The contribution of different fauna communities to improved soil health : A case of Zimbabwean soils under conservation agriculture

For improved and sustainable soil productivity, the application of soil conserving cropping systems is important. This study characterizes soil fauna as a basis for comparing conservation agriculture and conventional ploughing systems and focuses on soil health of sandy, sandy loam and clayey soils in smallholder farms under sub-humid and semi-arid conditions in Zimbabwe. Fauna contribution to soil health was explored. Beetle larva (Coleoptera), earthworm (Opisthophora), mycorrhiza spore (Glomales), nematode (Tylenchida and Dorylaimida) and termite (Isoptera) densities were measured in conventionally ploughed (CP), direct seeded (DS), ripped (RR) and basin (BA) treatments on farms at Henderson, Chinyanga, Kajengo (all in agro-ecological zone II), Makwara and Zhinya (agro-ecological zone IV). Maize and soyabean were used as test crops. Rates of maize mulch loss were determined for winter and summer seasons. Shannon Wiener indices were used to analyse the changes in species and genera of weeds and nematodes respectively. Weed species responses to treatments and weed management regimes were explored at each site. Perceptions of soil fauna on the farms were sought from farmers in Shamva and Zimuto. High species richness was measured under mulched ripper and direct seeder treatments. Beetle larvae and termite densities increased significantly (P k calculated from the exponential decay function y = a.e-kx during summer were 10-fold those in winter. The k values were lowest at Henderson, (0.017 and 0.17) and highest at Makwara (0.025 and 0.24) for winter and summer, respectively. Richardia scabra, Galinsoga parviflora and Eleusine indica were common weeds across the five sites. Introducing a late weeding treatment reduced weed densities significantly at Henderson compared to other sites. Participatory rapid appraisal results show that farmers perceived termites as the dominant fauna on the farm and as a pest to maize. Under conventional ploughing systems, complete crop residue removal is practised. Management of maize residues after harvest is mainly meant to secure livestock feed during the dry winter season. On a small scale, mulching was practiced using crop residues and tree litter in vegetable gardens. On farms with Chromic Luvisol, Ferrali-Gleyic Arenosol and Gleyic Luvisols and Brachstegia-Julbernadia dominated miombo savanna vegetation in eastern and southern Africa, in the short term, beetle larvae and termites densities responded to conservation agriculture better than nematodes and earthworms. The increased fauna biomass improves soil health. Macrofauna participates in decomposition, soil turnover and modification. Gallery building by termites, for example, increases surface clay, silt and organic matter contents in sandy soils. Furthermore, termites through their galleries, participate in mycorrhiza spore inoculation of the soil.Der Beitrag verschiedener Faunengemeinschaften zu verbesserter Bodengesundheit - Der Fall von Böden in Zimbabwe unter bodenschonenden Anbauverfahren F ür eine verbesserte und nachhaltige Bodenproduktivität sind bodenschonende Anbausysteme wichtig. Diese Studie untersucht Bodenfauna als eine Grundlage für den Vergleich zwischen Bodenschonenden Anbauverfahren (conservation agriculture) und konventionellem Anbau und legt dabei den Schwerpunkt auf Bodengesundheit in kleinbäuerlichen Farmen mit sandigen, sandig-lehmigen und lehmigen Böden in sub-humiden und semi-ariden Gebieten in Zimbabwe. Die Dichten von Käferlarven (Coleoptera), Regenwürmern (Opisthophora), Mykorrhiza-Sporen (Glomales), Nematoden (Tylenchida and Dorylaimida) und Termiten (Isoptera) wurden erfasst in auf konventionelle Weise gepflügten (CP) Feldern sowie Feldern unter Behandlung mit Direktsaat (DS), Untergrund-(Tiefen)-Lockerer (ripper; RR) and als "Becken" (BA) bei Kleinbauern in Henderson, Chinyanga, Kajengo (alle in der agroökologischen Zone II), Makwara und Zhinya (Zone IV). Mais und Soya wurden als Testanbaupflanzen eingesetzt. Maismulch-Verlustraten wurden für die Winter- und Sommersaison bestimmt. An jedem Standort wurde die Reaktion der Unkräuter auf Behandlungen und Unkrautmanagementmaßnahmen erfasst. Die Wahrnehmung der Bodenfauna durch Farmer wurde in Shamva and Zimuto erfasst. Shannon Wiener Indizes wurden benutzt, um die Änderungen in der Arten- und Gattungs-Zusammensetzung der Unkräuter und der Nematoden zu analysieren. Eine hohe Artenvielfalt wurde unter den gemulchten RR- und DS-Behandlungen bestimmt. Die Dichte von Käferlarven und Termiten nahm signifikant (P k, berechnet aus der exponentiellen Abbaufunktion y = a.e-kx, 10-mal höher als die Werte im Winter. Die k-Werte im Winter bzw. Sommer waren am niedrigsten in Henderson (0.017 bzw. 0.17) und am höchsten in Makwara (0.025 bzw. 0.24). Häufige Unkrautarten an allen Standorten waren Richardia scabra, Galinsoga parviflora und Eleusine indica. Ein spätes Entfernen des Unkrauts reduzierte die Unkrautdichte signifikant stärker in Henderson als an den anderen Standorten. Die Ergebnisse einer partizipativen Schnellerfassung (rapid participatory appraisal) zeigen, dass die Bauern die Termiten als die am häufigsten vorkommende Fauna und als Maisschädling beurteilten. Daten zu Schädlingsbefall bei Mais konnten diese Ansicht allerdings nicht bestätigen. Bei den konventionellen Bodenbearbeitungssystemen werden die gesamten Ernterückstände entfernt, hauptsächlich für Tierfutter während des trockenen Winters. In geringem Umfang wird Mulchen mit Ernterückständen sowie Baumstreu in den Gemüsegärten eingesetzt. Auf Farmen mit Chromic-Luvisol, Ferrali-Gleyic-arenosol und Gleyic-Luvisol-Böden unter Brachystegia-Julbernadia- dominierter Miombo-Vegetation im östlichen und südlichen Afrika erhöht sich unter bodenschonenden Anbauverfahren die Dichte von Termiten und Käferlarven kurzfristig schneller als die von Nematoden und Regenwürmern. Die erhöhte Faunendichte führt zu einer verbesserten Bodengesundheit. Die Makrofauna beteiligfts ich an Zersetzung, Bodenturbation und -modifikation. Die Galeriekonstruktion durch die Termiten erhöht bei sandigen Böden den Gehalt an Ton, organischem Material und Schluff an der Bodenoberfläche. Die Termiten sind durch ihre Galerien außerdem an der Inokulation des Bodens mit Mycorrhizasporen beteiligt

Performance intensification of the coagulation process in drinking water treatment

Surface water pollution has increased, owing to industrial development and population growth. Consequently, it is important to find alternative drinking water treatment strategies, which cater for changes in the quality of raw water. This study compared the efficiency of different coagulants in treating raw water that feeds a drinking water treatment plant (WTP). Using jar testing equipment and a number of physicochemical parameters, an investigation was conducted to establish optimum conditions for aluminium chloride (A),  ferric chloride (B), and chitosan (C), and their performance compared with aluminium sulphate (D), which is the coagulant used at the WTP. The turbidity removal efficiencies for the single coagulants were in the order: B (95.7%) > A (94.7%) > C (94.4%), at optimum coagulant doses of 60, 50, and 0.6 mg/L, respectively. The coagulants achieved high removal efficiencies for turbidity, total dissolved solids (TDS), ultraviolet absorbance at 254 nm (UV254) and conductivity under acidic conditions. For dual coagulants, there was a  gradual increase in the removal efficiencies of the tested parameters with increasing pH. Combined coagulants were more effective compared to single coagulants, with highest removal efficiencies being exhibited by the A/C combination. Overall, the coagulants proved to be suitable alternatives to D, since they had comparable performances

Waste Management Policy Implementation in South Africa: An Emerging Stakeholder Participation Paradox

The need to eliminate plastic shopping bags from South Africa’s environment has resulted in the formation and implementation of the Plastic Carrier Bags and Plastics Flat Bags Regulations (hereafter referred to as the Plastic Bags Regulations).The new law requires manufacturers to produce thicker, reusable and recyclable plastic shopping bags sold at purchase points.However, some major retailers have refused to charge customers for the new bags claiming that they were not party to the policy process. Consumer organisations have called for boycotts and urged shoppers to support retailers that continue issuing ‘free’ bags. Drawing theoretical insights from actor network theory (ANT) and other actor oriented and practice-based policy frameworks, this small-scale study established that the failure to consider key actors and actants in the policy implementation process, and the role of powerful actor networks in the process have adversly affected the policy implementation process. Given that South Africa placed emphasis on consultative national environmental policy process approaches, the unfolding events and emerging policy process models show an emerging stakeholder participation paradox in implementing policies on waste management in South Africa

Actor/Actant-Network Theory as Emerging Methodology for Environmental Education Research in Southern Africa

This paper deliberates on actor/actant-network theory (AANT) as methodology for policy research in  environmental education (EE). Insights are drawn from work that applied AANT to research environmental  policy processes surrounding the formulation and implementation of South Africa’s Plastic Bags Regulations of 2003. The paper reveals that the application of AANT methodology made it possible to trace relationships,  actors, actants and actor/actant-networks surrounding the Plastic Bags Regulations as quasi-object (token). The methodology also enabled a focus on understanding and investigating tensions, debates and responses  emerging from the policy process. The findings were that after the promulgation of the first draft of the Plastic Bags Regulations in May 2000, tensions emerged around the nature of regulation (whether to use the command and control approach – preferred by Organised Government – or self regulation – preferred by Organised Business and Organised Labour). From these findings, a series of conceptual frameworks were drawn up as identified around key actors and actor/actant-networks. The conceptual frameworks included among them, Organised Government, Organised Business and Organised Labour

The role of churches in tackling HIV stigma in eastern Zimbabwe

Much has been written about the need to involve communities in efforts to reduce HIV stigma. However less is known about the psycho-social pathways between participation and stigma reduction or the most appropriate strategies for ensuring such participation. Drawing on Campbell’s social psychological conceptualisation of social capital and the ‘HIV competent community’, this study explores how community groups in eastern Zimbabwe, and in particular churches--the most established formal social network in the area--tackle HIV stigma, drawing on data collected between 2005 and 2009. The thesis explores four issues: the effect of participation in community groups on stigmatizing attitudes; the extent to which church groups perpetuate or reduce stigma; possible differences between the role played by the Protestant, Apostolic and Catholic churches in relation to stigma and the potential for using the ‘community conversations’ (CCs) approach to develop more effective responses to stigma amongst the three churches. The quantitative analysis from over 15,000 respondents used multivariable logistic regression modelling to explore relationships between participation and stigmatizing attitudes. Fewer of the individuals who participated in community groups than those who did not were found to report stigmatising attitudes towards people living with HIV (PLHIV). The qualitative research involved a total of 30 individual interviews and 24 CCs and explored how church groups respond to PLHIV. Participants discussed the strategies to combat HIV stigma and suggested that the church facilitated unhelpful attitudes, as well as helpful attitudes and actions. CCs workshops provided participants with opportunities to formulate a range of creative plans to tackle stigma in their communities. However over time it emerged that various obstacles stood in the way of putting these plans into action in their lives beyond the context of workshop discussions. l conclude that CCs have an important role to play in promoting reflection and action planning amongst participants. However, external constraints limit the extent to which people are able to turn this reflection and planning into action. To address these constraints I argue for the need to create sustainable bridges with external support agencies

Book Review: Understanding Environmental Policy Processes: Cases from Africa

Keeley, J., & Scoones, I. (2003). Understanding Environmental Policy Processes: Cases from Africa. London: Earthscan