Mechanical Harvesting Methods Research Articles

A Review of Perception Technologies for Berry Fruit-Picking Robots: Advantages, Disadvantages, Challenges, and Prospects

Berries are nutritious and valuable, but their thin skin, soft flesh, and fragility make harvesting and picking challenging. Manual and traditional mechanical harvesting methods are commonly used, but they are costly in labor and can damage the fruit. To overcome these challenges, it may be worth exploring alternative harvesting methods. Using berry fruit-picking robots with perception technology is a viable option to improve the efficiency of berry harvesting. This review presents an overview of the mechanisms of berry fruit-picking robots, encompassing their underlying principles, the mechanics of picking and grasping, and an examination of their structural design. The importance of perception technology during the picking process is highlighted. Then, several perception techniques commonly used by berry fruit-picking robots are described, including visual perception, tactile perception, distance measurement, and switching sensors. The methods of these four perceptual techniques used by berry-picking robots are described, and their advantages and disadvantages are analyzed. In addition, the technical characteristics of perception technologies in practical applications are analyzed and summarized, and several advanced applications of berry fruit-picking robots are presented. Finally, the challenges that perception technologies need to overcome and the prospects for overcoming these challenges are discussed.

Potential waste from felling of Eucalyptus pellita trees using Komatsu PC130F-7 in industrial plantation forest

East Kalimantan has seen an increase in mechanized harvesting methods in recent years. Timber production activities in Surya Hutani Jaya Industrial Plantation Forest, Sebulu District have implemented a mechanical harvesting system, including tree felling activities. In the harvesting system by mechanical means, the presence of felling waste is inseparable. Therefore, the volume of felling waste from stumps, stems, and tree tops was calculated. From the stump waste with an area of 0.25 ha in the research plot, 50 samples were taken with a volume produced of 0.0427 m3 or 0.1707 m3 ha−1. In stem waste, 10 samples were taken with a total volume produced of 0.0453 m3 or 0.1811 m3 ha−1. From the tree top waste, 50 samples were taken with a total volume produced of 0.0374 m3 or 0.1496 m3 ha−1. Waste stump, stem, and tree top waste amounted to 0.5014 m3 ha−1 or 0.45%. The results of this study used the Komatsu PC130F-7, the lowest remaining stump height was 1.7 cm and the highest was 12.6 cm. Meanwhile, the mean stump height is only 5.44 cm. From research, it is known that this company has been able to carry out logging efficiently because the waste produced has a relatively small value. The advantage of harvesting trees with a Komatsu PC 130F-7 equipped with a shearing head is the minimum amount of wood debris that accumulates in the field.

Modelling and simulation of self powered triboelectric nano generator sensor for heart beat monitoring

The triboelectric generators works on the principle of voltage produced by charge accumulation as a result of friction between between heterogenous materials. Self powered sensors is the most needed development in medical industry. Biosensors are power supply dependant.The power supply need for biosensors are catered by using mechanical energy harvesting Triboelectric Nano generators (TENGs) working on mechanical energy harvesting method is applied for developing biosensors. TENGs work on the principle, of producing charges carriers by enabling friction between two distinct materials. The generated electric energy acts as a reservoir to power the device. In bioimplantable sensors, power supply systems replacement is complex, as it needs a surgical intervention. Hence heartbeat energy is harvested for the powering pacemakers. Simulation and modelling of contact separation mode based TENGs with Spice (Simulation Program with Integrated Circuit Emphasis) software is discussed in this paper. The signal generation of the TENGs has been simulated by SPICE and analytical samplings have been carried out for the circuit analysis. Recently invented heart rate monitors are not suitable for daily usage. Hence TENGs are identified as cost effective biosensors with unique features such as light weight and high sensitivity.

Advances in Rice Seed Shattering.

Seed shattering is an important trait that wild rice uses to adapt to the natural environment and maintain population reproduction, and weedy rice also uses it to compete with the rice crop. The loss of shattering is a key event in rice domestication. The degree of shattering is not only one of the main reasons for rice yield reduction but also affects its adaptability to modern mechanical harvesting methods. Therefore, it is important to cultivate rice varieties with a moderate shattering degree. In this paper, the research progress on rice seed shattering in recent years is reviewed, including the physiological basis, morphological and anatomical characteristics of rice seed shattering, inheritance and QTL/gene mapping of rice seed shattering, the molecular mechanism regulating rice seed shattering, the application of seed-shattering genes, and the relationship between seed-shattering genes and domestication.

Re-shaping pruning improves the dynamic response of centuries-old olive trees to branch-shaker vibrations application.

The Mediterranean basin is home to centuries-old large olive trees; high-vigor cultivars are widespread, with training forms poorly adapted to mechanical harvesting by trunk/branch shakers. The significant quantity of leaves, the considerable tree height, and the presence of multiple dichotomous hanging branches reduce the transmission of vibrations applied by the branch-shaker machines. Thus, re-shaping pruning may improve the performance of this modern mechanical harvesting method by focusing on removing both the hanging branches and those forming dichotomies. The goal of this study was to evaluate the dynamic responses of large-sized olive trees to pruning (or not) through various field tests under different excitation forces. We hypothesized that more rational pruning could significantly increase vibration transmissions. To assess the transmission of vibrations, tests were conducted before and after the pruning on representative trees. Tri-axial accelerometers packed in a small titanium housing were used. Trees were assessed before and after the re-shaping pruning. This study reports the first data about the dynamic behavior of centuries-old tree skeletons, in the context of very large-sized olive trees, while taking into account the effects of two different vibrations application modes: a realistic one represented by the system vibration head-tree, originated when the gripper of a shaking machine wrapped and fastened the main branch of the olive trees, and a more speculative one, represented by a single impulse of a short-duration force originated by a hammer. After pruning, spectral density increased 10 fold in the tertiary branches of pruned trees (ranging 1.0-10 m s-2) compared to that of not-pruned ones (ranging 0.1-1.0 m s-2) at frequency >50 Hz under vibration excitation. Moreover, vibrational decay times (120-150 ms) and amplitude (>10-1 m s-2) were higher under single-impulse excitation. A more rational pruning applied to ancient large-sized olive trees significantly increased the vibration transmission under both impulse and vibratory excitation forces, without affected their typical "look". Moreover, these insights are helpful in turn in achieving maximum fruit-removal efficiency. These insights could be applied to various horticultural conditions which would improve the economic sustainability of monumental olive trees, a key portion of the Mediterranean landscape and cultural heritage.

Development of a method to harvest mechanical energy to use as an alternative to electrical energy in electric powered rides

Mechanical energy harvesting, storage and utilization methods and devices are a little explored area with a potential to replace electrical energy in machines operated with electricity and which is environmentally friendly. Energy harvesting from human actions is an optimistic solution to provide energy supply. There are various methods and techniques that discuss energy harvesting from human actions. The problem is that most of these methods deal with tiny energy output. The object of this study is to design and characterize a flat spiral spring based method to harvest enough mechanical energy, to store and to drive a ride as in an amusement park instead of electricity. A flat spiral spring is specifically designed and fabricated for this purpose. To begin with, a life-size prototype of the kids' ride using the flat spiral spring is modeled, analyzed, fabricated and implemented on the kids' ride prototype. The stability of the ride is analyzed by modeling the impact of the collision between two kids' rides. Energy is harvested by winding the spring by hands using a handle or by pulling back the kids’ ride and is stored in the spring. Experimental results show that the proposed method of harvesting, storing and utilization of mechanical energy can be an alternative to electrical energy in operating high-power machines like kids' rides. An optimum width of 30 mm and a thickness of 1.4 mm for the flat spiral spring are found to help in ease of manufacturability, ease of rotation by human and compactness. The average force required to wind the spring is calculated to be 16.06 N, which is approximately 33 % of the force that can be exerted by a human hand. The stability of the proposed system in case of collision is verified by calculating the roll angle, which is less than 3.83 degrees, which is well below the recommended roll angle limit in case of collision.

Oil Quantity, Chemical and Organoleptic Properties of Three Olive Cultivars Grown under Irrigation at a Typical Arid Region in Jordan as Influenced by Harvesting Method and Date

An experiment was conducted to investigate the influence of harvesting method and harvesting date on the quality and quantity of three olive genotypes. Olive fruits of cultivars "Ayvalik", "Grossa de Spain" and "Nabali" were harvested on October 20 and November 13, 2017, using hand and mechanical (by combs) harvesting methods. Olive fruits were pressed then, olive oil samples were analyzed for acidity, peroxide value, refractive index, olive oil percentage, and sensory properties. The results showed that the harvesting method did not significantly affect oil quantity and chemical analysis, but affected sensory properties of olive oil, where the harvesting method by hand gave the highest (fruity, bitter, and pungent) and the lowest negative attributes (fusty, musty and rancid). Furthermore, as ripening progressed, there was an increase in olive oil percentage, oil acidity and peroxide value. The positive attributes (fruity, bitter and pungent) were significantly decreased while negative attributes (fusty, musty and rancid) were increased as ripening progressed. On the contrary, the refractive index (at 25°C) remains almost constant. The response of olive cultivars to harvesting was inconstant and did not respond similarly, "Ayvalik" had the highest acidity and peroxide value, while "Grossa de Spain" had the highest oil percentage. In addition, "Nabali" had the highest positive attributes. The lowest acidity, peroxide value and negative attributes were obtained for "Nabali". The result proved that olive cultivars and harvesting date and method combine together to influence acidity, peroxide value and sensory properties (fusty, musty, rancid, fruity, and bitter) of olive oil.

RNA-Seq and Genome-Wide Association Studies Reveal Potential Genes for Rice Seed Shattering

The loss of the shattering ability is one of the key events in rice domestication. The strength of the seed shattering ability is closely related to the harvest yield and the adaptability of modern mechanical harvesting methods. In this study, using a population of 587 natural rice cultivars, quantitative trait loci associated with seed shattering were detected by genome-wide association studies (GWASs). We consider the quantitative trait loci (QTLs) qBTS1 and qBTS3 to be the key loci for seed shattering in rice. Additionally, the abscission zone (AZ) and nonabscission zone (NAZ) of materials with a loss of shattering (DZ129) and easy shattering (W517) were subjected to RNA-Seq, and high-quality differential expression profiles were obtained. The AZ-specific differentially expressed genes (DEGs) of W517 were significantly enriched in plant hormone signal transduction, while the AZ-specific DEGs of DZ129 were enriched in phenylpropanoid biosynthesis. We identified candidate genes for the lignin-associated laccase precursor protein (LOC_Os01g63180) and the glycoside hydrolase family (LOC_Os03g14210) in the QTLs qBTS1 (chromosome 1) and qBTS3 (chromosome 3), respectively. In summary, our findings lay the foundation for the further cloning of qBTS1 and qBTS3, which would provide new insights into seed shattering in rice.

Lightweight mobile stick-type water-based triboelectric nanogenerator with amplified current for portable safety devices

ABSTRACT Due to its abundance, mechanical energy is a promising ambient energy source. Triboelectric nanogenerators (TENGs) represent an effective mechanical energy harvesting method based on the use of contact electrification. The existing liquid-based TENGs can operate robustly without surface damage; however, the output of these TENGs is considerably smaller than that of solid-based TENGs. Notably, liquid-based TENGs in which the liquid directly contacts the conductive material can produce an electrical current of more than few mA. However, the liquid reservoir must have an adequate volume, and sufficient space must be provided for the liquid to move for generating the electrical output. To ensure a compact and lightweight design and produce electrical output in the low input frequency range, we introduce a mobile stick-type water-based TENG (MSW-TENG). The proposed MSW-TENG can generate an open-circuit voltage and closed-circuit current of up to 710 V and 2.9 mA, respectively, and be utilized as self-powered safety device. The findings of this study can promote the implementation of TENGs in everyday applications.

Improving forest management by implementing best suitable timber harvesting methods

Efficient forest operations are required for the provision of biodiversity and numerous ecosystem services, such as wood production, carbon sequestration, protection against natural hazards and recreation. In numerous countries, under difficult terrain conditions, the costs of forest management and harvesting are not covered by timber revenue. One possible option to increase the cost-effectiveness of the forestry sector is the application of state-of-the-art harvesting and extraction techniques, so-called best suitable harvesting methods. We present a case study from Switzerland, where a lack of competitiveness in the forestry sector is of particular interest, with the aim of quantifying the efficiency gains if estimated best suitable harvesting methods were to be rigorously applied instead of the currently applied harvesting methods. For this purpose, we developed a spatial decision support system to allocate estimated best suitable harvesting methods to plots, while concurrently considering hauling route limitations, extraction route properties and stand characteristics. Our approach was based on productivity models and supported with expert-defined decision trees. The evaluation of the estimated best suitable harvesting methods and the comparison with the currently applied harvesting methods were completed for all 6500 National Forest Inventory (NFI) plots in Switzerland. We draw the following three major conclusions from our study: First, our modeling approach is an effective method to allocate estimated best suitable harvesting methods to NFI plots. Second, applying estimated best suitable harvesting methods would lead to cost reductions, in particular in the regions that include steep terrain and where harvesting mainly relies on cable- and air based extraction methods. Third, assuming an average timber price of 75 CHF m −3, 64 % instead of 52 % of the forest area could be harvested economically over the whole country if estimated best suitable methods were applied. This advantage would mainly be caused by a shift towards more mechanized harvesting methods. Improving the cost-effectiveness of the forestry sector is of high global relevance, as the increased use of domestic timber resources is a cost-efficient way to reduce atmospheric carbon emissions. The methodological framework described here was developed for Switzerland in particular, but it could be applied to Central Europe and other parts of Europe with a large amount of mountain forests.

Parameter Optimization of Vibrating and Comb-Brushing Harvesting of Lycium barbarum L. Based on FEM and RSM

The current mechanical harvesting methods of Lycium barbarum L. are labor intensive and cause too much damage, but vibrating and comb-brushing harvesting can increase the efficiency while minimizing the damage. However, optimizing the main factors and their parameter values of vibrating and comb-brushing harvesting is challenging. To achieve the high-efficiency and low-damage harvesting of L. barbarum, firstly, the mechanical models of the materials used in the experiments were established based on the physical tests. Then, the vibrating and comb-brushing harvesting simulations were conducted based on FEM to acquire the ranges of the parameter values. The effects of the rotating speed, material, and amplitude on the harvesting rate of ripe fruit and harvesting rate of unripe fruit, as well as the damage rate of ripe fruit were determined based on RSM. Finally, the optimized parameters were obtained and verified using the field experiments. The field experiments showed that the harvesting rate of ripe fruit was 85.8%, the harvesting rate of unripe fruit was 10.5%, and the damage rate of ripe fruit was 9.7%. The findings provided the optimal parameter values, which were a design basis for the vibrating and comb-brushing harvesters of L. barbarum.

Occupational tree felling fatalities: 2010-2020.

Logging and landscape work are among the most hazardous occupations, and one of the most dangerous tasks in these occupations is tree felling. While much research has been conducted to examine fatalities from logging and landscape services, there is a dearth of research looking specifically at tree felling. There is a need to focus on hazards associated with tree felling activities so that proactive prevention strategies can be developed. An Occupational Safety and Health Administration (OSHA) database was used to identify occupational tree-felling fatalities in the United States during the period from 2010 through the first half of 2020. We compared data for the two industry segments of logging and landscaping services. There were 314 fatalities over the period. The victims were overwhelmingly male with the median age being 43. Struck-by was the number one event type causing fatalities, with the head being the number one body part involved in fatalities. Falls from elevation was the only event type significantly different between the logging and landscaping industries. Poor decision-making is noted as a key component of fatal incidents, but bystanders were fatally injured due to the actions of others. Tree felling is one of the most hazardous activities for both loggers and commercial landscapers and is a common cause of fatalities; significant differences in events and source are encountered in those two occupations. Loggers should continue efforts to adopt mechanized harvesting methods. Landscape services tree fellers should receive training related to fall prevention.

Timeliness Harvesting Loss of Rice in Cold Region under Different Mechanical Harvesting Methods

The yield loss during the process of harvesting is a great challenge in rice production. A suitable harvesting time and harvesting method can help to reduce the yield losses of rice, and decisions about the harvest date have important implications for labor management as well as for agricultural machinery scheduling. Nonetheless, the comprehensive composition of timeliness harvesting loss (THL) and its changing rules for different harvesting methods remain poorly understood. The objective of this study was to determine the effect of harvest date and mechanical harvesting methods on grain dry matter timeliness loss (GDMTL) and mechanical timeliness losses (MTL) of rice in the cold region. To this end, the field experiment was conducted from 45 days after heading (45 DAH) to 59 days after heading (59 DAH), adopting a full-feeding and semi-feeding combine harvester (FCH and SCH) from 2019 to 2020. The results showed that harvest date had a significant effect on GDMTL and four kinds of MTL including header timeliness loss (HTL), cleaning timeliness loss (CTL), un-threshed timeliness loss (UTTL), and entrainment timeliness loss (ETL, only under FCH). With the prolonged harvest date, the HTL and CTL increased and the UTTL and ETL decreased, which ranged from 0.15–0.31%, 0.36–0.67%, 0.72–0.18%, and 0.69–0.31%, respectively for FCH. For SCH, the variation range of HTL, CTL, and UTTL was 0.41–0.59%, 0.66–0.98%, and 0.64–0.21%, respectively. The GDMTL increased first and then decreased, ranging from 2.84–0.87%. The mechanical harvesting methods had no significant effect on the GDMTL of rice, but the MTL could be large between FCH and SCH. In general, optimal harvest period was 52 DAH~53 DAH for both harvesting methods, which exhibited the highest yield and the lowest loss, i.e., 9269.3 kg/hm2 and 1.70%, respectively, and the mechanical operating mode on different harvest dates was recommended to minimize the mechanical loss. The optimal harvest date for rice in a cold region ensured both quality and quantity for mechanized harvesting, and provided a reference for the reasonable allocation of operating harvesters in the harvesting season.

Modal Analysis and Experiment of a Lycium barbarum L. Shrub for Efficient Vibration Harvesting of Fruit

The most common harvesting method of Lycium barbarum L. (L. barbarum) is manual harvesting, resulting in low efficiency and high cost. Meanwhile, the efficiency of vibration harvesting, which is considered an efficient mechanical harvesting method, can be significantly improved if the optimized resonance frequency of the shrub can be obtained. To vibration harvest fruit efficiently, a 3D model of the shrub was established based on measurements of the shape parameters, and material mechanics models of the branches were established based on physical tests. The modal analysis of the shrub based on finite element method (FEM) simulation was performed to obtain the range of resonance frequency, and the modal experiment of the shrub using acceleration sensors and an impact hammer was conducted to obtain the accurate resonance frequency. Based on the results of the modal analysis and experiment, the optimized resonance frequency was determined to be 2 Hz. The field experiment showed that the fruit fell off when the branches were vibrated at this frequency. The results provide the design basis for the efficient vibration harvesting of L. barbarum.

High output triboelectric nanogenerator based on PTFE and cotton for energy harvester and human motion sensor

Recently, a novel mechanical energy harvesting method named triboelectric nanogenerator (TENG) is reported, and it has aroused great repercussions in the academic fields. But, the complex preparation process still limits its wide application. In this paper, the cotton film was used as the triboelectric material to fabricate a novel wearable TENG (W-TENG). The polytetrafluoroethylene (PTFE) film and cotton film play the role of triboelectric pair. The W-TENG can be used to harvest low-frequency mechanical energy in our environment, especially for human body mechanical energy, and then convert them to electrical energy. In addition, the cotton coated with conductive ink plays the role of conductive material for TENG. The Voc and Isc of W-TENG can reach 556 V and 26 μA, respectively. As for the maximum power density of W-TENG, it can arrive at 0.66 mW/cm2. Also, a combined W-TENG was proposed to improve the electrical output. Moreover, the W-TENG can play the role of human motion sensor for human walking posture monitoring. This will open up a new path for the preparation of high output TENG at low cost, and promote the TENG devices in the field of sports monitoring.

A REVIEW OF PHYSICAL AND MECHANICAL PROPERTIES OF CASSAVA RELATED TO HARVESTING MACHINES

For many years now, harvesting of cassava is difficult because there has not been a well-designed machine to harvest, separate, and convey the crop in a one-time operation. In all the unit operations in cassava production, several machines and types of equipment have been mechanized successfully. However, cassava harvesting and peeling have remained a global challenge to engineers involved in machine design. In light of this, some pieces of literature on the physicomechanical properties of cassava were qualitatively reviewed. The study presents harvesting methods for cassava around the globe, considering its merits and limitations for future development. We found out that cutting shear stress and force increased with increasing cassava tuber age because of an increase in density and starch content. Additionally, the ratio of the peel of cassava tuber ranges from 0.106 to 0.215. The frictional properties of cassava are essential to design and develop machines for post-harvest operations of cassava roots. Whereas, the angle of repose for the unpeeled cassava is required for the design of the hopper and that of the peeled is required for the design of the chute. The manual, semi-manual and fully mechanized harvesting methods require the capacity of about 22-51 man h/ha, 16-45 man h/ha, and 1-4 man h/ha respectively. The fully mechanized method is very efficient, and the field is plowed alongside harvesting which saves time, fuel, and cost of operation. Even though less research is carried out on cassava harvesting mechanization compared to other crops, the current development is a harvesting machine hitched to a tractor with a conveyor unit powered by the PTO system. The knowledge of this review would be a blueprint for engineers in designing cassava mechanical harvesters.

The vibrational response of simulated Ginkgo biloba fruit based on their frequency spectrum characteristics.

The most effective method for harvesting forest fruit is the mechanical vibration harvesting method. During the forced vibration process, the fruit will be shed from the tree when the inertia of the fruit is greater than the fruit’s pedicel retention force. In order to study the movement response characteristics of the Ginkgo biloba fruit in depth, for a small Ginkgo biloba fruit tree, the frequency curve of the fruit tree had been obtained in this paper, based on the pulse hammer excitation method, and four resonant frequencies and four trough point frequencies, in the frequency range of 10 Hz~25 Hz, were determined as the test excitation frequency. Through a comparison test between the simulated fruit and the Ginkgo biloba fruit, both the simulated fruit and the real Ginkgo biloba fruit demonstrated good response consistency, and the results had shown that the simulated fruit could be used to replace the Ginkgo biloba fruit. The acceleration response of the resonant frequency and the trough point frequency for two test points of the two primary branches had also been analyzed. It was found that the resonant frequency caused an obvious harmonic response. For the same frequency, the fruit at some points produced a very strong vibrational response, while at other points the fruit was almost stationary. Therefore, it was difficult for a fruit tree to completely shed all its fruit through excitation at a single frequency. It was more difficult to induce a strong vibrational response of fruit on branches of higher stiffness. On the contrary, it was easier to induce a strong vibrational response on more flexible branches regardless of the resonant frequency or the trough point frequency excitation.

Evaluation of a Harvester-Baler System Operating in a Rockrose (Cistus laurifolius L.) Shrubland

Biomass collection could contribute to the reduction of wildfire prevention costs by obtaining solid biofuels from shrublands that pose a high fire risk, using mechanical harvesting methods that have not been sufficiently tested in shrub formations. The objective of this study is to evaluate the performance of a harvester-baler system (Biobaler WB55) for collecting rockrose (Cistus laurifolius L.) shrublands biomass, to asses the influence of the cutting rotor tool (blades or hammers) on weight and surface productivities and operating costs, as well as to determine the influence of the standing shrub biomass load on productivity and biomass collection efficiency.A 31-hour test was conducted on 21 ha of a typical Mediterranean shrubland in the centre of Spain. Data collection included time study, daily collected area, fuel consumption and bale measurements. Samples of fresh biomass from bales were collected for the determination of moisture content. The average collected biomass was 2.3 tDM·ha-1 (tonnes of dry matter per hectare), with an average productivity of 1.6 tDM·PMH-1 and an average yield of 0.7 ha·PMH-1. Better results were obtained with blades than with hammers in the cutting rotor tool (35% more collected biomass, 42% higher weight productivity, 61% higher collection efficiency and 14% greater surface productivity). The average harvest-baling costs with blades were estimated at 99.5 €∙PMH-1, 142.1 €∙ha-1 and 53.9 €∙tDM-1 (34.0 €∙tWM-1, € per tonne of wet matter), and with hammers 91.5 €∙PMH-1, 152.5 €∙ha-1 and 81.4 €∙tDM-1 (51.1 €∙tWM-1).The analysed harvester-baler was operated without difficulty in this type of vegetation and was able to collect up to 31% of the shrub biomass load in the study area. The amount of uncollected biomass and the decrease in biomass collection efficiency, as shrub biomass load increases, suggest that possible mechanical improvements are needed to improve biomass collection efficiency.

Biodiversity functions of short rotation coppice stands - results of a meta study on ground beetles (Coleoptera: Carabidae)

The functions of short rotation coppices (SRC) with regard to biodiversity are often thought to be limited because of the monoculture and even-aged plantation character, highly mechanized harvesting methods and short rotation cycles. Of the many studies conducted there are varying results, though most concluded that only very young SRC in the establishment phase are of particular value for species protection. For a better evaluation of biodiversity functions of SRC with the potential to be generalized, we conducted a meta study combining existing data from 14 projects with a total of 73 plots from SRC in Central Europe (Germany and Czechia), using ground beetles (Carabidae). Ground beetles are a speciose and well-studied family, with a long tradition as indicators of several aspects of biodiversity because of their diverse habitat requirements and species traits. Results show that SRC not only provide benefits for biodiversity by providing endangered pioneer species an ephemeral pioneer habitat (particularly during the establishment phase of the SRC), but also at the fringes. A second function is that of providing strict forest species of limited dispersal ability with habitat corridors, which is the case particularly in older, long-existing SRC. Age of the plantation is much more important in this regard than the length of the rotation intervals. In the future, multifunctional landscapes which aim to maintain open fields and cultivate forest biodiversity would benefit from a stronger consideration of SRC.

Harvesting-induced stress in broilers: Comparison of a manual and a mechanical harvesting method under field conditions

Harvesting of broilers is a stressful event, whether done mechanically or manually. The use of harvesting machines might compromise animal welfare less than manual harvesting methods because it is less influenced by environmental and flock-specific factors. In this paper, a mechanical and a manual harvesting method are compared in regard to stress-induced behavioural and physiological reactions. The stationary person test and the avoidance distance touch test were applied before harvesting to estimate pre-treatment fear of humans in the flocks. We then recorded the behaviour of the flocks during harvesting and evaluated stress-induced behaviour such as wing flapping and escape behaviour. Furthermore, we took blood samples at the abattoir and analysed the corticosterone concentration and heterophil/lymphocyte ratio. In a statistical analysis, all assessed parameters were related to environmental and flock-specific factors, as well as to the risk of lesions such as haematomas and fractures. Our aim was to figure out if the use of a harvesting machine, in this case the Apollo Generation 2, puts less stress on broilers during harvesting than manual catching. The applied behaviour tests indicate the excitability and fear of humans of the flocks but are complex to interpret. Compared with mechanical harvesting, manual harvesting was more influenced by environmental and flock-specific factors such as average weight (odds ratio [OR] = 1.49; 95% confidence interval [CI] [1.11; 2.22]) or catching duration (OR = 1.79; 95% CI [1.44; 2.19]). The results verified a correlation between stress-induced behaviour and the occurrence of lesions. The risk for haematomas was influenced by escape behaviour during manual harvesting (OR = 1.07; 95% CI [1.02; 1.13]) and by bumps against the containers (OR = 1.06; 95% CI [1.05; 1.07]) and flips (OR = 6.23; 95% CI [3.99; 9.27]) during mechanical harvesting. The risk for fractures during mechanical harvesting was influenced by the occurrence of flips (OR = 2.74; 95% CI [1.07; 5.67]). The risk for wing flapping was twice as high during manual harvesting as during mechanical harvesting (OR = 2.11; 95% CI [1.82; 2.44]). The blood parameters showed no correlations with the initial behaviour test results and the assessed stress-induced behaviour during harvesting. Corticosterone concentration was strongly influenced by light intensity (beta = 3.75; 95% CI [2.55; 4.95]) and outdoor temperature (beta = 46.34; 95% CI [39.18; 53.27]) during manual harvesting. The results showed weak points of both harvesting methods, and we offer suggestions to improve animal welfare during harvesting.