scholarly journals Variation and adaptation in limpograss (Hemarthria altissima)

Author(s):  
P.W. Woods ◽  
J.N. Couchman ◽  
H.A. Barlow

Persistent and productive cultivars of limpograss (Hemarthriu altissima (Poir.) Stapf et C.E. Hubb.) are required if the species is to be useful in Northland cattle systems. A study was undertaken to investigate plant morphological traits, adaptation and persistence of 8 accessions. A series of abandoned research sites was revisited to determine long-term persistence and adaptation. Trials were established at 4 new sites throughout the northern North Island to assess morphological variation and plant survival. There was considerable variation in morphological traits assessed and plant survival, allowing scope for future selection. Bigalta used in earlier research trials had largely failed to persist under normal pasture management practices. Future work should use the cultivar Floralta. Keywords: adaptation, flowering, Hemarthria altissima, leaf, morphological variation, persistence, seed, stolon

Soil Research ◽  
2011 ◽  
Vol 49 (4) ◽  
pp. 320 ◽  
Author(s):  
K. Y. Chan ◽  
M. K. Conyers ◽  
G. D. Li ◽  
K. R. Helyar ◽  
G. Poile ◽  
...  

In addition to its important influence on soil quality and therefore crop productivity, soil organic carbon (SOC) has also been identified as a possible C sink for sequestering atmospheric carbon dioxide. Limited data are available on the impact of management practices on the rate of SOC change in agricultural soils in Australia. In this paper, results of three long-term trials (13–25 years) located near Wagga Wagga in temperate Australia were used to assess C dynamics under different tillage and stubble management practices, and under cropping intensities in pasture/crop rotations. Experimental results confirm the importance of management practices and pasture in determining first the steady-state SOC concentrations that are characteristic of given rotations and crop management systems, and second the rates of change of SOC concentrations as they approach steady-state concentrations in agricultural soils of this agro-ecological zone. A long-term crop/pasture experiment at a site with initial high SOC showed that the rate of SOC change in different treatments ranged from –278 to +257 kg C/ha.year over 0–0.3 m soil depth. Under continuous cropping, even under conservation agriculture practices of no-tillage, stubble retention, and crop rotation, the high initial SOC stock (0–0.3 m) present after a long-term pasture phase was, at best, maintained but tended to decrease with increased tillage or stubble burning practices. The effect of tillage was greater than that of stubble management. Increases in SOC were observed only in rotations incorporating a pasture phase. Our results suggest that improved soil nutrient and grazing management of permanent pasture can lead to an increase of 500–700 kg C/ha.year where the initial SOC concentrations are well below steady-state concentrations that could be expected after long periods of improved management. No difference was found between perennial pasture and annual pasture to the depth measured (0–0.3 m). Our results suggest that pasture holds the key to maintaining, and even increasing, SOC under crop/pasture in this environment.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10258
Author(s):  
Yichao Yang ◽  
Amanda J. Ashworth ◽  
Jennifer M. DeBruyn ◽  
Lisa M. Durso ◽  
Mary Savin ◽  
...  

The persistence of antimicrobial resistant (AMR) genes in the soil-environment is a concern, yet practices that mitigate AMR are poorly understood, especially in grasslands. Animal manures are widely deposited on grasslands, which are the largest agricultural land-use in the United States. These nutrient-rich manures may contain AMR genes. The aim of this study was to enumerate AMR genes in grassland soils following 14-years of poultry litter and cattle manure deposition and evaluate if best management practices (rotationally grazed with a riparian (RBR) area and a fenced riparian buffer strip (RBS), which excluded cattle grazing and poultry litter applications) relative to standard pasture management (continuously grazed (CG) and hayed (H)) minimize the presence and amount of AMR genes. Quantitative PCR (Q-PCR) was performed to enumerate four AMR genes (ermB, sulI, intlI, and blactx-m-32) in soil, cattle manure, and poultry litter environments. Six soil samples were additionally subjected to metagenomic sequencing and resistance genes were identified from assembled sequences. Following 14-years of continuous management, ermB, sulI, and intlI genes in soil were greatest (P < 0.05) in samples collected under long-term continuous grazing (relative to conservation best management practices), under suggesting overgrazing and continuous cattle manure deposition may increase AMR gene presence. In general, AMR gene prevalence increased downslope, suggesting potential lateral movement and accumulation based on landscape position. Poultry litter had lower abundance of AMR genes (ermB, sulI, and intlI) relative to cattle manure. Long-term applications of poultry litter increased the abundance of sulI and intlI genes in soil (P < 0.05). Similarly, metagenomic shotgun sequencing revealed a greater total number of AMR genes under long-term CG, while fewer AMR genes were found in H (no cattle manure) and RBS (no animal manure or poultry litter). Results indicate long-term conservation pasture management practices (e.g., RBS and RBR) and select animal manure (poultry litter inputs) may minimize the presence and abundance of AMR genes in grassland soils.


2020 ◽  
Vol 301 ◽  
pp. 107060 ◽  
Author(s):  
Helen C.S. Amorim ◽  
Amanda J. Ashworth ◽  
Philip A. Moore ◽  
Brian J. Wienhold ◽  
Mary C. Savin ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Yichao Yang ◽  
Amanda J. Ashworth ◽  
Lisa M. Durso ◽  
Mary Savin ◽  
Jennifer M. DeBruyn ◽  
...  

Runoff from land-applied manure and poultry litter is one mechanism by which manure-borne bacteria are transported over large distances in the environment. There is a global concern that antimicrobial resistant (AMR) genes may be transmitted through the food chain from animal manures to soil to surface water. However, details are lacking on the ecology of AMR genes in water runoff as well as how conservation management practices may affect the runoff microbiome or minimize the movement of AMR genes. The aim of this study was to identify microbial community structure and diversity in water runoff following 14-years of poultry litter and cattle manure deposition and to evaluate the amount of AMR genes under five conventional and conservation pasture management strategies. Since 2004, all watersheds received annual poultry litter at a rate of 5.6 Mg ha−1 and were consistently managed. Surface runoff samples were collected from each watershed from 2018 to 2019, characterized using Illumina 16S rRNA gene amplicon sequencing and enumerated for four AMR-associated genes (ermB, sulI, intlI, and blactx-m-32) using quantitative PCR. Overall, long-term pasture management influenced water microbial community structure, with effects differing by year (p &lt; 0.05). Bacterial richness (Chao1 index) was influenced by pasture management, with the lowest richness occurring in the control (nearby non-agricultural water source) and the greatest under fields that were hayed (no cattle presence). Runoff bacterial richness in watersheds increased following poultry litter applications, indicating poultry litter is a possible source of bacteria and altered runoff community structure. The blactx-m-32 gene was not detected in any surface water sample. The remaining three AMR genes were absent in the non-agricultural control, but present in agricultural samples. However, there was no impact (p &gt; 0.05) from pasture management on the abundance of these genes, indicating both conventional and conservation practices have similar ecologies for these targets; however, there was a greater detection of sulI genes from runoff in continuously grazed systems in 2019, with hay being lowest in 2019. Results illustrate that the edge of field buffer strips may increase bacterial richness in water runoff, but these changes in richness do not greatly impact target AMR genes in the United States largest land-use category.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ricardo González-Quintero ◽  
Rolando Barahona-Rosales ◽  
Diana María Bolívar-Vergara ◽  
Ngonidzashe Chirinda ◽  
Jacobo Arango ◽  
...  

Abstract There are few reports on dual-purpose cattle systems characterization in Latin America and Colombia based on large datasets. This limits our understanding of their dynamics, and the establishment of public policies and government programs to improve their productive performance, promotion and rural development. This study aimed to characterize very small, small, medium, and large dual-purpose farms in Colombia from technical and environmental perspectives. The data analysed were obtained from the Ganadería Colombiana Sostenible and the LivestockPlus projects, which gathered information from a total of 1313 dual-purpose farms in Colombia. Farms were classified as being either very small (1 to 30 bovines), small (31 to 50 bovines), medium (51 to 250 bovines), or large farms (more than 251 bovines). Numerical and categorical variables were distributed into five components: (1) General Farm Information, (2) Herd Composition and Management, (3) Pasture Management, (4) Production Information, and (5) Environmental Information. Each component was analysed using the factorial analysis of mixed data (FAMD) method. According to FAMD, for the components General Farm Information, Herd Composition and Management, Pasture Management, and Production Information, the distribution of variables led to a spatial separation of the centroid from each category of producers. For the component Environmental Information, there was no separation of the centroid. In general, medium-sized and large farms showed better infrastructure, better machinery and equipment, and better reproductive practices; however, this was not reflected in a significant improvement of productive parameters, except for a lower mortality rate. Larger livestock producers need to plan their livestock husbandry activities properly, based on their better available infrastructure and livestock management practices, with the purpose of increasing productivity. The main features identified for each livestock producer category can be the basis to guide and establish policies and programmes for their technological development. The development of better livestock management practices and the implementation of technology, as well as technical assistance, should focus on small- and medium-sized livestock producers, which could lead to reaching a better productive and reproductive performance of dual-purpose systems.


2019 ◽  
Vol 67 (2) ◽  

Moderate endurance training is known to improve cardiovascular risk factors, and prolongs life expectancy. On the other hand, there has been some discussion whether “too much” exercise might have a contrarious effect by accelerating coronary atherosclerosis. The goal of this review was to evaluate the current literature on the effects of long-term vigorous endurance training on the coronary vasculature. In summary, data point to an increased calcium score, and a higher burden of atherosclerotic plaque in male athletes compared to sedentary controls. However, the plaques found in athletes were more prone to be calcified. The pathogenesis and clinical relevance of this athlete coronary artery disease phenotype remains incompletely understood and represents an area of important future work.


2019 ◽  
Vol 67 (2) ◽  

Moderate endurance training is known to improve cardiovascular risk factors, and prolongs life expectancy. On the other hand, there has been some discussion whether “too much” exercise might have a contrarious effect by accelerating coronary atherosclerosis. The goal of this review was to evaluate the current literature on the effects of long-term vigorous endurance training on the coronary vasculature. In summary, data point to an increased calcium score, and a higher burden of atherosclerotic plaque in male athletes compared to sedentary controls. However, the plaques found in athletes were more prone to be calcified. The pathogenesis and clinical relevance of this athlete coronary artery disease phenotype remains incompletely understood and represents an area of important future work.


1986 ◽  
Vol 18 (4-5) ◽  
pp. 53-61 ◽  
Author(s):  
P. B. Birch ◽  
G. G. Forbes ◽  
N. J. Schofield

Early results from monitoring runoff suggest that the programme to reduce application of superphosphate to farmlands in surrounding catchments has been successful in reducing input of phosphorus to the eutrophic Peel-Harvey estuary. In the estuary this phosphorus fertilizes algae which grow in abundance and accumulate and pollute once clean beaches. The success of the programme has been judged from application of an empirical statistical model, which was derived from 6 years of data from the Harvey Estuary catchment prior to a major change in fertilizer practices in 1984. The model relates concentration of phosphorus with rate of flow and time of year. High phosphorus concentrations were associated with high flow rates and with flows early in the high runoff season (May-July). The model predicted that the distribution of flows in 1984 should have resulted in a flow-weighted concentration of phosphorus near the long-term average; the observed concentration was 25% below the long-term average. This means that the amount of phosphorus discharged into the Harvey Estuary could have been about 2 5% less than expected from the volume of runoff which occurred. However several more years of data are required to confirm this trend.


Author(s):  
Ilana Seager ◽  
Douglas S. Mennin ◽  
Amelia Aldao

Generalized anxiety disorder (GAD) is a debilitating condition characterized by excessive, pervasive, uncontrollable, and paralyzing worries about a wide range of future situations. Individuals with this condition frequently find themselves stuck in worry and tension cycles in futile attempts at reducing uncertainty and increasing control. GAD has been associated with substantial impairments in functioning and reduced quality of life. GAD remains poorly understood, and the long-term efficacy and end-state functioning resulting from treatment are weaker compared to other anxiety disorders. Some treatments (e.g., emotion regulation therapy, acceptance-based behavioral therapy) have improved efficacy, partly by targeting emotional dysfunction. Basic psychopathology research has focused on identifying the role of negative affect in GAD, so little is known about how positive affect is experienced and regulated in this disorder. This is particularly important in light of the overlap of this condition with major depressive disorder, which is characterized by low or suppressed positive emotion. Developing such an understanding is essential to further improve the efficacy of emotion-based treatments. This chapter reviews current and future directions in the study of positive affect in GAD. The chapter reviews the nascent research on positive affect and GAD, then illustrates dimensions of future work.


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