Transactions of the ASABE Vol. 55(1): 21-28 E 2012 American Society of Agricultural and Biological Engineers ISSN 2151-0032 21 RECOVERING KIWIFRUIT PRUNING RESIDUES FOR BIOMASS PRODUCTION R. Spinelli, R. Spinelli, N. Magagnotti, C. Nati, L. Pari, J. L. Vanneste ABSTRACT. Three systems for recovering kiwifruit pruning residues were compared for their cost‐effectiveness. The systems were a shredder with a built‐in dumping container; a shredder with drop‐down re‐usable bins, of the type normally used for fruit collection, working with a dedicated bin‐collection system; and a round baler equipped with an add‐on bale storage unit. All systems were light enough to be towed or carried behind a compact vineyard tractor. Harvesting and processing productivity, including all delays, ranged from 1.8 to 3.7 tonnes per scheduled machine hour (SMH). After standardization, calculated recovery cost varied between 8.4 and 28.6 Euros t ‐1 for the residue delivered at the field edge. The shredder with a built‐in dumping container emerged as the best performer, favored because of a faster pick‐up and a more efficient single‐pass work mode. Overall, this system is simpler, more productive, and offers the lowest processing cost. The annual utilization of all the dedicated recovery implements tested should at least be 50 ha year ‐1 (approx. 500 t year ‐1 ) in order to obtain acceptable cost results. Kiwifruit orchards offer a very high residue yield, about four times higher than vineyards and olive tree groves. This favors cost‐effective recovery and makes them a significant potential source of energy biomass, the exploitation of which may also simplify residue management and improve plant health conditions. Keywords. Baling, Biomass, Harvesting, Pruning, Shredding. iwifruit (Actinidia deliciosa) production is a glob‐ al industry spanning both hemispheres; planta‐ tions are concentrated in Italy, China, New Zealand, and Chile (Testolin and Ferguson, 2009). The recent and overwhelming success of this relatively new crop is the result of a number of factors, not least the excep‐ tional vigor of the species. Because of this strong growth, the annual pruning of kiwifruit orchards produces substantial amounts of pruning residues, the disposal of which may re‐ quire more work than normally needed for other, less vigor‐ ous crops. Currently, most farmers dispose of pruning residues by mulching them with tractor‐mounted shredders. However, this practice can favor the spreading of diseases onto healthy vines. The mulched material might provide a food resource for some pathogens, offering them an opportu‐ nity to survive, and therefore acting as a reservoir for inocu‐ lum in the future. Several bacterial plant pathogens such as Submitted for review in September 2010 as manuscript number PM 8765; approved for publication by the Power & Machinery Division of ASABE in December 2011. Reference to specific makes and models of agricultural equipment is solely for the purpose of helping readers assess the study correctly and does not imply any endorsement of these specified makes and models to the exclusion of similar machines produced by other manufacturers. The authors are Riccardo Spinelli, Technical Manager, Zespri Italia, Cisterna di Latina, Italy; Raffaele Spinelli, Researcher, and Natascia Magagnotti, Researcher, National Research Council Institute for the Exploitation of Wood and Tree Species (CNR‐IVALSA), San Michele all'Adige, Trento, Italy; Carla Nati, Researcher, CNR‐IVALSA, Sesto Fiorentino, Florence, Italy; Luigi Pari, Researcher, Council for Research and Experimentation in Agriculture (CRA‐ING), Rome, Italy; and Joel L. Vanneste, Researcher, New Zealand Institute for Plant and Food Research, Ruakura Research Centre, Hamilton, New Zealand. Corresponding author: Raffaele Spinelli, CNR‐IVALSA, Via Biasi 75, San Michele all'Adige (TN), Italy; phone:+39‐055‐5225641; fax: +39‐055‐5225643; e‐mail: spinelli@ivalsa.cnr.it. Xanthomonas translucens, which causes pistachio die back, have been shown to survive on infected pistachio wood bur‐ ied for seven months (Vu Thanh et al., 2009). Xanthomonas campestris pv. campestris survived on cabbage stem residue buried in soil for over 500 days (Schultz and Gabrielson, 1986). Kiwifruit in Italy are affected by several plant pathogenic bacteria ( Pseudomonas syringae pv. syringae, P. syringae pv. actinidiae , and P. viridiflava) that might be able to survive on infected prunings. One of the most effective ways of reducing the incidence of such diseases is to ensure a high level of hy‐ giene in the affected orchards, which requires the infected material to be carried out of the orchard. The rapid development of bioenergy has generated a growing demand for fuel biomass in Italy (Masera et al., 2006) as well as in New Zealand (Hall and Jack, 2009). Prun‐ ing residues have already been identified as a potentially im‐ portant source of biomass (Bernetti et al., 2006), and they can effectively replace traditional wood assortments for industri‐ al use (Ntalos and Grigoriou, 2002). Alternatively, they can be turned into a balanced organic fertilizer through compost‐ ing (Wang et al., 2004). To ensure that biomass production is a viable economical activity, technologies for the collection, processing, and de‐ livery of pruning residues have been developed. European machine manufacturers are now offering dedicated imple‐ ments for collecting pruning residues. Today, residue collec‐ tion machinery typically incorporates either shredding technology or baling technology. Machines designed to pick up, shred, and collect the residue derive from conventional shredders, which have been equipped with a storage bin or a blower, the latter designed to direct the flow of shredded resi‐ due toward an accompanying trailer. As an alternative, grow‐ ers can use balers that pick up the residue, compact it into units of regular size and shape, tie the bales, and drop them K