2008 On-Farm Research Projects

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Concerns about climate change and drought were evident in proposal submissions this year. OS08-044 builds on the work of a previous On-Farm Research grant that tested alternative treatments for internal parasites in small ruminants. The previous project took place during a season of above average rainfall following a drought year and produced some unexpected results. By continuing to refine the alternative system, project results should produce more exact recommendations for producers. Climate and water issues were evident in another winning proposal, OS08-040. In Alabama producers who just started diversifying row crops with rabbiteye blueberries, have been set back by alkaline irrigation water during two seasons of drought. This project looks at ways to acidify the irrigation water and make the best use of irrigation.

Proposals addressing economics, particularly input costs, were abundant this year, possibly due to nationwide concern over rising prices in general. A cover crop project in Oklahoma (OS08-041) was sited as being particularly timely in the wake of increased nitrogen fertilizer costs. Reviewers noted that while cover crops research is not novel, ithe project isextremely valuable in demonstrating sustainability to producers. A project in Florida (OS08-043), based on a previous SARE graduate student project is looking at saving input costs of expensive organic fertilizers and preventing water pollution by closely monitoring nutrient uptake by plants during drip irrigation and at what point leaching occurs.

Another way of tackling economic issues is to find new ways to meet strong demand for a product. That's one of the things reveiwers liked about OS08-042, which will be testing ways to make organic no-till soybeans and corn a reality in the Southeast, particularly North Carolina where organic poultry and dairy producers are importing tons of organic grains each year. If local growers can meet the demand for organic feed grains, not only will more money be kept in the local economy but fuel consumption will be reduced.

Keep up with these projects by reading progress reports which are posted online each April. Just click on Projects and follow the link to the data base.

OS08-040 Sustainable Irrigation Methods for Alternative Crop Production, $15,000

Blueberry producers with alkaline irrigation source water must take steps to reduce the alkaline effect of this water on their plants or the chance of the enterprise to fail is prominent. Irrigation is a determinant factor in the growth and production of blueberry. The root system is superficial and confined, with a small amount of root hairs, which restricts the water uptake capacity (Gough, 1980; Freeman, 1983). Furthermore, blueberry plants are especially sensitive to irrigation water quality. Alkaline irrigation water will eventually raise the soil pH to a level harmful to blueberries that is why continuous acid injection would be required to lower pH to an acceptable level (Kidder and Hanlon, Jr.).

Assessment of methods to utilize acid injection through the irrigation system is suggested as an effective solution in the proposed on-farm research project. A precise seasonal irrigation schedule to provide a maximum development of blueberry plants will be tested. Proper scheduling also permits a vegetative tissue growth that ensures production in the following season (Holzapfel and Hepp, 2002). According to Bell, (1982), and Gough, (1982) the periods of maximum water requirement in blueberries are the first two weeks after petal-fall and the two weeks before and after harvest. Brightwell and Austin (1980) demonstrated that the bud break period of blueberries is also characterized by high water requirement. In general, it is possible to infer from several studies that frequent applications of small volumes of water create the best condition for blueberry growth. Lyrene and Crocker (1991) recommended irrigating daily in sandy soils as to prevent leaching of nutrients, improve a deeper root development, and diminish calcium carbonate deposits that increase soil pH.

When selecting the irrigation system, a consideration should be given to economic and technical parameters such as the type of orchard, availability and quality of water, type of soil, human resources, and costs (Holzapfel et al., 1985). The most common irrigation systems used to irrigate blueberries are microjet and drip (Freeman, 1983; Holzapfel et al., 2003; Holzapfel et al., 2004). Holzapfel et al., (2004) found that during the first 2 years of harvest, plants under drip irrigation produced higher yields compared to those with the microjet system, at all levels of water application. However, in the fourth and subsequent season microjet surpassed drip irrigation.

Another alternative is enhancing soil organic matter to help retain water in the root zone and buffer soil pH changes. Spiers, (1983, and 1986) analyzed three methods to preserve the soil water content (irrigation, peat moss, and mulch) and evaluated their effect on root development, concluding that mulch produced the most significant effect. However, maximum root development was obtained with the use of the three techniques simultaneously (Spiers, 1986), showing that under these conditions it is possible to maintain a high soil water content with a good level of aeration in the soil. Lafond, (2004) demonstrated that paper mill biosolids mixed with ground bark is a potential nutrient source for blueberry on poor sandy soils without short term loss in crop yield.

Elina Coneva
Auburn University
101 Funchess Hall
Auburn , AL 36849-5408
Ph: 334-844-7230
Fax: 334-844-3131
Em: edc0001@auburn.edu

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OS08-041 Increasing the Sustainability of Oklahoma Cropping Systems Using Cover Crops

The purpose of this project is to gain a deeper understanding of the benefits of cover cropping systems in the southern Plains and to educate growers on the associated cost/benefits of cover cropping. Producers will establish replicated plots on their farms. These plots will be used to explore the benefits of cover crops and help others determine the feasibility of including them into their cropping systems.

In addition to providing ground cover and, in the case of a legume, fixing nitrogen, cover crops also help suppress weeds and reduce insect pests and diseases. Cover crops take up space and light, thereby shading the soil and reducing the opportunity for weeds to establish themselves. Providing weed suppression through the use of allelopathic cover crops and living mulches has become an important method of weed control in sustainable agriculture. Allelopathic plants are those that inhibit or slow the growth of other nearby plants by releasing natural toxins, or "allelochemicals." The mulch that results from mowing or chemically killing allelopathic cover crops can provide significant weed control in no-till cropping systems. Claassen (2004) observed soybean and sunn hemp effectively suppressed volunteer wheat and, in the fall, reduced the density of henbit compared to areas having no cover crop.

Dryland producers in the southern Plains struggle to maintain economic stability mainly due to variable growing conditions (moisture) and commodity prices. Making cropping systems more “self-sustaining” through leguminous cover crops would likely reduce inorganic inputs and decrease overall input costs. Cover cropping promotes a diverse community of organisms which play critical roles in decomposition, nutrient cycling, bioremediation, pest suppression, plant health, and enhancement of physical and chemical soil properties (Crossley, et al. 1992). Relative to pest management, cover crops may provide habitats that conserve natural enemies and reduce pest impact (Keenan, et al., 2007). In the southern Plains impacts of cover crops on soil quality, N-use efficiency and net-returns have not been evaluated.

A major benefit obtained from cover crops is the addition of organic matter to the soil. During the breakdown of organic matter by microorganisms, compounds are formed that are resistant to decomposition, such as gums, waxes, and resins. These compounds and the mycelia, mucus, and slime produced by the microorganisms help bind together soil particles as granules, or aggregates. A well-aggregated soil is well aerated and has a high water infiltration rate.

This project is a producer driven idea that will examine sustainability of cover crops in the southern Plains. We hypothesize that the use of cover crops will increase nitrogen use efficiency, improve soil quality and enhance indigenous pest suppression, which will increase the sustainability of cropping systems in the region. On-farm study locations will allow the research team and producers to improve our scientific understanding and improve our educational efforts in regards to sustainable cropping systems.

Chad Godsey
Oklahoma State University
368 Agricultural Hall
Stillwater , OK 74078
Ph: 405-744-3389
Fax: none
Em: chad.godsey@okstate.edu

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OS08-042 New Tools to Make Organic No-till Soybeans and Corn a Reality

Demand for organic corn and soybeans in North Carolina is growing. Braswell Milling in Nashville, NC estimates they need at least 500,000 bushels of organic corn and 7,000 tons of organic soybean meal each year to supply their organic egg farms. A group of farmers in eastern North Carolina have incorporated as Eastern Carolina Soy Products, LLC to build a soybean crusher that will process up to 400,000 bushels of organic soybeans each year. Five dairies in our state transitioned to organic in 2007 and more are expected in 2008. The state currently imports a majority of its organic corn and soybeans to meet market demand and imports will increase as additional buyers move in. This new market is an opportunity for grain farmers who are prepared for the challenges involved with organic production.

Currently, weed management in organic soybean production relies heavily upon multiple secondary tillage passes over the field each season. Increased tillage can result in increased soil erosion (Beale et al., 1955) and soil compaction (Raper et al., 2000), increased fossil fuel requirements (Hargrove, 1990), increased CO2 release (Paustian et al., 1998), increased labor costs (Weersink et al., 1992), increased equipment costs (Weersink et al., 1992) and decreased soil residue cover (Hargrove, 1990).

Some cover crops such as rye have demonstrated allelopathic (releases weed inhibiting chemicals) properties (Barnes et al., 1987). A newly designed chevron roller can be utilized to effectively kill the rye and create a thick biomass layer on the soil surface. By planting soybeans into such a biomass layer, weed growth can be greatly inhibited. This system has been successful at the Rodale Institute in the Northeast, but it has not been investigated for the Southeast region. With the increased research and development of organically certified herbicides (Tworkoski, 2002), use of corn gluten (shown to possess weed suppressive qualities (Christians 1993)) and high residue cultivation equipment (Paarlberg et al., 1998), more options have become available to successfully implement no-till organic grain production.

Most of NC's organic grain farmers are located in the Tidewater region; an area of poorly drained, high organic matter soils. These farmers would like a cover crop to contribute significantly to the nitrogen budget of their corn crop. In organic systems, reliance on manures for nitrogen is not sustainable due to increasing phosphorus levels and concerns of environmental contamination (Bulter et al., 2005). Crimson clover is typically recommended for adding large amounts of biomass with high nitrogen content. However, crimson clover is inhibited on poorly drained soils (Yenish et al., 1996; Cavigelli et al., 2007). Hairy vetch is also a significant contributor of nitrogen and known to tolerate wet soils (Anderson et al., 1990). In an attempt to incorporate no-till into a full rotation system, farmers have identified the need to further investigate the limitations of crimson clover on poorly drained soils and the potential use of hairy vetch, a cover crop more tolerant to wet soils but rarely used in North Carolina grain rotations.

We propose an on farm trial to compare no-till organic soybean systems utilizing different combinations of the following tactics: planting soybeans into a rye cover crop compared to planting into no cover crop; planting soybeans into a rolled down rye cover crop compared to planting into an undercut rye cover crop; planting soy with a 7 inch band of corn gluten over the crop row, use of post crop emergence vinegar organic herbicides with sprays directed under crop foliage and the use of one pass of a high residue cultivator to control weeds between crop rows.
We also propose a multi-location investigation of nitrogen contribution by crimson clover and hairy vetch cover crops grown on poorly drained soils preceding corn as part of the no-till organic grain rotation.

S. Chris Reberg-Horton
North Carolina State University
Campus Box 7620
Raleigh , NC 27695
Ph: 919-515-7597
Fax: 919 515 5855
Em: chris_reberg-horton@ncsu.edu

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OS08-043Monitoring Nutrient Availability and Leaching Below the Root Zone in Organic Vegetable Production

The demand for locally grown produce is so strong nation-wide and particularly in Florida that certified organic vegetable growers have a hard time keeping up with market needs. High-value vegetable crops such as tomato, bell pepper, eggplant, and watermelon are well suited for the growing conditions in the Southeastern United States, especially when plasticulture is used. Typically, fertilization practices for these crops include a pre-bedding application of an approved compound fertilizer (often 8-5-5 Nature Safe), followed by fertigation events late in season using sodium nitrate (but the NOP clearly states that no more than to 20% of total N may come from this N source). The combined high risk of leaching in Florida's sandy soil with the poor predictability of the nutrient release from the pre-plant fertilizer often results in a shortage of N and K in the middle or end of the season, thereby reducing yield and quality. Increasing the in-bed rate of the organic fertilizer is currently not an economical option.

Previous efforts coordinated by the University of Florida Extension Service and supported by Southern Region SARE projects have (1) improved drip-irrigation scheduling practices by showing how fast water moves through the soil profile by using soluble dye, and (2) demonstrated the usefulness of weekly petiole sap testing analyses of nitrate and potassium to monitor plant nutritional status (Hochmuth et al., 2003, 2006; Simonne et al., 2005). Yet, these two techniques alone are insufficient for managing N and K in certified organic production because (1) the rate of organic fertilizer mineralization is not known and (2) the 20% sodium nitrate restriction leaves little flexibility for rescue fertilizer applications. Over-application of the preplant is not an option, because of philosophical objections and added cost. Other projects conducted by this group in North Florida have shown that nutrient movement below the root zone may be assessed with simple drainage lysimeters. Drainage lysimeters also allow the calculation of a seasonal nutrient load by multiplying volume of leachate by nutrient concentration (Gazula et al., 2006). Hence, by measuring leachate parameters (volume, composition) and using sap testing results, the grower should better understand the impact of fertilizer and irrigation practices on N and K release and losses. This approach will help organic growers increase efficiency in use of expensive organic fertilizers and at the same time improve best management practices by reducing N and K losses, thus making a positive contributing to improving water quality in the Suwannee Valley area of Florida. Our hypotheses are that (1) costly certified organic fertilizer rate may be reduced without reducing productivity by improving irrigation management and (2) dual measurement of leachate electrical conductivity and plant petiole nutritional status allows for a better understanding of when nutrient shortage occurs due to insufficient fertilizer nutrient release or from nutrient leaching caused by excessive irrigation.

The application of this work to other sites may be simplified by using suction-cup lysimeters when the grower does not need any further information on the nutrient load. However, suction cup lysimeters provide an estimate of nitrate concentration in the soil solution, but do not allow the calculation of a load (the volume of hte soil providing hte water sample is not known ; Gazula et al., 2007). In this project, the grower cooperator and UF personnel want to estimate nitrate load.

Eric Simonne
University of Florida
1241 Fifield Hall
Gainesville , FL 32611-0690
Ph: 352-392-1928
Fax: none
Em: esimonne@ufl.edu

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OS08-044 The Use of Controlled Grazing, Chicory Pasture and Herbal Treatments to Prevent Parasitism in Sheep and Goats, Phase II

Through the SARE funded on-farm research project ,“The Use of Controlled Grazing and Two Herbal Treatments to Prevent Parasitism in Sheep and Goats,” Heifer Ranch documented the benefits related to controlled grazing techniques and herbal treatments (garlic juice and papaya) for preventing and treating parasites in sheep and goats. This project will build upon the research conducted in phase I and expand the trials.

During the phase I trials, it was found that with high rainfall and in wet climates, there are higher risks and rates of parasitism. Because of the unusually high amounts of rain during the summer of 2007, it was found that straight garlic juice treatments were not as effective as had been found during drier times. Rotational grazing proved to be quite effective even during times of high rain in preventing elevated levels of parasite infestation. Phase I also determined that grazing on chicory pastures improved the overall health of grazed animals, but did not have a measurable effect on fecal egg counts and FAMACHA scores. Papaya seeds also decreased mortality, but too few animals needed this treatment to fully understand its effect.

As a result of the phase I trials and findings, along with some promising results of the use of papaya, farmers have expressed a need for further investigation into the management strategies of controlled grazing, the use of a chicory (Cichorium intybus) pastures and alternative herbal treatments (papaya seeds and garlic juice with green walnut hulls). Side by side trials of continuously grazed pasture along with controlled grazing will help quantify the benefits of intensive grazing strategies. In addition, much needs to be found out about pasture plants that have anthelmintic properties. This phase II project will help determine how often and how long animals should be grazed on anthelmintic pastures. Cooperating farmers will also work with Heifer and extension staff to analyze animals' resilience to parasite infection and to select animals showing resistant characteristics.

The sheep flock at Heifer Ranch and one of the cooperator's farms were involved in the phase I trials and will continue in phase II, in order to look at long-term effects of the treatments. Two additional farmers requested to enroll their flocks in the phase II trials. These animals will provide multiple locations to test the various methods and treatments proposed, to better assess efficacy and efficiency.

The overall goal of the project is to have no clinical cases of parasitism in the participating sheep. Given the high levels of parasites in the South, such a goal is hard to achieve. This project will test alternative prevention and treatment options in order to ultimately achieve this goal. Because of the success with the intensive grazing management strategies and the preliminary results of the papaya and garlic treatments, we feel that these slight modifications to these approaches can provide sheep and goat producers with effective, economically-viable control measures.

Ann Wells
Heifer International
One World Avenue
Little Rock , AR 72202
Ph: 479-409-8772
Fax: 501-907-2803
Em: annw@pgtc.com

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