Greenhouse studies were conducted to explore soil texture and planting depth effects on emergence of large crabgrass, Virginia buttonweed, and cock’s-comb kyllinga. Soil textures examined were sand, loamy sand, and clay loam with planting depths of 0, 0.5, 1, 2, 4, 6, and 8 cm. Percent emergence was standardized relative to surface emergence to allow comparisons among tested weed species. The three-way interaction of weed species, planting depth, and soil texture was never significant for emergence. Significant interactions occurred between weed species and soil texture, weed species and planting depth, and soil texture and planting depth. For all weed species and soil textures, emergence decreased as planting depth increased with the greatest percent emergence at the soil surface. The planting depth at which weed emergence was decreased 50% [relative to surface emergence (D50)] was predicted by regression analysis. Large crabgrass emerged from deepest depths (8 cm) followed by Virginia buttonweed (6 cm) and cock’s-comb kyllinga (2 cm). Large crabgrass, Virginia buttonweed, and cock’s-comb kyllinga D50 occurred at 3.9, 1.1, and 0.8 cm, respectively. Sand, loamy sand, and clay loam D50 occurred at 0.9, 2.3, and 1.9 cm, respectively, with D50 higher in the soils with greater water-holding capacity.
Jared A. Hoyle, J. Scott McElroy, and Elizabeth A. Guertal
Gerald Henry, Rebecca Grubbs, Chase Straw, Kevin Tucker, and Jared Hoyle
Previous research involving turfgrass response to soil moisture used methodology that may compromise root morphology or fail to control outside environmental factors. Water-table depth gradient tanks were employed in the greenhouse to identify habitat specialization of hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy] and manilagrass [Zoysia matrella (L.) Merr.] maintained at 2.5 and 5.1 cm. Turfgrass quality (TQ), normalized difference vegetation index (NDVI), canopy temperature (CT), and root biomass (RB) were used as metrics for plants grown in monoculture in sandy clay loam soil. Mowing height did not affect growth of turfgrass species in response to soil moisture. Turfgrass quality, NDVI, and RB were greatest, whereas CT was lowest at wetter levels [27- to 58-cm depth to the water-table (DWT)] of each tank where plants were growing at or above field capacity. However, bermudagrass RB was greatest at 27-cm DWT, whereas manilagrass RB at 27-cm DWT was lower than RB at 42.5- to 73.5-cm DWT in 2013 and lower than all other levels in 2014. Both species responded similarly to droughty levels (120- to 151-cm DWT) of the tanks. Turfgrass quality, NDVI, and RB were lowest, whereas CT was highest at higher droughty levels. Bermudagrass may be more competitive than manilagrass when soil moisture is high whereas both species are less competitive when soil moisture is low.
Gerald M. Henry, Jared A. Hoyle, Leslie L. Beck, Tyler Cooper, Thayne Montague, and Cynthia McKenney
Field experiments were conducted at the Central Texas Olive Ranch in Walburg, TX, in 2011 and 2012 to evaluate the efficacy of mulch and/or preemergence herbicides for weed control in high-density olive (Olea europaea L.) production during orchard establishment. Treatments were initiated on 1 Apr. 2011 and 28 Mar. 2012 and consisted of a nontreated control, isoxaben (2.2 kg a.i./ha), oryzalin (4.5 kg a.i./ha), oxadiazon (3.36 kg a.i./ha), and mesotrione (0.14 kg a.i./ha). Hardwood mulch was applied to half of each plot following herbicide application. Weed counts, combined across species (camphorweed, texas croton, lanceleaf sage, pinnate tansymustard, tumble pigweed, common purslane, and prostrate spurge), were conducted to assess % weed cover at 4 and 12 weeks after treatment (WAT). In 2011, compared with the nonmulched no herbicide treatment, adding mulch reduced weed counts by 23 and increased weed control by 70% 4 WAT. All preemergence herbicide treatments, regardless of mulching regime, resulted in ≥97% weed control 4 WAT with the exception of oryzalin without mulch (91% weed control, 3 weeds/plot). In 2012, compared with the nonmulched no herbicide treatment, adding mulch reduced weed counts by 35 and increased weed control by 64% 4 WAT. Mulching in combination with mesotrione resulted in 100% weed control, significantly greater than mesotrione applied without mulch (98%, 2 weeds/plot) 4 WAT. Oryzalin without mulch resulted in greater weed control (94%, 4 weeds/plot) in 2012 4 WAT; however, this treatment provided the least amount of weed control of all preemergence herbicides tested. By 12 WAT, weed counts were reduced by 21 and 22 in 2011 and 2012, respectively, in response to mulching in the nontreated plots resulting in a 52% and 42% increase in weed control in 2011 and 2012, respectively. Mesotrione was the only treatment affected by mulching regime 12 WAT in 2011 and 2012. Mesotrione in combination with mulch resulted in 100% weed control in 2011 and 2012, while mesotrione without mulch resulted in 93% weed control (3 and 4 weeds/plot) 12 WAT in 2011 and 2012, respectively. Although not statistically significant, isoxaben applied alone in 2011 resulted in 97% weed control (1 weed/plot), while isoxaben in combination with mulch resulted in 94% weed control (3 weeds/plot) 12 WAT. In 2011, oryzalin and oxadiazon resulted in 87% to 92% control, regardless of mulching regime 12 WAT. Weed control in response to isoxaben in 2012 was 95% 12 WAT, regardless of mulching regime. The combination of oxadiazon + mulch resulted in similar weed control (95%, 3 weeds/plot) 12 WAT; however, oxadiazon alone and oryzalin with and without mulch resulted in 87% to 89% weed control. All preemergence herbicides evaluated provided good to excellent weed control. Isoxaben and oryzalin are labeled for use on nonbearing fruit trees or during orchard establishment, while oxadiazon is only labeled for woody ornamentals. Although not labeled for use in orchards, mesotrione may be an alternative for use in olive production. The addition of mulching did not increase weed control except when used in conjunction with mesotrione. Mulch alone provided moderate weed control when preemergence herbicides were not applied. Furthermore, the utilization of mulch in combination with preemergence herbicides may help reduce photodegradation and/or volatilization when irrigation/rainfall is limited.
Jared. A. Hoyle, Gerald M. Henry, Travis Williams, Aaron Holbrook, Tyler Cooper, Leslie L. Beck, and Andrew J. Hephner
Growing concern over the sufficiency and variability of present water supplies in the arid Southwest has led to the examination of buffalograss [Buchloe dactyloides (Nutt.) Engelm.] for water conservation. Increasing acceptance of buffalograss will require investigation into conversion techniques for its establishment. The objectives of this study were to evaluate the effects of seedbed preparation and seeding rate on the establishment of buffalograss after bermudagrass desiccation with glyphosate. Research was conducted at the Texas Tech Quaker Research farm in 2009 and 2010 on a mature ‘Riviera’ common bermudagrass [Cynodon dactylon (L.) Pers.] rough. Bermudagrass was sprayed with glyphosate at 1.1 kg acid equivalent (ae)/ha 5 and 1 weeks before seedbed preparation. Plots were scalped after desiccation. Treatments were arranged in a two × four factorial, randomized complete block design with four replications. two buffalograss seeding rates and four seedbed preparation treatments. Seedbed preparation treatments consisted of no seedbed preparation, topdressing alone (0.6-cm layer), hollow-tine aerification + topdressing, or verticutting + topdressing. ‘TopGun’ buffalograss was planted on 1 June 2009 and 4 June 2010 at 146 or 195 kg·ha−1. Grid counts were conducted to determine buffalograss cover one, two, and three months after planting (MAP). Counts were then converted to percent cover (0% to 100%). Greater buffalograss cover was observed when seed was applied at the higher rate (196 kg·ha−1) except within treatments that did not receive seedbed preparation treatment. No seedbed preparation resulted in unacceptable buffalograss cover. Percent buffalograss cover three MAP was 75%, 83%, and 86% for topdressing alone, aerification + topdressing, and verticutting + topdressing treatments seeded at 195 kg·ha−1, respectively.
Elizabeth T. Barton, Emily A. Barton, Susan Barton, Cheryl R. Boyer, Jim Brosnan, Paul Hill, Jared Hoyle, Judson Reid, Jamie Seger, and Eric Stafne
We held a technology session at the 2016 Annual Meeting of the American Society for Horticultural Science in Atlanta, GA, to provide guidance for technology choices in extension education and an opportunity to learn more about engaging new audiences, including the millennial generation (people born between 1982 and 2000). The use of technology is now an integral part of extension-client interaction. Presenters in the session gave examples of when technologies such as blogs, social media accounts, or web conferencing tools allowed extension personnel to increase engagement with online consumers and ultimately help fulfill extension’s mission of extending knowledge and changing lives. Effective engagement requires both educators and learners to be satisfied with the exchange. It is critical to monitor the quality of these digitally facilitated exchanges as compared with traditional face-to-face interactions. Additionally, it is possible to quantify digital engagement with readily available metrics, such as “retweets” (a reposted or forwarded message) or “likes” (indication an item is appreciated). These allow innovative and substantive reporting to further justify continued use of digital technologies for enhancing client-extension relations.