In 1999, West Virginia University (WVU) established an organic farming systems project with a market garden section consisting of 32 plots measuring 16 × 25 ft arranged in a completely randomized design. Sixteen of these plots were managed as high-input and 16 as low-input plots. High-input plots received 10 tons/acre per year of dairy manure and a rye-vetch (Secale cereale and Vicia villosa) cover crop during each winter season since the inception of the experiment in 1999. Fertility in low-input plots was managed solely with an annual rye-vetch cover crop while both treatments also received 5 tons/acre of mixed species hay used as mulch in 2 of every 4 years. A 4-year rotation of crops, green bean (Phaseolus vulgaris), zucchini (Cucurbita pepo), tomato (Solanum lycopersicum), green pepper (Capsicum annuum), and lettuce (Lactuca sativa) in the Fabaceae, Cucurbitaceae, Solanaceae, and Asteraceae families, was established in 1999 and has been maintained ever since. Soil organic matter (SOM) in the upper 6 inches of the soil profile (4.4% in 1999) has remained unchanged in low-input plots at 5.2% in 2004 and 5.4% in 2014, the year following transition and most recent data collection, respectively. During this same time period, significant increases in SOM from 6.4% in 2004 to 8.7% in 2014 were observed in high-input plots. Bulk density was lower in high-input plots than low-input plots in 2014. Despite these improvements in soil quality, high-input plots showed very high levels of phosphorus and potassium. Over the duration of the experiment, yearly manure application increased yields by 22% in all crops combined; however, individual crops responded quite differently. The yield was 9%, 25%, 24%, and 24% higher in high-input plots than in low-input plots for tomato, pepper, zucchini, and green bean, respectively. Manure application in addition to green manures and hay mulch incorporation was found to result in significant economic returns.
Sven Verlinden, Louis McDonald, James Kotcon and Silas Childs
George E. Boyhan, Suzanne O’Connell, Ryan McNeill and Suzanne Stone
past 20 years ( U.S. Department of Agriculture, 2014 ). There has been a 300% growth in certified organic production from 2002 to 2015 ( U.S. Department of Agriculture, 2016 ). A survey of Georgia direct-market growers indicated a preference for OP
Carol Miles, Lisa DeVetter, Shuresh Ghimire and Douglas G. Hayes
their list of allowed synthetic substances [7 Code of Federal Regulations (CFR), Section 205.601; USDA, 2014b ]. Before this, the only synthetic biodegradable mulch allowed in certified organic production was paper mulch. On 22 Jan. 2015, the NOP
Shaun R. Broderick and Williams B. Evans
, exceptional quality (EQ) biosolids exceed all of these safety requirements and are cleared for most agricultural applications including use on edible crops with exception of all USDA-certified organic production. Grade B biosolids do not meet all of the safety
George E. Boyhan, Julia W. Gaskin, Elizabeth L. Little, Esendugue G. Fonsah and Suzanne P. Stone
local organic produce. This increased demand has sparked an interest among conventional vegetable growers in certified organic production techniques and has put increasing demand on existing organic growers. Discussions with organic growers, particularly
George E. Boyhan, Suzzanne Tate, Ryan McNeill and Jeffrey McConnaughey
Tomato (Solanum lycopersicum) is a popular crop among organic growers, particularly open-pollinated varieties; however, there is a lack of information evaluating these varieties in comparison with commercial F1 hybrids. This study was undertaken to compare conventionally produced commercial F1 tomato varieties available in the southeastern United States with open-pollinated varieties popular among organic growers. Nineteen tomato varieties were evaluated in 2011 and 2012 using the U.S. Department of Agriculture National Organic Program guidelines; however, the land used had not been in 3 years of organic production. Staked tomatoes were grown on plastic mulch. Data collected included early and total graded yield. In general, F1 hybrid, determinate or semideterminate varieties, had the best early and total yields compared with open-pollinated varieties. HSX 8115H and ‘Celebrity’ had the highest early total yield. ‘Costoluto Fiorentino’, an open-pollinated variety, also had good early total yield, but significantly less than HSX 8115H or ‘Celebrity’. ‘Costoluto Fiorentino’ was the only open-pollinated variety among the five highest yielding varieties for early total yield. In addition, ‘Celebrity’ had the greatest total yield of all the entries tested. All of the top five varieties for total yield were F1 hybrids and either determinate or semideterminate types. ‘Costoluto Fiorentino’ had total yield of 22,046 lb/acre, which was 14.3% lower than the lowest yielding variety in the top five yielding varieties. ‘Florida Pink’ had the largest average fruit weight, which also had the lowest total yield of all the entries. Although the open-pollinated varieties, popular among organic and local growers, yielded less than F1 hybrids, they may possess characteristics of color, flavor, or texture that are desired and were not evaluated in this study. This may be an opportunity for plant breeders to develop varieties desired by local organic growers that have unique characteristics, in addition to high yields and disease resistance.
Kristen Harper and Curt R. Rom
Since the passage of the Organic Foods Production Act in 1990, certified organic produce has begun to make a large impact on national markets. However, USDA statistics indicate that many states in the southern region have considerably reduced certified organic acreage when compared to other regions in the United States. The absence of organic acreage may perhaps originate with a lack of training and educational materials provided to producers due to unanticipated growth of organic markets. A thorough review of all Arkansas Cooperative Extension Service (ACES) materials, such as bulletins, publications, and workshops over the past 10 years, would reveal what information has been provided to producers on certified organic production. This review of ACES materials defines the existing groundwork on which ACES could construct future organic publications and outreach programs in order to sustain and stimulate organic farming within the state.
R.K. Striegler, M.A. Mayse, U. O'Keefe and D.R. Wineman
Consumer concerns about pesticide residues and environmental degradation are having a significant impact on the California grape industry. Growers are using a variety of practices, from integrated pest management to certified organic production, to reduce the amount of pesticides and other synthetic inputs used in vineyards. This experiment was established to test selected sustainable cultural practices in a mature `Thompson Seedless' vineyard. Treatments included in the experiment were row middle management (cultivated vs. perennial legume cover crop) and nitrogen fertilization (compost vs. synthetic). Vine nutritional status, yield, fruit composition, pruning weight, and population levels of the variegated leafhopper were monitored each season (1992–1994). In addition, efforts were expanded during the 1994 season to include assessment of spider, herbivorous mite, and beneficial arthropod densities. Conventional cultural practices (cultivation and synthetic fertilizer) produced the highest yields during the 1992 and 1993 seasons. This result may have been due to the nutritional status of vines, which was generally better for the cultivation and synthetic fertilizer treatment, especially in 1992. In 1994, significant treatment effects on yield were not observed, indicating that legume cover crop plots had become fully established. Sustainable cultural practices had little impact on growth, fruit composition, or insect pest pressure. `Thompson Seedless' grapes were grown for three seasons without the use of insecticides or herbicides. Vine diseases were managed by cultural practices and application of sulfur.
Mark Gaskell and Tim Hartz
Nutrient management practices must be tailored to the crop, environment, and production system if nutrient efficiency and environmental water quality protection are to be achieved. This requires consideration of fertilizer choice, placement, application rate, and timing. These factors have been characterized as the “4Rs” of nutrient stewardship—right material, right placement, right rate, and right timing. The factors affecting the choice of fertilizer material have been described previously for agronomic crops, and include plant nutritional requirements, soil conditions, fertilizer delivery issues, environmental risks, product price, and economic constraints. Although those factors are applicable to all crops, the unique features of intensive horticultural production systems affect their interactions. This article discusses fertilizer choice as it affects productivity, profitability, sustainability, and environmental impact of intensive horticultural crop production. Diverse fertilizer materials are available for specialized application to provide nitrogen, phosphorus, potassium, and other plant nutrients for different horticultural needs. These fertilizer sources can be formulated as dry or liquid blends, but increasingly higher solubility materials are used to target plant growth needs even in field operations. Composts can have useful applications—particularly for certified organic production—but their high cost, bulk, and relatively low efficiency limit their use. Profitability can be affected by fertilizer cost—typically a relative small percentage of overall costs in intensive production systems—and the improved efficiency of these specialized materials often improves profitability. There are also sustainability issues with the manufacture, transport, and efficient use of different fertilizer sources. Such factors as soil chemical reaction changes, effects on soil salinity, and loss of organic matter also can adversely affect sustainability, but systems are available to maintain soil quality while using more efficient fertilizer sources.
John R. Yeo, Jerry E. Weiland, Dan M. Sullivan and David R. Bryla
Phytophthora cinnamomi Rands causes root rot of northern highbush blueberry (Vaccinium corymbosum L.), which decreases plant growth, yield, and profitability for growers. Fungicides are available to suppress the disease, but are prone to development of resistance in target pathogens and cannot be used in certified organic production systems. Alternative, nonchemical, cultural management strategies were evaluated to reduce phytophthora root rot in a field infested with P. cinnamomi. The field was planted with ‘Draper’ blueberry, which is highly susceptible to the pathogen. The soil was either amended with gypsum or not before planting, and the plants were irrigated using narrow (adjacent to plant crown) or widely spaced (20 cm on either side of the plant crown) drip lines and mulched with douglas fir sawdust or black, woven geotextile fabric (weed mat). A fungicide control treatment was also included in the study and consisted of applying two conventional fungicides, mefenoxam and fosetyl-Al, to plants irrigated with narrow drip lines and mulched with sawdust. Initially, root infection by P. cinnamomi was lower with the combination of gypsum, wide drip lines, and sawdust mulch than with any other treatment, except the fungicide control. The soil under weed mat accumulated more heat units than under sawdust and resulted in faster hyphal growth by the pathogen. However, plant growth was similar in both mulch types. The effects of drip line placement and gypsum, on the other hand, were interactive, and plants grown with a combination of wide drip lines and gypsum produced the greatest amount of biomass among the cultural treatments. Narrow drip lines negated the disease-suppressive effects of gypsum by moving zoospore-inhibiting Ca2+ away from the plant root zone, and also resulted in wetter soil near the crown of the plants, which likely promoted zoospore discharge and root infection. However, wide drip lines resulted in N deficiency symptoms during the first year after planting and, therefore, resulted in less plant growth than the fungicide control. Thus, if N is managed properly, this study suggests that concerted use of gypsum and wide drip lines can help suppress phytophthora root rot in northern highbush blueberry and increase production in field soils where the pathogen is present.