EVALUATION OF LABOR REQUIREMENTS FOR BURLEY TOBACCO STALK-NOTCHING HARVESTERS

Transcription

1 EVALUATION OF LABOR REQUIREMENTS FOR BURLEY TOBACCO STALK-NOTCHING HARVESTERS John H. Wilhoit* and George A. Duncan Stalk-notching harvesters initially received a lot of interest by growers because they were the only reasonably priced commercially available options that actually mechanized the harvest of burley tobacco. Field studies were conducted at four different farms one with a MarCo harvester and the other three with Kirpy harvesters observing harvesting and hanging operations. Harvesting labor productivity was fairly consistent for three of the four farms with similar wagon load sizes, and considerably higher at the fourth farm that had a much larger wagon load size. Harvesting labor requirements ranged from about 16 to 27 worker-hours (w-hr)/ha (6.7 to 11 w-hr/ac), compared with 64 w-hr/ha (26 w-hr/ac) for traditional stick harvesting of burley tobacco. Hanging labor requirements ranged from about 55 to 76 w-hr/ha (23 to 31 w-hr/ac), comparable with standard hanging labor requirements for hanging stick tobacco in multitiered traditional barns, but considerably higher than reported for hanging stick tobacco on single tier-height field structure. Interest and use of the notching harvesters by tobacco producers seems to have decreased substantially despite the potential labor savings. Likely reasons for the decrease include cost, the need to build extensive wire-strung fieldcuring structures, a high rate of leaf loss, constraints to using the harvesters with crooked plants and in wet field conditions, and incompatibility with large-scale tobacco production relying on migrant labor. INTRODUCTION The opportunity for burley tobacco growers to grow larger crops after the buyout legislation and termination of the federal tobacco quota system in 2005, and increasing shortages of labor for harvesting and stripping, sparked a resurgence of interest in burley mechanization in the mid 2000s. An indication of that interest was given by tobacco mechanization field days held in Kentucky in 2006 and 2007 where several commercial and prototype burley harvesting machines were demonstrated (4,7). Following those field days, two commercial tobacco plant-notching harvesters, one manufactured in the United States by MarCo Manufacturing Company, LLC, and the other one manufactured in France by Kirpy, received a surprising amount of interest, and some adoption, by growers because they were the only reasonably priced options available that actually mechanized the harvest of burley tobacco. These two harvesting machines are shown in Figures 1 and 2. The two machines, which functioned in very similar ways, evolved from earlier versions of plant-notching harvesters. The stalk-notching and handling concept was based on methods used in France (9) and on observations of experiments in Maryland (8). The basis of the concept is cutting a 45u notch in the base of the stalk and then hanging the stalks by the notch on wire-strung structures for curing, rather than spearing the stalks onto sticks and hanging the sticks across a pair of rails as with traditional manual harvesting (1). Powell Manufacturing produced a tractor-towed commercial version of a harvester developed at the University of Kentucky based on the stalknotching concept that used portable wire-strung frames carried on the harvester. The harvester cut the tobacco *Corresponding author: J.H. Wilhoit; jwilhoit@bae.uky.edu Biosystems and Agricultural Engineering Department, University of Kentucky, Lexington, KY stalks at ground level with a powered saw and elevated them by sticker chain past a notching saw to three to four workers riding on the machine who hung the notched plants on the frames (11). Both the MarCo and Kirpy notching harvesters function similarly to the Powell harvester, with single rows of tobacco plants cut off slightly above ground level with large-diameter saws, and the plants conveyed in an upright position past an angled notching saw. They differ from the earlier machine, however, in that the plants are off-loaded off the end of a conveying chain onto a field trailer pulled adjacent to the harvesters (3). Both the MarCo and Kirpy harvesters are tractor-mounted and hydraulically powered using power takeoff-driven pumps. There are various differences in design and operation of the harvesters, but the main difference is that the Kirpy machine uses a log chain-type conveyor with small spikeladen metal plates attached to the chain links and guided by ultra-high-molecular-weight plastic groves, whereas the Marco machine conveys plants with a sticker chain of the type that has traditionally been used for conveying tobacco plants upright. In typical field operations with either of these machines, a standard farm wagon pulled alongside the harvester can be filled quickly with loosely stacked plants in feet of row, and then the filled wagon is changed out for an empty one (4). Notched plants from these harvesters are hung on wire for curing. Some growers and researchers experimented with methods for stringing wire in barns initially, but it soon became apparent that anything higher than a single tier height was impractical from a labor efficiency standpoint for hanging individual plants (Young, personal communication). Most growers settled on some variation of high-tensile wire strung on a wooden framework for curing notched tobacco in plastic-covered field structures (3). Typical hanging operations consisted of 4 5 workers pulling plants from the wagon and Tobacco Science (2012) 49: Tobacco Science tbcs d 23/8/12 08:38:20 25 Cust # R

2 Figure 1. MarCo burley stalk-notching harvester. Figure 2. Kirpy burley stalk-notching harvester. hanging the individual plants on the wires. Some growers have had workers pull the plants from the wagon onto the ground, and then pick up individual plants from off the ground for hanging, whereas others have had workers on the trailer hand individual plants to workers on the ground for hanging. These harvesting machines cut and load the plants onto wagons at a fast rate. A harvester moving as slowly as 1.6 km/hr (1 mi/hr) is still cutting at a rate of over 3,000 plants/hr at typical burley tobacco plant spacing. Observations of such fast mechanical harvest rates, coupled with relatively low machine costs (initial price quotes of $27,500 for the MarCo and $23,000 for the Kirpy (5)), probably contributed to initial high expectations for significant harvest cost reductions with these machines (2). However, it is very time consuming to hang individual notched plants on wires (compared with handling six plants at a time on sticks). Also, utilizing the harvester efficiently requires a large crew to balance harvesting and hanging operations. In an attempt to get an estimate of the actual labor requirements using notching harvesters, and to evaluate the requirements for balanced harvest operations, field studies were conducted at two different farms in 2007 observing tobacco harvesting and hanging operations. At one of the farms, the MarCo notching harvester was used, and at the other the Kirpy was used. Field studies were conducted again in At that time, data were collected on two different farms, both utilizing the Kirpy notching harvesters. This article reports the results of on-farm performance of notching harvesters during the 2007 and 2010 harvesting seasons. observed cutting tobacco plants and loading them onto wagons for 11 loads. Observations of hanging operations were done on 10 of those 11 wagon loads. The field layout at this farm was such that the harvester filled a wagon in a single pass along the length of the field, and the number of plants harvested in each wagon load was estimated on the basis of the field length and plant spacing used. At the Lykin farm, the Kirpy havester was observed cutting and loading tobacco onto wagons for 16 loads (see Figure 2). Hanging operations, shown in Figure 3, were observed for 13 of those 16 loads. The field at this farm was longer than the distance for filling an individual wagon, so the distance covered by the harvester for each load was flagged and later measured to use in estimating the number of plants on the basis of the plant spacing. Harvesting and hanging operations were observed at the Cornett farm near London, KY, and the Young farm in Trimble County, KY in Both of these farms were using the Kirpy harvesters. At the Cornett farm, the FIELD STUDY PROCEDURES Harvesting and hanging operations were observed and documented during the 2007 burley harvesting season at the Wingham farm in Trimble County, KY, where a MarCo notching harvester was used, and at the Lykins farm in Azalia, IN, where a Kirpy notching harvester was used. At the Wingham farm, the MarCo harvester was Figure 3. Hanging notch tobacco plants on wire-strung field structure from plants pulled off the wagon onto the ground. 26 Tobacco Science (2012) 49:25 30 Tobacco Science tbcs d 23/8/12 08:38:38 26 Cust # R

3 Table 1. Field-study results for evaluation of harvest labor requirements of burley tobacco stalk-notching harvesters. Farm Harvester # Wagon Loads # Field Workers # Plants/ Wagon Harvest Time (min) Turn & Stop Time/ Wagon (min) Field Efficiency (%) Harvest Rate (plants/hr) Harvest Rate (plants/w-hr) Wingham MarCo , Lykins Kirpy , Cornett Kirpy ,045 Young Kirpy , harvester was observed loading wagons 11 times, and hanging operations were observed for 7 of those same wagons. The number of plants in each wagon load was estimated on the basis of distance covered and plant spacing. At the Young farm, the harvester was observed loading wagons 9 times, and hanging operations were observed for 5 wagon loads. At this farm, the number of plants in each wagon loaded for the harvester observations was estimated on the basis of distance covered and plant spacing, but the wagons used for observing hanging operations were not necessarily the same ones for which the harvesting operations were observed, so the actual number of plants hung during observations was counted. During harvesting operation observations, the start and stop time for each wagon load was recorded sequentially and the number of workers involved driving the tractor with harvester and the tractors pulling wagons was noted. During hanging operations, the start and stop times for each wagon load were recorded. The number of workers unloading the wagons, and the times that the different workers started or stopped working on unloading a particular wagon, were recorded. RESULTS AND DISCUSSION The results for the notching harvester observations and analysis are shown in Table 1. At the Lykins and Cornett farms, 2 tractors pulling wagons were used to service the harvester, so the unproductive time spent by the harvester between each load was minimized and consisted mainly of the time needed to turn the harvester at the end of the row, or for the filled wagon to pull out and the empty wagon to maneuver into place for the next load (plus occasional stoppage for other reasons). At the Wingham and Young farms, only 1 tractor with wagon was used to service the harvester, so the harvester typically had several minutes of time waiting for that tractor to transport a filled wagon to the field structure and return with an empty wagon. Accordingly, the unproductive time ( turn/stoppage time in the table) was much higher and the field efficiency (actual harvest time divided by actual harvest time plus turn/stoppage time) of the harvester much lower than for the other 2 cases. Interestingly, the labor productivity was fairly consistent for the 3 of the 4 farms with similar wagon load sizes (about plants/load), with 647 plants per workerhour (plants/w-hr) at Young farm (Kirpy), 724 plants/w-hr at the Wingham farm (MarCo), and 758 plants/w-hr at the Lykins farm (Kirpy). These results give an indication of consistent harvest rates among the 2 different brands of notching harvesters. The labor productivity was considerably higher at the Cornett (Kirpy) farm, at 1,045 plants/whr. The increased productivity can be attributed to the much larger wagon loads, 643 plants/load, as well as to more trouble-free harvester operation and more efficient coordination between wagon drivers and harvesting that kept turn/stoppage times to a minimum. For a standard population of 17,200 plants/ha (7,000 plants/ac), the labor requirement for the 3 farms filling the smaller wagon loads was around 25 w-hr/ha (10 w-hr/ac), and was 16.5 w-hr/ha (6.7 w-hr/ac) at the Cornett farm filling the larger wagon loads. Even with the smaller wagon loads, there is considerable labor savings compared with the standard labor requirement of 64 w-hr/ha (26 w-hr/ac) for traditional stick harvesting of burley tobacco (10). The results for the hanging observations and analysis are shown in Table 2. The average hanging labor requirement ranged from 55.4 w-hr/ha (22.5 w-hr/ac) at the Lykins farm to 75.5 w-hr/ha (30.7 w-hr/ac) at the Cornett farm. It is interesting to note the differences in the methods used for hanging during the observations at the different farms. At the Lykins farm, which had the lowest hanging labor requirement, plants were pulled off the wagons in mass onto the ground first, and then individual plants were picked up from piles on the ground for hanging. This seemed to result in more efficient hanging operations, but also in considerable leaf loss as indicated by the leaves left on the ground after hanging, as seen in Figure 3 (note that no assessment of leaf loss was done during these tests). At the Cornett farm, workers standing on the wagons handed down individual plants to workers on the ground who hung them (Figure 4). Although Table 2. Field-study results for evaluation of labor requirements for hanging notched tobacco plants on wire-strung field structure. Farm Harvester # WagonLoads # Plants/Wagon Productivity (w-hr/ha) Wingham MarCo Lykins Kirpy Cornett Kirpy Young Kirpy Tobacco Science (2012) 49: Tobacco Science tbcs d 23/8/12 08:39:18 27 Cust # R

4 Figure 4. Hanging notched tobacco plants on wire-strung field structure, picking up individual plants from the top of the load on the wagon. seemingly slower (this was the least labor-efficient hanging operation), this method allowed the workers to pick the individual plants from off of the top of the pile rather than trying to pull them out from within the pile. The farmer explained that this method allowed him to leave plants piled on wagons overnight if necessary, something that other growers have said they could not do because the wilted plants stuck together too much. Finally, at all of the farms, the number of workers per wagon was usually 4 or 5, but often ranged from 3 up to as many as 7, and in 1 case a single worker unloaded most of a wagon. The labor efficiency varied from load to load among all of the farms, but did not seem to be much affected by the number of workers. Overall, the hanging labor requirements in these tests was comparable with the standard hanging labor requirement of 64 w-hr/ha (26 w-hr/ac) hanging stick tobacco in multitiered traditional barns (10). However, considerably less labor is required for hanging stick tobacco on single tier-height field structure, with a rate of 34 w-hr/ha (14 w-hr/ac) reported (6). So, looking at comparable hanging situations in terms of tier height, this difference indicates a considerable increase in labor requirements for hanging individual notched tobacco plants compared with hanging tobacco on sticks. It should be noted, however, that workers since the early trials with notching harvesters have found hanging individual plants at ground level to be easier and safer than hanging sticks of tobacco in a tall barn or even in single tier-height field structure. Considering the total harvest and hanging labor requirements for the notching harvester systems, it ranged from about 78 to 97 w-hr/ha (32 to 39 w-hr/ac) at the 4 farms where the evaluations were done (Table 3). By comparison, standard values for traditional manual harvesting onto sticks of 64 w-hr/ha (26 w-hr/ac) for cutting, 20 w-hr/ha (8 w-hr/ac) for load and haul, and 34 w-hr/ha (14 w-hr/ac) for hanging on field structure give a total labor requirement of 118 w-hr/ha (48 w-hr/ac) (10,6). The very substantial reduction in harvesting labor requirements with the notching harvesters was offset somewhat by the increase in labor requirements for hanging the individual plants. Total labor requirements were still reduced considerably compared with reported results for traditional harvest, in the 25 w-hr/ha (10 w-hr/ac) range in most cases, and by much more, about 40 w-hr/ha (16 w-hr/ac) in 1 case, that of the Lykins farm. On the basis of the results of these field studies, an optimum balance between harvest and hanging operations with the notching harvesters would probably be achieved with 2 hanging crews of 5 unloading wagons delivered by 2 tractors loaded from 1 harvester. A hanging crew of 10 workerswithalaborproductivityof64w-hr/ha(26w-hr/ac) would have a hanging capacity of about 0.15 ha/hr (0.38 ac/hr), nearly the same as a harvesting crew of 3 with a labor productivity of 20 w-hr/ha (8 w-hr/ac). Despite the potential reduction in tobacco harvest labor requirements indicated by the results of these evaluations, the initial high level of interest by tobacco farmers in notching harvesters has decreased significantly in the last few years. Anecdotal evidence suggests that the majority of the growers that purchased these machines are not using them anymore. There are many possible reasons for the decline in their use. The potential labor reduction, although substantial, may not be enough to justify the cost. A labor reduction of 25 w-hr/ha (10 w-hr/ac) equates to a labor cost savings of only $250/ha ($100/ac) at a wage rate of $10/hr. Even for a harvesting machine that costs only $25,000, it is difficult to justify the cost at that rate of labor cost savings. The need for building extensive wire-strung field-curing structures adds to that cost. The high rate of leaf loss is another major limitation with these harvesters. These evaluations did not assess leaf loss, but significant leaf loss was observed, especially from hanging operations, and has been observed in other studies as well (12). The reduction in revenue from the leaf loss may significantly offset the labor cost savings Table 3. Field-study results for evaluation of total labor requirements (harvesting and hanging combined) for burley tobacco stalknotching harvesters. Farm Harvester Harvesting Labor Requirement (w-hr/ha) Hanging Labor Requirement (w-hr/ha) Total Labor Requirement (w-hr/ha) Wingham MarCo Lykins Kirpy Cornett Kirpy Young Kirpy Tobacco Science (2012) 49:25 30 Tobacco Science tbcs d 23/8/12 08:39:18 28 Cust # R

5 from using the harvesters, making the cost even harder to justify. Another problem is one that is common to most mechanical harvesting concepts for tobacco, which is the difficulty in handling crooked stalks. Burley tobacco stalks are prone to getting badly crooked if exposed to strong winds at a certain stage of growth, a condition that adds difficulty to but does not preclude operations such as spraying and cutting by hand, and that can make mechanical harvesting operations very difficult to nearly impossible. An associated problem with trying to use mechanical harvesters is the difficulty of taking the machines into the field when conditions are too wet. One of the harvest seasons in Kentucky between 2007 and 2010 was so wet that almost no harvesting was done with the notching harvesters, and both situations (crooked stalks and wet conditions) contributed to the gap in time that data could be collected on these systems for this study. A final reason may be that producers do not find these harvesting machines to fit well with the current production culture that relies primarily on migrant labor. As producers grapple with managing larger tobacco crops since the buyout and termination of the federal quota systems, it has become increasingly important for them to be able to assign their labor crews to harvesting operations with minimal oversight, and migrant laborers are very accustomed to traditional stick-harvesting methods. Some growers have commented that the easier work of hanging individual plants at a single tier height (compared with handing up sticks of tobacco in a barn) increases the potential for getting local workers to hang tobacco. But for most larger growers relying on migrant crews, it seems to be more important for them to keep tobacco production practices standard so their workers can do the work with minimal supervision. SUMMARY AND CONCLUSIONS Field studies were conducted to evaluate the labor efficiency of burley tobacco-harvesting operations using stalk-notching harvesters on several different farms. In 2007, the MarCo notching harvester was evaluated at 1 farm, and the Kirpy notching harvester was evaluated at another. In 2010, harvesting operations with the Kirpy machine were evaluated at 2 different farms. For harvesting, the labor productivity was fairly consistent for 3 of the 4 farms with similar wagon load sizes (about plants/load), ranging from 647 to 758 plants/whr, giving an indication of consistent harvest rates among the two different brands of notching harvesters. The labor productivity was considerably higher (1,045 plants/w-hr) at the fourth farm that had a much larger wagon load size, 643 plants/load, and also more trouble-free harvester operation with minimum turn/stoppage times. Labor requirements for harvesting with the notching machines ranged from about 16 to 27 w-hr/ha (6.7 to 11 w-hr/ac), considerably lower than the standard labor requirement of 64 w-hr/ha (26 w-hr/ac) for traditional stick harvesting of burley tobacco (10). Hanging labor requirements ranged from about 55 to 76 w-hr/ha (23 to 31 w-hr/ac), comparable with standard hanging labor requirement of 64 w-hr/ha (26 w-hr/ac) hanging stick tobacco in multitiered traditional barns (10), but considerably higher than the standard rate of 34 w-hr/ha (14 w-hr/ac) reported (6) for hanging stick tobacco on single tier-height field structure. Combined harvest and hanging labor requirements for the notching harvester systems ranged from about 78 to 97 w-hr/ha (32 to 39 w-hr/ac), compared with a standard value for traditional manual harvesting onto sticks, load and haul, and hanging on field structure of 118 w-hr/ha (48 w-hr/ac) (10,6). Interest and use of the notching harvesters by tobacco producers seems to have decreased substantially despite the potential labor savings. Likely reasons for the decrease include cost, a high rate of leaf loss, the need to build extensive wire-strung field-curing structures, constraints to using the harvesters with crooked plants and in wet field conditions, and incompatibility with large-scale tobacco production relying on migrant labor. ACKNOWLEDGMENTS The work described in this article was conducted by the Kentucky Agricultural Experiment Station and is published with the approval of the director. Mention of trade names is for information purposes only. The Burley Tobacco Growers Cooperative Association supported this work financially. The authors express appreciation to the Burley Cooperative for their financial support, and also thank farmers B. G. Wingham, Talara Lykins, Brent Cornett, and Brian Young for their cooperation and contributions. LITERATURE CITED 1. 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