Progress 07/15/07 to 07/14/09

Outputs
OUTPUTS: NON-TECHNICAL SUMMARY: The practice of organic farming has been gaining popularity among vegetable producers, especially near urban markets where there has been a growing demand for organically grown fresh produce and processed food products, and because of their premium price in the market. The one year project was to initiate research to develop best management practices and economic budgets for mitigating insect pests, diseases and weeds and for improving soil health and vegetable crop productivity in the southeastern U.S. OBJECTIVES: This project was initiated in August 2007 as a multi-disciplinary team research effort from Alabama A&M University. The funding enabled our research team to establish four cover crop plots including a fallow control at the Winfred Thomas Agricultural Research Station (WTARS), and to evaluate the effect of the cover crops on soil health, pest and diseases on vegetable through two main objectives: (1) to evaluate cover crops species on soil quality particularly on microbial population, weeds and diseases on organic vegetable production (2) and, to evaluate the economic (cost-benefit) outcomes of this system. APPROACH: The site for the study was an acre lot within a five-acre block set aside for fifteen years for organic production. In summer 2007, the field was planted with a mixture of Iron clay peas and sudan-sorghum hybrid seeds. In preparation for cover crops planting, Iron clay peas and sudan-sorghum hybrid mixture was mowed and laid on the soil surface. In fall 2007, four cover crops (crimson clover (CC), rye, hairy vetch (HV), and Austrian winter peas (AWP) and were planted and arranged in a randomized complete block with three replications. In May 2008 cover crops were harvested and incorporated into soil as green manure. The plots were planted with tomato and pepper seedling, and cowpea seeds into the mulch under a no-till system. All plants were fertilized with pelletized poultry litter (PL), and with Multibloom and Pinnacle through drip irrigation. Weed control in the plots was done using cotton gin trash, and occasionally by manual weeding. Insect pests and tomato hornworm were controlled with Neem oil and Bacillus thuringiensis sprays. To evaluate cover crops species and their effects on soil quality particularly microbial population, soils were sampled in March 2008 and 2009, approximately 2 weeks after the cover crops were incorporated, and before PL application. Each year a composite sample was taken from each treatment at two depths. Soils were analyzed for C and N by dry combustion using an Elementar CNS analyzer. The enzymatic activity was assayed on duplicate less than 2mm filed-moist samples at their optimal at their optimal pH values. Disease assessment was done at 9 weeks after planting and at harvest using a scale of 0 to5 where 0 is no disease and 5 is 81 to 100 percent symptomatic foliage or fruit or dead plant. Cover crop and weed biomass were taken prior to cover crop mowing, and fruit yield at harvest. All data were subjected to the analysis of variance using GLM procedure of SAS and treatment means were separated using Tukey's test at 5 percent probability. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
IIMPACT: The parameters analyzed responded as expected for this type of treatment system. The yield of tomato, cowpea and pepper obtained under this system were above the average yields of conventional production in the state of Alabama. The higher tomato yields were found in rye and HV as compared to fallow plots from the first year trial. Inconsistent yield data was obtained in year 2 due to very high rain fall and persistent cloudiness that resulted in crop failure over fifty percent of the trial. However, CC outperformed both HV and fallow treatments on pepper production. Pepper yield on rye was better than on AWP plots. Cowpea yielded high under fallow and AWP. Disease and weed. Incidence of bacterial leaf and early blight were observed in tomato, although there was no significant difference between cover crop treatments. Fruit rot was significantly lower in HV and AWP plots compared to the fallow plots. There was a significant difference in weed biomass between the cover crop and the fallow plot, whereas no difference was observed between cover crops biomass. The high weed suppression observed under cover crops seems to be resulting from the cover crops mulch. The most destructive pests observed on tomato were armyworms, and hornworms. Late season tomatoes were heavily damaged by leaf-footed bug resulting in fruit scarring. Soil quality. Initial soil analyses show that soil chemical properties did not vary consistently among cover crops. While no significant difference was observed for selected soil nutrients under cover crops, total P and acid phosphatase were significantly affected by cover crops the first year. The highest P availability was found under CC, which was statistically higher than HV, AWP, rye, and fallow. The concentration of SOC and N were significantly impacted by the cover crop and the no-till system. The enzyme activities are often used as indices of microbial activities that provide a useful tool to monitor long-term soil quality potentials. The enzyme activities were used in this study to evaluate the microbial activity. For the preliminary study only two enzyme assays (acid phosphatase and glucosidase) were used based on their importance in nutrient cycling and organic matter decomposition. The results from this study show no significant differences among the studied enzymes except for acid phosphatase which was significantly different the first year of the study at 0-5 cm depth. However, HV and the AWP cover crops showed higher enzyme activities in year 2 and in both depths. Higher enzymes activities were found in the surface horizon than in subsurface horizon which can be attributed to low microbial activities with depth, related to decrease in OM. A field day was held at the WTARS (August 2009), involving a wide array of small organic, conventional, transitioning farmers and vegetable gardeners. The results obtained from this project could help to develop practical strategies for soil and pest management in organic farming and to identify the cover crop most adapted to the Southeastern U.S region. There is an ongoing research with different mulches for weed control with cover crop treatment as the base line.

Publications

• PUBLICATIONS AND PRESENTATIONS TO DATE 1PUBLICATIONS AND PRESENTATIONS TO DATE 1. Nyochembeng,L.M., R.N. Mankolo, S.R. Mentreddy and G. Mayalagu. 2009. Effect of fall cover crops on tomato and pepper diseases and fruit yield under organic production in North Alabama. Phytopathology 99:S95.
• 2. Nyochembeng,L.M., R.N. Mankolo, S.R. Mentreddy and G. Mayalagu. 2009. Effect of fall cover crops on tomato and pepper diseases and fruit yield under organic production in North Alabama. Annual Conference of the American Phytopathological Aug. 2-5, 2009. Society, Portland, OR. 3. Mankolo R.N, L.M. Nyochembeng, S.R. Mentreddy, R. Ward and G. Mayalagu. 2009. Cover crop effect on nutrient availability and vegetable production under organic and conventional production systems. ASA-CSSA-SSSA Annual Meetings, Nov. 2-7, 2009, Pittsburgh, PA, (Agronomy Abstr)

Progress 07/15/07 to 07/14/08

Outputs
This report covers the first four months of year 1 of our Integrated Organic Program research project funded in August 2007. This initial funding (bridge grant) enabled our research team to establish four cover crops including a fallow control at the Winfred Thomas Agricultural Research Station (WTARS) in North Alabama, and to evaluate their effect on soil health, pest and diseases in southern peas and tomato. The field site for the study is a one acre lot within a five-acre block set aside for organic certification. Historically, this field has not been cultivated for the last fifteen years and has not been sprayed with any pesticides. In summer 2007, the field was tilled and planted with a mixture of Iron clay peas and a sudan x sorghum hybrid seeds. In preparation for planting the selected cover crops, iron clay peas and sudan x sorghum hybrid mixture was mowed and the residue left on the soil surface. In fall 2007, the field was planted with four cover crop species (crimson clover, rye, hairy vetch, Austrian winter peas) and a fallow control plot. All treatments were arranged in randomized complete block design with three replications. Soil samples were collected from0-5, 5-10, and 10-20cm depths, before cover crop planting and three weeks after cover crop establishment to be analyzed for pH, C, N, P, micronutrients, and microbial population. The results from pH analyses showed no statistical differences between cover species. The pH values varied from 6.19 to 6.73 at 0-5cm depth, 5.60 to 6.60 at 5-10cm depth and t5.32 to 5.51 at 10-20 cm depth. These results were expected since this is a baseline data and the cover crops have been in the field for only three weeks. Currently, an analysis of C, N, P, micronutrients, and microbial population is being performed. Further analysis will include: the impact of this cultural practice on pests and diseases in southern peas and tomato, and economic outcome of the system in relation to crop yield, pest management, and soil quality in 2008.

Impacts
One PhD student is breing trained on how organic practices affect soil microbial community dynamics and distribution of trace elements in soil. The overall immpact of the cover crop will be determined at the completion of field experiments in the 2008 growing season.

Publications

• No publications reported this period