Mechanical Harvesting Systems Research Articles

Design, modelling, and testing of a vibration energy harvester using a novel half-wave mechanical rectification

Portable and wearable electric devices are an important part of our life and the energy supply is critical for their functions. Energy harvesting from human motion is a promising solution to provide the energy supply. This paper presents the design, modeling and testing of a vibration energy harvester using a novel half-wave mechanical rectification to enhance the performance of suspended energy harvesting backpack. The proposed half-wave mechanical rectification mechanism uses one set of rack-pinion and a one-way clutch that converts bidirectional vertical oscillation into unidirectional rotation of the generator with nonlinear inertia. As validated by both modelling and bench tests, the proposed half-wave mechanical rectification-based energy harvesting system can obtain about twofold average output power as the previous full-wave mechanical rectification system in the desired dominant excitation frequency and also maintains larger output power in the target frequency range. The influences of external resistance, human walking speed, and payload mass are also studied to comprehensively characterize the performance and robustness of the proposed design. Treadmill tests on different human subjects demonstrate an average power range of 3.3–5.1 W under a walking speed of 4.8 km/h (3 mph) with a 13.6 kg (30 lbs.) payload. Experimental results indicate that the proposed suspended energy harvesting backpack could continuously generate an amount of electricity suitable for powering portable and wearable electronic devices, which can be applied to the military, field workers, outdoor enthusiasts and disaster relief scenarios.

Impact of Cultivar, Harvest Date and Threshing Parameter Settings on Floret and Carthamidin Yield of Safflower

The industrial need for safflower (Carthamus tinctorius L.) increased over the last decade due to its potential use as food colorant. Safflower is mainly cultivated in Asia for its use as floret. In Germany, an economically attractive cultivation for floret use would require a mechanization of harvest. In order to develop a mechanical harvesting system, field experiments were conducted at the experimental station Ihinger Hof of the University Hohenheim in 2017 and 2018. Safflower was harvested with a combine harvester to obtain the florets. Two safflower (i) cultivars were harvested with (ii) three threshing parameter settings on (iii) five harvest dates to evaluate threshed floret yield, dry matter and carthamidin content, and carthamidin yield. Results showed that the maximum threshed floret yield was achieved at the latest harvest date (784.78–1141.76 kg ha−1), while the highest carthamidin contents were observed depending on cultivar on the first two harvest dates (0.53–3.14%). The decisive and resulting amount of carthamidin yield reached its maximum with the Chinese cultivar and the threshing parameter setting P3 between the fourth and fifth harvest date in 2018 (19.05–19.36 kg ha−1). Highest dry matter contents were achieved at the last harvest date (62.67–77.77%). Individual capitula weight and carthamidin content decreased with later harvest dates. Further investigations should clarify whether the individual capitula weight and carthamidin content correlate with each other or are independent of the date of harvest. This could be a decisive criterion for the selection of cultivars for harvesting florets with a combine harvester. Reduced costs of machine harvesting compared to hand harvesting will make the cultivation of safflower for the food coloring industry in Germany more attractive in the future.

Straw Removal Effects on Sugarcane Root System and Stalk Yield

The sugarcane (Saccharum spp. L.) mechanical harvesting system leaves a large amount of straw mulch on the soil surface. The straw mulch may affect soil conditions, root regrowth, and sugarcane yield. Thus, this study assessed the response of sugarcane root system growth and stalk yield to different rates of straw removal. An experiment was conducted in a Rhodic Kandiudox with sand clay loam texture to test the impact of four rates of straw removal: no removal (18.9 Mg ha−1 of dry mass); moderate removal (8.7 Mg ha−1); high removal (4.2 Mg ha−1) and total removal on sugarcane root system and stalk yield. Higher concentrations of roots (60%) were found in the first 40 cm of soil. Moderate straw removal resulted in higher root mass (3.6 Mg ha−1) and stalk production (23 Mg ha−1 of dry mass). However, no straw removal reduced root mass by <40% (2099 kg ha−1) and reduced stalk yield by >20% (105 Mg ha−1). Through regression analysis, it was estimated that retaining between 8.5 and 13 Mg ha−1 of straw resulted in the highest root mass and stalk yield. Managing straw removal to retain a moderate amount enables producers to sustain suitable soil conditions for sugarcane root growth and stalk production while providing straw for industrial use.

Mechanical Hop-Picking Solutions in Italian Cultivated Areas

Hops for beer production are a crop of growing interest in Italy, requiring specialized harvesting equipment and infrastructure. Several studies have been conducted on hop cultivation and harvesting around the world, but information on Italian hop production is still very scarce. As it turns out, only a few Italian farms are self-sufficient, employing a mechanical harvesting system, while most of them resort to hand-picking. In this study, hand and mechanical hop-picking were investigated, highlighting the longest time necessary for the manual cut (65 ± 5 min for approximately 2 kg of fresh cones). Furthermore, different mechanical solutions for hop harvesting were evaluated; in particular, one hop-picking machine was tested at different settings (full speed and 75% of chain feed). At full speed, it was possible to collect an average of around 96 kg h−1 of fresh cones, while approximately 13% of cones were left unpicked. A speed reduction of approximately 25% made it possible to reduce the cone loss to 8%, with a cone collection of around 86 kg h−1. Lost and picked cones, however, were strongly related to the number of side-arms growing from the main bines. This experience made it possible to test an old solution for this emerging crop at moderate cost and with good sustainability for the Italian territory.

Determination of key canopy parameters for mass mechanical apple harvesting using supervised machine learning and principal component analysis (PCA)

As availability of skilled harvest labour is in decline, the sustainability of fresh market apple production in the USA is threatened. A mass mechanical harvesting of apples offers an alternative and promising solution. In addition to harvester design elements, it is important to understand the key canopy parameters of apple trees as they are closely integrated and interact with each other during the harvest process. In this study, the impact of eleven canopy parameters on mechanical harvesting were investigated for vertically-trained “Scifresh” and V-trellis grown “Envy” trees during harvesting trials. A supervised machine learning algorithm with weighted k-nearest neighbours (kNN) was adopted to analyse our canopy datasets. Overall, 2678 ground-truth data points (apples) were classified into two binary classes of fruit removal status: “mechanically harvested” and “mechanically unharvested” apples. For the training dataset (85%), the adopted algorithm achieved overall prediction accuracies of 76–92% and 62–74% for “Scifresh” and “Envy”. With the remaining 15% dataset, the overall test accuracies were 81–91% on “Scifresh” but only 36–79% on “Envy”. The principal components analysis (PCA) was adopted to determine the key canopy parameters by calculating the coefficients of principal components (PCs). The PC1–PC5 explained at least 80% of the data variance. By assuming a coefficient greater than 0.5 as being highly relevant, fruit load per branch, branch basal diameter, and shoot length were the most relevant among all. These results provide guidance for growers in canopy management that could improve efficiency of a mechanical harvesting system.

Forwarder Productivity in Salvage Logging Operations in Difficult Terrain

Large scale windthrow salvage logging is increasing in Central Europe because of the growth of severe atmospheric events due to global heating. Sustainable forest operations in these conditions are challenging in terms of both productivity performances and safety of the operations. Fully mechanized harvesting systems are the preferred solution on trafficable terrains and proper slopes. However, different work methods and logistic organization of the operations could largely change the overall performances. The study observed three harvesting sites based on fully mechanized cut-to-length systems and located in areas affected by the Vaia storm, which hit north-eastern Italy in October 2018. The objectives were to estimate forwarder productivity in salvage logging in difficult terrain and to identify significant variables affecting this productivity under real working conditions. Time and motion studies were carried out and covered 59.9 PMH15, for a total of 101 working cycles, extracting a total volume of 1277 m3 of timber. Average time consumption for each site was 38.7, 42.2, and 25.1 PMH15 with average productivity of 22.5, 18.5, and 29.4 m3/PMH15, respectively, for Sites A, B, and C. A total of seven explanatory variables significantly affected forwarder productivity. Average load volume, maximum machine inclination during loading, and number of logs positively affected the productivity. On the contrary, travel distance, load volume, maximum ground slope during moving and loading have a negative influence. With an average travel distance of 500 m, the productivity resulted 20.52, 16.31, and 23.03 m3/PMH15, respectively, for Sites A, B, and C. An increase of 200 m of travel distance causes a decrease in productivity of 6%.

Field Evaluation of Targeted Shake-and-Catch Harvesting Technologies for Fresh Market Apple

HighlightsThree shaking methods and vibratory harvesting systems were evaluated and compared.Multi-year field evaluations were performed with up to six cultivars trained to formal architectures.The updated semi-automated system achieved the highest fruit removal efficiency and the best fruit quality.Abstract. Apple is the most economically important agricultural crop in Washington State. In 2018, Washington State produced ~3.3 billion kg of apple, accounting for approximately 63% of U.S. production. Fresh-market apple is currently harvested manually, requiring large numbers seasonal semi-skilled workers for a small harvest window. To overcome the increasing challenges of uncertain labor availability and raising labor costs, a promising mechanical harvesting system, using a targeted shake-and-catch approach, is under development at Washington State University. This study evaluated the system by analyzing its fruit harvest efficiency and fruit quality with three shaking methods, i.e., continuous non-linear, continuous linear, and intermittent linear shaking, on up to six apple cultivars trained to formal tree architectures. Results showed that intermittent linear shaking achieved 90% fruit removal efficiency for ‘Scifresh’ cultivar, while continuous linear shaking achieved only 63% removal efficiency for ‘Gala’. This study also compared three vibratory systems: a hand-held system, a hydraulically driven system, and a semi-automated hydraulic system. The semi-automated system achieved the highest fruit removal efficiency (90%), followed by the hand-held (87%) and hydraulic (84%) systems, mainly due to the different shaking methods employed. However, the differences were statistically insignificant. Fruit catching efficiency varied among the harvesting systems, with the hand-held system achieving the highest efficiency (97%), followed by the hydraulic (91%) and semi-automated (88%) systems. Among the three tested technologies, the prototype semi-automated system achieved the highest level of mechanization, as well as high fruit removal efficiency and the best fruit quality. Because the semi-automated system did not include an auto-positioning function, positioning its shaker head took about eight times longer (~103 s) than the actual shaking time (~13 s), which suggests that a fully automated system is desirable to further increase productivity. This study showed that the shake-and-catch approach has great potential for practical adoption in harvesting of fresh-market apple and therefore can have a positive economic impact on the U.S. apple industry. Keywords: Automation in apple production, Bulk mechanical harvest, Semi-automated system, Shaking method, Time efficiency.

Soil disturbance and stream-adjacent disturbance from tethered logging in Oregon and Washington

Over the past century, the primary method for harvesting trees on steep slopes in the Pacific Northwest (PNW) was felling with chainsaws and yarding with cable systems, such as towers. Concerns over safety and higher logging costs on steep slopes have caused a shift in felling and/or yarding to ground-based machines tethered to an anchor, generally at the top of the slope. With the recent shift to tethered operations, there has been growing interest in the potential impact of machinery on steep slopes on streams and site productivity. We compared soil disturbance and stream-adjacent disturbance of tethered logging and conventional cable harvest methods on steep slopes in Oregon and Washington, USA. We sampled 30 harvest units that included either conventional (n = 15) or combination units with tethered (n = 15) harvesting systems to examine soil disturbance within a harvest unit and along stream channels. We compared potential impacts to stream adjacent-disturbance, erosion, and site productivity both between harvesting types within a harvest unit and between conventional versus combination units with tethered operations. We found that combination units with tethered operations had more stream-adjacent disturbance and soil disturbance than conventional cable-harvesting systems, but overall effects were below applicable regulatory thresholds for stream-adjacent disturbance and soil disturbance. Further, at the entire harvest-unit and within-unit scale, tethered operations had similar amounts of soil disturbance as mechanized harvesting systems. We did not find evidence of strong relationships between stream-adjacent disturbance or soil disturbance with either slope or soil depth. Across a wide variation of local site conditions in the PNW, tethered harvesting operations did not have extensive negative impacts on either soil disturbance or stream-adjacent disturbance, but further research could contribute to evolving best management practices and aligning forest practice regulations with current technologies.

Harvesting Energy of Body Motion Through Single Electrode Based Self-Powered Triboelectric Nanogenerator

A self-powered mechanical energy harvesting system consists of the storage system and the energy scavenging TENG. Triboelectric nanogenerator includes a system which integrates a self-powered sensor and the power generator, this triboelectric nanogenerator has the potential to be used in a modern wearable electronic TENG. It has been reported that triboelectric nanogenerator working under complicated deformation like bending, stretching and twisting brings the main problem. Here we have fabricated the shape adaptive Triboelectric nanogenerator which solves all the deformation issues and can harvest the mechanical energy through human body motion in any deformation, the fabricated TENG is a self-powered sensor which can sense the different human activities and can monitor the health issues, the TENG stores the energy directly to the capacitor for powering the wearable electronics. A human skin based triboelectric nanogenerator was designed from the silicon rubber and the copper acetate-II used as the electrode, which makes the TENG flexible self-powered sensor, it can be stretched up to 200%. The stretchable nature and the flexibility of the human skin based silicon rubber triboelectric nanogenerator makes it the promising flexible and shape-adaptive energy harvesting TENG. The fabricated TENG generated the open circuit voltage 70 V and the short circuit current 11 μA and delivered the power 55 μW at the load of 80 MΩ. 42 LEDs were powered directly from the TENG. The fabricated TENG has human skin tactile property which does not harm the human skin while using it multiple times. The layer of copper acetate is completely coated with silicone rubber. The fabricated TENG is flexible, biocompatible and cost effective.

A novel piezoelectric power generator integrated with a compliant energy storage mechanism

One of the practical solutions for low-power wireless wearable devices is to use mechanical energy harvesting devices to supply uninterrupted power. A device for harvesting mechanical energy from human movement can convert the energy into electrical energy which can supply microelectronic device. Although foot impact energy is the most easily utilized mechanical energy, there is a large damping loss during the conversion process due to its short duration of action on the energy harvesting device. It is necessary to design a transient elastic energy storage device for storing mechanical energy during periods of no impact load. In this study, a spring energy storage device consisting of a crank rocker mechanism and a compliant spring was integrated in a mechanical energy harvesting system. The system can store and release instantaneous footstep energy to drive piezoelectric energy harvesters to generate electricity. The performance of the energy storage device was evaluated by finite element analysis and topology optimization design. Finally, a prototype was made and proven to work effectively.

CsTFL1 inhibits determinate growth and terminal flower formation through interaction with CsNOT2a in cucumber.

ABSTRACTCucumber (Cucumis sativus L.) is an important vegetable crop that carries on vegetative growth and reproductive growth simultaneously. Indeterminate growth is favourable for fresh market under protected environments, whereas determinate growth is preferred for pickling cucumber in the once-over mechanical harvest system. The genetic basis of determinacy is largely unknown in cucumber. In this study, map-based cloning of the de locus showed that the determinate growth habit is caused by a non-synonymous SNP in CsTFL1. CsTFL1 is expressed in the subapical regions of the shoot apical meristem, lateral meristem and young stems. Ectopic expression of CsTFL1 rescued the terminal flower phenotype in the Arabidopsis tfl1-11 mutant and delayed flowering in wild-type Arabidopsis. Knockdown of CsTFL1 resulted in determinate growth and formation of terminal flowers in cucumber. Biochemical analyses indicated that CsTFL1 interacts with a homolog of the miRNA biogenesis gene CsNOT2a; CsNOT2a interacts with FDP. Cucumber CsFT directly interacts with CsNOT2a and CsFD, and CsFD interacts with two 14-3-3 proteins. These data suggest that CsTFL1 competes with CsFT for interaction with CsNOT2a-CsFDP to inhibit determinate growth and terminal flower formation in cucumber.

ESTIMATING RUT DEPTH DURING SKIDDING WITH A RUBBER-TIRED SKIDDER

Mechanized harvesting systems provide higher quality products and safer operation environment than that of conventional systems. However, heavy harvesting equipment with rubber-tires generate deep ruts over forest soil, which causes several problems such as excessive delays in operations, serious impacts on physical properties of forest soil, and damages on tree roots. In order to overcome these problems, potential rut depth generated by harvesting equipment must be carefully estimated prior to harvesting system planning. In this study, a model was developed to estimate the rut dept resulted from a rubber-tired skidder. The accuracy of the model was tested in a field study where the results indicated an agreement with the results from the model. The model underestimated the rut depths with the average rate of 9%. The results indicated that reduced tire inflation pressure decreased the rut depths with the average rate of 11%. Besides, it was indicated that one of the main factors in formation of deep rut depths was the amount of wheel load. Keywords: Mechanized harvesting systems, Skidders, Rut depth.

Assessment of paddy harvesting practices of Southern Delta Region in Bangladesh

Paddy in Bangladesh is an important cereal crop for national food security. Harvesting is the process of collecting mature paddy from the field. Timely harvesting operation is known as crucial and influential processes on quantity, quality and production cost of paddy. The aim of the study was to assess the manual and mechanical harvesting systems of paddy in southern delta region of Bangladesh in terms of labor cost, infield harvesting losses, and time required for harvesting. Several experiments were conducted to compare mechanical and manual harvesting systems. Mechanical harvesting of Aman paddy (November-December 2016) and Boro paddy (April-May 2017) was conducted using two models of reaper and a mini-combine harvester at Dumuria and Wazirpur Upazilas of Khulna and Barisal districts, respectively. An experiment was also conducted at the same locations to determine labor requirement and time for harvesting paddy manually. To determine manual harvesting loss, an experiment was conducted at BAU farm, Mymensingh. Total cost savings in paddy harvesting were found 52% and 37% for mini-combine harvester and reaper, respectively over manual harvesting system. Similarly, labor savings using mini-combine harvester and reaper were found 65% and 52%, respectively over manual harvesting system. The total harvesting losses (including harvesting, threshing and cleaning) were also found 1.24%, 4.22% and 6.36% for using mini-combine, reaper and manual harvesting systems, respectively. The results indicated that manual harvesting is a slow and cost involving system. On the other hand, lack of awareness among farmers about the benefits of mechanical harvesting system and lack of skill manpower for operating and servicing harvesters are major barriers for adopting mechanized harvesting system in southern delta region. This study revealed that mechanical harvesting of paddy using either reaper or mini-combine harvester will assist to strengthen food security in southern delta of Bangladesh.
 Progressive Agriculture, Vol. 30, Suppl. 1: 57-64, 2019

Modified Over-the-Row Machine Harvesters to Improve Northern Highbush Blueberry Fresh Fruit Quality

Improved blueberry mechanical harvesting (MH) equipment that maintains fresh market quality are needed due to rising costs and decreasing availability of laborers for harvesting by hand. In 2017, a modified over-the-row (OTR) blueberry harvester with experimental catch surfaces and plates designed to reduce fruit bruising was evaluated. The catch surfaces were made of neoprene (soft catch surface; SCS) or canvas (hard catch surface; HCS) and compared to hand-picked fruit (control). Early- and early/mid-season ‘Duke’ and ‘Draper’, respectively, were evaluated in Oregon, while late-season ‘Elliott’ and ‘Aurora’ were evaluated in Washington. Harvested berries were run through commercial packing lines with fresh pack out recorded and bruise incidence or fresh fruit quality evaluated during various lengths of cold storage. The fresh pack out for ‘Duke’ and ‘Draper’ were 83.5% and 73.2%, respectively, and no difference was noted between SCS and HCS. ‘Duke’ fruit firmness was highest among MH berries with SCS, but firmness decreased in storage after one week. Firmness was highest among hand harvested ‘Draper’ followed by MH with SCS. For ‘Elliott’ and ‘Aurora’, fruit firmness was the same across harvesting methods. ‘Draper’ exhibited more bruising than ‘Duke’, but bruise ratings and the incidence of bruising at ≤10% and ≤20% were similar between hand and MH ‘Draper’ with SCS after 24 h of harvest. ‘Aurora’ berries had similar bruise ratings after 24 h between hand harvesting and MH with SCS, while ‘Elliott’ showed more bruise damage by MH with both SCS and HCS than hand harvested fruit. Although our studies showed slightly lower fresh market blueberry pack outs, loss of firmness, and increased bruise damage in fruit harvested by the experimental MH system compared to hand harvested fruit, higher quality was achieved using SCS compared to HCS. We demonstrated that improved fresh market quality in northern highbush blueberry is achievable by using modified OTR harvesters with SCS and fruit removal by either hand-held pneumatic shakers or rotary drum shakers.

The role of intermolecular forces in contact electrification on polymer surfaces and triboelectric nanogenerators

The present study reports the origin of surface charge on the polymer surface upon triboelectrification and is a step forward towards the development of next generation of mechanical energy harvesting systems.

Performance Analysis of a Harvester during Timber Extraction Activities in Bursa, Turkey

In Turkey, the use of mechanized harvesting technology in forestry has recently increased due to demands of private forest industry for large amounts of woods. In order to implement these systems effectively and efficiently, their applications should be well planned considering the factors that affect the performance of harvesting equipment. Performances of the mechanized harvesting systems are mainly influenced by factors such as tree size, tree formations, terrain conditions, operator motivation and skills. In this study, a single-grip harvesting operation was evaluated by using time and motion study analysis. Also, the main factors that affect harvesting operation were evaluated using statistical analysis. The study was implemented during a clear-cut operation in Brutian pine (Pinus brutia) stands located in Osmangazi Forest Enterprise Directorate in the city of Bursa, Turkey. Three stages of harvesting operation were evaluated; harvester moving to the trees, grabbing and felling trees, and processing (i.e. delimbing and bucking) trees. The average time of the work stages was examined, and the results indicated that most of the time was spent on tree processing. The productivity of the harvesting operation was found to be 24 m3/hr ranging between 6 m3/hr to 57 m3/hr. This productivity was mostly affected by the tree size, which directly influenced the total processing time of the felled trees in the study area. According to the statistical analysis results, it was found that there is a significant relationship between tree volume and the time spent on tree processing stage. The results from this study cannot be generalized but it suggests that mechanized harvesting using a harvester should be well planned ahead taking into considering the volume and size of the felled material in order to operate the harvester with optimal efficiency. Optimum machines and configurations should be selected based on machine specifications and stand characteristics.

ANALYSIS OF TIMES AND EFFICIENCIES OF THE MECHANIZED HARVEST OF SUGARCANE (Saccharum spp.)

Sugarcane culture directed to sugar mills is of great economic and social importance in Brazil. Harvesters are the most important equipment in the sugarcane mechanized harvesting system, since the production process in sugar mills depends on machine operating performance, which is directly related to field efficiency. Therefore, efficiency is relevant because it involves the service time and operational efficiency of the harvester and it takes place when the operation is implemented. The current study aims to analyze the times and efficiencys in sugarcane mechanized harvesting. To current study took under consideration primary data on the mechanized harvesting of a sugarcane plant, which were analyzed using descriptive statistics. The reduction in time lost increases the time worked. Operational and use efficiency have strong impact on the mechanized harvesting performance.

Techno-economic evaluation of microalgae harvesting and dewatering systems

Microalgal biomass is processed into products by two main process steps: 1) harvesting and dewatering; and 2) extraction, fractionation and conversion. The performance of unit operations for harvesting and dewatering is often expressed in qualitative terms, like “high energy consumption” and “low in operational cost”. Moreover, equipment is analysed as stand-alone unit operations, which do not interact in a chain of operations. This work concerns a quantitative techno-economic analysis of different large-scale harvesting and dewatering systems with focus on processing cost, energy consumption and resource recovery. Harvesting and dewatering are considered both as a single operation and as combinations of sequential operations. The economic evaluation shows that operational costs and energy consumption are in the range 0.5–2€·kg−1 algae and 0.2–5kWh·kg−1 of algae, respectively, for dilute solutions from open cultivation systems. Harvesting and dewatering of the dilute systems with flocculation results in the lowest energy requirement. However, due to required chemicals and loss of flocculants, these systems end at the same cost level as mechanical harvesting systems. For closed cultivation systems the operational costs decrease to 0.1–0.6€·kg−1 algae and the energy consumption to 0.1–0.7kWh·kg−1 algae. For all harvesting and dewatering systems, labour has a significant contribution to the total costs. The total costs can be reduced by a high level of automation, despite the higher associated investment costs. The analysis shows that a single step operation can be satisfactory if the operation reaches high biomass concentrations. Two-step operations, like pressure filtration followed by spiral plate technology or centrifugation, are attractive from an economic point of view, just as the operation chain of flocculation followed by membrane filtration and a finishing step with spiral plate technology or centrifugation.

Analysis of the Almond Harvesting and Hulling Mechanization Process: A Case Study

The aim of this paper is the analysis of the almond harvesting system with a very high level of mechanization frequently used in Apulia for the almond harvesting and hulling process. Several tests were carried out to assess the technical aspects related to the machinery and to the mechanized harvesting system used itself, highlighting their usefulness, limits, and compatibility within the almond cultivation sector. Almonds were very easily separated from the tree, and this circumstance considerably improved the mechanical harvesting operation efficiency even if the total time was mainly affected by the time required to manoeuvre the machine and by the following manual tree beating. The mechanical pick-up from the ground was not effective, with only 30% of the dropped almond collected, which mainly was caused by both the pick-up reel of the machine being unable to approach the almonds dropped near the base of the trunk and the surface condition of the soil being unsuitably arranged for a mechanized pick-up operation. The work times concerning the hulling and screening processes, carried out at the farm, were heavily affected by several manual operations before, during, and after the executed process; nevertheless, the plant work capability varied from 170 to 200 kg/h with two operators.

La meccanizzazione nella raccolta di impianti di arboricoltura da legno: produttività di lavoro e costi

Abstract: Harvesting mechanization in plantations for wood production: working productivity and costs. Tree farming has developed rapidly since the early 1990s. Today, tree plantations play an important role in wood supply (including quality wood) and they can partly bridge the gap between national demand and supply which currently leads to substantial wood imports. The opportunity to start new local supply chains or improve the existing ones will have positive effects on the national economy. Against this background, the introduction of mechanized harvesting systems will result in a dramatic reduction of supply cost. This paper reports a full range of harvesting productivity and cost figures for the following plantation types: fast-growing conifers, high-value hardwoods (established following the ex-2080 EU grant scheme), eucalyptus and cottonwood. The purpose of this study is to provide essential information that may lead to the selection of the best technology option, adapted to the specific type of plantation and to the technology level of the harvesting contractor.