No abstract

These studies suggest that the changes in the dissipation or distribution of glyphosate following repeated applications of glyphosate may be related to shifts in the soil microbial community composition.

Globally, many schools are replacing traditional classrooms with innovative flexible learning spaces to improve academic outcomes. Little is known about the effect on classroom behaviour. Students from nine secondary schools (n = 60, M age = 13.2±1.0y) were observed via momentary time sampling for a 30 minute period, in both a traditionally furnished and arranged classroom and a flexible learning space containing a variety of furniture options to accommodate different pedagogical approaches and learning styles. The teaching approaches in both conditions were documented. In traditional classrooms the approach was predominantly teacher-led and in the flexible learning space it was student-centred. Students in flexible learning spaces spent significantly more time in large group settings (d = 0.61, p = 0.001), collaborating (d = 1.33, p = 0.001), interacting with peers (d = 0.88, p = 0.001) and actively engaged (d = 0.50, p = 0.001) than students in traditional classrooms. Students also spent significantly less class time being taught in a whole class setting (d = -0.65, p = 0.001), engaged in teacher-led instruction (d = -0.75, p = 0.001), working individually (d = -0.79, p = 0.001), verbally off-task (d = -0.44, p = 0.016), and using technology (d = -0.26, p = 0.022) than in traditional classrooms. The results suggest that the varied, adaptable nature of flexible learning spaces coupled with the use of student-centred pedagogies, facilitated a higher proportion of class time interacting, collaborating and engaging with the lesson content. This may translate into beneficial learning outcomes in the long-term.

Field experiments were conducted to compare large crabgrass control by clethodim or sethoxydim applied alone and with selected fungicides registered for use in peanut. Fluazinam, propiconazole plus trifloxystrobin, or tebuconazole did not affect efficacy of clethodim or sethoxydim. Azoxystrobin, boscalid, chlorothalonil, and pyraclostrobin reduced efficacy of clethodim and sethoxydim in some experiments. Increasing the herbicide rate increased large crabgrass control regardless of the addition of chlorothalonil. In laboratory experiments,14C absorption was less when14C-clethodim or14C-sethoxydim was applied with chlorothalonil. Pyraclostrobin and tebuconazole did not affect absorption of14C-clethodim or14C-sethoxydim.

Introduction and rapid adoption of dicamba-resistant (DR) soybean led to an increase of post-emergent applications of dicamba. This resulted in a widespread increase in non-target dicamba injury to non-DR soybean in 2017. Field studies were conducted in Manhattan, KS in 2018 and 2019 and in Ottawa, KS in 2019 to investigate the injury and yield response of soybean varieties with varying herbicide-resistance traits and maturity groups when exposed to dicamba. Four varieties were tested: ‘Credenz 3841LL’ (glufosinate resistant), ‘Credenz 4748LL’ (glufosinate resistant), ‘Asgrow AG4135RR2Y’ (glyphosate resistant), and ‘Stine 40BA02’ (glyphosate and isoxaflutole resistant), which will be abbreviated as CR3841, CR4748, AG4135, and ST40B, respectively. Soybean were treated with 5.6 g ae ha-1 of dicamba at V3 and R1. Percent soybean injury, soybean height, soybean yield and yield components, and injury to offspring were evaluated. Four weeks after treatment (WAT) at V3, the greatest injury was observed in ‘Asgrow AG4135RR2Y’ and ‘Stine 40BA02’. Dicamba application at R1 resulted in the greatest injury to ‘Stine 40BA02’ both 4 WAT and at senescence. Minimal injury was observed in all varieties treated at V3 at senescence and yield loss was 5% or less. Dicamba application at R1 resulted in 19 to 34% yield loss, with the least yield loss in ‘Credenz 4748LL’, and the greatest in ‘Stine 40BA02’. Varieties with greater injury at senescence generally yielded less than other varieties.

The recent introduction of imidazolinone-tolerant rice varieties allow imazethapyr to be used in commercial rice. Little is known about imazethapyr photodegradation in the rice field. Laboratory studies were conducted to determine the direct and indirect photolysis rates for imazethapyr and to evaluate the photolysis of imazethapyr in three rice paddy waters. The reaction quantum yield (phi I) for imazethapyr was determined to be 0.023 +/- 0.002, while the hydroxyl radical rate constant (K(I)*OH) was 2.8 x 10(13) M(-1) h(-1). These results show that imazethapyr is susceptible to both direct and indirect photolysis reactions in water. The results also show that imazethapyr photolysis in paddy water will be affected by turbidity because of its impact on the availability of sunlight to drive direct and indirect photolysis reactions.

Experiments were conducted during 1999, 2002, and 2003 to evaluate sicklepod control by 2,4-DB applied alone or in mixture with selected fungicides and insecticides registered for use in peanut. The fungicides boscalid, chlorothalonil, fluazinam, propiconazole plus trifloxystrobin, pyraclostrobin, or tebuconazole and the insecticides acephate, carbaryl, esfenvalerate, fenpropathrin, lambda-cyhalothrin, methomyl, or indoxacarb applied in mixtures with 2,4-DB did not reduce sicklepod control by 2,4-DB compared with 2,4-DB alone. The fungicide azoxystrobin reduced control in some but not all experiments. Sicklepod control was highest when 2,4-DB was applied before flowering regardless of fungicide treatment. Seed production and germination were reduced when 2,4-DB was applied 81 to 85 d after emergence when sicklepod was flowering. Applying 2,4-DB before flowering and at pod set and pod fill did not affect seed production.

Diclosulam is generally applied either PPI or PRE to peanut to control certain broadleaf weeds and suppress sedges. Research was conducted to determine efficacy and peanut response to POST applications of diclosulam at 9, 13, 18, and 27 g ai/ha. Efficacy of diclosulam was affected by application rate and environment. Common ragweed control ranged from 60 to 100%, entireleaf morningglory control from 56 to 100%, marestail control from 78 to 85%, and nodding spurge from 50 to 97%. Smooth pigweed and common lambsquarters were both controlled less than 35%. Diclosulam controlled yellow nutsedge and eclipta less than 70 and 80%, respectively. In separate experiments, diclosulam and imazapic controlled dogfennel more effectively than acifluorfen, bentazon, imazethapyr, lactofen, paraquat, or 2,4-DB. Visual estimates of peanut injury were 15% or less for all rates during both years. Peanut yield ranged from 3,340 to 3,730 kg/ha in 2002 and 5,230 to 5,820 kg/ha in 2003. Foliar injury and peanut pod yield were influenced by diclosulam rate, although no clear relation was evident. Cultivar and diclosulam rate did not interact with respect to visual injury or pod yield.