Low yields and high harvesting costs are long-standing problems in mango (Mangifera indica L.) cultivation. In an effort to increase productivity in the scion 'Kensington Pride' we examined the impact of nine different rootstocks over a 10-year period. Rootstock effects on fruit production were significant in most seasons, and cumulative yields (nine seasons of cropping) for the best treatment ('Sg. Siput') exceeded those of the poorest treatment ('Sabre') by 141%. Yield efficiencies (expressed on both a trunk cross-sectional area and canopy silhouette area basis) were also significantly affected by rootstock. Rootstock effects on yield and yield efficiency were generally consistent across seasons, despite large seasonal variations in yield. Harvest rates were also influenced by rootstock, and were poorly correlated with tree size. These results demonstrate possibilities for manipulating mango scion productivity through rootstock genotype.
Malcolm W. Smith, Mark D. Hoult, and Jeremy D. Bright
Michele R. Warmund, Andrew K. Biggs, and Larry D. Godsey
The time required to harvest and field sort chinese chestnuts (Castanea mollissima) with two types of paddock vacuums and with a manual nut-harvesting tool was compared. Pickup time for harvesting chinese chestnuts was faster with a small paddock vacuum (Paddock Vac) than with a manual nut-harvesting tool (Nut Wizard), but field sorting plant material and soil, as well as movement of the small vacuum, was time-consuming. With minor equipment modifications to facilitate sorting, harvest time for a larger paddock vacuum (Maxi Vac) was 2 seconds faster per nut than that for the manual nut-harvesting tool. Economic analyses revealed that the larger modified vacuum also reduced labor costs by $237 when the wage rate was low ($8 per hour) and with total production at 1000 kg. However, with the lower equipment cost, the manual nut-harvesting tool was more economical to use than the modified paddock vacuum, with $8 per hour labor costs and <6370 kg of harvested chestnuts. As labor costs and nut production increased, it was more economically efficient to use the modified paddock vacuum as compared with a manual nut-harvesting tool. At $10, $12, and $15 per hour labor, the modified pasture vacuum was the lowest cost method of harvesting chestnuts at yields >4555, 3466, and 2510 kg, respectively. Thus, the modified pasture vacuum may provide a relatively inexpensive method for new, small producers to mechanize chestnut harvest.
Olya Rysin and Frank J. Louws
be components of future analysis. Therefore, annual production costs were assumed equal for the two systems, including fumigation and disease management costs, with the exception of transplant prices and harvest costs. Annual variable production costs
Jacqueline K. Burns, Louise Ferguson, Kitren Glozer, William H. Krueger, and Richard C. Rosecrance
initiation in Feb. 2006 in California's Central Valley olive production areas markedly reduced yield in a year when lower yield was expected as a result of alternate bearing. Extremely low yield combined with labor pressures increased harvesting costs further
Charles R. Hall and Dewayne Ingram
, liner, and field production phases combined) amounted to $37.74 per marketable tree, comprised of $9.90 for labor, $21.11 for materials, and $6.73 for equipment use, respectively. However, post-harvest costs (e.g., transportation, transplanting, take
Carlos Carpio and D. Scott NeSmith
This study evaluates the effect of irrigation on the profitability of the muscadine grape (Vitis rotundifilia) operation. Data from a 3-year experiment in which muscadine grapes were grown under four irrigation regimes were used to establish the relationship between yields and irrigation. Assuming a muscadine fruit price of $0.50/lb, harvesting costs of $0.21/lb, and irrigation costs of $16.75/acre-inch, the profit-maximizing level of irrigation was estimated to be 13.1 acre-inches for a season, or 7 gal/day per plant. Water requirements for profit maximization are 9% lower than water requirements for yield maximizing. Moreover, it is concluded that the effect of an adequate use of irrigation in the profitability of the muscadine grape operation can be substantial.
T.K. Hartz, A. Baameur, and D.B. Holt
A study was conducted to determine the feasibility of fieldscale CO2 enrichment of vegetable crops grown under tunnel culture. Cucumber, squash and tomato were grown under polyethylene tunnels in a manner similar to commercial practices in southern California. The buried drip irrigation system was used to uniformly deliver an enriched CO2 air stream independent of irrigation. CO2 concentration in the tunnel atmosphere was maintained between 700-1000 ppm during daylight hours. Enrichment began two weeks after planting and continued for four weeks. At the end of the treatment phase, enrichment had significantly increased plant dry weights. This growth advantage continued through harvest, with enriched plots yielding 20%, 30% and 32% more fruit of squash, cucumber and tomato, respectively. As performed in this study, the expense of CO2 enrichment represented less than a 10% increase in total pre-harvest costs. Industrial bottled CO2 was used in this study; since bottled CO2 is captured as a byproduct of industrial processes, this usage represents a recycling of CO2 that would otherwise be vented directly to the atmosphere.
Wesley K. Asai
In an effort to maximize early return on investment and labor efficiency, cling peach growers in California are using two different types of high-density plantings; the perpendicular-V (1.8m × 4.8m = 930 Trees/ha), and the cordon (2.4m × 4.2m = 925 Trees/ha). The V has the advantage of being more traditional in its establishment, where the cordon has the advantage of higher yields and no need for wires, props or ladders to prune, thin and pick.
This study evaluated the cultural and economic considerations of the two systems with respect to their yields during the orchards' establishment years.The cumulative labor costs, specific to the style of training for the first 3 years was $1258 and $901 per hectare for the cordon and V respectively.
Cumulative yields were 40.4 tons/ha for the cordon and 22.0 tons/ha for the V. When contrasting the net returns per hectare, the cordon, in spite of its higher labor input (due largely to higher thinning and harvest costs), had a net profit advantage of $3362.50 per hectare during the first 3 years of establishment.
Dale E. Marshall
For over 86 years producers, processors, engineers, and equipment manufacturers have attempted to mechanize the harvest of asparagus. Over 60 U.S. patents have been issued. Probably the most sophisticated harvester tested was started in 1987 by Edgells Birdseye, Cowra, Australia. After successful field tests of the 3-row, selective (fiber optic), harvester for flat-bed green asparagus used in canning, 3 more were built at a cost of $US 4.5 million, and harvested 500 acres until 1991 when the company ceased canning. Recovery was 30 to 80% with 50% being typical. Wollogong University in Australia is now researching a selective (fiber optic), harvester for flat-bed green asparagus. It utilizes multiple side-by-side 3 in. wide by 24 in. dia. rubber gripper discs which rotate at ground speed. No harvester prototype has been commercially acceptable to the asparagus industry due to poor selectivity, low overall recovery (low yield relative to hand harvest), mechanical damage to spears, low field capacity per harvester, or overall harvesting costs that exceed those for hand harvesting. The reality may be that asparagus production will cease in the traditional geographical areas where growing costs and labor costs are high, although niche fresh markets may help some growers survive.
Zhenyong Wang and David R. Dilley
AVG applied alone to `Gala' and `Jonagold' apples delayed maturity and the onset of the ethylene climacteric and delayed red color development. AVG followed by ethephon delayed maturity and the onset of the ethylene climacteric, but promoted red color development of both cultivars. Ethephon applied alone advanced maturity, ethylene production, ripening, and red color development compared to AVG alone. In other studies, the ripening-related effects of these treatments were reflected in the storability of fruit in CA storage. AVG - and AVG + ethephon-treated fruit were still at preclimacteric ethylene levels after 6 months in CA storage, with excellent retention of flesh firmness and shelf-life, while ethephon and control fruits had significantly higher ethylene levels and softened more during storage and shelf-life evaluation. Collectively, our results indicate that an ethephon application following AVG treatment may be useful to overcome the delay of red color development of apples treated with AVG only and that this can be achieved without overly stimulating fruit ripening. Thus, a once-over harvest of `Gala' and `Jonagold' apples may be achieved with a significant reduction in harvest costs. We attribute the promotion of red color development of apples receiving AVG treatment with a follow-up application of ethephon to the action of ethylene temporally-released from ethephon stimulating the development of the anthocyanin biosynthetic pathway, while AVG inhibits the development of the endogenous ethylene climacteric. Inhibiting endogenous ethylene production delays fruit from producing their own ethylene. We attribute maturation uniformity to the action of AVG allowing the less mature fruits to gain maturity while slowing maturity development of the more mature fruits. Improved storability of AVG + ethephon-treated fruit is attributed to the same ethylene-related phenomena.