Melon wilt (MW) is one of the main diseases affecting the cucurbitaceous crops in the Pacific Central region of Mexico. The use of resistant varieties is the most effective strategy to reduce the damage caused by MW; however, variety performance depends on the fungal race occurring in the field. The use of fungicides, such as benzimidazols and methyl bromide, is a common practice, but there are contamination concerns, and a search is on for alternatives to diminish the negative effects on the agro-ecosystem. The aim was to determine the effect of the application of soil amendments and mulching on the incidence of MW, and on melon yield. Soil amendments incorporated were: rice straw (3 t·ha-1); compost 1, prepared with chicken and bovine manure, and banana and orange wastes (5.7 t·ha-1); compost 2, prepared with bovine and horse manure, coconut wastes and grasses (8 t·ha-1), vermicompost (3 t·ha-1), and a control. All treatments were established using transparent mulching during 21 days. The number of MW propagules in amended soils were similar at 5, 10, and 20 cm deep, but the percentage of diseased plants was higher (4.5%) in the control, which could be caused by the incidence of other fungi propagules, perhaps antagonistic, that contributed in diminishing the MW when compared with the control. The fruit weights and fruit sizes were not different between treatments on small (21–30 sizes), medium (15–18 sizes), and large (9–12 sizes), but total fruit numbers were 1.15-, 1.07-, 0.99-, and 1.09-fold higher when compared with the control. The application of soil amendments affected the antagonistic fungal populations even when it did not affect the cantaloupe yield. We suggest that soil amendments will improve soil fertility and increase melon yields, and studies are currently running.
Mario Orozco-Santos, Javier Farías-Larios, Jaime Molina-Ochoa and José Gerardo López-Aguirre
within the college as well as the department. Greg's life was devoted to church, family, and profession. He was born 12 Dec. 1955 in Manassas, VA. He graduated from Berea College with a BS in agriculture in 1979, Virginia Tech with a MS in soil chemistry/fertility
Mitchell W. Goyne and Michael A. Arnold
Four underutilized small trees, Chilopsis linearis, Rhus lanceolata, Acacia wrightii, ×Chitalpa tashkentensis, and a commercial control Fraxinus velutina, were grown outdoors in 15-L containers. Four media combinations, 3 pine bark: 1 sand, 3 pine bark: 1 coconut coir pith, 3 kenaf stalk core: 1 sphagnum peat, and 3 kenaf stalk core: 1 coconut coir pith (v/v), were amended with Sierrablen 18N–2.6P–10K at three rates, 3.6, 7.1, and 10.7 kg·m-3. Fraxinus velutina and C. linearis seedlings were transplanted to the field to evaluate initial landscape establishment. Growth was typically reduced, in both the field and container, when kenaf media was used during production. EC was greatest early and with higher fertility rates. Leachate pH decreased over time, and was lower at high fertility rates. Soil particle size >6.0 mm decreased substantially in kenaf media over time. Water holding capacity increased, while air space and total root volume decreased in kenaf media. Physical characteristics and growth responses were similar with coconut coir and peat moss.
David Devenney, John Frett, Wallace Pill and Gary Smith.
Ten 10 wildflower species grew satisfactorily in a 1:1 (vol.) mix of Ironrich (IR, mineral co-product of the titanium dioxide industry) and Fairgrow (FG, co-composted sewage sludge and solid waste). Shoot fresh weights in the low fertility IR and in the high fertility FG averaged 35% and 157%, respectively, those grown in IR+FG. Wildflower establishment in 10cm-deep outdoor seedbeds of IR, FG, or IR+FG were compared to those in soil (control) plots. Maximum percentage seedling emergence and emergence rate and synchrony were lower in FG than in IR, values in IR+FG being intermediate and similar to those for control plots. Shoot fresh weights, however, were greater from the IR+FG than from IR, FG or the control plots. Total shoot dry weights of wildflowers from 1 m2 subplots after 3 months were FG > IR = IR+FG > control, being respectively 8.4, 8.5, 5.1 and 1.1% those of total shoot dry weights of weeds.
Kim Patten, Gary Nimr and Elizabeth Neuendorff
Blueberry production is enhanced by the use of an organic mulch. An alternative to off-farm sources of mulch is the production of winter and summer living mulch cover crops grown in the row middles of the blueberry planting. These crops are mowed and then windrowed for use as a mulch. We evaluated living mulch crops for blueberries for the following parameters: adaptation to low soil pH, mulch production, ease and cost of stand establishment, mowing tolerance, allelopathic weed control, and N contributed by mulch. Rye, ryegrass, and crimson clover were the most overall suitable crops for the winter; while for summer, pearl millet was best adapted. Nitrogen was the major limiting factor that affected nonlegume production. Legume yields were limited by deer foraging and low soil pH. Pearl millet had the greatest allelopathic response on weeds of all cover crops tested. Maximum dry matter production for the living mulches ranged from 6000 kg/ha for elbon rye in the winter, to 30,000 kg/ha for pearl millet in the summer. With the appropriate cover crop selection and adequate soil fertility living mulches appear to be a efficacious practice to aid blueberry production in the south.
Amy Oberly, John Masiunas and Mosbah Kushad
Rye (Secale cereale) residues used in an alternative cropping system will affect nutrients, soil moisture, and soil temperatures. Each of these factors can affect tomato fruit quality. A field study was conducted comparing the effects of a rye cover crop, tomato variety, and N fertility on tomato fruit quality. In October, cereal rye was seeded at 100 kg·ha–1 to one-half of the plots. The rye was killed in mid-May by applying glyphosate at 1.1 kg·ha–1. Tomato seedlings were planted into the rye and bare-ground plots in late May. Four tomato varieties differing in cracking and soluble solids were used. There were two fertilizer regimes, no additional fertilizer, and N fertilizer applied broadcast before tomato planting, and as a sidedress based on soil tests, leaf analysis, and current recommendations. Tomato quality was evaluated based on 1) color as assessed using a Minolta chromameter, 2) cracking based on type and severity, and 3) soluble solids as determined by HPLC.
John Sloan, Cynthia McKenney, James McAfee and Wayne Mackay
Dairy manure compost (DMC) may be an effective soil amendment when establishing new urban landscapes. The objective of this study was to evaluate the bioavailability of DMC nutrients to typical urban landscape plants. In March 2003, DMC rates of 0, 9, 18, and 27 kg/m2 (0, 1.25, 2.5, 5 cm) were incorporated into the top 10 to 15 cm of Austin silty clay soil. Half of each 6 x 6-m plot was established with bermudagrass sod and the other half with six types of ornamental plants consisting of annual, perennial, and woody species. During the third 2005 growing season, plant tissue was harvested from selected landscape plants to measure biomass production and nutrient uptake. Plant growth and nutrient contents were compared to plant available soil nutrients that were measured during fall 2004 and 2005. Plant available P in the upper 7.5 cm of soil ranged from 89 to 170 mg/kg in September 2004 and from 31.3 to 105.5 mg/kg in August 2004. Potassium and trace elements (Fe, Cu, and Zn) were also increased in the upper 7.5 cm by DMC applications. Increased concentrations of plant available soil nutrients in DMC-amended plots were correlated to overall increases in plant growth and nutrient uptake. Bermuda grass exhibited increased growth and increased tissue concentrations of N, P, K, and Zn. Penta biomass and nutrient uptake were also increased by DMC applications. Lantana stem weights significantly increased with DMC application rate up to 18 kg/m2, but no additional increases were obtained with the 27 kg/m2 rate. Results of this study show that, after three growing seasons with no additional fertilization, a 1- to 2-cm application of dairy manure compost is sufficient to provide continued fertility to landscape plants.
F. Kultur, H.C. Harrison and J.E. Staub
Muskmelon (Cucumis melo L.) genotypes, Birdsnest 1 [`Qalya' (BN1)], Birdsnest 2 (BN2), and `Mission' (V) were used to determine the effects of plant architecture and spacing on fruit sugar concentration and yield. The BN1 and BN2 genotypes possessed a highly branched growth habit specific to birdsnest melon types but not characteristic of standard indeterminate vining types (e.g., `Mission'). Experiments were conducted at the Hancock (sandy soil, <1% organic matter) and Arlington (heavy, praire loam soil, >4% OM) Experimental Farms in Wisconsin. Plant response to two within-row spacings [35 cm (72,600 plants/ha) and 70 cm (36,300 plants/ha)] in rows on 210-cm row centers was examined. Genotypes were grown in a randomized complete-block design with four replications at each location and evaluated for primary lateral branch number, fruit number per plant, fruit number per hectare, average fruit weight, yield (g) per plant, yield (MT) per hectare, and fruit sugar concentration. All genotypes produced higher yield, fruit number and sugar concentration on the mineral soil at Arlington compared to the sands at Hancock. The main effect of genotypes was significant for all traits examined. BN1 and V genotypes had greater yield (gram per plant, yield per hectare, and average fruit weight) as well as higher fruit quality (fruit sugar concentration) than the BN2 genotype. Spacing affected all traits examined except primary branch number and fruit sugar concentration. As withinrow spacing increased from 35 to 70 cm, fruit number per plant, yield per plant and average fruit weight increased. However, yield (MT) per hectare and fruit number per hectare decreased. Fertility was adjusted according to soil tests for the two different soil types at the two farm locations.
I.A. Merwin, D.A. Rosenberger, C.A. Engle, D.L. Rist and M. Fargione
Natural (hay, wood chips, recycled paper pulp) and synthetic (polypropylene film and polyester fabric) mulches were compared with mechanical tillage and residual herbicides as orchard groundcover management systems (GMSS). In two New York orchards-the Clarke farm and Hudson Valley Lab (HVL—GMSS were applied from 1990 to 1993 in 1.8-m-wide strips under newly planted apple (Malus domestica; `Liberty', `Empire', `Freedom', and advanced numbered selections from the disease-resistant apple breeding program at Geneva, N.Y.) trees. GMS impacts on soil fertility, tree nutrition and growth, yields, crop value, and vole (Microtus spp.) populations were evaluated. After 3 years at the Clarke orchard, extractable NO3, Mn, Fe, B, and Zn concentrations were greater in soil with herbicides than synthetic mulches; soil K and P concentrations were greater with herbicides and wood chips than synthetic mulches. At the HVL orchard, topsoil NO3, K, and Mg concentrations were greater with hay mulch than herbicides or other mulches; Mg, Fe, and B concentrations were lower in soil with wood chips than other GMSs. Soil organic matter content was not affected by GMS. Apple leaf N, K, Cu, and Zn concentrations were greater with herbicides, hay mulch, and polypropylene mulch than cultivation or recycled paper mulch at the HVL orchard during hot, dry Summer 1991. Despite transient differences among GMSS during the initial years, after 4 years of treatments there were no consistent GMS trends in cumulative tree growth or gross yields. The higher establishment and maintenance costs of several mulches were offset by their prolonged efficacy over successive years; crop market values from 1992 to 1994 were considerably greater for trees with polypropylene film, polyester fabric, and hay mulches than herbicides, cultivation, or other mulches. Voles caused more serious damage to trees in synthetic and hay mulches, despite the use of mesh trunk guards and rodenticide bait.
Michael P. Croster and John B. Masiunas
Studies established the critical period for eastern black nightshade (nightshade) (Solanum ptycanthum Dun.) competition in pea (Pisum sativum L.) and determined the effect of N fertility on pea and nightshade growth. In 1992, pea yields were most affected when nightshade was established at planting and remained for 4 or 6 weeks, while in 1993, competition for 6 weeks caused the greatest reduction in pea yields. In a sand culture study, pea biomass and N content were not affected by three N levels (2.1, 21, and 210 mg·L-1). Nightshade plants were five to six times larger in the highest N treatment than at lower N levels. Nitrogen content of nightshade was 0.76% at 2.1 ppm N and 3.22% at 210 ppm N. Choosing soils with low N levels or reducing the N rates used in pea may decrease nightshade interference and berry contamination of pea.