Progress 10/01/00 to 09/30/05
Outputs
A series of related experiments were conducted in this project. In a long-term apple orchard experiment, four groundcover management systems (GMS) have been maintained since 1992 in 2-m wide tree-row strips: Pre-emergence herbicides (Pre-H: diuron + norflurazon + glyphosate in May each year); Post-emergence herbicide (Post-H: glyphosate treatments in May and July each year); mowed-sod (Grass); and composted hardwood bark mulch (Mulch) treatment. We are monitoring yields and fruit quality, rhizosphere soil microbial community species and dynamics (with PCR-DGGE), root morphology, depth distribution and mortality (with rhizotrons), and nitrogen/phosphorous leaching and runoff in each GMS. Soil microbial respiration rates were higher under Mulch than Grass and herbicide GMSs. Surface vegetation in the Grass and Post-H plots altered soil bacterial community composition relative to the other systems. In dendrogram analyses of DGGE band patterns, the Post-H and Grass
treatments comprised one variance cluster, and Pre-H and Mulch treatments another. The soil fungal community was less diverse (fewer DGGE bands) than the bacterial community, and was less strongly affected by GMS, although fungi were more dominant in the Mulch plots. The effects of GMS on soil microbial abundance, activity, and composition were associated with observed differences in soil organic matter inputs and turnover, nutrient availability, and apple tree growth and yields among the four GMS treatments. Three projects were completed during 2005 in Finger Lakes winegrape vineyards, comparing geotextiles and bark mulch as vineyard floor management systems (VFMSs). A reflective white geotextile groundcover under vine rows increased the total light on grape clusters by almost 20 percent on sunny days, and doubled pruning weights on vines compared with the standard herbicide vine row treatment. A composted bark mulch VFMS provided more weed suppression than mechanical tillage, but
less than geotextile mulches in an organic vineyard. Harvestable yields of Cabernet Franc were greater because of increased cluster weights in the reflective geotextile treatment relative to a conventional herbicide VFMS, without differences in Brix, pH, or titratable acidity in berries among the different treatments. The costs of establishing geotextiles and bark mulch treatments were four to eight times more than conventional herbicide VFMSs, and the potential benefits of these alternative VFMSs did not compensate for their higher costs. Heritage or antique cider and dessert apples are being evaluated in several plantings, and nitrogen fertilizer effects on yeast-available-N have influenced the quality of ciders fermented from these apple varieties. The heritage varieties have fetched top prices in local markets, and are being recommended for apple growers interested in high value niche market alternatives to conventional varieties.
Impacts
Our orchard soil management research has provided useful information about long-term economic and ecological impacts of different floor management systems, and has shown that residual herbicides that maintain a weed-free soil surface under apple trees have several important disadvantages relative to post-emergence herbicides or biomass mulches. The vineyard research tested non-chemical systems for managing the vineyard floor while improving wine-grape quality and yields. The variety trials identified new fruit crops and varieties for niche-market fruit growers in the NorthEast.
Publications
- Merwin. I., M. Kahn, and R. Byard. 2005. Field performance of grafted and seedling chestnuts in New York. New York Fruit Quarterly 13(1): 33-37.
- Merwin, I., G. Peck and E. Vollmer. 2005. Organic orchards in the Northeast: Progress, practices and problems. Proc. of 3rd Nat. Symp. Of Organic Tree Fruit Research, Chelan, WA.
- Rumberger, A., I. Merwin and J. Thies. 2005. Monitoring changes in microbial community composition in the rhizosphere of five apple rootstock cultivars in an ARD infested soil. Proc. ASA-CSSA-SSA Int. Ann. Mtgs.
- Rumberger, A., I. Merwin and J. Thies. 2005. Is the stoolbed a major source for microbial species in the apple rhizosphere? Proc. Of ASA-CSSA-SSSA N.E. Mtg.
- Yao, S., I.A. Merwin, and J.E. Thies. 2005. Apple rootstocks and pre-plant soil treatments alter soil microbial community composition in a New York orchard. HortScience 40(4):965.
- Yao, S., I.A. Merwin, and M.G. Brown. 2005. Replant apple tree performance, and rhizotron observations of root development, distribution and survival, for three rootstock clones in a New York orchard. HortScience 40(4):949.
- Yao, S. I.A. Merwin, G.W. Bird, G.S. Abawi, and J.E. Thies. 2005. Orchard floor management practices that maintain vegetative or biomass groundcover stimulate soil microbial activity and alter soil microbial community composition. Plant and Soil. 271:377-389.
- Merwin, I.A. 2005. Antique apples: A guide for eaters and growers. Pp. 16-23 in: The best apples to buy and grow (B. Hanson, ed.) Brooklyn Botanic Garden All-Region Guides Handbook No. 181. Science Press, Brooklyn, NY.
- Merwin, I.A. 2005. The makings of a good cider. Pp. 23-26 in: The best apples to buy and grow (B. Hanson, ed.) Brooklyn Botanic Garden All-Region Guides Handbook No. 181. Science Press, Brooklyn, NY.
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Progress 01/01/04 to 12/31/04
Outputs
Several ongoing experiments are described in this report. In a long-term apple orchard experiment, four groundcover management systems (GMS) have been maintained since 1992 in 2-m wide tree-row strips: Pre-emergence herbicides (Pre-H: diuron + norflurazon + glyphosate in May each year); Post-emergence herbicide (Post-H: glyphosate treatments in May and July each year); mowed-sod (Grass); and composted hardwood bark mulch (Mulch) treatment. We are monitoring yields and fruit quality, rhizosphere soil microbial community species and dynamics (with PCR-DGGE), root morphology, depth distribution and mortality (with rhizotrons) in each GMS. Soil microbial respiration rates were higher under Mulch than Grass and herbicide GMSs. Surface vegetation in the Grass and Post-H plots altered soil bacterial community composition relative to the other systems. In dendrogram analyses of DGGE band patterns, the Post-H and Grass treatments comprised one variance cluster, and Pre-H and
Mulch treatments another. The soil fungal community was less diverse (fewer DGGE bands) than the bacterial community, and was less strongly affected by GMS, although fungi were more dominant in the Mulch plots. The effects of GMS on soil microbial abundance, activity, and composition were associated with observed differences in soil organic matter inputs and turnover, nutrient availability, and apple tree growth and yields among the four GMS treatments in this experiment. Three new projects were initiated during 2004 in Finger Lakes region wine-grape vineyards, testing geotextiles and bark mulch as vineyard floor management systems (VFMSs). A reflective white geotextile groundcover under vine rows increased the total light on grape clusters by almost 20 percent on sunny days. A composted bark mulch VFMS provided more weed suppression than mechanical tillage, but less than geotextile mulches in an organic vineyard. Harvestable yields of Cabernet Franc were about 10 percent greater in
the reflective geotextile treatment relative to a conventional herbicide VFMS at two vineyards, without observable differences in Brix, pH, or titratable acidity in berries among the different treatments. The costs of establishing geotextiles and bark mulch treatments were four to eight times greater than conventional herbicide VFMSs, and additional research is planned to determine whether the potential benefits of these alternative VFMSs will compensate for their higher costs.
Impacts
Our orchard soil management research to date provides useful information about long-term economic and ecological impacts of different floor management systems, and has shown that residual herbicides that maintain a weed-free soil surface under apple trees have several important disadvantages relative to post-emergence herbicides or biomass mulches. The vineyard research may provide non-chemical systems for managing the vineyard floor while improving wine-grape quality and yields.
Publications
- Greene, D. et al. 2004. Multidisciplinary evaluation of new apple cultivars: The NE-183 regional project. Jnl. of Amer. Pomol. Soc. 58(2):61-64.
- Hampson, C.R. et al. 2004. Performance of Braeburn, Golden Delicious and Yataka Fuji apple on Mark and M.9 rootstocks at multiple locations across North America. Jnl. of Amer. Pomol. Soc. 58(2):78-89.
- Leinfelder, M.M., I.A. Merwin, G. Fazio and T. Robinson. 2004. Resistant rootstocks, preplant compost amendments, soil fumigation, and row repositioning for managing apple replant disease. HortScience 39(4):841.
- Miller, S., R. McNew, R. Belding, L. Berkett, S. Brown, J. Clements, J. Cline, W. Cowgill, R. Crassweller, E. Garcia, D. Greene, G. Greene, C. Hampson, I. Merwin, R. Moran, T. Roper, J. Schupp, and E. Stover. 2004. Performance of apple cultivars in the 1995 NE-183 regional project planting: II. Fruit quality characteristics. Jnl. of Amer. Pomol. Soc. 58(2):65-77.
- Rumberger, A., S. Yao, I.A. Merwin, E.B. Nelson and J.E. Thies. 2004. Rootstock genotype and orchard replant position rather than soil fumigation or compost amendment determine tree growth and rhizosphere bacterial community composition in an apple replant soil. Plant and Soil 264:247-260.
- Wargo, J.M., I.A. Merwin and C.B. Watkins. 2004. Nitrogen fertilization, midsummer trunk girdling, and AVG treatments affect maturity and quality of Jonagold apples. HortScience 39(3):493-500.
- Yao, S., I.A. Merwin, G.W. Bird, G.S. Abawi, and J.E. Thies. 2005. Orchard groundcover management practices that maintain soil vegetative groundcover stimulate soil microbial activity and alter soil microbial community composition. Plant and Soil (in press).
- Yao, S., I.A. Merwin, J.E. Thies, and G. Abawi. 2004. Groundcover management systems influence soil microbial community composition in an apple orchard. HortScience 39(4):842.
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Progress 01/01/03 to 12/31/03
Outputs
Two ongoing experiments are described in this report. In Nov. 2001, Empire apple trees on five rootstocks (M.26, M.7, G.16, CG.6210, and G.30) were planted into four preplant soil treatments--commercial compost at 492 kg/ha soil incorporated and 492 kg/ha surface-applied; soil fumigation with 400 liters/ha of 1,3-dichloropropene plus chloropicrin five weeks prior to replanting; compost plus fumigant combination; and untreated controls--at an apple replant disease (ARD) site in Ithaca, NY. Trees were replanted in rows perpendicular to, and either in or out of, previous orchard rows. N-P-K fertilizer was applied to all non-compost treatments to compensate for nutrients in compost treatment. After two growing seasons, the rootstock factor has contributed most to tree-growth differences. CG.6210 rootstock supported greater growth in trunk diameter, central leader height, and lateral shoot growth, regardless of preplant soil treatments and replant position. Trees on M.26
grew least over two years. Replant growth was greater in old grass lanes than in old tree rows, despite higher root-lesion nematode populations in previous grass lanes. Growth responses to preplant soil fumigation were negligible. Preplant compost did not increase tree growth during year one, but did increase lateral branch growth in year two. Results thus far suggest that replanting apple trees out of the old tree-row locations, and using ARD tolerant rootstocks such as CG.6210, may be more effective than soil fumigation for control of ARD in some sites. In another apple experiment, 4 groundcover management systems (GMS) have been maintaines since 1992 in 2-m wide tree-row strips: Pre-emergence herbicides (Pre-H: diuron + norflurazon + glyphosate); Post-emergence herbicide (Post-H: glyphosate); mowed-sod (Grass); and composted hardwood bark mulch (Mulch) treatment. In May and Sept. 2003, we sampled topsoil beneath trees in each GMS, and used PCR-DGGE and sequencing to characterize
soil microbial community composition. Mulch had more culturable soil bacteria than the Pre-H treatment. Soil in Grass plots had the most culturable fungi. Soil microbial respiration rates were higher under Mulch than Grass and herbicide GMSs. Surface vegetation in the Grass and Post-H plots strongly influenced soil bacterial community composition. In Principal Component Analyses, Post-H and Grass treatments comprised one variance cluster, and Pre-H and Mulch treatments another. The soil fungal community was less diverse (fewer DGGE bands) than the bacterial community, and was less affected by GMS. Treatments with more surface vegetation (Post-H and Grass) also had more free-living and phyto-nematodes. A total of 47 clones from 12 DGGE bands yielded 31 unique DNA sequences. Of these, 15 were novel sequences with no matches in the GenBank (NCBI) database. Another 10 (27 clones) could be matched with known fungal species at 96-100 percent identity. The primer pair used, ITS1F/ITS2,
amplified a considerable number of Basidiomycetes and Ascomycetes, but there was no amplification for Zygomycetes and Oomycetes.
Impacts
Our research to date indicates that several new clonal apple rootstocks may provide effective alternatives to soil fumigation, with potential benefit to fruit growers and the environment. Information about soil microbial species and functional differences after 12 years of alternative GMSs provides useful information about long-term ecologicl impacts and sustainability of different orchard floor management systems.
Publications
- Merwin, I.A. 2003. Orchard Floor Management Systems. Pp. 303-318 in: Apples: Botany, Production and Uses (D.C. Ferree and I. Warrington, eds.) CABI Publ., Wallingford, England.
- Merwin, I.A. 2003. Orchard floor management. Pp. 195-202 in: The Concise Encyclopedia of Temperate Tree Fruits (S. Singha and T. Baugher, eds.) Haworth Press, Binghampton, NY.
- Merwin, I.A. , R. Byard, and K.W. Pomper. 2003. Survival, growth, and establishment of grafted pawpaws in upstate New York. HortTechnology 13(3): 421-422.
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Progress 01/01/02 to 12/31/02
Outputs
The objectives of this project are: 1. Develop and implement a comprehensive system for diagnosis and sustainable management of soilborne apple replant disease and related problems in New York orchards; 2. Investigate and integrate orchard soil and nutrition management systems that improve fruit quality, optimize tree productivity and health, protect and conserve vital soil resources, and minimize surface or groundwater pollution by nitrogen and soil erosion; 3. Improve weed management strategies by evaluating the interactions among groundcover vegetation, fruit tree physiology and productivity, and selected pests of tree fruits; and 4. Evaluate new apple varieties, alternative fruit crops such as Asian chestnuts and pawpaws, and new uses for traditional fruits such as apples intended for fermented cider production. A new experiment in apple replant management was initiated in 2002, evaluating the resistance or tolerance of various apple rootstocks (M.9, M.7, M.26,
G.16, CG.30, and CG.6210) and the influence of previous tree row position on subsequent growth and yields of apple in an old orchard site. Tree growth was relatively more stunted on most rootstocks planted where the previous tree rows were located, relative to the previous grass drive lanes of the old orchard. Two of the new rootstock clones (CG.6210 and CG.30) performed better in the old tree rows than the conventional rootstocks. In another experiment, evaluations are continuing for traditional European high-tannin apple varieties (bittersweets and bittersharps) used for fermented cider production. Under typical climatic conditions in upstate New York, these cider apples are consistently ripening two to four weeks earlier than they do in France and England, responding to more rapid seasonal accumulation of heat units in our more continental climate. The tannin content of these varieties has also been lower under our growing conditions, with potential implications for the antioxidant
and nutritional value of ciders made from these apples. Heat stress and fruit damage to well-exposed apples have been observed for many of the traditional European cider apples during the past two summers in central New York.
Impacts
Orchard replant problems are serious and common worldwide when fruit-growers attempt to establish modern high-density plantings of new and more profitable apple varieties. In the past, soil fumigants such as methyl bromide have been used to manage apple replant disease, but safer and more sustainable alternatives are badly needed for this problem. Our research to date indicates that several new apple rootstock clones may provide effective alternatives to soil fumigation, with potential benefit to fruit growers and the environment.
Publications
- Merwin, I.A. 2002. Adaptive soil and nutrition management in Northeast orchards. Proceedings of the New England Fruit Growers Mtg. Jan. 2002. Sturbridge, MA.
- Merwin, I.A. 2002. Developing an integrated program for diagnosis and control of replant problems in New York orchards. Proceedings of the New England Fruit Growers Mtg. Jan. 2002. Sturbridge, MA.
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Progress 01/01/01 to 12/31/01
Outputs
The objectives of this new project are: 1. Develop and implement a comprehensive system for diagnosis and sustainable management of soilborne apple replant disease and related problems in New York orchards; 2. Investigate and integrate orchard soil and nutrition management systems that improve fruit quality, optimize tree productivity and health, protect and conserve vital soil resources, and minimize surface or groundwater pollution by nitrogen and soil erosion; 3. Improve weed management strategies by evaluating the interactions among groundcover vegetation, fruit tree physiology and productivity, and selected pests of tree fruits; and 4. Evaluate new apple varieties, alternative fruit crops such as Asian chestnuts and pawpaws, and new uses for traditional fruits such as apples intended for fermented cider production. A comprehensive statewide survey of biological and chemical controls for apple replant disease was completed in 2001, demonstrating that management
and site variability were important factors in this disease complex that often determined responses to preplant soil treatments. Diagnostic preplant bioassays predicted tree growth and yield gains of about 50 percent to soil fumigation at 19 sites; but subsequent responses to these soil treatments were insignificant in most orchards. In another study, soil physical properties affecting water infiltration and retention were measured after eight years of different orchard groundcover management systems (GMSs). Extensive compaction was observed in soil beneath grass, attributed to frequent machinery traffic for mowing of that GMS. Infiltration and porosity were improved in a composted bark mulch treatment. In stable isotope N-15 studies at the same test site, the release, retention, partitioning and losses of N were quantified and compared in four GMSs. Two herbicide systems )pre- and post-emergence) consistently released more N to surface and groundwaters through runoff and subsurface
drainage in comparison with mowed sod and bark mulch treatments. After four years of very minimal fertilizer N additions (only 41 grams of N-15 per hectare annually), mature apple trees increased their affinity and uptake of isotopically labeled potassium nitrate, with rapid appearance of fertilizer N in aboveground tissues following May, July and September treatments. Groundcover vegetation also rapidly assimilated fertilizer N, at higher concentrations than leaves and stem of apple trees. Yields and fruit size remained excellent despite the negligible fertilizer N inputs. In a test planting of traditional European bittersweet and bittertart apples for high quality hard cider production, their regional climate responses, precocity and productivity, storage and after-ripening characteristics, and pre-fermentation juice characteristics are being evaluated. These apples ripen several weeks earlier in New York than in France and England. Most after-ripened and remained in good condition
after 2 to 4 months at 3-5 degrees C in regular air. Test fermentations are underway at a local cidery.
Impacts
Our data on N cycling and losses in orchards will provide essential information for nutrient budgets for N in orchards, that is essential to protect soil and water quality. Our apple replant disease research has shown inconsistent responses to chemical treatments of orchard soils where apple replant disease has been a problem, and we are investigating non-chemical alternatives to soil fumigation. Our cider apple research may lead to new uses and value added products for apple growers and processors.
Publications
- Merwin, I.A., Byard, R., Robinson, T.L., Carpenter, S, Hoying, S.A., Iungerman, K.A. and Fargione, M. 2001. Developing an integrated program for diagnosis and control of replant problems in New York apple orchards. New York Fruit Quarterly 9(1):11-15.
- Merwin, I.A. Hopkins, M.A., and Byard, R.B. 2001. Groundcover management influences nitrogen release, retention, and recycling in a New York apple orchard. HortScience. 36(3):451.
- Oliveira, M.T., and Merwin, I.A. 2001. Soil physical conditions in a New York orchard after eight years under different groundcover management systems. Plant and Soil. 234:233-237
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