The citrus industry in Florida has 193,000 ha of sweet oranges [ Citrus sinensis (L.) Osbeck] grown principally for the fresh juice industry ( Anonymous, 2008 ) of which ≈13,153 ha are mechanically harvested ( Florida Department of Citrus, 2008
Robert C. Ebel, Jacqueline K. Burns, and Kelly T. Morgan
James N. Moore
Expansion of blueberry culture in North America has occurred during the past decade and is projected to continue into the next century. Thirty-six U.S. states and six Canadian provinces report some blueberry production. The area planted to blueberries has inreased by 19% in 10 years, with the largest increase (47%) in cultivated types and only 11% in wild blueberries. It is projected that the total area will increase by an additional 14% by the year 2000. New cultivars are proving of value and are affecting the composition of plantings. Greater interest is being given to mechanical harvesting, and new cultural and pest control innovations are being employed to enhance the economics of production. The expansion of blueberry production is being undergirded by expanded programs in problem-solving research.
Brian A. Kahn
Paprika pepper (Capsicum annuum L.) plants were subjected to a single, destructive harvest in either October, November, or December to determine an optimal month for once-over harvest. Studies were conducted at two locations in Oklahoma each year for 2 years. Total and marketable fruit yields were highest with October harvest dates in three of the four experiments. Marketable fruit red pigment intensity decreased between the November and December harvest dates at both locations in the second year. When the crop is established by transplanting, paprika harvest should be completed during October in the southwestern United States.
Blair Buckley III and Katharine C. Pee
An investigation was conducted in 1993 and 1994 to examine the effect of row spacing on yield and pod maturity distribution of machine-harvested, green-mature southernpeas [Vigna unguiculata (L.) Walp]. `Texas Pinkeye Purple Hull' was planted at row spacings of 53, 89, and 107 cm single drilled and 107 cm double drilled. Marketable yield increased linearly as row spacing decreased. A double drill on a standard 107-cm row spacing did not result in higher yield than a single drill. Marketable yield from the double-drilled, 107-cm row spacing was less than yield from the 53-cm spacing. The seeding rate per hectare for the two treatments was the same. In 1993, the mature pod percentage at harvest increased linearly as row spacing decreased. Row spacings as narrow as 53 cm can be used to increase yield of machine-harvested, green-mature southernpeas.
Yaying Wu, Brian A. Kahn, Niels O. Maness, John B. Solie, Richard W. Whitney, and Kenneth E. Conway
Okra [Abelmoschus esculentus (L.) Moench] was grown at various highly dense (HD) plant populations for destructive harvest, and compared with control plants grown at spacings of 90 × 23 cm and harvested repeatedly by hand. Our objectives were to identify a HD plant arrangement and an optimum harvest timing to maximize marketable fruit yield per hectare with a single destructive harvest, and to evaluate the potential for regrowth of cut plants followed by one or more subsequent harvests. Within HD treatments, marketable fruit weight per hectare tended to increase as the plant population density increased. Spacings of 30 × 30 cm and wider were not dense enough for the destructive harvest system due to a low marketable yield potential. Wide spacings did favor regrowth of cut plants in two experiments, but total marketable yields were still highest with the highest plant populations tested. Delaying destructive harvest until many overmature fruit were present did not consistently affect marketable fruit yield, but always decreased the proportion (by weight) of marketable fruit to total harvested fruit. Overall, percentages of marketable yield obtained by destructive harvests of plots with HD plant populations were low relative to the cumulative marketable yield from control plots. The lack of concentrated fruit set in okra remains a limiting factor for destructive harvest. However, the labor-saving potential of this system should stimulate further research.
Diego Barranco, Octavio Arquero, Carlos Navarro, and Hava F. Rapoport
Desmond R. Layne and J.A. Flore
The influence of increasing levels of trunk damage on vegetative and reproductive capacity of 3- to 5-year-old `Montmorency' sour cherry (Prunus cerasus L.) trees was determined for three seasons. Removal of or damage to bark up to halfway around the trunk circumference minimally affected growth and productivity. The total wound callus produced per tree was related to wound size. Wound repair was variable depending on the type or extent of injury. Removal of damaged bark greatly reduced wound repair. Girdling 75% or 100% of the trunk circumference resulted in no tree mortality at one site and 17% and 50% mortality, respectively, at another. Differentiated phloem in wound callus of trees with 100% bark removal and survival 4 years following injury indicated that vascular reconnection occurred across wounds.
R. Karina Gallardo and David Zilberman
manually and mechanically harvesting highbush blueberries for both the fresh and processing markets. We apply our model to the blueberry industry in the state of Washington, where mechanical harvesters are currently used mostly for blueberries for the
Sergio Castro-Garcia, Uriel A. Rosa, Christopher J. Gliever, David Smith, Jacqueline K. Burns, William H. Krueger, Louise Ferguson, and Kitren Glozer
nature of the product, quality of the fresh fruit is the most important factor in developing mechanical harvesting in olives destined for table consumption ( Ferguson, 2006 ). Mechanical harvesting methods for olives destined for oil have been developed
Michael D. McCullough, James E. Motes, and Brian A. Kahn
Two problems associated with machine harvesting of peppers (Capsicum annuum L.) are plant lodging during growth and uprooting. Factorial combinations of four bedding treatments and two N rates were compared for effects on lodging, uprooting, and fruit yield of chile and paprika-type peppers in Fort Cobb and Bixby, Okla. Bedding treatments were 1) no bed (T1); 2) no bed with 5 cm of soil hilled to the plant bases (T2); 3) bedded preplant, but bed not sustained (i.e., allowed to erode) during the growing season (T3); and 4) bedded preplant and bed sustained during the growing season (T4). All plots received preplant N at 45 kg·ha–1. In 1992, one-half of the plots were sidedressed with 45 kg N/ha. In 1993, one-half of the plots were sidedressed with N at 45 and 90 kg·ha–1 for paprika and chile, respectively. The higher N rates consistently produced larger and higher-yielding chile plants and generally increased yield and stem and leaf weights of paprika plants. The force required to uproot plants was not significantly affected by N rates. Plant lodging was significantly worse at the higher N rates in only one of five studies. Bedding treatments did not have a consistent influence on fruit yield. The force required to uproot plants was greater with T2 and 4 compared to T1 and 3 in three of four studies. Plant lodging was not influenced by the bedding treatments.