A Connection Management System to Enable the Wireless Transmission of MIDI Messages
- Authors: Shaw, Brent , Foss, Richard
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426829 , vital:72394 , https://www.aes.org/e-lib/browse.cfm?elib=18030
- Description: This paper examines the design and implementation of a wireless system for the distribution of MIDI messages for show control and studio environments. The system makes use of the MIDI and MIDINet protocols, creating wireless nodes that will enable the transmission of MIDI between devices on a wireless network with connection management capabilities through the use of embedded web servers. The paper describes the current state of the art, configuration of the system, hardware architectures, software design, and implementation.
- Full Text:
- Authors: Shaw, Brent , Foss, Richard
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426829 , vital:72394 , https://www.aes.org/e-lib/browse.cfm?elib=18030
- Description: This paper examines the design and implementation of a wireless system for the distribution of MIDI messages for show control and studio environments. The system makes use of the MIDI and MIDINet protocols, creating wireless nodes that will enable the transmission of MIDI between devices on a wireless network with connection management capabilities through the use of embedded web servers. The paper describes the current state of the art, configuration of the system, hardware architectures, software design, and implementation.
- Full Text:
A description of gametogenesis in the panga Pterogymnus laniarius (Pisces: Sparidae) with comments on changes in maturity patterns over the past two decades
- Booth, Anthony J, Hecht, Thomas
- Authors: Booth, Anthony J , Hecht, Thomas
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123542 , vital:35452 , https://doi.org/10.1080/02541858.1997.11448428
- Description: A description of gametogenesis in the panga Pferogymnus laniarius, a common endemic seabream species inhabiting the Agulhas Bank, South Africa, is presented. After sexual maturity, oogenesis and spermatogenesis continued throughout the year and were found to be similar to these processes in other seabream species and teleosts in general. Analysis of maturity data over the past two decades revealed a significant change in both age and size-at-maturity, a response to fishing pressure.
- Full Text:
- Authors: Booth, Anthony J , Hecht, Thomas
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123542 , vital:35452 , https://doi.org/10.1080/02541858.1997.11448428
- Description: A description of gametogenesis in the panga Pferogymnus laniarius, a common endemic seabream species inhabiting the Agulhas Bank, South Africa, is presented. After sexual maturity, oogenesis and spermatogenesis continued throughout the year and were found to be similar to these processes in other seabream species and teleosts in general. Analysis of maturity data over the past two decades revealed a significant change in both age and size-at-maturity, a response to fishing pressure.
- Full Text:
DDoS Attack Mitigation Through Control of Inherent Charge Decay of Memory Implementations
- Herbert, Alan, Irwin, Barry V W, van Heerden, Renier P
- Authors: Herbert, Alan , Irwin, Barry V W , van Heerden, Renier P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430339 , vital:72684 , https://www.academic-bookshop.com/ourshop/prod_3774091-ICCWS-2015-10th-International-Conference-on-Cyber-Warfare-and-Security-Kruger-National-Park-South-Africa-PRINT-ver-ISBN-978191030996.html
- Description: DDoS (Distributed Denial of Service) attacks over recent years have shown to be devastating on the target systems and services made publicly available over the Internet. Furthermore, the backscatter1 caused by DDoS attacks also affects the available bandwidth and responsiveness of many other hosts within the Internet. The unfortunate reality of these attacks is that the targeted party cannot fight back due to the presence of botnets and malware-driven hosts. These hosts that carry out the attack on a target are usually controlled remotely and the owner of the device is unaware of it; for this reason one cannot attack back directly as this will serve little more than to disable an innocent party. A proposed solution to these DDoS attacks is to identify a potential attacking address and ignore communication from that address for a set period of time through time stamping.
- Full Text:
- Authors: Herbert, Alan , Irwin, Barry V W , van Heerden, Renier P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430339 , vital:72684 , https://www.academic-bookshop.com/ourshop/prod_3774091-ICCWS-2015-10th-International-Conference-on-Cyber-Warfare-and-Security-Kruger-National-Park-South-Africa-PRINT-ver-ISBN-978191030996.html
- Description: DDoS (Distributed Denial of Service) attacks over recent years have shown to be devastating on the target systems and services made publicly available over the Internet. Furthermore, the backscatter1 caused by DDoS attacks also affects the available bandwidth and responsiveness of many other hosts within the Internet. The unfortunate reality of these attacks is that the targeted party cannot fight back due to the presence of botnets and malware-driven hosts. These hosts that carry out the attack on a target are usually controlled remotely and the owner of the device is unaware of it; for this reason one cannot attack back directly as this will serve little more than to disable an innocent party. A proposed solution to these DDoS attacks is to identify a potential attacking address and ignore communication from that address for a set period of time through time stamping.
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Effect of temperature on development of the blowfly, Lucilia cuprina (Wiedemann)(Diptera: Calliphoridae)
- Kotzé, Zanthé, Villet, Martin H, Weldon, Christopher W
- Authors: Kotzé, Zanthé , Villet, Martin H , Weldon, Christopher W
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442116 , vital:73960 , https://doi.org/10.1007/s00414-015-1153-y
- Description: The blowfly Lucilia cuprina is a primary colonizer of decaying vertebrate carrion, and its development provides a temperature-dependent clock that may be used to estimate the post-mortem interval of corpses and carcasses in medicolegal forensic investigations. This study uses the development of L. cuprina raised on a substrate of chicken liver at six constant temperatures from 18 to 33 °C to calibrate a thermal accumulation model of development for forensic applications. Development was optimal near 24 °C; above this temperature, survival of post-feeding life stages was increasingly compromised, while below it, development was increasingly retarded. The lower developmental threshold (~12 °C) and thermal summation constants of L. cuprina are distinct from those reported for Lucilia sericata, verifying that it is essential to identify African Lucilia specimens accurately when using them to estimate post-mortem intervals.
- Full Text:
- Authors: Kotzé, Zanthé , Villet, Martin H , Weldon, Christopher W
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442116 , vital:73960 , https://doi.org/10.1007/s00414-015-1153-y
- Description: The blowfly Lucilia cuprina is a primary colonizer of decaying vertebrate carrion, and its development provides a temperature-dependent clock that may be used to estimate the post-mortem interval of corpses and carcasses in medicolegal forensic investigations. This study uses the development of L. cuprina raised on a substrate of chicken liver at six constant temperatures from 18 to 33 °C to calibrate a thermal accumulation model of development for forensic applications. Development was optimal near 24 °C; above this temperature, survival of post-feeding life stages was increasingly compromised, while below it, development was increasingly retarded. The lower developmental threshold (~12 °C) and thermal summation constants of L. cuprina are distinct from those reported for Lucilia sericata, verifying that it is essential to identify African Lucilia specimens accurately when using them to estimate post-mortem intervals.
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Global Cicada Sound Collection I: Recordings from South Africa and Malawi by BW Price and MH Villet and harvesting of BioAcoustica data by GBIF
- Baker, Ed, Price, Benjamin W, Rycroft, Simon, Villet, Martin H
- Authors: Baker, Ed , Price, Benjamin W , Rycroft, Simon , Villet, Martin H
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441420 , vital:73886 , https://bdj.pensoft.net/articles.php?id=5792
- Description: Sound collections for singing insects provide important repositories that underpin existing research (eg Price et al. 2007 at http://bio. acousti. ca/node/11801; Price et al. 2010) and make bioacoustic collections available for future work, including insect communication (Ordish 1992), systematics (eg David et al. 2003), and automated identification (Bennett et al. 2015). The BioAcoustica platform (Baker et al. 2015) is both a repository and analysis platform for bioacoustic collections: allowing collections to be available in perpetuity, and also facilitating complex analyses using the BioVeL cloud infrastructure (Vicario et al. 2011). The Global Cicada Sound Collection is a project to make recordings of the world's cicadas (Hemiptera: Cicadidae) available using open licences to maximise their potential for study and reuse. This first component of the Global Cicada Sound Collection comprises recordings made between 2006 and 2008 of Cicadidae in South Africa and Malawi.
- Full Text:
- Authors: Baker, Ed , Price, Benjamin W , Rycroft, Simon , Villet, Martin H
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441420 , vital:73886 , https://bdj.pensoft.net/articles.php?id=5792
- Description: Sound collections for singing insects provide important repositories that underpin existing research (eg Price et al. 2007 at http://bio. acousti. ca/node/11801; Price et al. 2010) and make bioacoustic collections available for future work, including insect communication (Ordish 1992), systematics (eg David et al. 2003), and automated identification (Bennett et al. 2015). The BioAcoustica platform (Baker et al. 2015) is both a repository and analysis platform for bioacoustic collections: allowing collections to be available in perpetuity, and also facilitating complex analyses using the BioVeL cloud infrastructure (Vicario et al. 2011). The Global Cicada Sound Collection is a project to make recordings of the world's cicadas (Hemiptera: Cicadidae) available using open licences to maximise their potential for study and reuse. This first component of the Global Cicada Sound Collection comprises recordings made between 2006 and 2008 of Cicadidae in South Africa and Malawi.
- Full Text:
Immersive audio content creation using mobile devices and ethernet avb
- Rouget, Antoine, Foss, Richard
- Authors: Rouget, Antoine , Foss, Richard
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426786 , vital:72391 , https://www.aes.org/e-lib/browse.cfm?elib=18009
- Description: The goal of immersive sound systems is to localize multiple sound sources such that listeners are enveloped in sound. This paper describes an immersive sound system that allows for the creation of immersive sound content and real time control over sound source localization. It is a client/server system where the client is a mobile device. The server receives localization control messages from the client and uses an Ethernet AVB network to distribute appropriate mix levels to speakers with in-built signal processing.
- Full Text:
- Authors: Rouget, Antoine , Foss, Richard
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426786 , vital:72391 , https://www.aes.org/e-lib/browse.cfm?elib=18009
- Description: The goal of immersive sound systems is to localize multiple sound sources such that listeners are enveloped in sound. This paper describes an immersive sound system that allows for the creation of immersive sound content and real time control over sound source localization. It is a client/server system where the client is a mobile device. The server receives localization control messages from the client and uses an Ethernet AVB network to distribute appropriate mix levels to speakers with in-built signal processing.
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Incipient genetic isolation of a temperate migratory coastal sciaenid fish (Argyrosomus inodorus) within the Benguela Cold Current system
- Henriques, Romina, Potts, Warren M, Sauer, Warwick H H, Shaw, Paul W
- Authors: Henriques, Romina , Potts, Warren M , Sauer, Warwick H H , Shaw, Paul W
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124710 , vital:35652 , https://doi.10.1080/17451000.2014.952309
- Description: The Benguela Cold Current system, located in the south-eastern Atlantic, features cold sea surface temperatures, bounded to the north and south by tropical currents (the Angola and Agulhas Currents, respectively) and a perennial upwelling cell off central Namibia that divides the region into two sub-systems with different characteristics (Shannon 1985; Hutchings et al. 2009). The colder sea surface temperatures of the Benguela Current have been considered an important biogeographic barrier, isolating tropical and warm-temperate fauna of the Atlantic and Indo-Pacific Oceans (Avise 2000; Floeter et al. 2008). However, recent studies revealed that other oceanographic features, such as the perennial upwelling cell, may also play an important role in shaping the population structure of warm temperate fish populations within the Benguela system, as complete disruption of gene flow was documented both in Lichia amia (Linnaeus, 1758) and Atractoscion aequidens (Cuvier, 1830) (Henriques et al. 2012, 2014). Little is known, however, regarding the influence of the Benguela system on genetic population connectivity of cold-water-tolerant species.
- Full Text:
- Authors: Henriques, Romina , Potts, Warren M , Sauer, Warwick H H , Shaw, Paul W
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124710 , vital:35652 , https://doi.10.1080/17451000.2014.952309
- Description: The Benguela Cold Current system, located in the south-eastern Atlantic, features cold sea surface temperatures, bounded to the north and south by tropical currents (the Angola and Agulhas Currents, respectively) and a perennial upwelling cell off central Namibia that divides the region into two sub-systems with different characteristics (Shannon 1985; Hutchings et al. 2009). The colder sea surface temperatures of the Benguela Current have been considered an important biogeographic barrier, isolating tropical and warm-temperate fauna of the Atlantic and Indo-Pacific Oceans (Avise 2000; Floeter et al. 2008). However, recent studies revealed that other oceanographic features, such as the perennial upwelling cell, may also play an important role in shaping the population structure of warm temperate fish populations within the Benguela system, as complete disruption of gene flow was documented both in Lichia amia (Linnaeus, 1758) and Atractoscion aequidens (Cuvier, 1830) (Henriques et al. 2012, 2014). Little is known, however, regarding the influence of the Benguela system on genetic population connectivity of cold-water-tolerant species.
- Full Text:
Multi sensor national cyber security data fusion
- Swart, Ignus, Irwin, Barry V W, Grobler, Marthie
- Authors: Swart, Ignus , Irwin, Barry V W , Grobler, Marthie
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430393 , vital:72688 , https://www.academic-bookshop.com/ourshop/prod_3774091-ICCWS-2015-10th-International-Conference-on-Cyber-Warfare-and-Security-Kruger-National-Park-South-Africa-PRINT-ver-ISBN-978191030996.html
- Description: A proliferation of cyber security strategies have recently been published around the world with as many as thirty five strategies documented since 2009. These published strategies indicate the growing need to obtain a clear view of a country’s information security posture and to improve on it. The potential attack surface of a nation is extremely large however and no single source of cyber security data provides all the required information to accurately describe the cyber security readiness of a nation. There are however a variety of specialised data sources that are rich enough in relevant cyber security information to assess the state of a nation in at least key areas such as botnets, spam servers and incorrectly configured hosts present in a country. While informative both from an offensive and defensive point of view, the data sources range in a variety of factors such as accuracy, completeness, representation, cost and data availability. These factors add complexity when attempting to present a clear view of the combined intelligence of the data.
- Full Text:
- Authors: Swart, Ignus , Irwin, Barry V W , Grobler, Marthie
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430393 , vital:72688 , https://www.academic-bookshop.com/ourshop/prod_3774091-ICCWS-2015-10th-International-Conference-on-Cyber-Warfare-and-Security-Kruger-National-Park-South-Africa-PRINT-ver-ISBN-978191030996.html
- Description: A proliferation of cyber security strategies have recently been published around the world with as many as thirty five strategies documented since 2009. These published strategies indicate the growing need to obtain a clear view of a country’s information security posture and to improve on it. The potential attack surface of a nation is extremely large however and no single source of cyber security data provides all the required information to accurately describe the cyber security readiness of a nation. There are however a variety of specialised data sources that are rich enough in relevant cyber security information to assess the state of a nation in at least key areas such as botnets, spam servers and incorrectly configured hosts present in a country. While informative both from an offensive and defensive point of view, the data sources range in a variety of factors such as accuracy, completeness, representation, cost and data availability. These factors add complexity when attempting to present a clear view of the combined intelligence of the data.
- Full Text:
Observed correlations of unsolicited network traffic over five distinct IPv4 netblocks
- Nkhumeleni, Thiswilondi M, Irwin, Barry V W
- Authors: Nkhumeleni, Thiswilondi M , Irwin, Barry V W
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430408 , vital:72689 , https://www.academic-bookshop.com/ourshop/prod_3774091-ICCWS-2015-10th-International-Conference-on-Cyber-Warfare-and-Security-Kruger-National-Park-South-Africa-PRINT-ver-ISBN-978191030996.html
- Description: Using network telescopes to monitor unused IP address space provides a favorable environment for researchers to study and detect malware, denial of service and scanning activities within global IPv4 address space. This research focuses on comparative and correlation analysis of traffic activity across the network of telescope sensors. Analysis is done using data collected over a 12 month period on five network telescopes each with an aperture size of/24, operated in disjoint IPv4 address space. These were considered as two distinct groupings. Time series’ representing time-based traffic activity observed on these sensors was constructed. Using the cross-and auto-correlation methods of time series analysis, moderate correlation of traffic activity was achieved between telescope sensors in each category. Weak to moderate correlation was calculated when comparing category A and category B network telescopes’ datasets. Results were significantly improved by considering TCP traffic separately. Moderate to strong correlation coefficients in each category were calculated when using TCP traffic only. UDP traffic analysis showed weaker correlation between sensors, however the uniformity of ICMP traffic showed correlation of traffic activity across all sensors. The results confirmed the visual observation of traffic relativity in telescope sensors within the same category and quantitatively analyzed the correlation of network telescopes’ traffic activity.
- Full Text:
- Authors: Nkhumeleni, Thiswilondi M , Irwin, Barry V W
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430408 , vital:72689 , https://www.academic-bookshop.com/ourshop/prod_3774091-ICCWS-2015-10th-International-Conference-on-Cyber-Warfare-and-Security-Kruger-National-Park-South-Africa-PRINT-ver-ISBN-978191030996.html
- Description: Using network telescopes to monitor unused IP address space provides a favorable environment for researchers to study and detect malware, denial of service and scanning activities within global IPv4 address space. This research focuses on comparative and correlation analysis of traffic activity across the network of telescope sensors. Analysis is done using data collected over a 12 month period on five network telescopes each with an aperture size of/24, operated in disjoint IPv4 address space. These were considered as two distinct groupings. Time series’ representing time-based traffic activity observed on these sensors was constructed. Using the cross-and auto-correlation methods of time series analysis, moderate correlation of traffic activity was achieved between telescope sensors in each category. Weak to moderate correlation was calculated when comparing category A and category B network telescopes’ datasets. Results were significantly improved by considering TCP traffic separately. Moderate to strong correlation coefficients in each category were calculated when using TCP traffic only. UDP traffic analysis showed weaker correlation between sensors, however the uniformity of ICMP traffic showed correlation of traffic activity across all sensors. The results confirmed the visual observation of traffic relativity in telescope sensors within the same category and quantitatively analyzed the correlation of network telescopes’ traffic activity.
- Full Text:
The development of an e-Health system for health awareness campaigns in poor areas
- Gremu, Chikumbutso, Terzoli, Alfredo, Tsietsi, Mosiuoa
- Authors: Gremu, Chikumbutso , Terzoli, Alfredo , Tsietsi, Mosiuoa
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430638 , vital:72705 , 10.1109/ISTAFRICA.2015.7190527
- Description: This paper discusses work to develop an e-Health system called HealthAware to assist health service organisations to carry out targeted health awareness campaigns in poor areas. The system comprises two components called the Dashboard and the Health Messenger, which are web-based, Java applications that run in a peer-to-peer fashion. The Dashboard is used to create, manage, and publish awareness campaigns. The HealthMessenger facilitates end-users' access to the relevant awareness campaigns. A targeted communication strategy which splits the target population into subgroups based on their demo-graphic characteristics and geographic locations is used to determine relevant campaigns for a user. The HealthMessenger is hosted on an application service integration platform called TeleWeaver, while the Dashboard is hosted independently of TeleWeaver. Message queuing is used to ensure reliable communication between the Dashboard and the HealthMessenger. The implementation of HealthAware contributes knowledge on developing a system that ensures that users access only the information that is relevant to them. This addresses the challenge of sifting through potentially irrelevant information before arriving at the important information which is posed by generic materials.
- Full Text:
- Authors: Gremu, Chikumbutso , Terzoli, Alfredo , Tsietsi, Mosiuoa
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430638 , vital:72705 , 10.1109/ISTAFRICA.2015.7190527
- Description: This paper discusses work to develop an e-Health system called HealthAware to assist health service organisations to carry out targeted health awareness campaigns in poor areas. The system comprises two components called the Dashboard and the Health Messenger, which are web-based, Java applications that run in a peer-to-peer fashion. The Dashboard is used to create, manage, and publish awareness campaigns. The HealthMessenger facilitates end-users' access to the relevant awareness campaigns. A targeted communication strategy which splits the target population into subgroups based on their demo-graphic characteristics and geographic locations is used to determine relevant campaigns for a user. The HealthMessenger is hosted on an application service integration platform called TeleWeaver, while the Dashboard is hosted independently of TeleWeaver. Message queuing is used to ensure reliable communication between the Dashboard and the HealthMessenger. The implementation of HealthAware contributes knowledge on developing a system that ensures that users access only the information that is relevant to them. This addresses the challenge of sifting through potentially irrelevant information before arriving at the important information which is posed by generic materials.
- Full Text:
Variation in urease and β-glucosidase activities with soil depth and root density in a ‘Cripp's Pink’/M7 apple orchard under conventional and organic management.
- Meyer, André H, Wooldridge, John, Dames, Joanna F
- Authors: Meyer, André H , Wooldridge, John , Dames, Joanna F
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444051 , vital:74181 , https://doi.org/10.1080/02571862.2015.1053155
- Description: The effects of conventional (CON; utilising synthetic fertiliser and herbicide) and organic (ORG; nutrients supplied in compost, weeds controlled with straw mulch) orchard floor management practices on depth-wise variation in urease and β-glucosidase activities in tree-row soils were compared in a Western Cape ‘Cripp's Pink’/M7 apple orchard. Urease and β-glucosidase activities were determined spectrophotometrically in soils from five depth intervals from the walls of trenches excavated across the tree rows after seven years of treatment application. Soil pH, organic carbon, nitrate (NO3 ) and ammonium (NH4 ) nitrogen were also determined, as was root density. Enzyme activities were higher in the ORG than the CON topsoils but did not differ significantly (p = 0.05) at depths >30 cm. The positive effects of the ORG treatments were attributed to the liming effect and carbon and nitrogen contributions of the compost. Urease and β-glucosidase activities correlated strongly. Activities of both enzymes correlated significantly and positively with carbon, NO3− and pH, with urease correlated more strongly than β-glucosidase. Only urease correlated with root density. Organic orchard floor management practices may be more effective than CON practices in promoting microbial enzyme activities in the 0–30 cm soil depth intervals of Western Cape apple orchard soils.
- Full Text:
- Authors: Meyer, André H , Wooldridge, John , Dames, Joanna F
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444051 , vital:74181 , https://doi.org/10.1080/02571862.2015.1053155
- Description: The effects of conventional (CON; utilising synthetic fertiliser and herbicide) and organic (ORG; nutrients supplied in compost, weeds controlled with straw mulch) orchard floor management practices on depth-wise variation in urease and β-glucosidase activities in tree-row soils were compared in a Western Cape ‘Cripp's Pink’/M7 apple orchard. Urease and β-glucosidase activities were determined spectrophotometrically in soils from five depth intervals from the walls of trenches excavated across the tree rows after seven years of treatment application. Soil pH, organic carbon, nitrate (NO3 ) and ammonium (NH4 ) nitrogen were also determined, as was root density. Enzyme activities were higher in the ORG than the CON topsoils but did not differ significantly (p = 0.05) at depths >30 cm. The positive effects of the ORG treatments were attributed to the liming effect and carbon and nitrogen contributions of the compost. Urease and β-glucosidase activities correlated strongly. Activities of both enzymes correlated significantly and positively with carbon, NO3− and pH, with urease correlated more strongly than β-glucosidase. Only urease correlated with root density. Organic orchard floor management practices may be more effective than CON practices in promoting microbial enzyme activities in the 0–30 cm soil depth intervals of Western Cape apple orchard soils.
- Full Text:
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