Mapping Soil Erosion Sensitive Areas in Organic Matter Amended Soil Associations in the Ntabelanga area, Eastern Cape Province, South Africa

The study aims to map areas sensitive to erosion by water and rainfall erosivity after addition of organic matter (OM) in highly unstable soils. A soil association map was created using digital soil mapping methodology. Soil samples from six soil associations were incubated and analysed for several soil erodibility measures and inferred to the soil association map. Soil stabilization against soil erosion by use of OM was evaluated for 30 weeks under two simulated rainstorms, intermittent rainstorms (IR) and single rainstorm (SR). Rainfall erosivity (R-factor) was calculated from theduration of a rainstorm and the total amount of rainfall received under rainfall simulations. Erodibility factor (K-factor) was estimated using the soil OM content and texture. Largest area (40%) was covered by shallow soils and K-factor range of 0.0693-0.0778 t.ha.hha-1MJ-1mm-1. Largest (60.2%) area had a structural stability index of 0.8 and 42.7% of the area was covered by a dispersion ratio value range of 0.65-0.70. The area size with erosion rates of > 15 t/ha/yr was drastically reduced from 1 to 8 weeks after OM application thereafter gradually increased under both IR and SR.  Soil erosion rates of < 5 t-1 ha-1 yr-1 and > 15 t-1 ha-1 yr-1 were most and least observed respectively under both storms. R-factor was higher under IR than SR and the smallest areas with soil erosion rates of > 15 t-1 ha-1 yr-1 contributed most to the lost soil. Organic matter confers soil resistance to erosion up to a certain period before losing its effectiveness. The study provided first assessment of erosion dynamics, basis for identifying  conservation priorities which may be applicable in similar areas. Keywords: Erosivity, planning, rainstorm, soil conservation, soil degradatio

Litter quality effects on soil stabiltiy and erodibility in the Ntabelanga Area, Eastern Cape, South Africa

Soil organic matter (SOM) plays a primary role in aggregation and stabilization of soils, hence reducing their susceptibility to erosion. In South Africa (SA), most soils have low ( 0.250 mm) were removed by passing through a 0.250 mm sieve. The remaining soil microaggregates ( 250 μm) decreased exponentially from week 1 to 30 and were significantly (p < 0.05) influenced by litter quality × soil horizon × time interactions. A similar trend for FiPOM fractions in macroaggregates was observed in the 53-250 μm microaggregates (p < 0.05). The greatest influence on changes in POM fractions occurred within the first 3 weeks of incorporation. Both V. karroo leaf litter and Z. mays stover significantly stabilized the macroaggregates within the first 3 weeks after incubation. Cumulative macroaggregates yields, mean weight diameter (MWD), percentage water stable aggregates (%WSA) and whole soil stability index (WSSI) in litter amended soils increased up to week 8 of incubation and thereafter gradually declined in all soils. An increase in macroaggregation resulted in increased MWD, WSSI values and large and small aggregates distribution. Aggregation was significantly higher in soils with higher clay content than sand content, suggesting that soil texture was highly influential in litter decomposition. Rate of litter decomposition was influenced by soil type × time interactions which determined extent and macroaggregation dynamics along a decomposition continuum. The amount of splashed sediments was determined from each soil horizon at 360 mm h-1 simulated rainfall intensity applied as either single 8minute rainstorm (SR) or 4 × 2minute intermittent rainstorms (IR) separated by a 72 h drying period. Results showed a reduction in splashed sediments under IR and SR storms in litter-amended soils during the first 8 weeks of incubation with gradual increase thereafter. More sediments were splashed under IR than SR and litter quality had no influence on splashed sediments per soil horizon. Soil horizons profile with more clay than sand particles enhanced the litter effects on the soil resistance against detachment. The amount of SOC loss was influenced by primary particle size distribution and initial SOC content of the soil. Rainfall pattern and the initial SOC content were the main factors by which different soils influenced SOC loss. More rainstorm patterns should be investigated on these soils

Mapping Soil Erosion Sensitive Areas in Organic Matter Amended Soil Associations in the Ntabelanga area, Eastern Cape Province, South Africa

The study aims to map areas sensitive to erosion by water and rainfall erosivity after addition of organic matter (OM) in highly unstable soils. A soil association map was created using digital soil mapping methodology. Soil samples from six soil associations were incubated and analysed for several soil erodibility measures and inferred to the soil association map. Soil stabilization against soil erosion by use of OM was evaluated for 30 weeks under two simulated rainstorms, intermittent rainstorms (IR) and single rainstorm (SR). Rainfall erosivity (R-factor) was calculated from the duration of a rainstorm and the total amount of rainfall received under rainfall simulations. Erodibility factor (K-factor) was estimated using the soil OM content and texture. Largest area (40%) was covered by shallow soils and K-factor range of 0.0693-0.0778 t.ha.hha-1MJ-1mm-1. Largest (60.2%) area had a structural stability index of 0.8 and 42.7% of the area was covered by a dispersion ratio value range of 0.65-0.70. The area size with erosion rates of &gt; 15 t/ha/yr was drastically reduced from 1 to 8 weeks after OM application thereafter gradually increased under both IR and SR. Soil erosion rates of &lt; 5 t-1 ha-1 yr-1 and &gt; 15 t-1 ha-1 yr-1 were most and least observed respectively under both storms. R-factor was higher under IR than SR and the smallest areas with soil erosion rates of &gt; 15 t-1 ha-1 yr-1 contributed most to the lost soil. Organic matter confers soil resistance to erosion up to a certain period before losing its effectiveness. The study provided first assessment of erosion dynamics, basis for identifying conservation priorities which may be applicable in similar areas

Vertical Coordination to Smallholder Small Grain Growers in Zimbabwe: Benefits of Contract Farming and Policy Implications

Zimbabwe’s agro-ecological regions IV and V lie in low rainfall areas and food security is a perennial concern. Vertical coordination strategies and market institutions provide hope for building farmer resilience in regions affected by climate change in Zimbabwe. This study focused on four districts (Binga, Chiredzi, Hwange, Matobo) which are in regions IV and V. A questionnaire was used to collect data from 281 respondents. Probit and Multiple linear regression models were used to evaluate the determinants. Results show that contract farmers allocated more than 3 hectares to small grains agricultural enterprise. The research established that long distances to markets, access to credit, extension services and affiliation to farming groups are some critical determinants which influence market participation and yields sold

Tagetes Minuta Formulation Effect Sitophilus Zeamais (Weevils) Control in Stored Maize Grain

Abstract The research was carried out at Chaminuka Training Centre in Mt Darwin district of Zimbabwe. Maize producers in the rural areas are challenged by storage pests particularly the Sitophilus zeamais. Affordable and readily available protectants are needed. A common weed, Tagetes minuta, was assessed for its potential to control Sitophilus zeamais. This provides a sustainable and degradable pesticide to the poor farmers. Maize grain samples arranged in a complete randomized design (CRD) were infected with 32 weevils each. The research was run for 8 weeks with the objectives to determine the efficacy of varying forms of Tagetes minuta on Sitophilus zeamais and to establish the effect of Tagetes minuta on maize grain weight loss. Weevil counts were taken on fortnight bases to establish mortalities. Grain weight loss was assessed using the Thousand Grain Method (T G M). There were variations on treatments with varied forms. The ground Tagetes minuta had the highest effect on both weight loss and weevil mortality compared to un-ground Tagetes minuta (p = 0.001). It was concluded that the ground Tagetes minuta works through a wider spectrum by causing physical and physiological effects on the weevil resulting in mortalities

Soil properties influencing erodibility of soils in the Ntabelanga area, Eastern Cape Province, South Africa

Soil erosion has serious off-site impacts caused by increased mobilization of sediment and delivery to water bodies causing siltation and pollution. To evaluate factors influencing soil erodibility at a proposed dam site, 21 soil samples collected were characterized. The soils were analyzed for soil organic carbon (SOC), exchangeable bases, exchangeable acidity, pH, electrical conductivities, mean weight diameter and soil particles’ size distribution. Cation exchange capacity, exchangeable sodium percentage, sodium adsorption ratio, dispersion ratio (DR), clay flocculation index (CFI), clay dispersion ratio (CDR) and Ca:Mg ratio were then calculated. Soil erodibility (K-factor) estimates were determined using SOC content and surface soil properties. Soil loss rates by splashing were determined under rainfall simulations at 360 mmh−1 rainfall intensity. Soil loss was correlated to the measured chemical and physical soil properties. There were variations in soil form properties and erodibility indices showing influence on soil loss. The average soil erodibility and SOC values were 0.0734 t MJ−1 mm−1 and 0.81%, respectively. SOC decreased with depth and soil loss increased with a decrease in SOC content. SOC significantly influenced soil loss, CDR, CFI and DR (P < .05). The soil loss rate was 5.60 t/ha per 8 minute rainstorm of 360 mmh−1. Addition of organic matter stabilize the soils against erosion

Influence of litter source on soil splash rates and organic carbon loss in different soil horizons

Organic litter stabilizes soil particles against the raindrop splash effect. To date, limited research has critically examined the effects of litter quality on soil aggregate detachment and soil organic carbon loss by raindrop splash impact. A study was conducted to determine the effects of different litter sources on quantity of splashed sediments and soil organic carbon (SOC) loss under simulated rainstorm patterns. Soils from seven sieved (&lt; 0.25 mm) horizons mixed with either high-quality Vachellia karroo leaf (C/N = 23.8) and/or low-quality Zea mays stover litter (C/N = 37.4) were incubated in a laboratory for 30 weeks. Splashed sediments and SOC were measured at 1, 3, 8, 14, 23 and 30 weeks of incubation for each soil at 360 mm/h simulated rainfall intensity applied as either single 8-min rainstorm (SR) or 4 × 2-min intermittent rainstorms (IR) separated by a 72-h drying period. Organic litter significantly (P &lt; 0.05) reduced the splashed sediments up to 8 and 14 weeks under IR and SR storms, respectively, and thereafter gradually lost its stabilizing effect on soil aggregates. In order to maintain low quantities of splashed sediments, fresh litter has to be re-applied after this stage. Generally, 13% and 25% more sediments were splashed under IR than SR at 1, 3 and 30, and 8, 14 and 23 weeks after incubation, respectively. Litter quality effect on splash sediments varied across soil horizons but were the same within a soil horizon. Soil horizons with more clay than sand particles had lower quantities of sediments. The SOC loss was influenced by the initial SOC content and primary particle size distribution. Rainstorm pattern and initial SOC content were the main factors that influenced SOC loss. However, more rainstorm patterns should be investigated for these soils

Macadamia Nuts (Macadamia intergrifolia) Value Chain and Technical Efficiency among the Small-scale Farmers in Zimbabwe

Agriculture value chains are an indispensable tool for stakeholder collaboration, improving market access, foreign currency generation and increase in macadamia nut production in most developing countries. In Zimbabwe macadamia nut is a relatively new crop that has potential to alleviate poverty and enhance livelihoods. Zimbabwe’s macadamia nut industry is still at its infancy and remains an under-researched area. Despite this, the technical efficiency of macadamia nuts production systems as proxied by production levels among small-scale farmers in the country is least understood. This study analyses the existing value chains by scrutinizing every step required in the production and marketing of macadamia nuts focusing on technical efficiency of value chain nodes. Macadamia nut value chain in Zimbabwe is predominantly an emergency value chain system that does not embrace the modular value chain model and associated networks to enhance technical efficiency and overall welfare. The value chain system is characterised by imperfect market conditions with limited knowledge of exact specifications, attributes and price of macadamia nuts. The existing value chain models for macadamia nut need to be re-aligned to accommodate all stakeholders, hence widening resource and knowledge sharing platforms. There is a need for the Zimbabwe macadamia nut value chain to shift towards captive networks which embrace and scale out practices such as out-grower contractual arrangements. There is potential to design macadamia nut value chain models in Zimbabwe to increase the technical efficiency of the industry

Educational Research and Reviews An analysis of challenges faced by students learning in virtual and open distance learning system: A case of Bindura University of Science Education (BUSE)

After realizing that the traditional modes of tuition in Zimbabwe&apos;s andragogy had either gone obsolete or over-crowded, BUSE ventured into a &apos;virtualised&apos; model of open and distance learning as a way of out-doing other competing universities. However, as the programme was rolled out, there came a myriad of challenges affecting the students ranging from financial, personal commitment, time, stereotypes, and social and work pressures. These constraints have, to some extent, negatively affected both the delivery of the programme and the pass rate of the students. The paper therefore seeks to make an analysis of challenges faced by students who are in the Virtual and Open Distance Learning (VODL) at BUSE based on a research conducted at the seven centres country-wide. Key words: Students, virtual and open distance learning, andragogy. INTRODUCTION According to The Virtual and Open Distance Learning (V.O.D.L) programme emerged as an institutionally born strategy to satisfy the training needs of the prospective Science Educators who are already employed or wished to be employed as school teachers. The current training policies and economic challenges on access to Higher Education and delivery systems in the country appear to deter many prospective science educators from training at Bindura University of Science Education (BUSE) and any other conventional institutions of Higher Learning in Zimbabwe and elsewhere. The high rate of brain drain mainly of science educators, low science trainee teachers&apos; enrolment in colleges and universities as well as economic challenges, currently being experienced following the 2003-2009 economic crises, has created a critical shortage in the Zimbabwean schools. The programme is also in pursuance of achieving the Millennium Development Goal number 2, which calls for Universal Education for All by 2015, by training science teachers who, in turn, will facilitate the teaching and learning processes for children. of bringing university to the doorstep of the student. The study therefore seeks to look at open and distance learning in relation to VODL, and in particular, pays attention to the challenges in the programme that are confronting the students. It will not be necessary to know the challenges alone without putting forward possible corrective measures. Therefore, the study will also make some recommendations on how the programme could be improved both for the university and students&apos;. THEORETICAL FRAMEWORK This research is based on the equivalency theory of open and distance learning by Keegan (1995). Basically, the theory equates tuition to the effect of real time television systems, whereby a student is electronically linked to the lecturer at various locations. The theory argues that distance education should be developed on a concept of equivalency to learning experiences. The theory will help us analyse whether the virtual component is being achieved in VODL and also establish how the aforementioned challenges arise and possibly how best they can be attended to