Halosulfuron (Sandea 75WG) is labeled for pre- or posttransplant use in tomato, cucumber, cantaloupe, among other vegetable crops. For pretransplant usage, the label specifies a 7-day waiting period after halosulfuron application under the plastic mulch before transplanting tomatoes. This period may be too long for growers who are busy in the spring with planting and pesticide sprays while on a race with the constantly changing climate of early spring. Experiments were conducted in the last 2 years to determine whether transplanting tomato within 7 days of halosulfuron application had any deleterious effects on tomato. In 2003, tomatoes were transplanted daily from day 0 through 7. Plant survival and height were collected. Tomato plants survived all dates of transplanting treatments. Plant height indicated that plants transplanted early were taller than those transplanted late, only because they had more time to establish and grow in the field. There was no adverse effect to tomato growth. In 2004, tomatoes were set on a 2-day interval from day 0 through 10 after halosulfuron application under the plastic mulch. Plant height, visual rating, % early blight infection, and yields were collected. A severe early blight infection confounded the results of herbicide applications. Still, it was clear that halosulfuron 0.026 or 0.051 kg a.i./ha had no effect on plant height or visual rating. Yields were not statistically different from those of the control, when the effect of early blight was factored out.
Joseph G. Masabni
Joseph G. Masabni
Experiments were conducted in the last 3 years to evaluate the safety and efficacy of halosulfuron (Sandea 75WG) application under the plastic mulch within 7 days of transplanting tomato. In 2003, tomato plants were transplanted daily from day 0 through 7 after halosulfuron 0.051 kg a.i./ha application. Plant survival and height were collected. Tomato plants survived all dates of transplanting treatments. Plant height indicated that plants transplanted early were taller than those transplanted late, only because they had more time to establish and grow in the field. In 2004, tomatoes were set on a 2-day interval from day 0 through 10 after halosulfuron application. Halosulfuron 0.025 or 0.052 kg a.i./ha had no effect on plant height or yield. In 2005, an experiment was initiated to determine whether addition of trifluralin to halosulfuron under the plastic mulch will improve grass control and remain safe to tomatoes. Halosulfuron at 0.025, 0.052, and 0.1 kg a.i./ha, was applied alone and combined with trifluralin 0.63 kg a.i./ha. All treatments were applied under the plastic mulch. Tomato plants were transplanted at 6 days after application (DBT) and 0 DBT. Halosulfuron 0.1 kg ai/ha resulted in slight stunting and yield reduction of tomato, whether applied at 6 or 0DBT. However, this stunting was not statistically significant. Trifluralin didn't affect tomato yield at 6DBT and significantly increased yields at 0DBT for 0.052 and 0.1 ka a.i./ha halosulfuron rates. Trifluralin reduced grass biomass but resulted in an increase of nightshade biomass. Halosulfuron was determined to be very safe on tomato growth and yield, even if tomato was transplanted on the same day of application. Trifluralin also was found to have little or no effect on tomato growth or yield, and appears to have a potential use as an herbicide for under plastic application in tomato production.
Joseph G. Masabni and Dwight E. Wolfe
Flumioxazin (Chateau 51WG) is an herbicide for the preemergence and early postemergence control of broadleaves and grasses. Chateau was recently labeled for use in non-bearing fruit trees and bearing grapes. Long-term weed control in apple, peach, and blueberry was investigated following fall application of herbicides. Treatments consisted of simazine 2.8 kg a.i., norflurazon 2.24 kg a.i., napropamide 2.24 kg a.i., and oryzalin 2.24 kg a.i. were applied on 11 Nov. 2003. Flumioxazin was also applied at 0.1 and 0.43 kg ai on apple and peach. All treatments included glyphosate 1 lb a.i. for burndown control of preexisting weeds. Weed control evaluation in mid-April or 4 months after application showed that flumioxazin-treated plots had no weeds present and no weed regrowth. Plots treated with napropamide, norflurazon, and oryzalin showed significant regrowth of dandelion, common ragweed, and chickweed. Simazine plots had fewer weeds germinating than the other herbicides. By early June or 6 months after application, no differences in residual weed control were observed for all treated plots when compared to the control. All plots were equally weedy and required immediate floor management measures. It appears that flumioxazin weed control benefit was exhausted by 6 months after application, compared to 4 months for all other herbicides. Fall application of flumioxazin can eliminate the need for early spring weed control. This time saved can be spent on other important activities such as pruning and disease and insect control.
Joseph G. Masabni and S. Alan Walters
A field study was conducted in 2010 and 2011 to determine the suitability of Earth-Kind® production principles for home vegetable gardening. Earth-Kind® production encourages water and energy conservation, and reduction of fertilizer and pesticide use. Seven vegetable cultivars [Sweet Banana and bell pepper (Capsicum annuum); Celebrity and Juliet tomato (Solanum lycopersicum); Spacemaster cucumber (Cucumis sativus); Ichiban eggplant (Solanum melongena); Spineless Beauty zucchini (Cucurbita pepo)] were grown in mushroom compost (MC) or city compost (CC). Both composts were incorporated preplant into the soil with shredded wood mulch placed over them. In each year, nitrogen (N) fertilizer (15.5N–0P–0K from calcium nitrate) was applied preplant to CC plots to bring initial soil fertility levels similar to MC plots. No additional fertilizer was applied during the growing season. Drip irrigation was supplemented weekly. One application each of neem oil and pyrethrin (organic insecticides) and chlorothalonil (synthetic fungicide) was applied before harvest in 2010, but none was applied in 2011. Results indicated that Earth-Kind® technique could be effectively implemented in a home vegetable garden. MC is better suited for Earth-Kind® vegetable production than CC for some vegetables. Banana pepper, bell pepper, and zucchini had twice the yield in MC plots when compared with CC plots. No yield differences (P > 0.05) were observed between composts for tomato, eggplant, or cucumber. With proper irrigation and soil preparation practices such as addition of compost and mulch, Earth-Kind® vegetable gardening techniques can be used for selected vegetable crops without additional N fertilizer or pesticides. Furthermore, Earth-Kind® vegetable gardening can be successful as long as the home gardener understands that low yields may result from using this production method. However, often the home gardener is more concerned about producing vegetables using sustainable, environmentally friendly methods than maximizing yields.
Bernard H. Zandstra, William R. Chase and Joseph G. Masabni
Pickling cucumbers (Cucumis sativus L.) for machine harvest were interplanted with barley (Hordeum vulgare L.), oat (Avena sativa L.), rye (Secale cereale L.), sorghum-sudan (Sorghum vulgare L.), or wheat (Triticum aestivum L.). Cover crops 3 to 5 (7.6 to 12.7 cm) or 6 to 10 inches (15.2 to 25.4 cm) tall were killed with sethoxydim. Cover crops seeded at ≈12 seeds/ft2 (129 seeds/m2) provided protection from wind erosion and minimal crop competition. Additional nitrogen to obtain maximum yield was required when small grain cover crops were interplanted with cucumbers. Barley emerged rapidly, grew upright, and was killed easily with sethoxydim, making it ideal for interplanting. All cover crops caused some cucumber yield reduction under adverse growing conditions.
Catur Herison, Joseph G. Masabni and Bernard H. Zandstra
Three onion (Allium cepa L.) cultivar transplants were grown in the greenhouse in 200-cell plastic trays with one, two, or three plants per cell; at 75, 150, or 225 ppm N; and for 8, 10, or 12 weeks. Increasing the number of plants per cell resulted in smaller seedlings at transplanting and reduced time to maturity in the field by 1 week. Two and three plants per cell yielded more bulbs ≥76 mm in diameter, but one plant per cell had the highest percentage of bulbs ≥102 mm in diameter. Older seedlings and higher N applications produced larger plants at transplant and larger bulbs at harvest. Increasing N applications reduced maturation time slightly. Bulb fresh weight at harvest and yield of bulbs ≥76 mm in diameter were highest with 10- and 12-week-old transplants, and at 150 and 225 ppm N.
Haijie Dou, Genhua Niu, Mengmeng Gu and Joseph G. Masabni
Consumption of basil (Ocimum basilicum) has been increasing worldwide in recent years because of its unique aromatic flavor and relatively high concentration of phenolics. To achieve a stable and reliable supply of basil, more growers are turning to indoor controlled-environment production with artificial lighting due to its high environmental controllability and sustainability. However, electricity cost for lighting is a major limiting factor to the commercial application of indoor vertical farming, and little information is available on the minimum light requirement to produce uniform and high-quality sweet basil. To determine the optimal daily light integral (DLI) for sweet basil production in indoor vertical farming, this study investigated the effects of five DLIs, namely, 9.3, 11.5, 12.9, 16.5, and 17.8 mol·m−2·d−1 on basil growth and quality. ‘Improved Genovese Compact’ sweet basil was treated with five DLIs provided by white fluorescent lamps (FLs) for 21 d after germination, and gas exchange rate, growth, yield, and nutritional quality of basil plants were measured to evaluate the effects of the different DLIs on basil growth and quality. Results indicated that basil plants grown under higher DLIs of 12.9, 16.5, or 17.8 mol·m−2·d−1 had higher net photosynthesis, transpiration, and stomatal conductance (g S), compared with those under lower DLIs of 9.3 and 11.5 mol·m−2·d−1. High DLIs resulted in lower chlorophyll (Chl) a+b concentration per leaf fresh weight (FW), higher Chl a/b ratios, and larger and thicker leaves of basil plants. The shoot FW under DLIs of 12.9, 16.5, and 17.8 mol·m−2·d−1 was 54.2%, 78.6%, and 77.9%, respectively, higher than that at a DLI of 9.3 mol·m−2·d−1. In addition, higher DLIs led to higher soluble sugar percent and dry matter percent than lower DLIs. The amounts of total anthocyanin, phenolics, and flavonoids per plant of sweet basil were also positively correlated to DLIs, and antioxidant capacity at a DLI of 17.8 mol·m−2·d−1 was 73% higher than that at a DLI of 9.3 mol·m−2·d−1. Combining the results of growth, yield, and nutritional quality of sweet basil, we suggest a DLI of 12.9 mol·m−2·d−1 for sweet basil commercial production in indoor vertical farming to minimize the energy cost while maintaining a high yield and nutritional quality.
Youping Sun, Genhua Niu, Joseph G. Masabni and Girisha Ganjegunte
A greenhouse experiment was conducted to determine the relative salt tolerance of pomegranate (Punica granatum) cultivars. Twenty-two pomegranate cultivars were irrigated weekly with a saline solution at an electrical conductivity (EC) of 10.0 dS·m–1 for 4 weeks and subsequently with a saline solution at an EC of 15.0 dS·m–1 for another 3 weeks (salt treatment). Another group of uniform plants was watered with a nutrient solution without additional salts at an EC of 1.2 dS·m–1 (control). No visual foliar salt damage (leaf burn, necrosis, or discoloration) was observed during the entire experimental period; however, salt treatment impacted pomegranate growth negatively, with a large variation among cultivars. Salt treatment reduced shoot length by 25% and dry weight (DW) by 32% on average for all cultivars. Cluster analysis classified the 22 tested pomegranate cultivars in two groups. The group consisting of ‘Arturo Ivey’, ‘DeAnda’, ‘Kazake’, ‘Russian 8’, ‘Apseronski’, ‘Purple Heart’, ‘Carolina Vernum’, ‘Chiva’, ‘Kunduzski’, ‘Larry Ceballos 1’, ‘ML’, ‘Salavatski’, ‘Spanish Sweet’, and ‘Wonderful’ was more salt tolerant than the group including ‘Al-Sirin-Nar’, ‘Kandahar’, ‘Surh-Anor’, ‘Early Wonderful’, ‘Angel Red’, ‘Ben Ivey’, ‘Utah Sweet’, and ‘Mollar’. The sodium (Na) concentration in the leaf tissue of all 22 pomegranate cultivars was less than 1 mg·g–1 on a DW basis. All pomegranate cultivars in the salt treatment had an average leaf chloride (Cl) content of 10.03 mg·g–1 DW—an increase of 17% from the control. These results indicate that pomegranate plants have a strong capability to exclude Na and Cl accumulation in leaf tissue. In conclusion, the pomegranate plant is very tolerant to saline water irrigation up to an EC of 15 dS·m–1 with little foliar salt damage and a slight growth reduction. Investigation is needed to determine the effects of saline water on the fruit yield and nutritional quality of pomegranate.
Jorge E. Arboleya, Joseph G. Masabni, Michael G. Particka and Bernard H. Zandstra
Dry bulb onion (Allium cepa) leaves may not dry down normally and bulbs may not attain dormancy during adverse growing seasons. An effective method of artificial leaf desiccation is needed to complement mechanical harvesting and onion conditioning for storage. Desiccants were tested in 1993, 1994, 1995, 2001, 2002, 2003 on onion leaves prior to harvest, and bulb quality was evaluated after 5 months or more of storage. Carfentrazone, diquat, and paraquat desiccated onion foliage well but increased bulb rot and reduced the percentage of marketable bulbs after storage. Bromoxynil and endothall desiccated onion foliage significantly without inducing rot or reducing the percentage of marketable bulbs. Copper sulfate and pelargonic acid increased desiccation of onion foliage but were not sufficiently effective for field use. Neither reduced the percentage of marketable bulbs. If bromoxynil or endothall were labelled for onion desiccation, they could be applied 10-14 days before harvest to enhance natural leaf senescence and facilitate mechanical harvest.
Jose G. Franco, Stephen R. King, Joseph G. Masabni and Astrid Volder
The inclusion of a smother crop used as a cash crop in an intercropping system may be an effective cultural control strategy for the management of weeds in organic production systems. In addition, a multilayered canopy created when intercropping species with different growth forms may limit germination cues for weed seeds and can allow for a more efficient utilization of resources that reduce competition to target crops from weeds. Watermelon (Citrullus lanatus) was evaluated for its ability to reduce weeds in a low-input organic system in Texas when planted alone or in various intercropping combinations that also included peanut (Arachis hypogaea), okra (Abelmoschus esculentus), cowpea (Vigna unguiculata), and hot pepper (Capsicum annuum). Watermelon significantly reduced total weed biomass when planted in monoculture and in all intercropping combinations compared with peanut, okra, cowpea, and pepper monocultures in year 1 of the 2-year study. Total weed biomass was reduced by 81%, 83%, 88%, and 92% in treatments containing watermelon on average as compared with pepper, peanut, okra, and cowpea grown in monoculture, respectively. Less effective weed suppression was obtained with watermelon in year 2. Pepper grown in monoculture had significantly higher weed biomass than all other treatments in year 2. Broadleaf weeds were effectively suppressed across all intercropping treatments in year 1, but nutsedges (Cyperus sp.) were consistently reduced both years, particularly when compared with monocrops with small leaf area such as pepper. The three and four species intercropping combinations consistently had high leaf area index (LAI) values, whereas pepper monoculture had significantly lower LAI values than all other treatments except for cowpea monoculture. There was a significant negative relationship between LAI and total weed biomass 33 d after last planting (r = −0.51, P < 0.01). There was a significant negative relationship between total weed biomass and total fruit yield in year 1 (r = −0.64, P < 0.01) but no significant relationship in year 2. Although findings were inconsistent in year 2 because of changes in precipitation amounts and in relative planting dates, these findings suggest that incorporating a multifunctional intercropping system that includes a low-growing vining crop such as watermelon or at least an architecturally complex mixture can optimize canopy density to reduce weed pressure from resilient perennial weeds such as nutsedge. This may offer organic producers another management tool for the control of perennial weeds.