We tested prairie dropseed (Sporobolus heterolepis) using six different germination treatments and found the best results with cold (40 °F), dry storage followed by direct seeding into a commercial germination mix placed in a 75 °F glass-glazed greenhouse with intermittent mist (5 seconds of mist every 8 minutes), and 600-W high-pressure sodium lighting with a 16-hour daylength. We found commercial laboratory viability analysis from tetrazolium staining did not correspond to germination results. Cold (34 °F), moist (2.3 g seed moistened with 2.5 mL deionized water) treatment, also known as cold conditioning, produced significantly less germination and fewer transplantable seedlings, and is not recommended for prairie dropseed.
Mary Hockenberry Meyer and Diane M. Narem
David W. Wolfe
Field studies conducted in 1993 on an Eel loam soil compared the growth and yield response of direct-seeded cabbage, cucumber, snap bean, and sweet corn, and transplanted cabbage, to a compacted soil layer (>2.5 MPa penetrometer resistance) at the 15 - 30 cm depth. Direct-seeded cabbage and snap bean were most severely affected by compaction, with 50% yield losses, and much smaller cabbage head size in compacted plots. Transplanted cabbage had a 30% lower yield in compacted compared to uncompactcd plots. Early vegetative growth of cucumber was less stunted by compaction compared to snap bean and cabbage, but compaction nevertheless resulted in a 50% reduction in total cucumber yield. Compaction delayed maturity and reduced early yield of cabbage, snap bean, and cucumber. Sweet corn yield was reduced by only 10% when grown on compacted soil, and there was no delay in maturity. Sweet corn responded more negatively to compaction in a 1992 field experiment,
Greenhouse studies found a reduction in total plant biomass at 21 days after planting of 30%, 14%, 1%. and 3% for snap bean, cabbage, cucumber, and sweet corn, respectively, in pots compacted at the 10 cm depth. Sweet corn had a significantly higher proportion of root biomass in the compacted zone compared to the other crops. For all species, the growth reductions could not be attributed to reductions in leaf turgor, photosynthetic rate per unit leaf area or leaf nutrient status.
Michael E. Bartolo and Frank C. Schweissing
Colorado-grown watermelons command a premium price on the market based on their sweetness and overall flavor. Unfortunately, melon production is limited to mid-August through early September. This study was conducted to determine whether intensive production methods could enhance the traditional marketing period. The effects of different combinations of establishment methods, mulches, and rowcovers on `Arriba' (Hollar Seeds) watermelon growth and productivity were investigated in a field trial at the Arkansas Valley Research Center in Rocky Ford, Colo. In 1997, the combinations of transplanting, clear plastic mulch, and perforated or slitted rowcovers produced the earliest harvest and highest yield and fruit weight. The first harvest of the earliest treatments occurred on 4 July. Direct-seeding through clear plastic mulch, both with and without rowcovers, also enhanced earliness relative to the traditional marketing period. However, compared to transplanting, yield and fruit weight were less if the crop was direct-seeded. Intensive plasticulture techniques could substantially increase the earliness of Colorado-grown watermelons. The increased cost of production would be easily off-set by higher productivity and early season prices
Marietta Loehrlein and Dennis T. Ray
Triploid watermelon seed does not germinate in cold, wet soils as well as diploids; germination is slower due to reduced embryo size and thicker seed coat; fissures on the seed coat provide safe harbour for fungal spores; and triploid fruit set is later than most diploid cultivars. Because of these problems producers often transplant rather than direct-seed seedless watermelons. Seed priming has been shown to improve germination in other crops and would be an attractive method allowing for direct seeding of seedless watermelons. Seed from open-pollinated 4n × 2n crosses were primed in solutions of H2O, polyethylene glycol 8000, KNO3, or left untreated. Treatment times were 1, 3, or 6 days, and treated seed were subsequently dried for either 1 or 7 d. Seed were scored for germination in the laboratory and emergence under field conditions. Germination was better using H2O than KNO3 and PEG but not always better than the untreated control. Treatment time of 1 day was superior to 3 or 6 days, but length of drying time was insignificant. In the field trial, treatments did not differ in emergence.
Elsa Sánchez, Kathleen Kelley, and Lynn Butler
Eight edamame [Glycine max (L.) Merrill] cultivars were evaluated in the field in 2002, 2003, and 2004 to determine their suitability for growing in central Pennsylvania. Each cultivar was direct seeded and data collected included plant populations (percentage of stand) and marketable yields. Plant populations ranged from less than 1% to 81% and, with one exception in 2002, were below 80%. Eighty percent plant populations or higher are considered optimal. Based on sub-optimal plant populations, none of the edamame cultivars evaluated in the field were determined to be suitable for direct seeding in central Pennsylvania. The effect of temperature on seedling emergence, and therefore, plant populations was then studied. Four of the edamame cultivars used in the field trial were evaluated in growth chambers programmed with varying day/night temperature regimes. Seedling emergence varied by cultivar and was generally below 80% with two exceptions. When grown in a 21.1 °C day/15.6 °C night temperature regime, `Butterbeans' and `Early Hakucho' exceeded 80% seedling emergence. These methods could be used to produce transplants; however, the economic feasibility of doing so should first be evaluated. In the field trial, conclusions on marketable yields were unattainable because soybean plants are known to compensate in yield for plants missing in sub-optimal plant populations. Plant compensation and sub-optimal plant populations rendered yield comparisons between cultivars questionable. The issue of sub-optimal seedling emergence and plant population needs to be studied further before suitability of growing these edamame cultivars in central Pennsylvania can be determined.
Erin Silva, Mark Renz, and Stephanie Walker
Chile pepper (Capsicum annum) production in the southwest can be impacted by many factors. In particular, factors that alter root growth and development can be critical to pepper productivity. Several factors can cause less-than-optimal taproot formation, including irrigation practices, planting method (seeds vs. transplants), climactic conditions, and competition from weed species for limiting resources. The goals of this research were to quantify the root development of chile peppers established from either seeds or transplants under furrow and drip irrigation. Research was conducted in 2005 at Artesia Plant Science Research Center in Artesia, N.M., using a state-of-the-art drip irrigation system. Differences in root development between both irrigation types and planting methods were measured using of the mini-rhizotron image capturing system. Measurements occurred at a weekly basis to document location, root length density, and pattern of root formation. At the time of harvest, yield and fruit quality were evaluated. Direct-seeded chile plants yielded more fruits than transplanted chile under both irrigation regimes. Patterns of root development differed over time for direct-seeded vs. transplanted and furrow vs. drip-irrigated chile peppers. Planting and irrigation method affected root growth differently at various points in the season. These data can aid in the optimization of management strategies for specific production practices.
Roland Roberts, David Bender, and Samuel Field
Extension-research teamwork supports Texas High Plains onion grower-shippers in transition from unprofitable labor intensive marketing and culture to profitable mechanical systems that are less stressful to workers. System comparisons include machine harvest vs. lifting and hand clipping; stationary seed grading and bagging vs. mobile field grading and bagging; transplant vs. fall seeding, spring seeding and dry set production. Old marketing systems cost growers $4.30/50-lb. sack, and the innovative system costs $2.59 to $3.00/sack. Old transplant systems average $450 to $500/acre and direct seeding costs $200/acre. Net increase in return to grower management from adoption of new systems range from $1,300 to $1,700. Extension and research conduct economic analysis, cultivar performance trials, seeding technique studies and on-farm demonstrations.
Charles S. Vavrina, Thomas A. Obreza, and John Cornell
`Tropical Quick' Chinese cabbage (Brassica rapa L., Pekinensis Group) was planted three times at 2-week intervals in Spring 1991 (direct-seeded) and two times in Fall 1991 (transplanted) in double rows on polyethylene-mulched beds to evaluate N source and rates. Calcium nitrate, ammonium nitrate, urea, urea-ammonium nitrate solution (Uran), and urea-calcium solution (Nitro-Pius) were applied preplant at 67,112, and 157 kg N/ha. The two later spring planting dates, compared with the earliest date, resulted in greater head fresh weights and higher insect damage incidence, but lower tipburn and flowering incidence. The earlier fall planting resulted in greater head fresh weight but a much higher flowering incidence than the later planting. Irrespective of planting date, head fresh weight increased quadratically, and tipburn and flowering incidence decreased linearly with increasing N rate. Although N source affected head fresh weight and tipbum incidence, differences were too small to be of practical value.
Michael N. Dana and Ricky D. Kemery
Interest in direct-seeding establishment of wildflowers as a component of landscape planting has continued to increase. Seed may be very expensive. Information is needed on the quality of seed available to consumers and the landscape industry. The goal of this work was to assess the level and consistency of seed quality available from the wildflower seed production/marketing industry. Eleven species of native prairie forb wildflowers and eight species of “garden” wildflowers from seven companies were purchased in 1992 and 1993 and subjected to germination testing. Germination procedures were those of AOSA where available, or generalized from the literature when no guidelines existed. Results showed significant variation among wildflower species, among companies supplying the same species, and over the two seed years tested in the study. These data reinforce the need for seed quality testing and reporting as a part of the sales of wildflower seed.
Richard G Greenland
Planting barley (Hordeum vulgare L.) as a living mulch with onions (Allium cepa L.) reduces soil erosion and protects the onions from wind damage. It can also reduce yield and size of onion bulbs if not managed correctly. In a 4-year study at the Oakes Irrigation Research Site in North Dakota, barley was planted in the spring at the same time that onions were direct-seeded. Barley rows were planted either parallel with or perpendicular to the onion rows. Barley was killed with fluazifop-P herbicide when ≈13, 18, 23, or 30 cm tall. Onion size and yields were reduced when barley was allowed to grow taller than 18 cm before killing it. Total onion yield was usually greater when barley was planted parallel with, rather than perpendicular to, onion rows. Chemical name used: (R)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid (fluazifop-P).