Soil tillage and cover crop on soil CO2 emissions from sugarcane fields     

Camila V. V. Farhate  Zigomar M. de Souza  Newton La Scala  Allan Charlles M. de Sousa  Ana Paula G. Santos  Joo Luis N. Carvalho 《Soil Use and Management》2019,35(2):273-282

Soil tillage is an agricultural practice that directly affects the global carbon cycle. Our study sought to assess the implications of adopting sunn hemp cover crops with different tillage practices on CO₂ emissions for two soil types (clayey and sandy soil) cultivated with sugarcane in Brazil. The experimental design was a split‐plot with randomized blocks, with the main plots being with cover crop or fallow and sub‐plots being under conventional or minimum tillage. Our results indicate that during the first 50 days after soil tillage, the variation in soil CO₂ emissions was stimulated by cover crop and soil tillage, while after that, it became dominated by the root respiration of sugarcane plants. We also found that over the first 97 days after the tillage, the clayey soil showed differences between minimum tillage with cover crop and fallow. Conversely, for sandy soil over the first 50 days following, there were differences between the tillage systems under cover cropping. Emissions from sugarcane rows were found to be greater than those from inter‐row positions. We concluded that soils under different textural classes had distinct patterns in terms of soil CO₂ emissions. The correct quantification of CO₂ emissions during the sugarcane renovation period should prioritize having a short assessment period (~50 days after soil tillage) as well as including measurements at row and inter‐row positions.  相似文献   

Modelling historical landscape changes     

Ridding  Lucy E.  Newton  Adrian C.  Redhead  John W.  Watson  Stephen C. L.  Rowland  Clare S.  Bullock  James M. 《Landscape Ecology》2020,35(12):2695-2712

Landscape Ecology - Historical maps of land use/land cover (LULC) enable detection of landscape changes, and help to assess drivers and potential future trajectories. However, historical maps are...  相似文献   

Digestive enzyme activities are higher in the shortfin mako shark,Isurus oxyrinchus,than in ectothermic sharks as a result of visceral endothermy     

Kyle C. Newton  James Wraith  Kathryn A. Dickson 《Fish physiology and biochemistry》2015,41(4):887-898

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A test of the cumulative effect of river weirs on downstream migration success,speed and mortality of Atlantic salmon (Salmo salar) smolts: An empirical study     

Matthew Newton  James Barry  Jennifer A. Dodd  Martyn C. Lucas  Patrick Boylan  Colin E. Adams 《Ecology of Freshwater Fish》2019,28(1):176-186

This study investigated the cumulative impact of weirs on the downstream migration of wild Atlantic salmon (Salmo salar) smolts in the River Foyle, Northern Ireland. In spring of 2013 fish were released in two tributaries of similar length; one tributary (impacted) had seven low‐head weirs along the migration pathway and the other was devoid of such structures (un‐impacted). Salmon smolts fitted with acoustic transmitters were monitored via a passive acoustic telemetry array during downstream migration. In 2014 the study was repeated only in the impacted tributary. Overall freshwater survival rates were high (>94%). There was no significant difference in mortality, movement pattern, delay or travel speeds between rivers or between years at any phase of migration. Escapement of salmon smolts through Lough Foyle (a marine sea lough) to the open ocean was low, approximately 18% in each year. Escapement did not differ between impacted and un‐impacted rivers. This study showed no postpassage effects of weirs on mortality, migration speed or escapement of downstream migrating smolts. This suggests that the elevated mortality at low‐head obstacles described in other studies is not inevitable in all river systems. Migration through rivers with natural riffle‐pool migration may result in similar effects as those from low‐head weirs. Causes of apparent high mortality in the early part of marine migration in this study, are unknown; however similar studies have highlighted the impact of fish predators on smolts.  相似文献   

Contrasting soil microbial responses to fertilizers and herbicides in a canola-barley rotation     

Newton Z. Lupwayi  Stewart A. Brandt  John T. O’Donovan  T. Kelly Turkington 《Soil biology & biochemistry》2010,42(11):1997-2004

The combination of high input costs and low commodity prices is forcing some farmers to consider reducing crop inputs like seed, fertilizer and herbicides. In a field trial in which different canola (Brassica napus L.) and barley (Hordeum vulgare L.) inputs were subtracted from a full package, or added to an empty package, we studied the effects of full or reduced fertilizer and herbicide inputs on soil microbiological characteristics at two sites from 2005 to 2008. The full package consisted of a high-yielding crop variety seeded at an optimum rate, with fertilizers and herbicides applied at recommended rates. The empty package consisted of a less expensive, low-yielding crop variety seeded at a low rate, with no fertilizer or herbicide applied. Between these two extremes were treatments in which fertilizers or herbicides were applied at 50% of recommended rates or not at all. Each treatment was repeated year after year in the same plot, i.e., treatment effects were cumulative. Fertilizer effects on soil microbial biomass C (MBC), β-glucosidase enzyme activity and bacterial functional diversity (based on community-level physiological profiles) were usually positive. Reduced fertilizer application rates reduced the beneficial fertilizer effects. Significant herbicide effects on soil microbiological properties occurred less often, were smaller in magnitude than fertilizer effects, and were mostly negative. Reduced herbicide rates reduced the deleterious herbicide effects. These significant fertilizer and herbicide effects were observed in canola more than barley, and mostly in the final year of the study, indicating the cumulative nature of treatment effects over time. Therefore, repeated applications of agricultural inputs like fertilizers and herbicides can have more significant effects on soil biology and biological processes than single applications indicate.  相似文献   

Evaluation of minichromosome maintenance protein 7 as a prognostic marker in canine cutaneous mast cell tumours     

Berlato D  Stewart J  Newton R  Maglennon GA  Monti P  Flindall A  Murphy S 《Veterinary and comparative oncology》2012,10(2):135-142

Minichromosome maintenance proteins (MCMs) are sensitive markers of cellular proliferation and have been shown to be significant predictors of survival in several human malignancies. MCM7 was evaluated as a prognostic marker in canine cutaneous mast cell tumours (MCTs). MCM7 immunohistochemistry was performed and an index of MCM7-positive cells calculated in dogs with known outcome. The Receiver Operating Characteristics method was used to individuate the best cut-off value of MCM7 score as predictor of survival. Survival analysis and prognostic variables were analysed with statistical methods. Ninety-five dogs were included with 31 dying of MCTs. A value of 0.18 was used as cut-off value of MCM7 score as a binary variable. The median survival time for MCM7 score ≤0.18 was not reached at 3668 days, whereas for MCM7 score >0.18 was 187 days (log-rank test; P < 0.0001). In the multivariable analysis, MCM7 was significantly associated with survival after controlling for age, surgical margins and histological grade (hazard ratio 9.2; P = 0.001).  相似文献   

Development of a quantitative multivariable radiographic method to evaluate anatomic changes associated with laminitis in the forefeet of donkeys     

SN Collins  SJ Dyson  RC Murray  JR Newton  F Burden  AF Trawford 《American journal of veterinary research》2012,73(8):1207-1218

Objective-To establish and validate an objective method of radiographic diagnosis of anatomic changes in laminitic forefeet of donkeys on the basis of data from a comprehensive series of radiographic measurements. Animals-85 donkeys with and 85 without forelimb laminitis for baseline data determination; a cohort of 44 donkeys with and 18 without forelimb laminitis was used for validation analyses. Procedures-For each donkey, lateromedial radiographic views of 1 weight-bearing forelimb were obtained; images from 11 laminitic and 2 nonlaminitic donkeys were excluded (motion artifact) from baseline data determination. Data from an a priori selection of 19 measurements of anatomic features of laminitic and nonlaminitic donkey feet were analyzed by use of a novel application of multivariate statistical techniques. The resultant diagnostic models were validated in a blinded manner with data from the separate cohort of laminitic and nonlaminitic donkeys. Results-Data were modeled, and robust statistical rules were established for the diagnosis of anatomic changes within laminitic donkey forefeet. Component 1 scores ≤ -3.5 were indicative of extreme anatomic change, and scores from -2.0 to 0.0 denoted modest change. Nonlaminitic donkeys with a score from 0.5 to 1.0 should be considered as at risk for laminitis. Conclusions and Clinical Relevance-Results indicated that the radiographic procedures evaluated can be used for the identification, assessment, and monitoring of anatomic changes associated with laminitis. Screening assessments by use of this method may enable early detection of mild anatomic change and identification of at-risk donkeys.  相似文献   

Control of foliar diseases in barley: towards an integrated approach     

Dale R. Walters  Anna Avrova  Ian J. Bingham  Fiona J. Burnett  James Fountaine  Neil D. Havis  Stephen P. Hoad  Gareth Hughes  Mark Looseley  Simon J. P. Oxley  Alan Renwick  Cairistiona F. E. Topp  Adrian C. Newton 《European journal of plant pathology / European Foundation for Plant Pathology》2012,133(1):33-73

Barley is one of the world??s most important crops providing food and related products for millions of people. Diseases continue to pose a serious threat to barley production, despite the use of fungicides and resistant varieties, highlighting the impact of fungicide resistance and the breakdown of host plant resistance on the efficacy of control measures. This paper reviews progress towards an integrated approach for disease management in barley in which new methods may be combined with existing measures to improve the efficacy of control in the long-term. Advances have been made in genetic mapping of resistance (R) genes and in identifying novel sources of genes in wild barley populations and land races. Marker assisted selection techniques are being used to pyramid R genes to increase the durability of resistance. Elicitors to induce host resistance used in combination with fungicides can provide effective disease control in the field and could delay the evolution of fungicide insensitivity. Traits that may contribute to disease tolerance and escape have been identified and the extent of genetic variation within barley germplasm is being determined. Tools are being developed to integrate the above methods via an assessment of the risk of economic injury occurring from disease to guide decisions on the requirement for fungicide treatment. Barriers exist to the adoption of integrated management approaches from growers and end-users further down the supply chain (e.g. acceptance of variety mixtures) and policy incentives from government may be required for it to be taken up in practice.  相似文献   

Risk factors for colic in horses after general anaesthesia for MRI or nonabdominal surgery: absence of evidence of effect from perianaesthetic morphine     

Andersen MS  Clark L  Dyson SJ  Newton JR 《Equine veterinary journal》2006,38(4):368-374

REASON FOR PERFORMING STUDY: Post anaesthetic colic is a recognised risk of general anaesthesia (GA), but causes are poorly understood. OBJECTIVES: To identify risk factors for development of colic following GA for magnetic resonance imaging (MRI) or nonabdominal surgery and to test whether the use of perianaesthetic morphine was associated with an increased risk of post anaesthetic colic. METHODS: A total of 553 anaesthetic and clinical records of 500 horses anaesthetised at the Animal Health Trust were analysed, 342 (62%) involved MRI and 211 (38%) nonabdominal, predominantly orthopaedic surgery. Multivariable logistic regression analysis was used to examine the association between post anaesthetic colic and explanatory variables, including use of perianaesthetic morphine. RESULTS: Twenty horses (3.6%) developed colic within 7 days of GA. A significantly larger (P = 0.001) proportion of the surgical cases developed post anaesthetic colic (7.1%) compared with MRI cases (1.5%). Having controlled for the effect of MRI/surgeon, there was evidence for a significantly increased risk of colic associated with maintenance of anaesthesia with isoflurane and administration of benzyl penicillin and/or ceftiofur. A reduction in risk of colic was associated with premedication with romifidine, longer duration of anaesthesia and sedation within 2 days of GA. Perianaesthetic morphine administration was not associated with increased risk. CONCLUSIONS: This study identified apparently novel risk factors for colic in horses following GA. Use of morphine was not found, after controlling for other MRI and surgery related risk factors, to be associated with an increased risk. The low prevalence of colic after GA and resulting low study power mean that further larger, multicentre collaborative studies are warranted to corroborate findings in this study. POTENTIAL RELEVANCE: Better knowledge of risk factors should lead to achievable measures to reduce frequency of occurrence.  相似文献   

Clinical evidence articles in Equine Veterinary Journal: progress since inception     

Marr CM  Newton JR 《Equine veterinary journal》2006,38(2):110-112

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