Final Report for LS02-137
Tuskegee University (TU): Weeds are a major problem in tomato production. Until now, methyl bromide has been used as a soil fumigant to control nematodes, weeds, insects, and diseases in tomato fields. However, methyl bromide (MB) has adverse effects on the environment and is due to be taken off the United States’ market in 2006. This makes it important to find an environmentally friendly alternative. Crop rotations that include legumes and grasses may be used as alternatives to methyl bromide. The objectives of this research were to: (1) evaluate yield of tomato in rotation with cover crops (crimson clover, black oat, and crimson clover-black oat mixture) under two tillage systems (conventional tillage and no-tillage) and (2) identify tomato pests and diseases under conventional and no-till systems.
The experimental field is located at the George Washington Carver Agricultural Experimental Station in Tuskegee University.* Cover crops were planted early in spring 2004, plowed and incorporated into soil or mowed and left on the soil surface. Prior to establishment of the cover crops, eight core soil samples were collected at 0-15 cm depth using an auger. The soil samples were air dried and passed through a 2-mm sieve. Organic C, N, and S were analyzed by using an automated CHNS Analyzer. Total P was analyzed by the perchloric acid digestion method and the P in the digest was determined by the Murphy and Riley procedure. Inorganic N (NH4+ and NO2- + NO3- ) was determined by steam distillation after extraction of 10 g soil with 50 mL of a 2 M KCl solution. The mixture was shaken for 1 hour on a shaker and filtered through a membrane filter (<0.45μm). A Berlese Funnel was used to extract soil arthropods which were identified using appropriate guidebooks. Sticky traps were also used to sample flying insects. Insect damage to tomato fruits and foliage was assessed at harvest. Tomato yields following crimson clover, black oat, or black oat-crimson clover mixtures incorporated in soils were 9.23, 7.69 or 2.10 t/ha, respectively. The yield of the control plot without cover crop was only 1.00 t/ha.
*The farm demonstration for spring 2005 was not successful. Consequently, land has been set aside and another cover crop has been planted both on the farmer’s field and at the Experiment Station for a re-trial in the spring. An amended report will then be filed.
Auburn University (AU): The fundamental question we were addressing was if an integrated sustainable system can be developed as a substitute for the conventional system of growing tomato in Alabama. The conventional system uses plowing, creation of raised beds, and plastic cover. The integrated system uses winter and summer cover crops, biological treatments, and no-till transplanting. The answer to our fundamental question appears to be yes, based on economics of the yield differences.
As expected, the first year that we used cover crops and minimum tillage, yields were markedly lower than in the conventional plastic system. The 2-site yield reduction in the first year was 26% less with the best integrated system than with the conventional plastic system. By the third year, yields in the best integrated system had increased and were 5% less than yields in plastic at Cullman and 20% less at Sand Mountain. Hence, the average lowest yield reduction with integrated systems at two locations was 12.5% in year 3.
Another impact of the research is clarifying the impact of biological treatments consisting of PGPR in an integrated system. Overall, treatments with the biologicals did not increase cumulative yields. However, there were other benefits. For example, the PGPR treatments decreased transplant shock and increased plant growth early in the season. Under conditions of mid- to late-season plant stress, this early-season growth enhancement would be expected to result in increased yields. Also, speeding up plant growth can result in faster tolerance to diseases that impact young plants more. The other impact of the PGPR in our studies was on disease. In 2003, PGPR treatments resulted in reduced damage to root-knot nematodes, and in 2004, they resulted in a lower incidence of tomato spot disease. An additional benefit of the PGPR treatments was to increase nutrient uptake by the plants.
AU and TU: The objectives for this project were as follows. 1) Maintain the viability and profitability of the grower participant farms by implementing an integrated sustainable production system. 2) Improve grower communication by facilitating networks of vegetable growers. 3) Remove marketing barriers by developing strategies to help growers gain the best price for their crop. 4) Secure the continuance of a systems approach in Alabama agriculture by developing classroom modules for increasing student knowledge of implementing sustainable agriculture.
For Tuskegee University the objectives were the same as Auburn’s except in objective one, in which they sought to (1) evaluate yield of tomato in rotation with cover crops (crimson clover, black oat, and crimson clover-black oat mixture) under two tillage systems (conventional tillage and no-tillage) and (2) identify tomato pests and diseases under conventional and no-till systems. Auburn University met objective one through the experiments discussed under the sections Material and Methods and Impacts.
TU: Core soil samples were collected at 0-15 cm depth from the experimental site at the George Washington Carver Experimental Station in spring 2004 and analyzed (pH 6.1; extractable P, 10 mg kg-1; extractable K, 78 mg kg-1; extractable Mg, 73 mg kg-1; and extractable Ca, 350 mg kg-1; NH4+, 2.14 mg N kg-1; and NO3-, 1.65 mg N kg-1). The experimental design was a split plot with two tillage systems (conventional and no-tillage) examining the effect of cover crops (control, crimson clover, black oat, and crimson clover-black oat mixture) on tomato yields, soil arthropods, and insects .The cover crops were planted in early spring 2004. Before harvest, the cover crops were sampled, dried in an oven at 65 ºC for 72 hours, ground to pass through a 0.5-mm sieve. The cover crops were then cut and incorporated into soil (conventional treatments) or left on the soil surface as a mulch (no-till treatments). Soil samples were also collected at 0-10 cm depth for identification of soil arthropods using a Berlese funnel. Tomato plants were transplanted in July 2004 and sticky traps were placed around the tomato plants after 2 and 3 weeks from planting during the growing season for 24 hours each time to sample insects. During plant growth, biometric measurements were taken. Trapped insects were counted and identified in the laboratory.
Two months after planting, tomato leaves were collected and examined for mites and thrips; tomato fruits were counted and estimates made of infested/damaged and non-infested fruits. After harvest, leaf samples were collected from the tomato plants and dried in an oven at 65 ºC for 72 hours. Dried samples were ground and passed through a 0.5-mm sieve for C, N, and S contents. Tomato yield was estimated from the two middle rows of each experimental plot.
Soil samples were collected at incremental depths of 0-5, 5-10, and 10-15 cm using an auger. The samples were air-dried and passed through a 2-mm sieve. Organic carbon, nitrogen, and sulfur contents of soil, cover crop, and tomato leaf samples were determined using a high temperature combustion Auto Analyzer (Vario ELIII CHNS, Elementar Americas). To determine total P, 0.5 g of the soil sample (< 100 mesh) was treated with a concentrated HNO3 to oxidize the soil organic matter then digested with HClO3 on a hot plate. The P content of the digest was determined by the Murphy Riley procedure. The absorbance was read at 880 nm on a spectrophotometer.
Inorganic N (NH4+ and NO2‾+NO‾3) was determined after extraction of 10 g of soil sample with a 50 mL of 2 M KCl solution for one hour on a shaker. The mixture was filtered through a membrane filter (0.45 μm) and inorganic nitrogen in the filtrate was determined by steam distillation.
AU: Research trials by Auburn personnel were conducted each year at two locations: Sand Mountain Research and Education Center in Crossville, AL and the North Alabama Horticultural Research Center in Cullman, AL. The overall approach was to develop an integrated system for growing tomato without the current conventional use of tilled-raised beds and plastic cover.
The aim of research in 2003 was to select one of three tested winter cover crops and either strip-till or no-till planting for tomato. The three cover crops evaluated were 1) a mixture of crimson clover, hairy vetch, and winter rye planted in fall 2002; 2) a mixture of black oat and rye planted in fall 2002; and 3) black oats planted in spring 2003. In each of the cover crop areas, three experimental treatments were planted with no-till transplanting and strip-till transplanting. The same three treatments were also evaluated under the conventional raised bed and plastic system. The treatments were two biological products and a nontreated control. The biological products were used because previous field work at Auburn and on-farm showed that the products promoted plant growth. Both products contained PGPR (plant growth-promoting rhizobacteria). Equity, by Naturize, is an aqueous product containing a complex mixture of over 40 strains of Bacillus spp. BioYield, by Gustafson, is a flaked product containing two bacilli. It is mixed into the growing medium used to prepare tomato transplants. During the growing year, measurements of plant growth were taken to determine if PGPR products under different cover crop and tillage regimes promoted plant growth. Cumulative yield of marketable tomato fruit was calculated. Root-knot nematodes were present at the Cullman site, so ratings were taken after harvest for severity of nematode damage.
Based on the results obtained in 2003, in 2004, a single winter cover crop system was used—the mixture of crimson clover, hairy vetch, and winter rye, using no-till transplanting and the same three treatments (2 PGPR products and a control). At the Cullman site, an additional evaluation was made to determine the potential benefit of attaching a subsoil shank to the no-till transplanter to help break up soil at the root zone. The three treatments were also evaluated in the conventional raised bed and plastic system. Early and mid-season plant growth as affected by PGPR was determined, and cumulative yield was recorded as in 2003.
Additional measurements made in 2004 included assessing the nutrient content in tomato leaves and recording the incidence of bacterial spot disease that occurred at Sand Mountain. Space within the winter cover crop area that was not planted to the tomato yield test was cropped with a summer cover of Sudan grass and velvet bean at both Cullman and Sand Mountain. In addition, a tomato cover was used at Cullman.
In 2005, the same integrated system tested in 2004 was evaluated—the mixture of three winter cover crops, no-till, and PGPR. Based on the results of 2004, all tests in 2005 used the subsoil shank. Early and mid-season effects of PGPR on plant growth were determined, and cumulative yield was calculated. Root-knot nematodes were present at Cullman, so damage was assessed.
TU: Results of the first year of the studies showed that different treatments affected plant growth and development differently. The tomato plants under no-till treatments were weed, water, and nutrient stressed. These plants did not produce any fruits. Therefore, no tomato fruits were harvested from the no-till plots. In the control plots under conventional tillage, plants were stunted because of nutrient deficiency. However, under conventional tillage, tomato plants preceded by cover crops showed much better performance. The results are summarized below.
1. Black oat had the highest organic carbon content (42.6 %) while crimson clover showed the highest nitrogen content (1.92 %). Sulfur content of the cover crop biomass is very low (< 0.2 %).
2. Biometric data showed that tomato plants in the conventional till plots performed significantly better than those under no-till.
3. There was no significant difference in yields obtained when tomato is preceded in the rotation by crimson clover or black oat. The mixture black oat-crimson clover significantly reduced tomato yield (2.10 t/ha); this result was unexpected and must be tested again in the next field experiments.
4. Disease incidence was generally low, but tomato fruits in control plots had more infected or damaged (14 %) fruit than other treatments.
5. Tomato leaf analysis showed similar carbon content for all treatments. However, concentration of N in the tomato leaves of the control plot is lower than that of other treatment plots.
6. Tomato plants in rotation with crimson clover showed higher C, N, and S uptake than that of plants in rotation with black oat or crimson clover-black oat mixture. The uptake of C, N, and S by the tomato plants following crimson clover was 3914, 472, and 93 kgha-1, respectively. Soil profile analysis of C, N, and S revealed no significant difference among the treatments for this year of experimentation.
Research trials by Auburn personnel were conducted each year at two locations: Sand Mountain Research and Education Center in Crossville, AL and the North Alabama Horticultural Research Center in Cullman, AL. The aim of research in 2003 was to select one of three tested winter cover crops and either strip-till or no-till planting for tomato.
The three cover crops evaluated were 1) a mixture of crimson clover, hairy vetch, and winter rye planted in fall 2002; 2) a mixture of black oat and rye planted in fall 2002; and 3) black oats planted in spring 2003. Cover crop density was examined in late spring prior to planting tomato. At both field locations, the 3-crop mixture had excellent plant density, while the other two cover crop systems were less vigorous. By mid summer, fields with rye + black oat and black oat alone had many more weeds than did fields with the 3-crop cover. Hence, the 3-crop cover was selected for all subsequent testing.
During the 2003 growing season, field tests were conducted to combine the use of cover crops with minimum tillage and biologicals and to compare tomato yields under these systems to yields obtained with conventional tomato production. The current conventional system in Alabama and many other states uses standard tillage with raised beds covered in plastic. The biologicals used are two commercially available formulations of PGPR (plant growth-promoting rhizobacteria). The two products, Equity and BioYield, were selected for use in this project because we had already found in field tests on research stations and in growers’ fields that tomato growth was enhanced by the products. Two minimum tillage systems were tested—no-till transplanting and strip-till transplanting—in the cover crop areas. Thus, the overall design was that each cover crop system included no-till and strip-till, and the three treatments (two biologicals and a non-treated control) were used in each combination of cover crop and tillage. In addition, the three treatments were applied to the conventional plastic block. Each treatment was replicated six times, and each replication consisted of a single 20-ft-long row with 20 tomato plants.
To measure effects of the biologicals on tomato growth early in the season, the plant growth index was determined on 5 plants per replication in each treatment by measuring the height X width of plant (in2). At both Cullman and Sand Mountain, the biological treatments promoted early season plant growth. These increases occurred with the 3-crop cover using strip-tillage and no-till and with the conventional plastic system.
Yield was determined by picking red fruit an average of two times per week. Cumulative weights and numbers of fruit in different sizes were determined. We decided to report only the cumulative fresh weight for all marketable sizes, as this is the major, economically important parameter for tomato growers in Alabama. Even though the biologicals increased early-season plant growth, they did not increase yield. The “plastic control” yield of 100.2 lbs serves as the conventional growing system control. The best yield with the integrated system (Equity under strip-till with the 3-crop cover) at Cullman was 22% less, and the best system at Sand Mountain (Equity under strip-till) was 30% less.
During the harvest, the presence of root-knot nematode damage on roots was noted. Therefore, we dug 10 plants per replication and rated for the severity of gall damage using the standard 0 – 10 rating scale. Results show that the two biologicals consistently decreased severity of root-knot nematode.
Based on the results of 2003 and discussions with our grower cooperators, we decided to concentrate 2004 testing on the 3-cover-crop system using no-till transplanting of tomato. The same three treatments (two biologicals and a nontreated control) were included. Because the no-till in 2003 grew less vigorously and yielded less than the strip-till, an additional variable at Cullman in 2004 was the inclusion of a subsoil shank on the no-till transplanter.
Because the 2004 replicated trials (3 treatments X 6 replication) were within the same large block (winter cover crop) used in 2003, the location of the trial was moved to avoid replanting in the same area. The remaining portions of the block were planted with summer cover crops which included Sudan grass and velvet bean at both Cullman and Sand Mountain. In addition, at Cullman only, tomato was included in the “summer cover crops” to simulate continual planting of tomato.
We again measured early season growth effects of the biologicals by calculating the growth index. At Cullman, we measured two times. The first measurement was 8 days after transplanting to assess effects of the biologicals on transplant shock, and the second measurement was at 27 days after transplanting. At both times, the two biologicals increased the average plant growth index in the sampled plots. It was particularly interesting to note that the biologicals reduced transplant shock as indicated by higher growth indexes at 8 days after transplanting.
At Cullman, the two biologicals increased plant growth indexes in the integrated system and in the conventional system at 44 days after transplanting.
Effects on yield were measured, as in 2003, by comparing cumulative weights of marketable fruit. The quality of the tomato plants grown under plastic was compromised for all treatments due to inferiority of transplants. While transplants used in all other blocks at Cullman were of good quality, those used for planting the plastic block were weak. Hence, the yield of the plastic control was lower than expected, and we cannot fairly make comparisons of the integrated system to the “conventional control” (plastic control) for 2004 at Cullman. At Sand Mountain, the plastic control yielded 228.9 lbs., and the best integrated system (Equity under no-till) yielded 179.3 lbs, which was a reduction of 21% compared to the control.
A major conclusion from 2004 was that the inclusion of the subsoil shank on the tomato transplanter increased plant performance and yield. The yield of the block at Cullman with subsoil shank was 140.2 lbs vs. 120.4 lbs for the block without the shank, representing a 16% yield increase using the shank.
We also examined yield data in 2004 to determine if the early growth enhancement observed with the use of biologicals resulted in more yield in the first two pickings. Results indicated that the biologicals indeed increased early yield.
No nematode damage was observed in 2004, so no ratings were made for root index.
Plant leaf tissue was collected at Sand Mountain at the time of fruit formation to determine if the nutritional status of plants was influenced by the use of biologicals or by cover crop. Results indicate that N, P, and K concentrations were increased in leaves by both biologicals under plastic cultivation and that in the integrated system N and P were increased by biologicals.
Weather conditions in 2004 were favorable for development of bacterial spot disease in portions of the state. This is a bacterial disease caused by Xanthomonas axonopodis pv. vesicatoria, and the disease is favored by warm, rainy weather. At the time of fruit maturity, the disease was common at Sand Mountain. Initial observations indicated less disease was on plants in the cover crop area than in the plastic area. Hence, we rated all plots for disease incidence by recording the number of plants in each replication that had any symptoms. Results indicated two important points. First, disease incidence was reduced by biological treatments, and this occurred both in the cover crop and the plastic blocks. Second, disease incidence was lower across all treatments in the cover crop area than in the plastic block. Hence, the integrated system of cover crops, no-till, and biologicals can lead to reduced foliar disease. Interestingly, one of our grower cooperators made the same observation in 2004, specifically noting that there was less bacterial spot disease on plants grown under the cover-crop system than on the rest of his farm.
The subsoil shank was used at both Cullman and Sand Mountain in 2005 because of the yield benefit observed with its use at Cullman in 2004. As indicated previously, within the large block of winter cover crop, areas that were not planted in the tomato yield trial in 2004 were planted with summer cover crops: velvet bean, Sudan grass, or tomato at Cullman; velvet bean and Sudan grass at Sand Mountain. Hence, in the 2005 replicated yield trials within the winter cover crop block, separate trials were conducted in areas that had been planted to each of the 2004 summer cover crops.
We again measured the plant growth index as an indicator of early and mid-season plant growth as impacted by the biological treatments. At Cullman, the results show that both biological treatments increase plant growth at 44 days after transplanting, and this effect was noted in all blocks, including in the conventional plastic system.
At Sand Mountain there was a problem with the application of Equity in 2005. Due to concerns about low bacterial counts in the initial application of product that was left over from 2004, new product was additionally applied and some formulation-related burning was noted. Hence, we need to exclude the 2005 Equity data from Sand Mountain only. In 2005 we measured plant growth twice at Sand Mountain. The first measurement was done 8 days after transplanting to determine if the previously observed reduction in transplant shock by biologicals occurred again. The results with BioYield demonstrate that the biological treatment again recovered from transplant shock earlier than did nontreated plants, and this effect was noted in all blocks. The increased plant growth induced by biological treatment persisted through the second measurement at 24 days after transplanting.
Cumulative yields in all blocks and all treatments were again determined. Results show that compared to the conventional control (plastic control) yield of 172.5, the best integrated system yield at Cullman (BioYield in no-till/Sudan) of 163.5 lbs was only 5% less. At Sand Mountain, the best integrated yield was 192.7 lbs with BioYield in the no-till/velvet bean, which was 20% less than the yield of the plastic control.
Educational & Outreach Activities
- Tuskegee and Auburn PIs presented research findings at Tuskegee’s Agriculture Workers Conference in December of 2004. Tuskegee University has utilized the Agriculture Workers Conference to present results from the SARE project and to promote sustainable agricultural practices to individuals from throughout Alabama and other states.
An organic vegetable research and outreach project began at Auburn University in April 2004. During various meetings with grower participants, growers raised questions about opportunities and challenges related to organic production. In April 2004, a portion of the North Alabama Horticultural Research Station at Cullman was set aside for research, certification, and education on organic vegetable production. This decision followed recommendations from a group of Alabama farmers who attended a workshop in November 2003 on challenges and opportunities related to organic vegetable production. The project expanded in the fall of 2004 when land was set aside at the E.V. Smith Research Center outside of Montgomery for organic plot research and certification. Later, a portion of Auburn’s Plant Growth Center’s operations was reserved for organic production of transplants. The decisions and activities outlined above have resulted in the creation of the position of Organic Vegetable Production Coordinator in October 2004. This is a half-time position funded jointly by Alabama Agriculture Experiment Stations (AAES) and Alabama Cooperative Extension Services (ACES).
Outreach at Auburn University as a result of SARE project
• Develop new partnerships with farmers interested in sustainable practices. We are now in touch with four additional farms (6 growers).
• Publish E-bulletin monthly on organic and sustainable practices.
• Maintain website that focuses on organic vegetable production research. The site, (http://www.ag.auburn.edu/aaes/organicveg/), contains information applicable to those who are interested in sustainable practices as well as in organic practices in vegetable production.
• Maintain a part-time position to answer phone calls and e-mails related to sustainable and organic production. Supported by funds from the Alabama Cooperative Extension System and the Alabama Agriculture Extension Station, the person in this position publishes the e-bulletin, maintains the website, and visits growers on their farms.
• Established an ongoing partnership with Alabama A & M University to conduct research on sustainable and organic practices. This partnership is the result of a grant received from the USDA Cooperative State Research Education and Extension Service’s (CSREES) Integrated Organic Program.
• Established a collaborative partnership with Alabama Sustainable Agriculture Network to provide marketing information and grower to grower advice to our participants.
• Prepared and distributed a CD containing articles from our presenters at our conferences. Presentations available both in print and on the CD include topics on disease control, insect and pest management, organic production of transplants in a greenhouse, soil nutrient management, cover crops, tillage, seed saving, and information on SARE’s programs.
TU: Producers growing tomatoes in the Black Belt counties range in size from using large family gardens to farms from 10 to over 100 acres of owned and rented land. Production on the farms reflects a variety of vegetable crops including tomatoes, squash, southern peas, watermelons, okra, snap beans, butter beans, field corn, cantaloupe, greens (collards, mustard, turnip) and other cash crops such as cotton.
Tomato production involves a diverse plan and farming system. While most farms involve conventional tillage, one farmer is in transition to organic production. Farmers produce two tomato crops a year: a spring crop, with transplanting mid-March and harvesting around mid-June; and a fall crop, with transplanting at the end of June and harvesting at the end of September. If they can get them, farmers prefer hybrid transplants such as those resistant to leaf blight and other diseases.
The major expenses for tomato production include plastic to cover the tomato beds ($85/roll, and one farmer uses between 4-5 rolls), and drip irrigation tape. Water is another expense, where irrigating for an hour or more a day is not uncommon. A key decision for the farmer each year is whether to invest in the plastic and irrigation tape. In years where there has been plenty of rain, the investment is wasted; however, if there is a dry spring and summer, a crop cannot be made without it. Other inputs include fertilizer that is applied through the drip tape, Treflan, and then Round-up to clean the fields. None of the farmers contacted used fumigants.
Marketing from the small to the larger producers involved taking the produce to the farmers’ markets in Troy, Eufala, Tuskegee, Union Springs and Dothan. Farmers also had on-farm sales at the field.
AU: One obvious result has been the establishment of informal communication network among growers. The catalyst for these “networks” was informal meetings held at restaurants and extension offices. During meetings one grower reported on experimental results she had heard from the other family, indicating that the participants were communicating with each other about the project. We also witnessed the growers discussing problems related to socio-economic challenges they were facing.
Additional support came from the Alabama Agricultural Experiment Station (AAES), indicating that on-farm research can develop into a partnership with land-grant university facilities. As an example, growers received assistance in the form of advice, equipment, and farm tours from the North Alabama Horticulture Research Center and the Sand Mountain Research Center. Both centers continue to maintain contact with the growers involved in this project.
Based on grower interest, we provided extensive information on growing vegetables to meet organic certification. However, neither grower family pursued organic certification as a means for marketing. One family attempted to purchase land that would be easy to certify, but the purchase was not completed.
We maintain contact with the growers and communicate information on marketing and growing produce for niche markets focused on organic production practices. Further, participants are invited to join farm tours sponsored by Alabama Sustainable Agriculture Network (ASAN) to learn about other farmers’ marketing strategies. The growers in this project have shown the most interest in Alabama’s farmers’ market program, “Buy Fresh Buy Local,” in which they sell their fresh produce at farmers’ markets in nearby towns.
In a 2003 spring meeting some grower participants expressed interest in organic certification. Further discussion of the matter continued with the participants, and we began planning and publicizing an organic vegetable production conference. In November 2003 the first conference, “Edging towards Organic Vegetable Production: Possibilities and Considerations for Alabama Growers,” was held at the Birmingham Botanical Gardens. Approximately 80 individuals attended and results of the SARE project were presented. Adding to our research presentation was the presence of two grower participants who shared their interest in organic production and their experiences with the SARE project.
The conference is now held annually, with 2005 being our third year. Topics that have been discussed include seed saving, soil and nutrient management, cover crops, and marketing. While we rely on extension staff and university professors to present research and findings, we recruit other growers to make presentations. Alex Hitt of Peregrine Farms in North Carolina spoke in 2004 on whole farm planning. Other growers have shared their experiences as operators of a small vegetable-based CSA, leaders of sustainable farming programs devoted to helping minority farmers, and managers of urban farms.
AU and TU: Objective 4 states that we would include the development of case studies, modified from the experiences with the project, to provide university students with a holistic view of growers’ problems. The goal is for students to assess an agricultural problem from a systems perspective by looking at the social, ecological, and economic needs of growers.
In carrying out this objective, Dr. Joe Kloepper, principal investigator, taught a Field Survey course in the summers of 2002 and 2004. There are no traditional classroom lectures. Instead, learning occurs primarily in the field, through a series of short trips. On each trip students have a “host” who is familiar with the region’s crops and associated production problems. Discussions are focused on producers who use sustainable management systems to confront fertility, weed, insect, and disease problems. Students enrolled in the courses have visited sustainable vegetable production research centers in Tifton, Georgia (University of Georgia) and in Ft. Pierce, Florida as well as local farms in the state and region.
Students write report summaries and discuss crops, pests (diseases, insects, and weeds), and management options for each crop/pest observed. Additionally, they are required to discuss, labor, political and social issues with growers. At the end of the course each student prepares one report for a 20 minute oral presentation. It must provide details on a sustainable cropping system that could be implemented to manage a production problem or a disease problem.
Students are required to read “Six Agricultural Fallacies” from Home Economics by Wendell Berry and write a reaction paper with their comments on each fallacy. Further, they must conduct Google searches for definitions of sustainable agriculture and Integrated Pest Management and provide their own definitions of the terms. Class discussions on these readings are held before and during field trips. The attachment “Field Survey” contains the course’s syllabus.
The course is scheduled for summer of 2006 and in alternate years thereafter. The main objective is to provide students with “real world” experiences with multiple aspects of field research on agronomic approaches to crop, ornamental and vegetable production. These experiences allow students a better understanding of how sustainable agriculture fits into the larger picture of crop, ornamental, and vegetable production.
TU: The major expenses for tomato production include plastic to cover the tomato beds ($85/roll, and one farmer uses between 4-5 rolls), and drip irrigation tape. Water is another expense, where irrigating for an hour or more a day is not uncommon. A key decision for the farmer each year is whether to invest in the plastic and irrigation tape. In years where there has been plenty of rain, the investment is wasted; however, if there is a dry spring and summer, a crop cannot be made without it. Other inputs include fertilizer that is applied through the drip tape, Treflan, and then Round-up to clean the fields. None of the farmers contacted used fumigants.
AU: An economic analysis of the different growing systems was conducted using the current Alabama Cooperative Extension tomato budget (Alabama Cooperative Extension System. Vegetable Planning Budgets, Alabama, 2005. Auburn University Dept of Agricultural Economics & Rural Sociology. AEC-BUD 2-2, January 2005). The budget was modified to reflect the actual growing systems used in the studies. All systems included winter cover crop costs and no fumigation. Fumigation is a common commercial system procedure that was not included in any of the budgets. If used, the inclusion would add $520/acre of additional cost. Yields for the different systems were converted to boxes per acre using a factor of 10.89 (experimental plots were 160 square feet and 1 box equals 25 pounds).
Our economic analysis indicates that the cost of growing on plastic verses a the integrated cover crop and no-till system is $441/ac. The use of BioYield or Equity adds $55/ac or $31/ac respectively. Harvest costs are considered to be variable costs in this analysis as they are yield dependent. For simplicity, all other growing costs up to the point of harvest (and including the cost of removing plastic) are considered fixed costs. Considering the reduced input cost of the integrated system, at a market price of $8/box, the yield of the integrated system could be 6.2% less than the conventional plastic system to result in the same net revenue. At a market value of $10/box, this “break even” point for the integrated system is 4.25% less yield than the conventional system.
One key question about our work is the following. What would be the economic effect of using the integrated system? At a market price of $10/box, a yield reduction of 60 and 63 boxes per acre for the integrated BioYield and Equity systems, respectively, would be economically equivalent to the standard plastic system. If the cost of fumigation were to also be included, these figures would more than double.
As discussed earlier, the yield of the integrated system increased during the study. The best yield was at Cullman in year three where one of the integrated systems yielded 5% less than the conventional control. Based on the breakeven figures given above, this yield reduction would result in the same net revenue as the conventional system at a market price of about $9 per 25 lb box. Market prices in Alabama during the season range from $8 to $12 per box. Hence, using the integrated system can result in profitability (net revenue) equivalent to the conventional system.
TU: Information will be provided in amended report.
AU: As a result of this project—and the financial need to reduce input costs such as fumigation—growers currently use cover crop rotations in the tomato production systems. According to our interviews, all growers utilize biologicals when feasible in irrigation to reduce fertilizer costs. They are also looking at equipment that will reduce tillage, which may result in further cooperation from local experiment stations.
Areas needing additional study
AU: Our results indicate that improvements in yield occurred each year that the integrated system was used. During the 3 year period some changes in the system were made each year. For example in 2004, the subsoil shank was added, and in 2005 the effects of summer crops established in 2004 were evaluated. We believe that when all components of an integrated sustainable cropping system have been optimized, yields would increase for several years upon repeated use of the system. Hence, the research conducted here constitutes “proof of concept” research. Because the best yields with the integrated system result in net income similar to the conventional plastic system, further research is warranted. Such research should further investigate specific tactics such as other summer cover crops and mixed vegetable production.