Search Results

You are looking at 81 - 90 of 10,962 items for :

  • agriculture x
  • Refine by Access: All x
Clear All
Free access

Marvin L. Baker

In North America, cultivation of Mayhaws (Crataegus opaca L.) is rare; most commercial harvest is taken from the wild. Crataegus opaca is distributed in northeast Texas, east Texas and southeast Texas along the flood plains of the Angelina and Neuches rivers and their watersheds. Mayhaws are difficult to define due to unusual factors relating to reproduction, including apomixis, or the development of an embryo from cells other than sex cells. Mayhaws are valued for economic use as food, medicine and ornamentals. Since the hawthorn has shown extremely low toxicity in every animal tested, the discovery of isolated constituents thru research has caused pharmacological interest. A small orchard plot of selections with ripened fruit measuring larger than 2.5 cm up to 3.1 cm with bright red or pink color is being established for selecting possible cultivars for medicinal or food uses.

Five Crataegus opaca selections were collected due to showing spurtype, large fruits and thornlessness. Yearly production of fruit was noted for five years (even after late freezes) while selections grew in Taggert's Flat, Neuches river bottom, Angelina County. Seedlings are being grafted for further evaluations and uses in sustainable agricultural ecosystems.

Free access

Todd Rosenstock and Patrick Brown

Alternate bearing exerts economic and environmental consequences through unfulfilled yield potential and fertilizer runoff, respectively. We will discuss a systematic biological–statistical modeling management integration approach to address the concert of mechanisms catalyzing alternate bearing. New engineering technologies (precision harvesting, spatially variable fertigation, and mathematical crop modeling) are enabling optimization of alternate bearing systems. Four years of harvest data have been collected, documenting yield per tree of an 80-acre orchard. These results have shown variability within orchard to range from 20–180 lbs per tree per year. Results indicate irregular patterns not directly correlated to previous yield, soil, or tissue nutrient levels, or pollen abundance. Nor does significant autocorrelation of high or low yields occur throughout the orchard, suggesting that genetically dissimilar rootstocks may have significant impact. The general division of high- and low-yielding halves of the orchard may infer a biotic incongruency in microclimates. This orchard does not display a traditional 1 year-on, 1 year-off cyclic pattern. Delineation of causal mechanisms and the ability to manage effectively for current demands will empower growers to evaluate their fertilization, irrigation, male: female ratio, site selection, and economic planning. In comparison to annual crops, the application of precision agriculture to tree crops is more complex and profitable. When applied in conjunction, the aforementioned methods will have the ability to forecast yields, isolate mechanisms of alternate bearing, selectively manage resources, locate superior individuals, and establish new paradigms for experimental designs in perennial tree crops.

Free access

Robert O. Miller, Steven E. Newman, and Janice Kotuby-Amacher

The accuracy of soil and plant analytical results are occasionally called into question by laboratory clientele. Although laboratories generally conduct internal quality assurance procedures, there are few external performance testing programs for the industry. In 1994, a proficiency testing program was initiated for soil and plant samples for agricultural laboratories in the western United States to provide an external quality control for the lab industry. The program involves the quarterly exchange of soil and plant samples on which soil salinity, soil fertility, and plant nutrition analyses are conducted. One hundred laboratories are annually enrolled in the program from 24 states and Canadian provinces. Results of 3 years of the program indicate soil nitrate, soil pH, extractable potassium, soil and organic matter are reproducible within 10% between laboratories. Soil-extractable phosphorus (by five methods), soil-extractable boron, and soluble chloride were only reproducible within 15% to 20% between laboratories. Plant nitrogen and phosphorus results were consistent across samples, laboratories, and methods. Variability in plant nitrate increased with decreasing tissue concentrations. Overall accuracy and precision of reported results, based on the use of NIST certified reference botanical samples, were excellent for N, P, K, Ca, and Cu. Generally, for any given analysis, the results of ≈10% of the laboratories exceed two standard deviations from the mean. Overall, significant improvement was noted in the laboratory industry proficiency through the course of the program.

Open access

G. J. Galletta, A. D. Draper, and D. H. Scott

Abstract

The U.S. Department of Agriculture strawberry breeding program has introduced 61 cultivars from 6 breeding locations in its 61-year history. Fifteen to 20 of these cultivars have been widely grown, and 5 of the recent releases show exceptional promise. From its inception, the program has been aimed at producing high-quality, multipurpose cultivars with disease resistance and broad regional adaptation. Because of disease pressures, genetic resistance has been emphasized, especially for red stele root rot. The USDA has become the principal source of red stele-resistant germplasm for breeding pruposes, and has constantly refined and improved its disease-screening techniques. Red stele and Verticillium resistance have now been incorporated into everbearing strawberries adapted to the eastern United States. Investigations concerning virus detection and eradication and the propagation of virus-free stocks have led to state virus-free plant certification programs, which assure the public of production of the cleanest possible strawberry nursery stocks. The work of the USDA and cooperating state stations has played a significant role in the improvement of strawberry cultivars and the development of modern strawberry production in the United States.

Full access

Robert Premier and Scott Ledger

Quality assurance (QA) in the horticultural industry has become well established in Australia; on-farm hazard analysis critical control point (HACCP)-based plans have been adopted due to pressures from supermarkets and other buyers, including fresh markets. Supermarkets' own systems and more general QA systems have been used by growers to meet these new requirements. Two QA systems, Freshcare and Safe Quality Food, have been introduced across the country with moderate success. A review of quality assurance parameters such as chemical residues and microbiological contaminants suggest that these QA systems have achieved some level of assurance. Local pressures, however, are not the only concern when it comes to QA. International demand for safe quality fruit and vegetables has meant that QA systems now need to be designed to satisfy export requirements. In addition to food safety, international demands must also address the environment and workers' health and safety. Many Southeast Asian governments have taken the initiative and developed country-specific QA systems to satisfy export markets and that are suitable for their farmers to use. Countries with schemes in place include Malaysia, Thailand, Indonesia, and Singapore, with other countries, such as the Philippines and Brunei Darussalam, in the process of introducing schemes. This presentation will discuss the status of QA systems in Australia and Southeast Asia, including the pressures behind their establishment, and the major differences between them. The presentation will also focus on the attempt by Southeast Asian governments to address a uniform standard through the development of the Association of Southeast Asian Nations (ASEAN) good agricultural practice (GAP), a GAP standard suitable for use by all 10 ASEAN member countries.

Free access

Harry Janes, James Cavazzoni, Guna Alagappan, David Specca, and Joseph Willis

A qualitative systems approach to controlled environment agriculture (CEA) is presented by means of several multi-institutional projects integrated into a demonstration greenhouse at the Burlington County Resource Recovery Complex (BCRRC), N.J. The greenhouse has about 0.4 ha of production space, and is located about 800 m from the about 40-ha BCRRC landfill site. A portion of the landfill gas produced from the BCRRC site is used for microturbine electricity generation and for heating the greenhouse. The waste heat from the turbines, which are roughly 15 m from the greenhouse, is used as the main heat source for the greenhouse in the winter months, and to desalinate water when heating is not required. Recovery of this waste heat increases the energy efficiency of the four 30-kW turbines from about 25% to 75%. Within the greenhouse, aquaculture and hydroponic crop production are coupled by recycling the aquaculture effluent as a nutrient source for the plants. Both the sludge resulting from the filtered effluent and the inedible biomass from harvested plants are vermicomposted (i.e., rather than being sent to the landfill), resulting in marketable products such as soil amendments and liquid plant fertilizer. If suitably cleaned of contaminants, the CO2 from the landfill gas may be used to enrich the plant growing area within the greenhouse to increase the yield of the edible products. Landfill gas from the BCRRC site has successfully been processed to recover liquid commercial grade CO2 and contaminant-free methane-CO2, with the potential for this gas mixture to be applied as a feedstock for fuel cells or for methanol production. Carbon dioxide from the turbine exhaust may also be recovered for greenhouse enrichment. Alternatively, algal culture may be used to assimilate CO2 from the turbine exhaust into biomass, which may then be used as a biofuel, or possibly as fish feed, thus making the system more self-contained. By recycling energy and materials, the system described would displace fossil fuel use, mitigating negative environmental impacts such as greenhouse gas emissions, and generate less waste in need of disposal. Successful implementation of the coupled landfill (gas-to-energy · aquaponic · desalination) system would particularly benefit developing regions, such as those of the Greater Caribbean Basin.

Full access

Jesús A. Gil-Ribes, Louise Ferguson, Sergio Castro-Garcia, and Gregorio L. Blanco-Rodán

organizations is needed. The cooperating researchers are engineers, horticulturists, food technologists, agricultural economists, producers, workers, and their representatives. The academic engineer actively participates in both the development and education

Full access

M.S. Schroeder, N.G. Creamer, H.M Linker, J.P. Mueller, and P. Rzewnicki

There is an increasing demand for education in organic and sustainable agriculture from undergraduates, graduate students and extension agents. In this paper, we discuss highlights and evaluations of a multilevel approach to education currently being developed at North Carolina State University (NCSU) that integrates interdisciplinary training in organic and sustainable agriculture and the related discipline of agroecology through a variety of programs for undergraduate students, graduate students, and extension agents. These educational programs are possible because of a committed interdisciplinary faculty team and the Center for Environmental Farming Systems, a facility dedicated to sustainable and organic agriculture research, education, and outreach. Undergraduate programs include an inquiry-based sustainable agriculture summer internship program, a sustainable agriculture apprenticeship program, and an interdisciplinary agroecology minor that includes two newly developed courses in agroecology and a web-based agroecology course. Research projects and a diversity of courses focusing on aspects of sustainable and organic agriculture are available at NCSU for graduate students and a PhD sustainable agriculture minor is under development. A series of workshops on organic systems training offered as a graduate-level course at NCSU for extension agents is also described. Connecting experiential training to a strong interdisciplinary academic curriculum in organic and sustainable agriculture was a primary objective and a common element across all programs. We believe the NCSU educational approach and programs described here may offer insights for other land grant universities considering developing multilevel sustainable agriculture educational programs.

Open access

Spark M. Matsunaga

Abstract

The theme that I am going to address, “Meeting the World Food Crisis through American Tropical Agricultural Research,” involves two basic assumptions:

First, there is, or there will be a world food crisis.

Second, that crisis can, at least in part, be met through American Tropical Agricultural Research

Open access

John E. Dunkelburger, Harry G. Ponder, and Joseph J. Molnar

Abstract

Compared to majors in agriculture as a whole, horticulture students were more likely to be female, to have a feeling that women have a place in agriculture, to have a higher grade point average, to come from larger high schools, to have transferred from another 4-year college, and to have changed majors. Horticulture students were less likely to have a farm background, to have parents with a farm background, to have farm work experience, and to have been primarily influenced by their parents on choice of major. Both groups had the same positive perception of agriculture as a career and both were financed during college by their parents.