SHOWALTER: MECHANIZED HARVESTING 20 Serious losses may occur due to infections through minute skin breaks caused by sand scar ring, as well as other factors. Bacteria and fungi are present on the fruits when harvested and are a constant threat thereafter. It is evident that any sand at all can be potentially serious. Any means of reducing sand contamination on fruit and foliage of tomatoes would enhance the chances of successfully mar keting the crop. The reduction of sand on the plants by means of plastic bed cover would les sen the build-up of sand contamination on ma chinery used to harvest fresh tomatoes. LITERATURE CITED 1. Doolittle, S. P. 191. Tomato diseases and their control. U. S. Dept. Agr. Handbook No. 20. 2. Gould, W. A. 19. Dust, soil, fruit breakage and mud problems. Proceedings, National Conference on the Mechanization of Tomato Production. -9.. Deen, W. W., Jr., J. W. Strobel, N. C. Hayslip, J. F. Beeman and C. B. Hall. 19. Preliminary studies on mechanical harvesting of tomatoes for fresh market. Proc. Fla. State Hort. Soc. 9: 120-12.. Mercer, W. A. 19. Handling, washing and utiliza tion of mechanically harvested tomatoes. Proceedings, Na tional Conference on the Mechanization of Tomato Produc tion. 1-12.. Ramsey, G. B., J. S. Wiant, and L. P. McColloch. 19. Market diseases of tomatoes, pepper and eggplant. U. S. Dept. Agr. Handbook No. 2. MECHANIZING THE HARVESTING AND POST-HARVEST HANDLING OF SNAP BEANS, CELERY AND SWEET CORN R. K. Showalter Department of Food Science University of Florida Gainesville Abstract harvesting of snap beans, celery and sweet corn was evaluated in fields and packing houses. The characteristics and amounts of har vested portions of the crops not suitable for packing were determined. The stems, leaves, damaged pods, rocks, and small immature pods in machine-harvested snap beans ranged from 11 to 20 percent of the total harvested. Present grading practices and equipment did not eliminate all these materials before packing. -harvested celery included 2 to 2 percent outer petioles and trimmings that were removed after hauling to the grading and pack ing facilities. -harvested sweet corn in cluded 1 to 2 percent immature ears, stalk sections, and leaves that were removed by hand before packing. INTRODUCTON harvesting of snap beans, celery, and sweet corn has advanced considerably in Florida during the past two years. Until re cently, growers rejected machines that did not Florida Agricultural Experiment Stations Journal Series No. 22. harvest their crop in a condition similar to the hand-harvested crop. However, increasing costs and unavailability of labor has influenced the industry to accept machine-harvested vegetables which may differ from hand-picked vegetables in defects, damage, leaves, stalks and range in maturity. In hand harvesting of snap beans and sweet corn, pods and ears of optimum ma turity are selected and detached with a minimum of stalks and leaves. With non-selective, machine harvesting all maturities are harvested along with variable quantities of trash. In order to advance the mechanizing of the entire harvesting and handling system for three of Florida's important vegetables, it is necessary to have information on the physical characteris tics of the vegetables as harvested by the ma chines presently available. This study was made to determine the amount of materials that needed to be separated from the harvested vegetables before they were packed for marketing. Snap Beans Florida has been one of the last areas in the United States to change from hand to machine harvesting of snap beans. Beans for processing are now harvested almost exclusively by ma chines. Increasing quantities of beans for fresh market have been machine harvested since 19. In 190, one of the problems of machine har vesting of beans in Florida was the excessive
20 FLORIDA STATE HORTICULTURAL SOCIETY, 19 amount of trash mixed with the beans (). Processors have added washers and blowers to eliminate the trash. At a Tennessee processing plant (1), machine harvested beans included. percent trash and rocks compared with only 1 percent trash in hand-harvested beans. During the spring of 19 characteristics of bean harvests by machine were determined for the rockland of Dade County and the sandy soils of the lower East Coast. Commerciallybuilt harvesters utilizing flexible steel fingers on rotating picking reels stripped the beans from the stems. The beans and trash not removed by a cleaning fan were conveyed to bags for transport to the grading and packing facilities located in the field or a packinghouse. Twenty-nine lots of beans from six locations ( or lots per field) were sorted by hand before commercial grading. Variable amounts of leaves, stems, broken and bruised pods, pods with de fects such as worm damage, small, immature pods, weeds, and small rocks (Homestead area) were found with the undamaged, mature beans. It was difficult to obtain paired comparisons be tween machine and hand harvesting. However, in one field of '' beans, the trash and immature pods averaged percent in the handharvested samples compared with percent for the machine-harvested beans (Table 1). Five of the lots of machine-harvested beans had 1 to 20 percent trash and immature beans, which indicates that mechanical harvesting greatly in creases the magnitude of the sorting and grad ing operation. Each grading facility used a revolving, rodtype, cleaner or sizer open at both ends to re move immature beans. The beans then moved through a conventional bean grader where blowers removed leaves and trash, and graders sorted out stems, rocks, and beans with defects. Some information was obtained on the total amount of material removed from hand and machine-harvested beans by the revolving sizer, blowers, and hand graders. Trash in handpicked beans averaged percent before grading and 1% percent after grading. One lot of Table 1 Trash and immature beans in hand and machine-harvested snap beans. method Variety No. lots of Trash and immature beans Hand 0 2.2 0.2 0. 11 1. 1 2.0 20 0.1 0.0
SHOWALTER: MECHANIZED HARVESTING 20 machine-harvested beans had percent imma ture and worm damaged pods after harvest, and still had percent after grading and packing due to over-crowding the sizer and graders. In another lot, with 11 percent defective beans after machine harvesting, there was a decrease of only 1 percent after grading and packing because the sizer and graders were over crowded and beans were bruised and broken during filling and lidding the hampers. All the beans from one field in Dade County were weighed after harvesting and again after grading and packing. The total packout was percent of the 2,00 pounds of machineharvested beans. The percent of trash and im mature beans found by sorting the small lots reported in Table 1 closely approximated this commercial grading where 1 percent of the harvest was discarded. For harvester A, the petioles discarded in stripping stalks weighed pounds and ac counted for 2 percent of the trans ported to the packing unit (Table 2). For harvester B, 2 percent of the harvested from 0 stalks was discarded in stripping. Occasionally outer petioles were bruised by the harvester, but they were usually removed during stripping. In the third harvesting system, only leaves at the tip of the stalk were removed by the har vester before the celery was hauled to a central packinghouse for hand stripping and machine trimming and sizing. Sixteen percent of the harvested of 0 stalks was removed in stripping and an additional percent in trim ming the stalks to 1 inches. Thus, 2 to percent of the stalk s from the three harvesters was packed in crates. Sweet Corn Celery Once-over harvesting machines cut all the celery in a field, but unlike snap beans and sweet corn, all celery sizes are marketable when sep arated into established size classifications. Me chanized equipment has been developed that will cut the roots at the proper place, top the stalks, and load them for transport to a central packing facility. A good correlation was found between stalk and diameter (2), and a sizer was recently adapted for machine sizing celery. Little information is available on the relationship be tween stalk size in the field and packed out or market size after the outer petioles are stripped off. In a study of yield forecasting () the amount of stalk stripping was calculated as 29 percent of the diameter in the field. Information was obtained on three new grower-built harvesting systems used during the spring of 19 in the Everglades. In two of the systems, the stalks were trimmed to 1 inches at the time the roots were cut. One harvester had a small stripping device that removed small outer leaves, but mechanical stripping of petioles will be difficult because of the stalk characteris tics. The of the trimmed stalks ranged from 1 to pounds, with 2 percent of them weighing from 2 to pounds. The bulk loads of celery were transported to a stationary "muletrain" in the celery field for hand stripping, grading, sizing, and packing. In the United States during 19, more than half of the sweet corn for processing was ma chine harvested (). Processing plants require extra ear sorting to remove cull ears harvested by machine. Much of Florida's sweet corn crop was harvested by machine for the first time in 19 as improved, grower-built harvesters be came available. The stalks were cut and all ears were removed and loaded for hauling to the packing facilities. Total yields were increased because hand harvesters miss some marketable ears and leave other ears in the field because of small size or defects. However, many immature ears, sections of stalks, leaves, and long shanks were included with the marketable ears. Sweet corn in Florida is generally graded according to the United States standards, which require a minimum cob length of inches, and the cob percent filled with kernels for the U. S. Fancy grade. This grade also requires the shank length not to exceed inches and mechanical injury not to exceed damaged ker nels per ear (). One of the chief concerns in developing a harvester for fresh market sweet corn is ear injury, but with the present har vesters, inspectors seldom report mechanical in jury. The main problem associated with the corn harvesters is elimination of small ears and other plant parts from the marketable ears. When the stalk with the ear passes through the har vester, the ear is detached where it joins the
20 FLORIDA STATE HORTICULTURAL SOCIETY, 19 Table 2 Amount of stripping and trimming of celery stalks after harvesting by three mechanical harvesters. Stalk stripping Stalk length trimming Celery packed A 22 2 2 B 2 0 2 * C 2 0 1 Stalks trimmed by harvester before cutting. stalk, or a stalk section is detached along with the ear. Some detached leaves were not sep arated from the ears by the blower on the harvester. In a study of ear characteristics (), the shanks on hand-harvested ears ranged from 1 to inches and averaged % to Vz of the total ear length. Measurements of trash and immature ears were made on lots of machine-harvested sweet corn in the Everglades and Zellwood areas during April and May, 19. In the first lots, the of stalk sections, leaves, and imma ture ears ranged from 1 to 2 percent of the total harvest (Table ). In the second lots when immature and defective ears were weighed separately from the stalk sections and leaves, the s of the two groups were about equally divided. When shanks were cut from fancy grade ears, they accounted for 9 to 12 percent of the total ear. These measure ments were made on sweet corn harvested dur ing warm weather when ear sizes were large. Shanks of 9 and inches were measured on some machine-harvested ears. Measurements in previous years during the winter showed that the discarded small and immature ears reached as high as percent of the harvested ears. Discussion and Conclusions Some features of the sweet corn and celery harvesting systems were similar. Both crops were graded and packed at stationary "muletrains" in the field and at central packinghouses. Celery stalks were stripped of their outer pe tioles, and sweet corn had the long shanks trim med off. In sizing, there is a distinct difference between sweet corn and celery. Celery stalks are divided into at least size classifications, and a definite number of stalks of each size are packed in a shipping container. A range in size of corn ears are packed together, and there is usually a variation of ears per crate among the crates in a single load. Mechanically trim ming ears to uniform lengths of inches with shanks and flags removed makes it possible to pack 0 ears in each container. When celery or sweet corn are harvested with a mobile mule-train, the trimmings and rejected ears fall to the ground where they present no waste disposal problem. When stationary muletrains are used for stripping celery or packing sweet corn, either the trash or the mule-train must be moved at frequent intervals. Waste dis posal from a central packinghouse is a much
SHOWALTER: MECHANIZED HARVESTING 20 Table Stalk sections, leaves and immature ears in machine-harvested sweet corn. Lot Variety Stalks, leaves Stalks Immature and and ears immature ears leaves No. 1 9 21 2 2 22 21 2 1 -- 22 1 9 0 2 1 1 1 1 9 Gold Cup 1 Gold Eagle 90 1 bigger operation than with the field packing systems. Shipments of machine-harvested snap beans, celery, and sweet corn for the fresh market in creased rapidly in Florida during 19 and 19. The harvesters do not cause excessive damage to the vegetables, but all maturities and sizes are harvested at one time and loaded in bulk or bags. Completely mechanized handling sys tems are needed to remove large quantities of non-marketable material and to pack uniformly sized lots. -harvested beans are now packed with more immature beans and trash than handpicked beans because of inadequate sizing and grading. -harvested celery did not re quire additional sorting, but emphasized the need for mechanical stripping equipment. Equipment is urgently needed to remove stalks and long shanks from machine-harvested sweet corn and to provide for better packing and crate closing. LITERATURE CITED 1. Goble, W. E. and W. C. Erwin. 19. Costs of machine vs hand-harvesting of snap beans. Tennessee Farm and Home Science. Progress Report : 2-. 2. Gull, D. D. 19. Homogeneity of sized celery in Florida. Proc. Fla. State Hort. Soc. : -1.. Showalter, R. K. 19. Ear size and charac teristics of Florida sweet corn. Proc. Fla. State Hort. Soc. :2-22.. Smith, C. R. 190. Mechanical bean harvesting in Florida. Proc. Fla. State Hort. Soc. : 1-119.. Stout, R. G. and R. H. Hancock. 192. Growth rates and projecting yields in celery production. Proc. Fla. State Hort. Soc. : 229-2.. United States Department of Agriculture. 19. United States standards for green corn. 19 F.R. 2221.. Wann, E. V. and S. H. Yarnell. 19. Commercial growing of sweet corn. United States Department of Agri culture Farmers' Bulletin No. 202.