Soil Carbon and Microfauna Changes as Influenced by Combinations of Bio-covers and Cropping Sequences of Glyphosate Tolerant Corn, Soybean, and Cotton

The objective of this research was to compare the effects of combinations of a wide range of cropping sequences and soil bio-covers on soil organic carbon (SOC) and Heterodera glycines under no-tillage. The experiment used a split-block design with four replications at the Milan (RECM) and Middle TN (MTREC) Research & Education Centers. The whole-block treatment was cropping sequences of corn (Zea mays), soybean (Glycine max), and cotton (Gossypium hirsutum). The split-block was bio-covers of winter wheat (Triticum aestivum), hairy vetch (Vicia villosa), poultry litter, and fallow. Soil samples were taken over four years of experimentation. A novel technique was developed to measure SOC called near infrared reflectance spectroscopy (NIR). Partial least squares regression was used to predict SOC as measured by NIR. Results were compared to assess the reliability of NIR determination of organic carbon. NIR analysis correlated well (r greater than 0.9) with SOC as determined by combustion. NIR was therefore considered sufficiently accurate for quantifying soil organic carbon. Overall, both sites showed a small but consistent loss in carbon over all treatments. The average losses of SOC at the 0-5 cm depth were 1.06 and 1.40 Mg ha-1 at RECM and MTREC, respectively. In the subsurface, mean SOC loss at RECM was 1.43 Mg ha-1. Conversely, the subsurface SOC at MTREC was 3.14 Mg ha-1 higher than preexperiment levels. Crop sequence had a significant effect on change in SOC (P ≤ 0.05) in both surface and subsurface regions at RECM. Sequences with two or more years of cotton tended to lose significantly more (P ≤ 0.05) SOC than those with two or more years of soybean. The poultry litter bio-cover lost less surface SOC (0.58 Mg ha-1) than those under vetch (1.33 Mg ha-1) or fallow (1.8 Mg ha-1). Soybean cyst nematode (SCN) eggs were found in sequences containing no soybean throughout the experiment, indicating survival of over seven years without soybean. Sequences with two or more years of soybean had significantly higher (P ≤ 0.01) SCN egg density than others, with continuous soybean having the greatest egg population density. One year of rotation with a non-host crop typically reduced SCN egg population density by more than 50%

What do older people do when sitting and why? Implications for decreasing sedentary behaviour

Background and Objectives: Sitting less can reduce older adults’ risk of ill health and disability. Effective sedentary behavior interventions require greater understanding of what older adults do when sitting (and not sitting), and why. This study compares the types, context, and role of sitting activities in the daily lives of older men and women who sit more or less than average. Research Design and Methods: Semistructured interviews with 44 older men and women of different ages, socioeconomic status, and objectively measured sedentary behavior were analyzed using social practice theory to explore the multifactorial, inter-relational influences on their sedentary behavior. Thematic frameworks facilitated between-group comparisons. Results: Older adults described many different leisure time, household, transport, and occupational sitting and non-sitting activities. Leisure-time sitting in the home (e.g., watching TV) was most common, but many non-sitting activities, including “pottering” doing household chores, also took place at home. Other people and access to leisure facilities were associated with lower sedentary behavior. The distinction between being busy/not busy was more important to most participants than sitting/not sitting, and informed their judgments about high-value “purposeful” (social, cognitively active, restorative) sitting and low-value “passive” sitting. Declining physical function contributed to temporal sitting patterns that did not vary much from day-to-day. Discussion and Implications: Sitting is associated with cognitive, social, and/or restorative benefits, embedded within older adults’ daily routines, and therefore difficult to change. Useful strategies include supporting older adults to engage with other people and local facilities outside the home, and break up periods of passive sitting at home

Responses of bioenergy sorghum cell wall metabolism to agronomic practices

ABSTRAC

Outcomes in grade 3B follicular lymphoma: an international study led by the Australasian Lymphoma Alliance

Grade (G) 3B follicular lymphoma (FL) is a rare FL subtype which exists on a histological continuum between ‘lowgrade’ (Grade 1, 2 and 3A FL) and diffuse large B-cell lymphoma (DLBCL) appearing to share features with each. Clinical characteristics and outcomes are poorly understood due to lack of adequate representation in prospective trials and large-scale analyses. We analyzed 157 G3BFL cases from 18 international centers, and two comparator groups; G3AFL (n=302) and DLBCL (n=548). Composite histology with DLBCL or low-grade FL occurred in approximately half of the G3BFL cases. With a median of 5 years follow-up, the overall survival and progression-free survival of G3BFL patients was better than that of DLBCL patients (P<0.001 and P<0.001, respectively); however, G3BFL patients were younger (P<0.001) with better performance status (P<0.001), less extranodal disease (P<0.001) and more frequently had normal lactate dehydrogenase (P<0.001) at baseline. The overall and progression-free survival of patients with G3BFL and G3AFL were similar (P=0.83 and P=0.80, respectively). After frontline immunochemotherapy, 24% of G3BFL relapsed; relapse rates were 63% in the DLBCL cohort and 19% in the low-grade FL cohort. Eight percent of relapses occurred beyond 5 years. In this G3BFL cohort, the revised International Prognostic Index successfully delineated risk groups, but the Follicular Lymphoma International Prognostic Index did not. We conclude that patients with immunochemotherapy-treated G3BFL have similar survival outcomes to those with G3AFL, yet a favorable baseline profile and distinctly superior prognosis compared to patients with DLBCL

Mobility of poultry litter phosphorus in a coastal plain forest soil

Loss of phosphorus (P) to surface waters from forest soils fertilized with P-rich poultry litter (PL) is likely less than P loss from pasture because forest soils are typically lower in P. This study examined Pmobility where PL was applied to forest soil in amounts constituting disposal. Triplicate plots (13.4 × 3.1 m) of 4-year-old loblolly pine (Pinus taeda) were amended once per year at 0, 5, 10, and 20 Mg PL/ha in 1996 and 1997-2001. Surface soil (0-15 cm) P was monitored annually during the application period and at varying frequencies until 2013. Cores to 1 m were taken in 2002 and 2013. Phosphate sorption in surface and subsoil was measured, and transport in surface soil was investigated. Sorption after 24 h followed the Langmuir model, which described retention during transport better than a linear model but not as well as a two-site kinetic Langmuir model with sorption capacity based on oxalate-extractable aluminum (Al) + iron (Fe). Phosphate sorption was least in 15-to 30-cm depth soil; sorption increased deeper into the Bt horizon. Neither the increase nor the decrease in surface soil P showed a clear effect of sorption nonlinearity. Treatment effects were significant to a depth of 45 cm in 2002 except for organic P (surface only). The profile distribution of P was generally consistent with sorption, with some evidence of preferential flow. Leaching from 2002 to 2013 was slow, moving P in 20-Mg ha-1 plots to 60 cm. However, leaching was likely increased by initial concentrations and fast relative to tree uptake

Harvest strategy and N fertilizer effects on bioenergy sorghum production

Bioenergy sorghum (Sorghum bicolor (L.) Moench) has the potential to be a very important cellulosic feedstock if it can be produced without degrading soil quality. Two important factors for achieving that goal are N management and the amount of residue (i.e. carbon) returned to the soil. This study evaluated two N rates (0 or 280 kg ha-1 yr-1) and three levels of residue return (0, 25%, or 50%) on Weswood silty clay loam near College Station, TX USA. Biomass sorghum was grown continuously from 2009 through 2014. Maximum dry biomass yield (23 Mg ha-1) was produced with added N and 25% residue return in a year with above average precipitation. Overall, N fertilization increased biomass yield by 43 to 104%, while residue return enhanced yield from &lt; 1 to 23% during the six-year study. Averaged for the six years, biomass production for the 0, 25%, and 50% residue return treatments was 16, 20, and 18 Mg ha-1, respectively. Returning 25% of the crop residue significantly increased K uptake in both the 1st and 6th years. Sorghum fertilizer N uptake efficiency (FNUE) with residue return by 2014 was significantly increased compared to 2009 values. Non-limiting N fertilization and 25% residue return significantly increased NO3-N, P, K, and soil organic C (SOC) concentrations in surface (0 to 5 cm) samples and soil total N (TN) and K concentrations within the 60 to 90 cm layer. This study confirms that N fertilization will be required to achieve high biomass sorghum yield and suggests that developing a harvest strategy to return 25% of the crop residue will be sufficient to maintain soil quality

Efficacy Assessment of a New Fungicide, Miravis Ace, for Control of Fusarium Head Blight in Wheat

Fusarium head blight (FHB) is a serious disease of wheat and barley that leads to significant economic losses and deteriorated grain quality because of the associated mycotoxins. Genetic resistance and use of fungicides are the methods used to control FHB. However, in weather conditions conducive for FHB epidemics, higher levels of genetic resistance as well as greater efficacy of fungicides are required to adequately control this disease. Due to the extensive use of a single mode of action for management of FHB, there is a need to diversify fungicides used to lower the risk of resistance development in pathogen populations. In this 2-year study, we evaluated the performance of a new fungicide, Miravis Ace (a proprietary mix of pydiflumetofen and propiconazole active ingredients produced by Syngenta) for controlling FHB. It is a mix of succinate dehydrogenase inhibitor and demethylation inhibitor fungicides and can add diversity to the fungicide toolkit for FHB management. The level of control of FHB and deoxynivalenol (DON) achieved by spraying Miravis Ace at anthesis (Feekes growth stage 10.5.1) was found to be equivalent to that provided by the currently recommended products for managing FHB and reducing DON in wheat and barley. </jats:p

Impact of Crop Rotation and Bio-covers on Soybean Cyst Nematode

This research examined the effects of crop rotations and winter soil bio-covers on soybean cyst nematode (SCN) egg population density (EPD) under no-tillage. A field experiment with split-block treatments and four replications was conducted over three years with the whole-block treatments being rotations of corn (Zea mays L.), soybean [Glycine max (L.) Merr], and cotton (Gossypium hirsutum L.). Split-block treatments were bio-covers of winter wheat (Triticum aestivum L.), hairy vetch (Vicia villosa Roth), poultry litter, and fallow. Eggs were found in soybean-free sequences all four years, indicating potential residual viable SCN eggs in soil for seven years. Rotations with higher frequencies of soybean had significantly higher (P ≤ 0.01) SCN EPD than others, with continuous soybean being greatest. We did not observe a significant difference due to bio-cover on SCN EPD. Accepted for publication 8 July 2011. Published 30 September 2011. </jats:p