Cranberry plants exclusively utilize ammonium forms of nitrogen. Nitrifi cation of applied ammoni... more Cranberry plants exclusively utilize ammonium forms of nitrogen. Nitrifi cation of applied ammonium and subsequent leaching through sandy soils is a potential problem for growers. Peat, sand, and striped soils were collected in cranberry beds in central Wisconsin and soil pH was adjusted to 3.5, 4.5, or 5.5. Twenty-fi ve grams of dry soil was placed in fl asks and half the fl asks were sterilized. Distilled water was added to half of the samples, and the other half received 15 N-labeled ammonium. Flasks were incubated at 20°C for up to 70 days. Striped soils showed no nitrifi cation at pH 3.5 or 4.5 during the 70 day incubation. At pH 5.5, nitrifi cation began at 20 days and was almost complete at 70 days. Nitrifi cation did not occur at any pH in sandy soils. This research suggests that ammonium fertilizer applied to cranberry is likely taken up before nitrifi cation would occur. 15-25 cm from plots treated 25 May 1995 with either hexazinone liquid formulation of Velpar L at 1.1 kg/ha, or as a granular in Pronone 10G, Pronone MG at 11.1 kg/ha, or Diammonium Phosphate (DAP) at 220 kg/ha impregnated with Velpar L at 1.1 kg/ha and an untreated control. The hexazinone liquid had the most leaching, the Velpar DAP formulation had the least leaching, and the Pronone formulation were intermediate. If hexazinone leaching into groundwater is a concern a particular site, then the Velpar/DAP fertilizer or Pronone formulations should be used over the liquid formulation. This project was done under a low rainfall year, 1995, and it should be reassessed with the new Velpar DF formulation and irrigation.
Journal of the American Society for Horticultural Science, Sep 1, 2000
One-year-old potted 'Mutsu' apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] tr... more One-year-old potted 'Mutsu' apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] trees on scion invigorating Malling-Merton 111 (MM.111) and scion dwarfing Malling 9 (M.9) rootstocks were grown outdoors in containers under three levels of water availability (irrigated at -20, -80, and -200 kPa) to investigate the effects of soil water availability on combined soil/root (rhizosphere) respiration rates, and developmental morphology of root systems. Rhizosphere respiration was measured with a portable infrared gas analyzer, and root biomass was estimated by electrical capacitance. These nondestructive measurements were compared with final root dry weights of harvested trees, to determine their reliability for estimating relative differences in root biomass. Water stress reduced final biomass similarly for both rootstocks, but the relative reduction in shoot growth was greater for MM.111. Root to shoot ratios were higher and average specific root respiration was lower for M.9 rootstock compared with MM.111. M.9 appeared to be more tolerant of water stress then MM.111, due to reduced canopy transpiration relative to root system mass. Water stress increased root to shoot ratios, specific root length, and the carbohydrate costs of root maintenance as indicated by specific respiration rates. Root dry weight (DW) was better correlated to rhizosphere respiration than to root electric capacitance. The observed r 2 values between root capacitance and root DW were as high as 0.73, but capacitance measurements were also influenced by soil water content and rootstock type. Electrical capacitance estimated total root biomass more accurately for M.9 than for MM.111.
Leaf impressions were made from two short-lived (4 and 5 d) inbreds, a longlived (11 d) inbred, a... more Leaf impressions were made from two short-lived (4 and 5 d) inbreds, a longlived (11 d) inbred, and their hybrids (8 and 9 d) of Antirrhinum majus L. using Super Glue and glass microscope slides. Leaves were taken from mid stem, pressed on glass slides (under side down), spread with a small amount of Super Glue, set for 3 to 4 s. Then, the leaf was peeled off leaving a permanent impression in the glue. Slides were placed under a microscope equipped with a video imaging system and computer images were taken to facilitate counting of stomatal complexes. Number of stomata ranged from 10,400 to 21,300 per cm 2 of leaf. A LI-COR LI-3100 area meter (LI-COR, Inc. Lincoln, Neb.) was used to measure total leaf area of 40-cm cut flower stems of each accession. Stomata per flowering stem ranged from 1,074,000 to 2,282,000, with the long-lived inbred having the fewest stomata, the hybrids intermediate with 11% to 21% more, and the shortlived inbreds having 40% to 113% more stomata per stem. It appears long postharvest life of A. majus is associated with flowering stems with fewer stomata per cut stem.
Germanium has been reported as a mineral element affecting plant cell metabolism. Many trials to ... more Germanium has been reported as a mineral element affecting plant cell metabolism. Many trials to supply germanium to fruit have been carried out since tests have confi rmed germanium's role as a medical substance. Supplying germanium to orchards by soil and foliar application was not effective because of loss from rainfall. Also, tree injection with germanium solution required the insertion of a tube to the tree xylem at each injection site. In order to increase germanium absorption by fruit, this study carried out the postharvest dipping of fruit into germanium solution. 'Niitaka' pear (Pyrus pyrifolia) fruit was treated with two types of germanium, GeO (inorganic type) and Ge-132 (organic type), in a concentration of 50 mg•L-1 just after harvest in early Oct. 2004. Flesh browning after peeling the fruit was delayed by germanium treatment, and polyphenoloxidase (PPO) activities were lowered. Postharvest potentials were maintained at high levels for fruit fi rmness, physiological disorders, and decayed fruit during cold storage at 0 to 1 °C for 2 months. Antioxidant and some phenolic compounds were higher than those of control fruit.
Success in the production of seasonal flowering plants requires adequate knowledge of plant growt... more Success in the production of seasonal flowering plants requires adequate knowledge of plant growth patterns and rates. In Easter lilies, pedicel growth is one the components of final plant height. Flower bud growth rates are important from the standpoint of timing of anthesis. To learn more about the localization of growth in Easter lily flower buds and pedicels, we conducted a time course experiment. Buds and pedicels were marked at 1.2 mm intervals using an inked bolt. Distances between ink marks were determined at 3 day intervals. Results indicate that 30 mm flower buds elongate almost exclusively from basal regions of the bud. The basal 1.2 mm segment elongated 16 mm in 20 days, while the apical 1.2 mm segment elongated 0.75 mm in the same period. Larger buds (initially 90 mm) gave similar results, although bud tip growth rate increased to some degree just prior to flowering. Pedicel elongation occurred almost exclusively at the apical end of the pedicel, adjacent to the region of greatest bud growth.
To determine when a paper is to be presented, check the session number in the Program Schedule or... more To determine when a paper is to be presented, check the session number in the Program Schedule or the Conference at a Glance charts. The Author presenting the paper is indicated by an asterisk.
Excessive nitrogen (N) applications can increase surface and water contamination, and leaching lo... more Excessive nitrogen (N) applications can increase surface and water contamination, and leaching losses may occur when N fertilizer rates are too high relative to crop demands and soil N availability. Quantifying nutrient inputs, cycling, and outputs from orchards provides a method to measure surplus of nutrients, particularly N, that may leach or runoff. We conducted a long-term study to develop N budgets based on observed nutrient dynamics under four groundcover management systems (GMSs) with and without N fertilization. Four GMS treatments were randomly assigned to 12 plots and maintained since 1992 in 2-m-wide strips within tree rows: pre-emergence residual herbicide (PreHerb), post-emergence herbicide (PostHerb), mowed-sod (Sod), and hardwood bark mulch (Mulch). We measured system N inputs in fertilizer, mulch biomass, rain, and irrigation water; N outputs in harvested fruit, surface runoff, and subsurface leaching; and internal N cycling from surface vegetation, soil mineralization, leaf fall, and pruned wood. For the year with N fertilizer (2005), the overall N balance was positive (inputs exceeded outputs) in all GMSs but greater in the PostHerb and Mulch treatments. In the year without N fertilizer (2007), the overall N balance was negative for PreHerb and PostHerb and positive for Mulch and Sod treatments. Soil mineralization and recycling groundcover biomass accounted for greater than 60% of internal N fluxes, and harvested fruit represented greater than 70% of N outputs from the system during both years. During the year with N fertilizer, N losses were 1% to 4% and 18% to 22% through surface runoff and subsurface leaching, respectively. During the year without fertilizer, surface runoff N losses were twice the subsurface leaching N losses in all GMSs.
To determine when a paper is to be presented, check the session number in the Program Schedule or... more To determine when a paper is to be presented, check the session number in the Program Schedule or the Conference at a Glance charts. The Author presenting the paper is indicated by an asterisk.
Temperate zone fruit crops undergo bud dormancy which can be described as a mechanism for avoidin... more Temperate zone fruit crops undergo bud dormancy which can be described as a mechanism for avoiding the exposure of tender fl owers and leaves to low winter temperatures. In Kenya, apple growing is mostly hampered by inadequate chilling that causes the plants to have prolonged dormancy leading to poor fl owering and consequently low yield. Although the chilling requirements are obligatory, under subtropical and especially tropical conditions avoidance is possible. To achieve this, it is necessary to select cultivars with low chilling requirements. This has proven effective in Zimbabwe with cultivar Matsu which is grown without a need for artifi cial breaking of dormancy. In Kenya like Zimbabwe, low chilling requiring cultivars such as Anna have been grown successfully. However, for cultivars with high chilling requirements, there is need to apply artifi cial techniques/methods to enhance bud break. Some of the cultural techniques used are: defoliation after harvesting and bending of the shoots holizontally. Defoliation after harvesting has particularly been used successfully in the island of Java in Indonesia and it enables two crops to be grown per year. Root chilling of rootstock has also been found to enhance bud break of the shoot. In addition, chemicals like KNO 3 , mineral oil and thiourea (TU) have been found to be effective in breaking bud dormancy in Kenya. This paper is reviewing the challenges encountered in growing apples in the tropics and Kenya in particular and the progress that has made in addressing them.
Root observations in situ with a rhizotron camera enabled us to compare the performance of apple ... more Root observations in situ with a rhizotron camera enabled us to compare the performance of apple (Malus •domestica Borkh.) trees on 3 rootstock clones planted in a New York orchard with a history of apple replant disease. Visual observations were conducted in situ at monthly intervals during 2 growing seasons through minirhizotron tubes for trees grafted onto 3 rootstocks: M.7 (M.7), Geneva 30 (G.30), and Cornell-Geneva 6210 (CG.6210). There were 3 preplant soil treatments (fumigation, compost amendment, and untreated checks) and 2 tree planting positions (within the old tree rows or in the old grass lanes of the previous orchard at this site). Preplant soil treatments and old-row versus grass-lane tree planting positions had no apparent influence on root systems, whereas rootstock clones substantially influenced root growth and demography. New root emergence was suppressed during the first fruit-bearing year (2004) on all 3 rootstock clones compared with the previous nonbearing year (2003). A root-growth peak in early July accounted for more than 50% of all new roots in 2003, but there was no midsummer root-growth peak in 2004. The median lifespan for roots of CG.6210 was twice that of G.30 and M.7 in 2004. Also, CG.6210 had more roots below 30 cm depth, whereas M.7 had more roots from 11 to 20 cm depth. Trees on CG.6210 were bigger, yielded more fruit, and had the highest yield efficiency in the third year after planting compared with trees on G.30 and M.7 rootstocks. Crop load appeared to inhibit new root development and changed root-growth dynamics during the first bearing year, with a resurgence in new root growth after fruit was harvested in October 2004. Rootstock genotype was the dominant influence on root lifespan and distribution in this study, whereas preplant soil fumigation, compost amendments, and replanting positions had little apparent impact on root characteristics despite their influence on above-ground tree growth and yield.
We conducted 3 years of field tests comparing two chemicals [methyl anthranilate (MA, a natural c... more We conducted 3 years of field tests comparing two chemicals [methyl anthranilate (MA, a natural compound used as a flavor additive) and Keyplex-350 (a proprietary micronutrient formulation)] that were reported to repel birds to exclusionary plastic netting and nontreated plots. Cumulative fruit damage from birds was monitored on sweet and tart cherry (Prunus avium L. and P. cerasus L.), blueberry (Vaccinium corymbosum L.), and wine grapes (Vitis vinifera x labrusca). Initial MA formulations caused injury to fruit and foliage. Two modified MA formulations with microencapsulation and photooxidation inhibitors provided significant reductions in bird damage and fruit splitting on sweet cherries in one of four experiments. A taste panel could not detect MA residues on sweet cherries at harvest. Bird damage was slightly reduced in MA-treated grapes, but damage to blueberries was similar in MA and control treatments. Keyplex did not deter birds from feeding on fruit and caused blemishes on and an unpleasant flavor in treated fruit. Many bird species were observed feeding on these fruit crops during successive years at the three experimental sites. Although these two chemicals have the potential to deter bird depredation, our work suggests that neither is consistently effective against all the frugivorous species in the northeastern United States. Chemical name used: 2-Aminobenzoic acid methyl ester [methyl anthranilate (MA)].
Journal of the American Society for Horticultural Science, Mar 1, 1994
This study was conducted to compare various orchard groundcover management systems (GMSs)-includi... more This study was conducted to compare various orchard groundcover management systems (GMSs)-including a crownvetch "living mulch" (CNVCH), close-mowed (MWSOD) and chemically growth-regulated (GRSOD) sodgrasses, pre-emergence (NDPQT) and two widths of post-emergence (GLY1.5 and GLY2.5) herbicides, hay-straw mulch (STMCH), and monthly rototillage (tilled)-during the first 6 years in a newly established apple (Malus domestica Borkh.) planting. Mean soil water potential at 5 to 35 cm deep varied substantially among treatments each summer, and treatment × year interactions were observed. During most growing seasons from 1986 to 1991, soil water availability trends were STMCH > NDPQT > GLY2.5 > GLY1.5 > tilled > GRSOD > MWSOD > CNVCH. Soil organic matter content increased under STMCH, CNVCH, and MWSOD and decreased under NDPQT and tilled treatments. Water infiltration and saturated hydraulic conductivity after 4 years were lower under NDPQT and tilled, and soil under STMCH and GRSOD retained more water per unit volume at applied pressures approximating field water capacity. Midsummer soil temperatures at 5 cm deep were highest (25 to 28C) in tilled and NDPQT plots, intermediate (22 to 24C) under GRSOD, and lowest (16 to 20C) under CNVCH and STMCH. These observations indicate that long-term soil fertility and orchard productivity may be diminished under pre-emergence herbicides and mechanical cultivation in comparison with certain other GMSs. water retention and availability, bulk density, pore size distribution, temperatures, soil organic matter content, groundcover biomass, and apple root distribution.
Journal of the American Society for Horticultural Science, Mar 1, 1996
Commercial apple (Malus domestica Borkh.) orchards in the northeastern United States receive heav... more Commercial apple (Malus domestica Borkh.) orchards in the northeastern United States receive heavy pesticide inputs and are often located on well-drained soils near surface and groundwater resources. Nonpoint-source water pollution by agrichemicals has been monitored in agronomic crop systems and simulated using computer models and laboratory soil columns, but inadequately studied at field scale in orchards. We monitored the concentrations of agrichemical tracers, nitrate-N, and benomyl fungicide in water samples from two apple orchards under mowed sodgrass (Mowed-Sod), shredded bark mulch (Bark-Mulch), preemergence residual herbicides (Resid-Herb), and postemergence herbicide (Post-Herb) groundcover management systems (GMSs). In one orchard, we evaluated subsurface spatial patterns and flow rates of a weakly adsorbed blue dye (pesticide analog) and potassium bromide (nitrate analog) under trees after six years of Post-Herb and Mowed-Sod treatments. Nitrate and pesticide tracers leached more rapidly and in higher concentrations under Post-Herb treatments, apparently via preferential macropore flowpaths such as root channels, soil cracks, and macrofauna burrows. At another orchard, we monitored subsurface leaching and surface runoff of benomyl and nitrate-N on a whole-field scale. Peak concentrations of benomyl (up to 29 mg•liter-1) and nitrates (up to 20 mg•liter-1) were observed in subsoil leachate under Resid-Herb plots during 1993. In 1994, nitrate concentrations were greater in leachate from all GMSs, with upper ranges from 48 to 66 mg•liter-1 , while benomyl concentrations were lower in all GMSs compared with the previous summer. In surface water runoff during 1993, the highest benomyl concentrations (387 mg•liter-1) and most frequent outflows occurred in Resid-Herb plots. During 1994, benomyl runoff was more frequent in both herbicide GMSs, with concentrations up to 61 mg•liter-1 observed in the Post-Herb plots. Weather patterns, irrigation intensity, differing soil conditions under each GMS, and the turfgrass/clover drive lanes affected the relative frequency and concentrations of benomyl and nitrate leaching and runoff. Preferential bypass flow appeared to be a major subsurface leaching pathway, and erosion sediment an important factor in surface movement of these agrichemicals. Our studies suggest that nitrate-N and benomyl fungicide may be more prone to leaching or runoff from orchard soils under some herbicide GMSs in comparison with mowed sodgrass or biomass mulch systems.
Meadow vole (Microtus pennsylvanicus L.) populations, feeding activity, and damage to young apple... more Meadow vole (Microtus pennsylvanicus L.) populations, feeding activity, and damage to young apple (Malus domestica Borkh.) trees were monitored by direct observation, trap counts, and a feeding activity index in different groundcover management systems (GMSs) for five years in a New York orchard. Vole populations differed greatly among GMSs, with consistently higher populations and more damage to tree trunks in crownvetch (Coronilla varia L.), hay-straw mulch, and red fescue (Festuca rubra L.)sodgrass GMSs. Vole populations were highest in the fall and lowest during the spring seasons each year. Anticoagulant rodenticides and natural predation did not result in adequate control of voles in GMSs that provided favorable habitat for nesting and feeding of this pest. The percent of soil surface vegetation coverage was not, but the amount of groundcover biomass was, a significant predictor of vole populations and damage to trees, independent of groundcover vegetation species. Trunk applications of thiram fungicide were less effective than 40-cm-high plastic mesh trunk guards, but better than no protective measures for controlling vole depredation in groundcover management systems (GMSs) with high rodent populations. A combination of late fall vole trapouts, close and consistent mowing of orchard floor vegetation, tree trunk protection with mesh guards, ample surrounding habitat for natural predators of voles, and suppression of tree row groundcover species with herbicides provided adequate control of meadow voles without the use of rodenticides at this orchard.
Journal of the American Society for Horticultural Science, Sep 1, 1989
Growth chamber evaluations of soil from an orchard replant site showed severe stunting of 'Northe... more Growth chamber evaluations of soil from an orchard replant site showed severe stunting of 'Northern Spy' apple (Malus domestica Borkh.) seedlings grown in field soil (FS) compared with pasteurized soil (PS) from the same site. The FS : PS seedling dry weight ratio of 0.44 indicated a serious replant problem. Leaf nutrient content was generally higher in PS than FS seedlings. Multiple-regression analysis indicated that leaf K and root-lesion nematode (Pratylenchus penetrans Filipjev) primary inoculum accounted for 75% of the variation in FS seedling dry weight. Apple seedling dry weight in FS was 97% of that in PS following a marigold (Tagetes patula L. cv. Sparky) cover crop, and 75% following oats (Avena sativa L. cv. Saia). Root-lesion nematodes were nearly eliminated from the plots with marigold. Other cover crops and a weed-free fallow period were less effective in controlling apple replant disease and/or phytonematodes. Received for publication 21 Sept. 1988. This paper is part of a thesis submitted by I.A.M. in partial fulfillment of the requirements for the MS degree. Thanks to Elizabeth Loder for technical assistance, to W.F. Mai for guidance and provision of growth chamber and laboratory space in the Dept, of Plant Pathology, and to Harris Seeds, Rochester, N .Y ., and International Seeds, Halsey, Ore., for providing 'Sparky' marigold and 'Companion M ix' grass seed, respectively. USDA Hatch Project funds (NYC J55414) helped support this research. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact. 'Graduate student. 2Profcssor.
Journal of the American Society for Horticultural Science, Mar 1, 1994
This study compared various conventional and alternative orchard groundcover management systems (... more This study compared various conventional and alternative orchard groundcover management systems (GMSs)including a crownvetch "living mulch" (CNVCH), close-mowed (MWSOD) and chemically growth-regulated (GRSOD) sodgrasses, pre-emergence (NDPQT) and two widths of postemergence (GLY1.5 and GLY2.5) herbicides, hay-straw mulch (STMCH), and monthly rototillage (tilled)-during 6 years in a newly established apple (Malus domestica Borkh.) planting. Trunk cross-sectional area and fruit yield were higher in STMCH, GLY, and NDPQT, intermediate in tilled, and lower in GRSOD, MWSOD, and CNVCH treatments after 5 years. Despite N and K fertilizer applications, extractable soil N and leaf N concentrations were reduced under MWSOD and GRSOD, and soil K, P, and B concentrations were greater under STMCH. Leaf K concentrations were usually highest in STMCH trees, even when heavily cropped; leaf K declined below the sufficiency range in GLY, NDPQT, and tilled trees as they began to bear fruit. Leaf Ca was marginally deficient in all trees and was unaffected by GMS. Foliar Mn, Zn, and B concentrations declined rapidly in all treatments during 2 years without micronutrient fertilizers. Leaf Cu was higher in herbicide and tilled treatments where seasonal soil water content was intermediate (22% to 27%) and lower where soil was very wet or dry for most of the 1988 growing season. Multiple regression analysis indicated that leaf N and B and soil organic matter in 1990, and mean soil water content during the unusually dry Summer 1988, were the best predictors of fruit yield in 1990. Phytophthora root rot and meadow vole depredation were serious problems in STMCH and CNVCH trees. GMSs greatly affected tree establishment, nutrition, and yield; each system involves tradeoffs among important short-and long-term impacts on the orchard agroecosystem.
We evaluated soil health in apple (Malus × domestica Borkh.) orchards of New York State. Our obje... more We evaluated soil health in apple (Malus × domestica Borkh.) orchards of New York State. Our objectives were to determine a parsimonious set of biological, chemical, and physical indicators for monitoring orchard soil health, and then to relate long-term management practices to soil health, orchard productivity, and ecosystem services. At one study site, four in-row groundcover management systems (GMS)-pre-emergence herbicide, post-emergence herbicide, mowed sod, and bark mulch-have been maintained in a 0.8 ha orchard for 17 years. Discriminant analysis showed that total soil carbon (%C), organic matter (%OM), and bulk density (g•cm-3 , BD) separated the GMS treatments. The %C and %OM were significantly higherand BD significantly lower-in mulched plots compared to the other GMS (P<0.05). Previous reports suggest that higher %C and %OM, and lower BD, indicate healthier soil. In regression analyses, %C and %OM positively correlated, and BD negatively correlated, with trunk cross-sectional area, confirming that healthier soils produce larger trees. While high vigor trees are often inefficient fruit producers, this was not observed in our study. Yield was statistically similar across GMS treatments since 2004; yet, there was a trend for trees in the post-emergence herbicide and mulch treatments to yield more than trees in the pre-emergence herbicide and sod treatments. Average pruning weights did not differ among treatments. We cannot conclude that healthier soil translates to higher profits based on yield alone, but system-wide carbon sequestration was significantly higher in the mulch treatment, where soil OM content doubled from 4.5 to 9% over the 17 years of the study. The mulch treatment had statistically higher carbon storage in the soil and in tree biomass. In agricultural programs where best management practices and/or ecosystem services are subsidized, orchard soils with higher organic carbon could be financially rewarded.
Cranberry plants exclusively utilize ammonium forms of nitrogen. Nitrifi cation of applied ammoni... more Cranberry plants exclusively utilize ammonium forms of nitrogen. Nitrifi cation of applied ammonium and subsequent leaching through sandy soils is a potential problem for growers. Peat, sand, and striped soils were collected in cranberry beds in central Wisconsin and soil pH was adjusted to 3.5, 4.5, or 5.5. Twenty-fi ve grams of dry soil was placed in fl asks and half the fl asks were sterilized. Distilled water was added to half of the samples, and the other half received 15 N-labeled ammonium. Flasks were incubated at 20°C for up to 70 days. Striped soils showed no nitrifi cation at pH 3.5 or 4.5 during the 70 day incubation. At pH 5.5, nitrifi cation began at 20 days and was almost complete at 70 days. Nitrifi cation did not occur at any pH in sandy soils. This research suggests that ammonium fertilizer applied to cranberry is likely taken up before nitrifi cation would occur. 15-25 cm from plots treated 25 May 1995 with either hexazinone liquid formulation of Velpar L at 1.1 kg/ha, or as a granular in Pronone 10G, Pronone MG at 11.1 kg/ha, or Diammonium Phosphate (DAP) at 220 kg/ha impregnated with Velpar L at 1.1 kg/ha and an untreated control. The hexazinone liquid had the most leaching, the Velpar DAP formulation had the least leaching, and the Pronone formulation were intermediate. If hexazinone leaching into groundwater is a concern a particular site, then the Velpar/DAP fertilizer or Pronone formulations should be used over the liquid formulation. This project was done under a low rainfall year, 1995, and it should be reassessed with the new Velpar DF formulation and irrigation.
Journal of the American Society for Horticultural Science, Sep 1, 2000
One-year-old potted 'Mutsu' apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] tr... more One-year-old potted 'Mutsu' apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] trees on scion invigorating Malling-Merton 111 (MM.111) and scion dwarfing Malling 9 (M.9) rootstocks were grown outdoors in containers under three levels of water availability (irrigated at -20, -80, and -200 kPa) to investigate the effects of soil water availability on combined soil/root (rhizosphere) respiration rates, and developmental morphology of root systems. Rhizosphere respiration was measured with a portable infrared gas analyzer, and root biomass was estimated by electrical capacitance. These nondestructive measurements were compared with final root dry weights of harvested trees, to determine their reliability for estimating relative differences in root biomass. Water stress reduced final biomass similarly for both rootstocks, but the relative reduction in shoot growth was greater for MM.111. Root to shoot ratios were higher and average specific root respiration was lower for M.9 rootstock compared with MM.111. M.9 appeared to be more tolerant of water stress then MM.111, due to reduced canopy transpiration relative to root system mass. Water stress increased root to shoot ratios, specific root length, and the carbohydrate costs of root maintenance as indicated by specific respiration rates. Root dry weight (DW) was better correlated to rhizosphere respiration than to root electric capacitance. The observed r 2 values between root capacitance and root DW were as high as 0.73, but capacitance measurements were also influenced by soil water content and rootstock type. Electrical capacitance estimated total root biomass more accurately for M.9 than for MM.111.
Leaf impressions were made from two short-lived (4 and 5 d) inbreds, a longlived (11 d) inbred, a... more Leaf impressions were made from two short-lived (4 and 5 d) inbreds, a longlived (11 d) inbred, and their hybrids (8 and 9 d) of Antirrhinum majus L. using Super Glue and glass microscope slides. Leaves were taken from mid stem, pressed on glass slides (under side down), spread with a small amount of Super Glue, set for 3 to 4 s. Then, the leaf was peeled off leaving a permanent impression in the glue. Slides were placed under a microscope equipped with a video imaging system and computer images were taken to facilitate counting of stomatal complexes. Number of stomata ranged from 10,400 to 21,300 per cm 2 of leaf. A LI-COR LI-3100 area meter (LI-COR, Inc. Lincoln, Neb.) was used to measure total leaf area of 40-cm cut flower stems of each accession. Stomata per flowering stem ranged from 1,074,000 to 2,282,000, with the long-lived inbred having the fewest stomata, the hybrids intermediate with 11% to 21% more, and the shortlived inbreds having 40% to 113% more stomata per stem. It appears long postharvest life of A. majus is associated with flowering stems with fewer stomata per cut stem.
Germanium has been reported as a mineral element affecting plant cell metabolism. Many trials to ... more Germanium has been reported as a mineral element affecting plant cell metabolism. Many trials to supply germanium to fruit have been carried out since tests have confi rmed germanium's role as a medical substance. Supplying germanium to orchards by soil and foliar application was not effective because of loss from rainfall. Also, tree injection with germanium solution required the insertion of a tube to the tree xylem at each injection site. In order to increase germanium absorption by fruit, this study carried out the postharvest dipping of fruit into germanium solution. 'Niitaka' pear (Pyrus pyrifolia) fruit was treated with two types of germanium, GeO (inorganic type) and Ge-132 (organic type), in a concentration of 50 mg•L-1 just after harvest in early Oct. 2004. Flesh browning after peeling the fruit was delayed by germanium treatment, and polyphenoloxidase (PPO) activities were lowered. Postharvest potentials were maintained at high levels for fruit fi rmness, physiological disorders, and decayed fruit during cold storage at 0 to 1 °C for 2 months. Antioxidant and some phenolic compounds were higher than those of control fruit.
Success in the production of seasonal flowering plants requires adequate knowledge of plant growt... more Success in the production of seasonal flowering plants requires adequate knowledge of plant growth patterns and rates. In Easter lilies, pedicel growth is one the components of final plant height. Flower bud growth rates are important from the standpoint of timing of anthesis. To learn more about the localization of growth in Easter lily flower buds and pedicels, we conducted a time course experiment. Buds and pedicels were marked at 1.2 mm intervals using an inked bolt. Distances between ink marks were determined at 3 day intervals. Results indicate that 30 mm flower buds elongate almost exclusively from basal regions of the bud. The basal 1.2 mm segment elongated 16 mm in 20 days, while the apical 1.2 mm segment elongated 0.75 mm in the same period. Larger buds (initially 90 mm) gave similar results, although bud tip growth rate increased to some degree just prior to flowering. Pedicel elongation occurred almost exclusively at the apical end of the pedicel, adjacent to the region of greatest bud growth.
To determine when a paper is to be presented, check the session number in the Program Schedule or... more To determine when a paper is to be presented, check the session number in the Program Schedule or the Conference at a Glance charts. The Author presenting the paper is indicated by an asterisk.
Excessive nitrogen (N) applications can increase surface and water contamination, and leaching lo... more Excessive nitrogen (N) applications can increase surface and water contamination, and leaching losses may occur when N fertilizer rates are too high relative to crop demands and soil N availability. Quantifying nutrient inputs, cycling, and outputs from orchards provides a method to measure surplus of nutrients, particularly N, that may leach or runoff. We conducted a long-term study to develop N budgets based on observed nutrient dynamics under four groundcover management systems (GMSs) with and without N fertilization. Four GMS treatments were randomly assigned to 12 plots and maintained since 1992 in 2-m-wide strips within tree rows: pre-emergence residual herbicide (PreHerb), post-emergence herbicide (PostHerb), mowed-sod (Sod), and hardwood bark mulch (Mulch). We measured system N inputs in fertilizer, mulch biomass, rain, and irrigation water; N outputs in harvested fruit, surface runoff, and subsurface leaching; and internal N cycling from surface vegetation, soil mineralization, leaf fall, and pruned wood. For the year with N fertilizer (2005), the overall N balance was positive (inputs exceeded outputs) in all GMSs but greater in the PostHerb and Mulch treatments. In the year without N fertilizer (2007), the overall N balance was negative for PreHerb and PostHerb and positive for Mulch and Sod treatments. Soil mineralization and recycling groundcover biomass accounted for greater than 60% of internal N fluxes, and harvested fruit represented greater than 70% of N outputs from the system during both years. During the year with N fertilizer, N losses were 1% to 4% and 18% to 22% through surface runoff and subsurface leaching, respectively. During the year without fertilizer, surface runoff N losses were twice the subsurface leaching N losses in all GMSs.
To determine when a paper is to be presented, check the session number in the Program Schedule or... more To determine when a paper is to be presented, check the session number in the Program Schedule or the Conference at a Glance charts. The Author presenting the paper is indicated by an asterisk.
Temperate zone fruit crops undergo bud dormancy which can be described as a mechanism for avoidin... more Temperate zone fruit crops undergo bud dormancy which can be described as a mechanism for avoiding the exposure of tender fl owers and leaves to low winter temperatures. In Kenya, apple growing is mostly hampered by inadequate chilling that causes the plants to have prolonged dormancy leading to poor fl owering and consequently low yield. Although the chilling requirements are obligatory, under subtropical and especially tropical conditions avoidance is possible. To achieve this, it is necessary to select cultivars with low chilling requirements. This has proven effective in Zimbabwe with cultivar Matsu which is grown without a need for artifi cial breaking of dormancy. In Kenya like Zimbabwe, low chilling requiring cultivars such as Anna have been grown successfully. However, for cultivars with high chilling requirements, there is need to apply artifi cial techniques/methods to enhance bud break. Some of the cultural techniques used are: defoliation after harvesting and bending of the shoots holizontally. Defoliation after harvesting has particularly been used successfully in the island of Java in Indonesia and it enables two crops to be grown per year. Root chilling of rootstock has also been found to enhance bud break of the shoot. In addition, chemicals like KNO 3 , mineral oil and thiourea (TU) have been found to be effective in breaking bud dormancy in Kenya. This paper is reviewing the challenges encountered in growing apples in the tropics and Kenya in particular and the progress that has made in addressing them.
Root observations in situ with a rhizotron camera enabled us to compare the performance of apple ... more Root observations in situ with a rhizotron camera enabled us to compare the performance of apple (Malus •domestica Borkh.) trees on 3 rootstock clones planted in a New York orchard with a history of apple replant disease. Visual observations were conducted in situ at monthly intervals during 2 growing seasons through minirhizotron tubes for trees grafted onto 3 rootstocks: M.7 (M.7), Geneva 30 (G.30), and Cornell-Geneva 6210 (CG.6210). There were 3 preplant soil treatments (fumigation, compost amendment, and untreated checks) and 2 tree planting positions (within the old tree rows or in the old grass lanes of the previous orchard at this site). Preplant soil treatments and old-row versus grass-lane tree planting positions had no apparent influence on root systems, whereas rootstock clones substantially influenced root growth and demography. New root emergence was suppressed during the first fruit-bearing year (2004) on all 3 rootstock clones compared with the previous nonbearing year (2003). A root-growth peak in early July accounted for more than 50% of all new roots in 2003, but there was no midsummer root-growth peak in 2004. The median lifespan for roots of CG.6210 was twice that of G.30 and M.7 in 2004. Also, CG.6210 had more roots below 30 cm depth, whereas M.7 had more roots from 11 to 20 cm depth. Trees on CG.6210 were bigger, yielded more fruit, and had the highest yield efficiency in the third year after planting compared with trees on G.30 and M.7 rootstocks. Crop load appeared to inhibit new root development and changed root-growth dynamics during the first bearing year, with a resurgence in new root growth after fruit was harvested in October 2004. Rootstock genotype was the dominant influence on root lifespan and distribution in this study, whereas preplant soil fumigation, compost amendments, and replanting positions had little apparent impact on root characteristics despite their influence on above-ground tree growth and yield.
We conducted 3 years of field tests comparing two chemicals [methyl anthranilate (MA, a natural c... more We conducted 3 years of field tests comparing two chemicals [methyl anthranilate (MA, a natural compound used as a flavor additive) and Keyplex-350 (a proprietary micronutrient formulation)] that were reported to repel birds to exclusionary plastic netting and nontreated plots. Cumulative fruit damage from birds was monitored on sweet and tart cherry (Prunus avium L. and P. cerasus L.), blueberry (Vaccinium corymbosum L.), and wine grapes (Vitis vinifera x labrusca). Initial MA formulations caused injury to fruit and foliage. Two modified MA formulations with microencapsulation and photooxidation inhibitors provided significant reductions in bird damage and fruit splitting on sweet cherries in one of four experiments. A taste panel could not detect MA residues on sweet cherries at harvest. Bird damage was slightly reduced in MA-treated grapes, but damage to blueberries was similar in MA and control treatments. Keyplex did not deter birds from feeding on fruit and caused blemishes on and an unpleasant flavor in treated fruit. Many bird species were observed feeding on these fruit crops during successive years at the three experimental sites. Although these two chemicals have the potential to deter bird depredation, our work suggests that neither is consistently effective against all the frugivorous species in the northeastern United States. Chemical name used: 2-Aminobenzoic acid methyl ester [methyl anthranilate (MA)].
Journal of the American Society for Horticultural Science, Mar 1, 1994
This study was conducted to compare various orchard groundcover management systems (GMSs)-includi... more This study was conducted to compare various orchard groundcover management systems (GMSs)-including a crownvetch "living mulch" (CNVCH), close-mowed (MWSOD) and chemically growth-regulated (GRSOD) sodgrasses, pre-emergence (NDPQT) and two widths of post-emergence (GLY1.5 and GLY2.5) herbicides, hay-straw mulch (STMCH), and monthly rototillage (tilled)-during the first 6 years in a newly established apple (Malus domestica Borkh.) planting. Mean soil water potential at 5 to 35 cm deep varied substantially among treatments each summer, and treatment × year interactions were observed. During most growing seasons from 1986 to 1991, soil water availability trends were STMCH > NDPQT > GLY2.5 > GLY1.5 > tilled > GRSOD > MWSOD > CNVCH. Soil organic matter content increased under STMCH, CNVCH, and MWSOD and decreased under NDPQT and tilled treatments. Water infiltration and saturated hydraulic conductivity after 4 years were lower under NDPQT and tilled, and soil under STMCH and GRSOD retained more water per unit volume at applied pressures approximating field water capacity. Midsummer soil temperatures at 5 cm deep were highest (25 to 28C) in tilled and NDPQT plots, intermediate (22 to 24C) under GRSOD, and lowest (16 to 20C) under CNVCH and STMCH. These observations indicate that long-term soil fertility and orchard productivity may be diminished under pre-emergence herbicides and mechanical cultivation in comparison with certain other GMSs. water retention and availability, bulk density, pore size distribution, temperatures, soil organic matter content, groundcover biomass, and apple root distribution.
Journal of the American Society for Horticultural Science, Mar 1, 1996
Commercial apple (Malus domestica Borkh.) orchards in the northeastern United States receive heav... more Commercial apple (Malus domestica Borkh.) orchards in the northeastern United States receive heavy pesticide inputs and are often located on well-drained soils near surface and groundwater resources. Nonpoint-source water pollution by agrichemicals has been monitored in agronomic crop systems and simulated using computer models and laboratory soil columns, but inadequately studied at field scale in orchards. We monitored the concentrations of agrichemical tracers, nitrate-N, and benomyl fungicide in water samples from two apple orchards under mowed sodgrass (Mowed-Sod), shredded bark mulch (Bark-Mulch), preemergence residual herbicides (Resid-Herb), and postemergence herbicide (Post-Herb) groundcover management systems (GMSs). In one orchard, we evaluated subsurface spatial patterns and flow rates of a weakly adsorbed blue dye (pesticide analog) and potassium bromide (nitrate analog) under trees after six years of Post-Herb and Mowed-Sod treatments. Nitrate and pesticide tracers leached more rapidly and in higher concentrations under Post-Herb treatments, apparently via preferential macropore flowpaths such as root channels, soil cracks, and macrofauna burrows. At another orchard, we monitored subsurface leaching and surface runoff of benomyl and nitrate-N on a whole-field scale. Peak concentrations of benomyl (up to 29 mg•liter-1) and nitrates (up to 20 mg•liter-1) were observed in subsoil leachate under Resid-Herb plots during 1993. In 1994, nitrate concentrations were greater in leachate from all GMSs, with upper ranges from 48 to 66 mg•liter-1 , while benomyl concentrations were lower in all GMSs compared with the previous summer. In surface water runoff during 1993, the highest benomyl concentrations (387 mg•liter-1) and most frequent outflows occurred in Resid-Herb plots. During 1994, benomyl runoff was more frequent in both herbicide GMSs, with concentrations up to 61 mg•liter-1 observed in the Post-Herb plots. Weather patterns, irrigation intensity, differing soil conditions under each GMS, and the turfgrass/clover drive lanes affected the relative frequency and concentrations of benomyl and nitrate leaching and runoff. Preferential bypass flow appeared to be a major subsurface leaching pathway, and erosion sediment an important factor in surface movement of these agrichemicals. Our studies suggest that nitrate-N and benomyl fungicide may be more prone to leaching or runoff from orchard soils under some herbicide GMSs in comparison with mowed sodgrass or biomass mulch systems.
Meadow vole (Microtus pennsylvanicus L.) populations, feeding activity, and damage to young apple... more Meadow vole (Microtus pennsylvanicus L.) populations, feeding activity, and damage to young apple (Malus domestica Borkh.) trees were monitored by direct observation, trap counts, and a feeding activity index in different groundcover management systems (GMSs) for five years in a New York orchard. Vole populations differed greatly among GMSs, with consistently higher populations and more damage to tree trunks in crownvetch (Coronilla varia L.), hay-straw mulch, and red fescue (Festuca rubra L.)sodgrass GMSs. Vole populations were highest in the fall and lowest during the spring seasons each year. Anticoagulant rodenticides and natural predation did not result in adequate control of voles in GMSs that provided favorable habitat for nesting and feeding of this pest. The percent of soil surface vegetation coverage was not, but the amount of groundcover biomass was, a significant predictor of vole populations and damage to trees, independent of groundcover vegetation species. Trunk applications of thiram fungicide were less effective than 40-cm-high plastic mesh trunk guards, but better than no protective measures for controlling vole depredation in groundcover management systems (GMSs) with high rodent populations. A combination of late fall vole trapouts, close and consistent mowing of orchard floor vegetation, tree trunk protection with mesh guards, ample surrounding habitat for natural predators of voles, and suppression of tree row groundcover species with herbicides provided adequate control of meadow voles without the use of rodenticides at this orchard.
Journal of the American Society for Horticultural Science, Sep 1, 1989
Growth chamber evaluations of soil from an orchard replant site showed severe stunting of 'Northe... more Growth chamber evaluations of soil from an orchard replant site showed severe stunting of 'Northern Spy' apple (Malus domestica Borkh.) seedlings grown in field soil (FS) compared with pasteurized soil (PS) from the same site. The FS : PS seedling dry weight ratio of 0.44 indicated a serious replant problem. Leaf nutrient content was generally higher in PS than FS seedlings. Multiple-regression analysis indicated that leaf K and root-lesion nematode (Pratylenchus penetrans Filipjev) primary inoculum accounted for 75% of the variation in FS seedling dry weight. Apple seedling dry weight in FS was 97% of that in PS following a marigold (Tagetes patula L. cv. Sparky) cover crop, and 75% following oats (Avena sativa L. cv. Saia). Root-lesion nematodes were nearly eliminated from the plots with marigold. Other cover crops and a weed-free fallow period were less effective in controlling apple replant disease and/or phytonematodes. Received for publication 21 Sept. 1988. This paper is part of a thesis submitted by I.A.M. in partial fulfillment of the requirements for the MS degree. Thanks to Elizabeth Loder for technical assistance, to W.F. Mai for guidance and provision of growth chamber and laboratory space in the Dept, of Plant Pathology, and to Harris Seeds, Rochester, N .Y ., and International Seeds, Halsey, Ore., for providing 'Sparky' marigold and 'Companion M ix' grass seed, respectively. USDA Hatch Project funds (NYC J55414) helped support this research. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact. 'Graduate student. 2Profcssor.
Journal of the American Society for Horticultural Science, Mar 1, 1994
This study compared various conventional and alternative orchard groundcover management systems (... more This study compared various conventional and alternative orchard groundcover management systems (GMSs)including a crownvetch "living mulch" (CNVCH), close-mowed (MWSOD) and chemically growth-regulated (GRSOD) sodgrasses, pre-emergence (NDPQT) and two widths of postemergence (GLY1.5 and GLY2.5) herbicides, hay-straw mulch (STMCH), and monthly rototillage (tilled)-during 6 years in a newly established apple (Malus domestica Borkh.) planting. Trunk cross-sectional area and fruit yield were higher in STMCH, GLY, and NDPQT, intermediate in tilled, and lower in GRSOD, MWSOD, and CNVCH treatments after 5 years. Despite N and K fertilizer applications, extractable soil N and leaf N concentrations were reduced under MWSOD and GRSOD, and soil K, P, and B concentrations were greater under STMCH. Leaf K concentrations were usually highest in STMCH trees, even when heavily cropped; leaf K declined below the sufficiency range in GLY, NDPQT, and tilled trees as they began to bear fruit. Leaf Ca was marginally deficient in all trees and was unaffected by GMS. Foliar Mn, Zn, and B concentrations declined rapidly in all treatments during 2 years without micronutrient fertilizers. Leaf Cu was higher in herbicide and tilled treatments where seasonal soil water content was intermediate (22% to 27%) and lower where soil was very wet or dry for most of the 1988 growing season. Multiple regression analysis indicated that leaf N and B and soil organic matter in 1990, and mean soil water content during the unusually dry Summer 1988, were the best predictors of fruit yield in 1990. Phytophthora root rot and meadow vole depredation were serious problems in STMCH and CNVCH trees. GMSs greatly affected tree establishment, nutrition, and yield; each system involves tradeoffs among important short-and long-term impacts on the orchard agroecosystem.
We evaluated soil health in apple (Malus × domestica Borkh.) orchards of New York State. Our obje... more We evaluated soil health in apple (Malus × domestica Borkh.) orchards of New York State. Our objectives were to determine a parsimonious set of biological, chemical, and physical indicators for monitoring orchard soil health, and then to relate long-term management practices to soil health, orchard productivity, and ecosystem services. At one study site, four in-row groundcover management systems (GMS)-pre-emergence herbicide, post-emergence herbicide, mowed sod, and bark mulch-have been maintained in a 0.8 ha orchard for 17 years. Discriminant analysis showed that total soil carbon (%C), organic matter (%OM), and bulk density (g•cm-3 , BD) separated the GMS treatments. The %C and %OM were significantly higherand BD significantly lower-in mulched plots compared to the other GMS (P<0.05). Previous reports suggest that higher %C and %OM, and lower BD, indicate healthier soil. In regression analyses, %C and %OM positively correlated, and BD negatively correlated, with trunk cross-sectional area, confirming that healthier soils produce larger trees. While high vigor trees are often inefficient fruit producers, this was not observed in our study. Yield was statistically similar across GMS treatments since 2004; yet, there was a trend for trees in the post-emergence herbicide and mulch treatments to yield more than trees in the pre-emergence herbicide and sod treatments. Average pruning weights did not differ among treatments. We cannot conclude that healthier soil translates to higher profits based on yield alone, but system-wide carbon sequestration was significantly higher in the mulch treatment, where soil OM content doubled from 4.5 to 9% over the 17 years of the study. The mulch treatment had statistically higher carbon storage in the soil and in tree biomass. In agricultural programs where best management practices and/or ecosystem services are subsidized, orchard soils with higher organic carbon could be financially rewarded.
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