Weed species composition and density under conservation agriculture with varying fertiliser rate

Conservation agriculture (CA) is a sustainable management system that optimises yield while reducing input costs. However, reduction in tillage intensity and frequency as practised under CA generally alters weed densities and composition. The objective of the study was to evaluate the effect of tillage, cropping system and fertiliser rate on weed density and diversity under CA systems compared with conventional tillage (CT). An on-station field trial with a split-plot, randomised complete block design, was used and included two tillage systems, three cropping systems and two fertiliser levels. Reduced tillage had significantly (p < 0.05) higher weed density (42 m−2) but lower weed biomass (154 g m−2) in contrast to CT with lower weed density (36 m−2) and higher weed biomass (242 g m−2). In a principal component analysis ordination, Datura ferox and Tribulus terrestris were more strongly associated with high fertiliser rate, whereas Zinnia peruviana was associated with CT. The increase in weed density and diversity under reduced tillage is likely to restrain the adoption of CA. Therefore, there is a need for alternative weed management options depending upon the weed spectrum, cropping system and fertiliser management.The ARC–Institute for Climate, Soil and Water, the Maize Trust and University of Pretoria .http://www.tandfonline.com/loi/tjps202019-04-13hj2018Plant Production and Soil Scienc

A systematic review of rodent pest research in Afro-Malagasy small-holder farming systems : are we asking the right questions

Rodent pests are especially problematic in terms of agriculture and public health since they can inflict considerable economic damage associated with their abundance, diversity, generalist feeding habits and high reproductive rates. To quantify rodent pest impacts and identify trends in rodent pest research impacting on small-holder agriculture in the Afro- Malagasy region we did a systematic review of research outputs from 1910 to 2015, by developing an a priori defined set of criteria to allow for replication of the review process. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We reviewed 162 publications, and while rodent pest research was spatially distributed across Africa (32 countries, including Madagascar), there was a disparity in number of studies per country with research biased towards four countries (Tanzania [25%], Nigeria [9%], Ethiopia [9%], Kenya [8%]) accounting for 51% of all rodent pest research in the Afro- Malagasy region. There was a disparity in the research themes addressed by Tanzanian publications compared to publications from the rest of the Afro-Malagasy region where research in Tanzania had a much more applied focus (50%) compared to a more basic research approach (92%) in the rest of the Afro-Malagasy region. We found that pest rodents have a significant negative effect on the Afro-Malagasy small-holder farming communities. Crop losses varied between cropping stages, storage and crops and the highest losses occurred during early cropping stages (46% median loss during seedling stage) and the mature stage (15% median loss). There was a scarcity of studies investigating the effectiveness of various management actions on rodent pest damage and population abundance. Our analysis highlights that there are inadequate empirical studies focused on developing sustainable control methods for rodent pests and rodent pests in the Africa-Malagasy context is generally ignored as a research topic.S1 Table. PRISMA checklist.S2 Table. List of rodent genera detected in rodent pest research in African agricultural systems from 1960±2015.S3 Table. List of different crops and cropping system as impacted by rodent pests in African agriculture (1960±2015).S1 List. Complete list of all publications used in the review±Publications in bold did not have full texts available at time of review.S2 List. Web of Science TM search history±.S1 Web of ScienceTM saved search.A European Union 9th European Development Fund grant from the African Caribbean and Pacific Science and Technology Programme (FED/2013/330-223), a grant from the United Kingdom's Department for International Development (AgriTT/894), a grant from the Sasol Agriculture Trust (South Africa), and International Foundation for Science (SE)-D/4984-2 to LHS.http://www.plosone.orgam2017Animal and Wildlife Science

A systematic review of rodent pest research in Afro-Malagasy small-holder farming systems: Are we asking the right questions?

Rodent pests are especially problematic in terms of agriculture and public health since they can inflict considerable economic damage associated with their abundance, diversity, generalist feeding habits and high reproductive rates. To quantify rodent pest impacts and identify trends in rodent pest research impacting on small-holder agriculture in the Afro-Malagasy region we did a systematic review of research outputs from 1910 to 2015, by developing an a priori defined set of criteria to allow for replication of the review process. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We reviewed 162 publications, and while rodent pest research was spatially distributed across Africa (32 countries, including Madagascar), there was a disparity in number of studies per country with research biased towards four countries (Tanzania [25%], Nigeria [9%], Ethiopia [9%], Kenya [8%]) accounting for 51% of all rodent pest research in the Afro-Malagasy region. There was a disparity in the research themes addressed by Tanzanian publications compared to publications from the rest of the Afro-Malagasy region where research in Tanzania had a much more applied focus (50%) compared to a more basic research approach (92%) in the rest of the Afro-Malagasy region. We found that pest rodents have a significant negative effect on the Afro-Malagasy small-holder farming communities. Crop losses varied between cropping stages, storage and crops and the highest losses occurred during early cropping stages (46% median loss during seedling stage) and the mature stage (15% median loss). There was a scarcity of studies investigating the effectiveness of various management actions on rodent pest damage and population abundance. Our analysis highlights that there are inadequate empirical studies focused on developing sustainable control methods for rodent pests and rodent pests in the Africa-Malagasy context is generally ignored as a research topic

The bii4africa dataset of faunal and floral population intactness estimates across Africa’s major land uses

Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species’ population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate ‘intactness scores’: the remaining proportion of an ‘intact’ reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region’s major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/ taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems

The bii4africa dataset of faunal and floral population intactness estimates across Africa’s major land uses

Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species’ population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate ‘intactness scores’: the remaining proportion of an ‘intact’ reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region’s major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems

Effects of Conservation Agriculture and Fertilization on Soil Microbial Diversity and Activity

Soil microbial communities perform critical functions in ecosystem processes. These functions can be used to assess the impact of agricultural practices on sustainable crop production. In this five-year study, the effect of various agricultural practices on soil microbial diversity and activity was investigated in a summer rainfall area under South African dryland conditions. Microbial diversity and activity were measured in the 0–15 cm layer of a field trial consisting of two fertilizer levels, three cropping systems, and two tillage systems. Using the Shannon–Weaver and Evenness diversity indices, soil microbial species richness and abundance were measured. Microbial enzymatic activities: β-glucosidase, phosphatase and urease, were used to evaluate ecosystem functioning. Cluster analysis revealed a shift in soil microbial community diversity and activity over time. Microbial diversity and activity were higher under no-till than conventional tillage. Fertilizer levels seemed to play a minor role in determining microbial diversity and activity, whereas the cropping systems played a more important role in determining the activity of soil microbial communities. Conservation agriculture yielded the highest soil microbial diversity and activity in diversified cropping systems under no-till

Manganese as fuel in slow-burning pyrotechnic time delay compositions

Manganese metal was evaluated as a fuel for slow-burning delay compositions press-filled in aluminium or compaction-rolled in lead tubes. Oxides of antimony, bismuth, copper, manganese and vanadium were considered as oxidants. Measured burn rates for binary mixtures varied between 5 and 22 mm s 1 but slower burning ternary and quaternary compositions were also found. The addition of fumed silica to the Mn/MnO2 system had little effect on the propagation rate but a low level addition of hollow glass sphere significantly reduced the burn rate. Mn MnO2 mixtures showed reliable burning over a wide stoichiometric range. In this system the fuel and the oxidant share a common metal. They combine to form the more stable intermediate oxide (MnO) releasing considerable quantities of heat in the process.Financial support from the THRIP programme of the Department of Trade and Industry and the National Research Foundation as well as African Explosives Limited is gratefully acknowledge

Modelling long-term yield and soil organic matter dynamics in a maize cropping system

Long-term cropping system experiments are one of the most reliable sources of information for informing sustainable agriculture and predicting future trends. When combined with crop modelling, expansion of findings on optimised management approaches is possible. In this study, results from a South African semi-arid region long-term (66 years) maize (Zea mays L.) trial are presented and combined with crop modelling to identify the impacts of fertilisation and residue management on yield and soil organic matter (SOM) levels. Simulated and observed results generally agreed well in calibration and testing exercises with APSIM. For the fertilised treatment, residue retention led to a 41% increase in average yield over the long term, and for unfertilised treatment the average yield increase was even higher at 59%. The greatest SOM decline of 46% was observed for the unfertilised plus residue removal treatment (over 66 years and considering a 60 cm soil depth). Fertilising and retaining residue reduced the SOM decline to 18%. Using only fertiliser without residue retention did not lead to a declining yield trend over the long-term for this soil. The study indicated that the APSIM model can be used to explore the ecological intensification of maize production in sub-Saharan Africa. Further attention is recommended, however, on testing the simulation of subsoil SOM dynamics. The results of this study give insight into soil fertility in low-input maize production systems and quantify the benefits of N fertiliser and residue retention guided by long-term measured data.The Water Research Commission and the Mastercard Foundation Scholars Programme at the University of Pretoria.https://link.springer.com/journal/107052023-09-07hj2023Plant Production and Soil Scienc

Correction: A systematic review of rodent pest research in Afro-Malagasy small-holder farming systems: Are we asking the right questions?

[This corrects the article DOI: 10.1371/journal.pone.0174554.]

Animal taxa contrast in their scale-dependent responses to land use change in rural Africa

<div><p>Human-dominated landscapes comprise the bulk of the world’s terrestrial surface and Africa is predicted to experience the largest relative increase over the next century. A multi-scale approach is required to identify processes that maintain diversity in these landscapes. Here we identify scales at which animal diversity responds by partitioning regional diversity in a rural African agro-ecosystem between one temporal and four spatial scales. Human land use practices are the main driver of diversity in all seven animal assemblages considered, with medium sized mammals and birds most affected. Even the least affected taxa, bats and non-volant small mammals (rodents), responded with increased abundance in settlements and agricultural sites respectively. Regional turnover was important to invertebrate taxa and their response to human land use was intermediate between that of the vertebrate extremes. Local scale (< 300 m) heterogeneity was the next most important level for all taxa, highlighting the importance of fine scale processes for the maintenance of biodiversity. Identifying the triggers of these changes within the context of functional landscapes would provide the context for the long-term sustainability of these rapidly changing landscapes.</p></div