four commercial grape harvest machines under actual field conditions on an intercontinental basis in two locations in Brazil and Spain. Machine performance measured by work (ha h−1) and processing capacity (kg h−1), together with field efficiency (%) and task quality, as measured by grape losses (%), in soil and plant, as well as must release (%), were considered in relation to plot geometry, adaption of plots to mechanical harvesting, and machine type, in order to assess whether the initial steps towards harvest mechanization in Brazil have led to similar performance and quality levels compared to Spain, which represents an example of well-established mechanization. The theoretical work capacities were similar for towed equipment in both countries (0.81 ha h−1 in Brazil and 0.87 ha h−1 in Spain) and lower compared to self-propelled capacity (1.34 ha h−1). Significant differences were observed in terms of losses of grapes and must, with the highest values prevailing in Brazil (2 % grape losses in the ground; up to 23 % of the plant undetached grapes and must losses of 2-4 % (per kg vine productivity)