@article{bulluck_ristaino_2002, title={Effect of Synthetic and Organic Soil Fertility Amendments on Southern Blight, Soil Microbial Communities, and Yield of Processing Tomatoes}, volume={92}, DOI={10.1094/PHYTO.2002.92.2.181}, abstractNote={Soil fertility amendments, including composted cotton-gin trash, swine manure, a rye-vetch green manure, or synthetic fertilizers, were applied to subplots and tillage on bare soil; or tillage followed by surface mulch with wheat straw were applied to main plots to determine the effect on the incidence of southern blight caused by Sclerotium rolfsii, yield of processing tomato, and soil microbial communities. The amendment-tillage interaction was significant in 1997 and disease incidence was 67% in tilled bare soil receiving synthetic fertilizers; whereas disease incidence was 3, 12, and 16% in surface-mulched plots amended with a composted cotton-gin trash, swine manure, or a rye-vetch green manure. The amendment effect was significant in 1998, and disease incidence was 61% in plots receiving synthetic fertilizer and was 23, 44, and 53% in plots receiving cotton-gin trash, swine manure, or rye-vetch green manure, respectively. In 1997, yields were highest in tilled surface-mulched plots amended with synthetic fertilizers, cotton-gin trash, or swine manure, respectively. In 1998, yields were low in all plots and there were no significant differences in yield due to treatment. Propagule densities of antagonistic soil fungi in the genus Trichoderma were highest in soils amended with composted cotton-gin trash or swine manure in both years. Propagule densities of fluorescent pseudomonads in soil were higher in plots amended with organic amendments than with synthetic fertilizers in both years. Propagules densities of enteric bacteria were elevated in soils amended with raw swine manure biosolids in both years. Our research indicates that some organic amendments, such as cotton-gin trash, reduced the incidence of southern blight in processing tomato and also enhanced populations of beneficial soil microbes.}, number={2}, journal={Phytopathology}, author={Bulluck, L. R. and Ristaino, J. B.}, year={2002}, month={Feb}, pages={181–189} }
 @article{bulluck_barker_ristaino_2002, title={Influences of organic and synthetic soil fertility amendments on nematode trophic groups and community dynamics under tomatoes}, volume={21}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0036784082&partnerID=MN8TOARS}, DOI={10.1016/S0929-1393(02)00089-6}, abstractNote={Research was conducted to examine the effects of organic and synthetic soil amendments and tillage on nematode communities in field soils planted to tomato (Lycopersicon esculentum) at two locations. The experimental design was a replicated split plot with chisel-plow tillage and bare-soil or chisel-plow tillage and surface mulch with wheat straw as main plots, and soil amendments of synthetic fertilizer, composted cotton-gin trash, swine manure, or a rye-vetch green manure as subplots. Tillage did not affect free-living or plant-parasitic nematode community dynamics, but soil amendments had a large impact on nematode community structure and diversity. Populations of bacterivorous nematodes mainly in the Rhabditidae and Cephalobidae, and fungivorous nematodes were greater after planting in soils amended with swine manure, composted cotton-gin trash, or rye-vetch, than in soils amended with synthetic fertilizer at both locations. Populations of nematodes in these trophic groups decreased through time in each year. Populations of Meloidogyne incognita in soil were not affected by soil amendments, but increased through time at each location. Root-gall indices were lower in plots containing swine manure or cotton-gin trash than in those with synthetic fertilizer or rye-vetch during the second season. The combined nematode maturity index values were greater at planting in soils amended with rye-vetch or fertilizer than in soils with swine manure and composted cotton-gin trash. Shannon’s diversity index decreased over time for both years at one location, regardless of soil amendment. At the second location, the Shannon’s diversity index decreased only in the second year. Use of descriptive indices, including the Enrichment index, structure index, and channel index provided useful information about the effects of organic amendments on the structure of nematode communities in tomato field soils.}, number={3}, journal={Applied Soil Ecology}, author={Bulluck, L.R and Barker, K.R and Ristaino, J.B}, year={2002}, month={Sep}, pages={233–250} }
 @article{bulluck_brosius_evanylo_ristaino_2002, title={Organic and synthetic fertility amendments influence soil microbial, physical and chemical properties on organic and conventional farms}, volume={19}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0036160296&partnerID=MN8TOARS}, DOI={10.1016/S0929-1393(01)00187-1}, abstractNote={Field experiments were conducted to examine the effects of organic and synthetic soil fertility amendments on soil microbial communities and soil physical and chemical properties at three organic and three conventional vegetable farms in Virginia and Maryland in 1996 and 1997. Two treatments, including either an alternative organic soil amendment (composted cotton-gin trash, composted yard waste, or cattle manure) or synthetic soil amendment (fertilizer) were applied to three replicated plots at each grower field location. Production history and time affected propagule densities of Trichoderma species which remained higher in soils from organic farms. Propagule densities of Trichoderma species, thermophilic microorganisms, and enteric bacteria were also detected in greater numbers in soils amended with alternative than synthetic amendments, whereas propagule densities of Phytophthora and Pythium species were lower in soils amended with alternative than synthetic fertility amendments. Concentrations of Ca, K, Mg, and Mn were higher in soils amended with alternative than synthetic fertility amendments. Canonical correlations and principle component analyses indicated significant correlation between these soil chemical factors and the biological communities. First-order canonical correlations were more negative in fields with a conventional history, and use of synthetic fertilizers, whereas canonical correlations were more positive in fields with a history of organic production and alternative soil amendments. In the first year, yields of corn or melon were not different in soil amended with either synthetic or organic amendments at four of six farms. In the second year, when all growers planted tomatoes, yields were higher on farms with a history of organic production, regardless of soil amendment type. Alternative fertility amendments, enhanced beneficial soil microorganisms reduced pathogen populations, increased soil organic matter, total carbon, and cation exchange capacity (CEC), and lowered bulk density thus improving soil quality.}, number={2}, journal={Applied Soil Ecology}, author={Bulluck, L.R and Brosius, M and Evanylo, G.K and Ristaino, J.B}, year={2002}, month={Feb}, pages={147–160} }