Carbon storage in soils of Southeastern Nigeria under different management practices

<p>Abstract</p> <p>Background</p> <p>Changes in agricultural practices-notably changes in crop varieties, application of fertilizer and manure, rotation and tillage practices-influence how much and at what rate carbon is stored in, or released from, soils. Quantification of the impacts of land use on carbon stocks in sub-Saharan Africa is challenging because of the spatial heterogeneity of soil, climate, management conditions, and due to the lack of data on soil carbon pools of most common agroecosystems. This paper provides data on soil carbon stocks that were collected at 10 sites in southeastern Nigeria to characterize the impact of soil management practices.</p> <p>Results</p> <p>The highest carbon stocks, 7906-9510 gC m^-2, were found at the sites representing natural forest, artificial forest and artificial grassland ecosystems. Continuously cropped and conventionally tilled soils had about 70% lower carbon stock (1978-2822 gC m^-2). Thus, the soil carbon stock in a 45-year old <it>Gmelina </it>forest was 8987 gC m^-2, whereas the parts of this forest, that were cleared and continuously cultivated for 15 years, had 75% lower carbon stock (1978 gC m^-2). The carbon stock of continuously cropped and conventionally tilled soils was also 25% lower than the carbon stock of the soil cultivated by use of conservation tillage.</p> <p>Conclusion</p> <p>Introducing conservation tillage practices may reduce the loss of soil carbon stocks associated with land conversion. However, the positive effect of conservation tillage is not comparable to the negative effect of land conversion, and may not result in significant accumulation of carbon in southeastern Nigeria soils.</p

Abundant Degenerate Miniature Inverted-Repeat Transposable Elements in Genomes of Epichloid Fungal Endophytes of Grasses

Miniature inverted-repeat transposable elements (MITEs) are abundant repeat elements in plant and animal genomes; however, there are few analyses of these elements in fungal genomes. Analysis of the draft genome sequence of the fungal endophyte Epichloë festucae revealed 13 MITE families that make up almost 1% of the E. festucae genome, and relics of putative autonomous parent elements were identified for three families. Sequence and DNA hybridization analyses suggest that at least some of the MITEs identified in the study were active early in the evolution of Epichloë but are not found in closely related genera. Analysis of MITE integration sites showed that these elements have a moderate integration site preference for 5′ genic regions of the E. festucae genome and are particularly enriched near genes for secondary metabolism. Copies of the EFT-3m/Toru element appear to have mediated recombination events that may have abolished synthesis of two fungal alkaloids in different epichloae. This work provides insight into the potential impact of MITEs on epichloae evolution and provides a foundation for analysis in other fungal genomes

Hiding from the Moonlight: Luminosity and Temperature Affect Activity of Asian Nocturnal Primates in a Highly Seasonal Forest

The effect of moonlight and temperature on activity of slow lorises was previously little known and this knowledge might be useful for understanding many aspects of their behavioural ecology, and developing strategies to monitor and protect populations. In this study we aimed to determine if the activity of the pygmy loris (Nycticebus pygmaeus) is affected by ambient temperature and/or moonlight in a mixed deciduous forest. We radio-collared five females and five males in the Seima Protection Forest, Cambodia, in February to May, 2008 and January to March, 2009 and recorded their behaviour at 5 minutes intervals, totalling 2736 observations. We classified each observation as either inactive (sleeping or alert) or active behaviour (travel, feeding, grooming, or others). Moon luminosity (bright/dark) and ambient temperature were recorded for each observation. The response variable, activity, was binary (active or inactive), and a logit link function was used. Ambient temperature alone did not significantly affect mean activity. Although mean activity was significantly affected by moonlight, the interaction between moonlight and temperature was also significant: on bright nights, studied animals were increasingly more active with higher temperature; and on dark nights they were consistently active regardless of temperature. The most plausible explanation is that on bright cold nights the combined risk of being seen and attacked by predators and heat loss outweigh the benefit of active behaviours

Practical guide to reservoir management

This report summarises a range of studies and consolidated practical knowledge related to reservoir management in the Australian context, which also have wider international application. The guide provides an overview of processes that impact upon drinking water quality in reservoirs and also a range of selected procedures and tools for reservoir management. This is supported by a series of case study investigations that were largely carried out within the Source Water Program of the CRC for Water Quality & Treatment. The first section of this guide deals with reservoir monitoring and modeling with discussion about the application of hydrodynamic models in reservoir management. It is followed by sections on catchmentderived contaminants, including description and case studies of the use of a simple model to assess contaminant transport, such as pathogens in reservoir inflows. The guide outlines the importance of natural organic matter dynamics and transformations in reservoirs. Subsequent sections address reservoir-derived contaminants such as cyanobacteria and iron and manganese and provide a case study of the use and importance of variable depth reservoir offtakes to optimise withdrawal of the best quality water. The guide includes discussion of managing the impacts of wildfire on water quality and has an overview of the emerging area of climate change and reservoir management. Reservoir management should be considered in the context of the Framework for Management of Drinking Water Quality contained in Chapter 2 of the Australian Drinking Water Guidelines (ADWG), (http://www.nhmrc.gov.au/publications/synopses/_files/adwg_11_06_chapter_2.pdf). This Framework offers effective means of assuring drinking water quality and the protection of public health through adoption of a preventive management approach that encompasses all steps in water production from catchment to consumer. When using the Framework there are a number of elements that need to be considered in relation to reservoir management including: assessment of the role and importance of the reservoir in the context of the overall supply system; identification of preventive measures available for water quality management in the reservoir; and the identification of operational and process controls available. It is important to note that reservoirs can form one of the important barriers to contamination in this preventive strategy from ‘catchment to tap’, however they can also be a source of water quality deterioration. The first step in the development of a reservoir management plan using this key element approach should be to consider the potential hazards from catchment activities and the circumstances under which these will develop as risks to water quality. This risk assessment not only informs the reservoir management plan but may also reveal opportunities for managing contaminants at the source. The most common contaminants of concern generated from catchments are pathogens, particulates and natural organic matter but in some cases industrial and agricultural chemicals may also be important. High rainfall and associated inflows represent the major risk period to deliver these contaminants. During storage of water in the reservoir a number of beneficial water quality changes can occur. Reduced water movement increases the rate of sedimentation of particulates. This reduces turbidity and may also result in the sequestering of the contaminants associated with the particles. Many of the pathogens of concern are attenuated by environmental conditions with temperature and UV being the most critical factors. They may also be consumed by grazers. Chemical contaminants may be subject to beneficial transformations that can de-toxify them. Understanding these mechanisms is criti cal to the understanding of the effectiveness of reservoirs as barriers to contamination. Of particular importance is a good knowledge of the hydrodynamic processes that control water movement in the...Justin Brookes, Mike Burch, Matthew Hipsey, Leon Linden, Jason Antenucci, Dennis Steffensen, Peter Hobson, Olivia Thorne, David Lewis, Stephanie Rinck-Pfeiffer, Uwe Kaeding and Paul Ramussenhttp://www.wqra.com.au/publications/document-search?q=qTJukfYt2zTCUDFcvqxYLbrp7tGxfz1