Harvesting orchard pruning residues in southern Piedmont: a first evaluation of biomass production and harvest loss

In recent years, interest in farming residues has grown and orchard pruning residues are no exception. Several factors define pruned branch mass and dimensional characteristics: fruit variety, vigor, training system used, and pruning intensity and periodicity. While many studies have been performed to determine residue biomass availability, dating and surveying are not always accurate. Detailed qualitative and quantitative knowledge is needed to evaluate the economic sustainability of exploiting orchard pruning residues as an energy source. To assess the real chain potential of renewable energy production from orchard pruning residues in the area of Cuneo, in the Region of Piedmont, northwestern Italy, a study was conducted on the species Actinidia (kiwi tree) pruned according to the Peyracchia system, and Malus (apple tree) pruned according to two different systems, i.e. traditional and taille longue. For each species, pruning residue amounts were quantified and their basal diameter measured. Surveys were performed on some half trees, spaced as crop, for three randomised replications. Pruning residues were determined by dynamometer (accuracy 0.02N); individual cut-off branch diameters were measured at their base with mechanical calipers. Pruning residues were blown by rotating rake and harvested by a modified fixed chamber round baler. Harvest losses were determined by the methodology used for the initial residue quantification. Results showed the average biomass availability was 2.51 Mg DM ha–1 (SD 0.83) for kiwi tree, 3.04 Mg DM ha–1 (SD 1.17) for traditionally-pruned apple trees, and 0.46 Mg DM ha–1 (SD 0.36) for apple trees pruned with the taille longue system. Harvest losses (total pruned dry mass) averaged approximately 19% in kiwi trees and 16% in apple trees (95% to 10% for variety

Advances in developing a new test method to assess spray drift potential from air blast sprayers

Drift is one of the most important issues to consider for realising sustainable pesticide sprays. This study proposes and tests an alternative methodology for quantifying the drift potential (DP) of air blast sprayers, trying to avoid the difficulties faced in conducting field trials according to the standard protocol (ISO 22866:2005). For this purpose, an ad hoc test bench designed for DP comparative measurements was used. The proposed methodology was evaluated in terms of robustness, repetitiveness and coherence by arranging a series of trials at two laboratories. Representative orchard and vineyard air blast sprayers in eight configurations (combination of two forward speeds, two air fan flow rates, and two nozzle types) were tested. The test bench was placed perpendicular to the spray track to collect the fraction of spray liquid remaining in the air after the spray process and potentially susceptible to drift out of the treated area. Downwind spray deposition curves were obtained and a new approach was proposed to calculate an index value of the DP estimation that could allow the differences among the tested configurations to be described. Results indicated that forward speed of 1.67 m/s allows better discrimination among configurations tested. Highest DP reduction, over 87.5%, was achieved using the TVI nozzles in combination with low air fan flow rate in both laboratories; conversely, the highest DP value was obtained with the ATR nozzles in combination with high air fan flow rate. Although the proposed method shows a promising potential to evaluate drift potential of different sprayer types and nozzles types used for bush and tree crops further research and tests are necessary to improve and validate this method.Postprint (published version

Development of Drift-Reducing Spouts For Vineyard Pneumatic Sprayers: Measurement of Droplet Size Spectra Generated and Their Classification

Pneumatic spraying is especially sensitive to spray drift due to the production of small droplets that can be easily blown away from the treated field by the wind. Two prototypes of environmentally friendly pneumatic spouts were developed. The present work aims to check the effect of the spout modifications on the spray quality, to test the convenience of setting the liquid hose out of the spout in cannon-type and hand-type pneumatic nozzles and its effect on the droplet size, homogeneity and driftability in laboratory conditions. Laboratory trials simulating a real sprayer were conducted to test the influence of the hose insertion position (HP), including conventional (CP), alternative (AP), outer (OP) and extreme (XP), as well as the liquid flow rate (LFR) and the airflow speed (AS) on the droplet size (D50, D10 and D90), homogeneity and driftability (V100). Concurrently, the droplet size spectra obtained by the combination of aforementioned parameters (HP × LFR × AS) in both nozzles were also classified according to the ASABE S572.1. Results showed a marked reduction of AS outside the air spout, which led to droplet size increase. This hypothesis was confirmed by the droplet size spectra measured (D50, D10, D90 and V100). A clear influence of HP was found on every dependent variable, including those related with the droplet size. In both nozzles, the longer the distance to CP, the coarser the sprayed drops. Moreover, LFR and AS significantly increased and reduced droplet size, respectively. A higher heterogeneity in the generated drops was obtained in XP. This position yielded V100 values similar to those of the hydraulic low-drift nozzles, showing an effective drift reduction potential. The classification underlines that the variation of HP, alongside AS and LFR, allowed varying the spray quality from very fine to coarse/very coarse, providing farmers with a wide range of options to match the drift-reducing environmental requirements and the treatment specifications for every spray application