Masters Degrees (Soil Science)

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Farm typology and spatial variability of selected soil fertility parameters on selected small-holder farms in KwaZulu-Natal province, South Africa.
(2022) Manqana, Lonwabo.; Dube, Nkosinomusa Nomfundo.; Muchaonyerwa, Pardon.
Diversity of resource endowment, soil and climatic conditions may affect the level of management and productivity and soil fertility in small-holder farms. The objectives of this study were to (i) develop farm typologies, (ii) assess fertility gradients, and (iii) map spatial variability of soil fertility in small-holder farms of uMbumbulu and Msinga regions in KwaZulu-Natal province, South Africa. To obtain data for the identification of farm typologies, a detailed open-ended questionnaire was used with topics including socio-economic attributes, local crops grown, soil amendments, management practices, labour, crop residue management, farmers perceptions and production constraints. The questionnaire was administered to fifty farmers per region. The data which had Kaiser-Meyer-Olkin (KMO) measure values of 0.67 and 0.51 for uMbumbulu and Msinga respectively, qualified for Principal component analysis (PCA). Three PCs which had significant eigenvalues of >1, provided key factors that determine the farm typologies, namely land size, livestock ownership, income from farming and external income. Multiple correspondence analysis (MCA) and cluster analysis were used to analyse quantitative and qualitative data, and variables and aggregate farms into clusters according to production, socioeconomics, and demographics. Three farm topologies were identified, namely (i) resource-endowed farms which have large land and profit from farming (type I), (ii) the middle-resourced group (type II), which is neither poor nor rich, and (iii) Poor resource groups (type III) with limited to no resources at all and have small land holdings and minimum profits from farming. For fertility gradients and mapping, soils were sampled from 0 – 20 cm depth, using a sampling interval of 5×5m and analysed for fertility parameters. There were no fertility gradients observed between homefields and outfields for both sites. Mapping was done only in uMbumbulu site with descriptive statistics (mean, standard deviation, covariance, skewness, and kurtosis) tested for normality to be used for kriging, and only the spherical model was tested in this study using R-Studio. For geo-statistics (Lag size, sill, and nugget) for semiviriograms produced was done using ArcMap-GIS as well as the maps. For type I farms the spatial dependency was strong (< 25%) for most variables tested (pH, total carbon, calcium, magnesium, potassium, and Clay %), while type III had a variety of spatial dependency from pH and clay % were weak (<75%), Ca and total carbon moderate (25-75%) to phosphorus, magnesium, potassium, and acid saturation strong (<25%). Overall implications of these maps can be very useful in targeting specific areas of poor or rich fertility and fertiliser recommendation, which is more economically viable to small-holder farmers to put in what is needed.
Assessing decomposition and soil carbon sequestration potential of sorghum residues from different cultivars.
(2022) Ntonta, Sipho.; Zengeni, Rebecca.; Muchaonyerwa, Pardon.; Chaplot, Vincent A. M.
Abstract available in PDF.
Quality parameters of organic amendments from Umbumbulu and Msinga farms and their effects on nitrogen and phosphorus mineralization.
(2022) Hlatshwayo, Khethukuthula Pacia.; Dube, Nkosinomusa Nomfundo.; Muchaonyerwa, Pardon.
Conventional agricultural management practices that farmers in Africa and South Africa have practiced have led to a decline in soil fertility. Organic amendments have shown to improve soil quality and fertility status when incorporated into the soil. Smallholder farmers manage their fields differently according to resource endowment, distance of fields from the homestead (i.e homefield and outfield), and labour. The use of organic inputs as fertilizers to remediate the soils from which the loss of nutrients occurred depends on their decomposition rates and nutrient release patterns. Factors such as soil type, climate and application rates of the amendments affect the decomposition and mineralization of these amendments in soils. The objective of this study was to determine (i) carbon and phosphorus pools from different fields from uMbumbulu and Msinga as affected by farmer typology and (ii) the characteristics of organic amendments and their decomposition and mineralization of nitrogen and phosphorus in soil. Three typologies (i.e. resource constrained, moderately resourced and resource endowed) were selected for both Msinga and Mbumbulu. Two fields per typology were used, namely homefield (<100m from homestead) and outfield (>150m from home) for Msinga while for uMbumbulu it was fields with mixed cropping and monocropping system. Three farms were selected per typology and field type with three replications. Soil samples were collected from the farms of different typologies at 0 – 20cm and analyzed for soil organic carbon (SOC) and phosphorus pools. Organic amendments including cattle manure, goat manure, accelerator and maize residues were sampled from different farms in Msinga and uMbumbulu and characterized. Composite samples of these amendments, separately and in combination, were then incorporated in soils and incubated for 84 days during which soil pH, P and mineral-N (ammonium-N and nitrate-N) were analyzed. Farmer typologies did not affect carbon and phosphorus pools of the soils on farms at Msinga and uMbumbulu. Carbon pools under different cropping systems and typologies for uMbumbulu showed significant difference with total carbon concentrations being the highest under monocropping system (40.3 g/kg) followed by c- POMC, f-POMC, MAOC and DOC and also under resource constrained typology, total carbon was the highest (44.6 g/kg). Carbon pools under Msinga did not follow the same trend both under cropping system and typology since there was no significant difference. More P was in a reductant P form in uMbumbulu soil both under different cropping systems and typology with concentration of 224-310 mg/kg under cropping system and 145-447 mg/kg within typology. Available P had lower concentrations in both cropping system (8.9-11.8 mg/kg) and typology (9.6-11.7 mg/kg) with Al-P and Fe-P showing no significant difference in uMbumbulu soil. Msinga soils followed the same trend of P pools showing no significant different in Al-P and Fe-P as uMbumbulu. Msinga soils showed more positive correlation between carbon and phosphorus pools than uMbumbulu soils. Msinga amendments appeared more beneficial than uMbumbulu with high pH levels and cattle manure having low C/N ratio content which allows rapid decomposition. More nutrients were available for plant uptake as Msinga amendments had higher concentrations of bases. The Accelerator had higher ammonium-N concentration (128 g/kg N on day 84) than other treatments showing higher decomposition rate in the uMbumbulu soil. When the manures were combined with maize residues, they had lower ammonium-N concentration due to C:N ratio of the maize residues. After day 7 of incubation, nitrate-N and mineral-N concentration increased in all treatment in both mg/kg soil and g/kg of N present. Like in the first incubation experiment (uMbumbulu soil), the control in the Msinga soil had higher nitrate-N than all treatment combinations containing maize residues between 14 to 56 days of incubation except for the accelerator+maize residues. Maize residues in both experiments (uMbumbulu and Msinga soils) showed lower mineralization of N and P and Msinga amendments had higher nutrient mineralisation than those from uMbumbulu. The findings of the study imply that carbon and phosphorus pools in the two study sites could be affected by environment factors more than management practices and that maize residues will require a longer period of time to allow maximum decomposition and mineralize nutrients compared to the accelerator, cattle, and goat manure. More studies need to be done on environmental factors such as climate, parent material, and topography, as they might be the primary drivers of carbon and phosphorus pools.
Effect of long-term application of nitrogen and liming on soil carbon dynamics in a semi-arid grassland.
(2022) Buthelezi, Kwenama.; Buthelezi, Nkosinomusa Nomfundo.
Abstract available in PDF.
Evaluating biological nitrogen fixation of bean and nitrogen use efficiency of maize cultivars of improving crop productivity and soil fertility in Lesotho.
(2021) Mofolo, Selebaleng Patricia.; Muchaonyerwa, Pardon.; Adu-Gyamfi, Joseph.
Abstract available in PDF.
Comparison of selected extractants for potassium requirement factor and evaluating potassium equilibria for soil testing and fertilizer recommendations.
(2020) Msane, Londeka Truth Thobeka.; Nongqwenga, Nqaba.; Muchaonyerwa, Pardon.
Abstract available in PDF.
Land use effects on characteristics and mineralization of nitrogen and phosphorus during incubation of humic topsoils from selected sites in KwaZulu-Natal, South Africa.
(2021) Dlamini, Ntethelelo.; Muchaonyerwa, Pardon.; Hughes, Jeffrey Charles.
Abstract available in PDF.
Characterisation of potato waste biochars and effect on carbon dioxide emission, liming potential and availability of primary macro-nutrients of two amended contrasting soils.
(2021) Vilakazi, Samukelisiwe Pinky.; Muchaonyerwa, Pardon.; Dube, Nkosinomusa Nomfundo.
Abstract available in pdf.
Nitrogen and phosphorus release in soil and fertiliser value of lemna minor biomass relative to chicken litter compost.
(2019) Jilimane, Kanya.; Muchaonyerwa, Pardon.
Intensive agricultural production systems produce nutrient-rich wastewaters, which may pollute the environment. High nutrient concentrations on surface water bodies encourages the growth of aquatic plants, and harvesting of these plants could improve water quality and produce an organic fertiliser. The fertiliser value of duckweed may depend on the effluent on which it grows, since it affects its nutrient composition. The aim of this study was to determine the effects of effluent types on duckweeds (lemna species) tissue composition and its influence on (i) mineral nitrogen (N) and phosphorus (P) release in the soil during an incubation and (ii) nutrient uptake and dry-matter yield of spinach (Spinacia oleracea) under greenhouse and field conditions, relative to chicken litter. Duckweeds were sampled from surface water at Ashburton (Lemna AB) enriched with effluent from sewage and cattle manure, at Baynesfield (Lemna BF) on effluent from a piggery, at Wartburg (Lemna WB) enriched with crocodile wastewater (crocodile farm) and chicken litter compost from RGS Drumnadrochit farm, all in the Midland region of Kwa-Zulu Natal. A loam soil was amended with dried Lemna AB, Lemna BF, Lemna WB or chicken litter at a rate of one percent (w/w) in one incubation, while in another incubation 2 and 4% rates were used with an un-amended soil as a control in both. The treatments were adjusted to field capacity moisture and incubated at 25oC for 28 days. Destructive sampling was done after 0, 7, 14, and 28 days of incubation, and analysed for pH, ammonium and nitrate-N, and extractable-P. A leaching experiment was also conducted were 2.0 g of dry matter Lemna AB, Lemna BF and Lemna WB were leached over a period of 0, 6, 12 and 24 hours on sandy soil using deionize water (25 ml). The leachates were analysed for ammonium and nitrate-N and extractable-P. A pot trial in the glasshouse was conducted with the same treatments used in the incubation experiment, at recommended rate of 100 kg N ha-1 replicated three times. Spinach (Spinacia oleracea) seedling were grown for six (6) weeks, and harvested before the determination of dry matter (DM), tissue composition and nutrient uptake. The experiment was repeated under field conditions with Lemna BF, Lemna WB, chicken litter compost, all applied at 100 kg N ha-1, and a negative control (no added N), after a two-week pre-incubation. In the first incubation ammonium-N was higher in the Lemna WB treatments, while nitrate-N was highest on the Lemna AB treatments with the highest peak observed on day 14. In the case of Lemna BF treatments had the highest amount of extractable-P, with the control having less of all determined parameters. Lemna WB rapidly leached higher nutrients (ammonium-N and exchangeable-P) at about 26.47 mg N/kg and 25.59 mg P/kg respectively, while Lemna AB (69.42 mg/kg) was high in nitrate-N within 24 hours in comparison to the other treatments on the leaching experiment. In the second incubation Lemna BF showed higher amounts of ammonium-N (230 mg/kg), nitrate-N (140.83 mg/kg) and extractable-P (10.66 mg/kg), throughout the incubation period than all other treatments, while the control had the least of all determined parameters. Ammonium-N was highest after 7 days of the incubation and declined thereafter while nitrate-N increased. Soil pH was highest in the chicken litter compost treatment, and it declined with incubation period. Spinach dry matter was similar for all duckweed treatments, while the negative control had lower levels in the pot experiment. However, under field conditions the Lemna BF treatment (74.2 g/plant) had higher spinach dry matter (DM) yield than all the other treatments which were similar in DM. The results suggested that duckweed N mineralises rapidly in soil and also has a significant value on spinach yield, both depending on the initial elemental composition of duckweed, which is affected by the effluent on which it grew.
Nitrogen and phosphorus release and potential fertiliser effects of biogas slurry on spinach yield.
(2018) Grootboom, Lunga Sincerely.; Muchaonyerwa, Pardon.; Tsubo, Mitsuru.; Tesfai, Mohammed.; Moeletsi, M'aseapa Mookho Violet.
Use of organic waste to produce biogas aids in waste management and produces organic residue, biogas slurry (BGS), with appreciable quantities plant nutrient and potential to improve soil productivity. Feedstock and retention time during anaerobic digestion influence the quality and fertilizer value of the biogas Slurry. The objective of the study was to determine the release nutrients of biogas slurry, its potential as nitrogen (N) source and effects of co-application with chemical fertilizer (CF) on spinach yields and soil chemical parameters. Samples of biogas slurry, produced from cattle dung, and cattle manure (CM) were collected from Qwa-qwa, in the Free State Province of South Africa. The samples were analysed for pH, electrical conductivity (EC), total carbon (C), nitrogen, phosphorus (P), exchangeable bases and trace elements. Dried biogas slurry and cattle manure were applied to Avalon and Hutton soils at 0, 1, 2 and 3% (w/w). Then moistened to field capacity moisture, and incubated for 8 week, with periodic moisture correction. Destructive sampling was used to collect soil samples at 0, 1, 2, 4 and 8 weeks and the samples were analysed for pH, electrical conductivity, ammonium and nitrate-nitrogen, available phosphorus and exchangeable bases. Three glasshouse experiments were conducted to determine the fertiliser value of BGS for spinach (Spinacia oleracea) grown for 8 weeks. In the first experiment, biogas slurry was compared with chemical fertilizer and cattle manure as nitrogen sources at 100 kg N/ha in the Avalon soil. The second experiment involved application of biogas slurry and cattle manure at increasing nitrogen application rates of 0, 100, 150, 200 and 250 kg N/ha in Avalon soil. While the third experiment involved co-application of biogas slurry with chemical fertilizer at 0/100, 40/60, 60/40 and 100/0 kg N/ha (BGS/CF) in Avalon and Hutton soils. Soil pH increased with increasing application rate on both soils, during incubation. The 1% application rate showed the least pH increase for Hutton soil, which was significantly higher by 1.89% for cattle manure and 3.70% for biogas slurry than the control at week 8. Ammonium-N declined by 73.6% in Avalon compared to the 36.7% in Hutton soil at 3% BGS NH4-N within 2 weeks, then increased steadily up to week 8 at all application rates for both soils. On the other hand, nitrate-nitrogen declined for biogas slurry and increased for cattle manure, with increasing application rate after 2, 4 and 8 weeks of incubation in both soils. Available phosphorus increased with increasing rate of both biogas slurry and cattle manure especially up to two weeks of incubation in soils. Spinach dry matter yield were comparable between biogas slurry (4.04 g/pot) and cattle manure (3.40 g/pot) as a nitrogen sources, even though greater nutrient uptake and soil residual fertility occurred in BGS treatment. Increasing application of biogas slurry and cattle manure increased spinach dry-matter (DM) accumulation significantly from 100 up to 150 kg N/ha by 32.9% for biogas slurry and 23.1% for cattle manure, beyond that rate there was no notable variation. Higher nutrient uptake was observed at 150 kg N/ha, which supports the higher yields. However, biogas slurry co-application with chemical fertilizer had no synergistic effect and increasing application rate showed no significant improvement in dry matter yield and nutrient uptake. The findings of the study implied that the fertiliser value of biogas slurry was similar to cattle manure and subsequent crop could benefit from residual fertility after biogas slurry and cattle manure.
Assessing water use effeciency and carbon sequestration potential of different wheat (Triticum aestivum) genotypes.
(2019) Mbava, Nozibusiso Odette.; Zengeni, Rebecca.
Poor soil fertility status and limited water availability have been identified as two of the major constraints to crop production in South Africa. Under these conditions, growing crop genotypes that will sequester more carbon into the soil and be more water use efficient is crucial to improve crop production thus alleviate food insecurity. The aim of the study was to assess water use efficiency and carbon sequestration potential of different wheat genotypes. The experiment was set up under field and greenhouse conditions using 100 wheat genotypes from CIMMYT. These were grown at 25% (water-stressed) and 75% (non-stressed) field capacity (FC) using an alpha lattice with 10 blocks and 10 genotypes per block. Treatments were replicated twice in the field and three times in the glasshouse. After harvest the 10 best wheat genotypes were separated into roots and shoots, their chemical composition was analysed prior to the incubation experiment. About 0.25 g each of wheat root (RT) or shoot (ST) of the selected wheat genotypes were thoroughly mixed with 100 g of soil then transferred into an air tight PVC pot. NaOH solution was also placed inside the incubation pot to trap CO2 released during decomposition, and this was measured on day 0, 7, 15, 23, 31, 39, 47, 55, 63, 77, 91,105, and 120 of incubation. The results from the field and glasshouse experiments showed that average wheat grain yield (GY) varied from 326 g m-2 to 2062 g m-2, shoot biomass (SB) ranged from 1873 g m-2 to 3726 g m-2 while total plant biomass (PB) ranged from 2992 g m-2 to 6289 g m-2. Grain carbon stocks (GCS) averaged 132 g C m-2 and 167 g C m-2 in the glasshouse under stressed and non-stressed conditions, respectively. The total plant carbon stocks (PCS) ranged from 691 g m-2 to 3093 g m-2 (i.e. 348% difference) in the glasshouse, while they ranged from 835 g m-2 to 4016 g m-2 (i.e. 381% difference) in the field. Water use efficiency for grain yield production (WUE-GY) ranged from 0.12 g m-2 mm-1 to 2.10 g m-2 mm-1 (i.e. 18 fold increase) in the glasshouse under stressed conditions while it was 0.57 g m-2 mm-1 to 4.01 g m-2 mm-1 in the field under stressed conditions. WUE components varied amongst wheat genotypes. LM75 exhibited higher WUE-GY under stressed conditions while genotypes LM48 and LM47 exhibited lower WUE-GY under non-stressed conditions. LM75 was also ranked the best genotype for WUE-PCS while BW162 was ranked the best genotype for WUE-RCS. In the incubation experiment the shoot treatments evolved higher net CO2-C compared to root treatments. Net CO2-C was highest within the first two weeks and declined with time. Amongst the root treatments, BW140 RT evolved the highest net CO2-C (86.6 mg CO2-C kg-1 soil), while LM70 RT evolved the lowest (48.8 mg CO2-C kg-1 soil). In shoot treatments BW162 ST and BW140 ST evolved the highest net CO2-C with average values of 218.7 and 223.8 mg CO2-C kg-1 soil respectively. Comparing all the 10 treatments LM70 RT evolved the lowest while BW140 ST and BW162 ST had the highest net CO2-C. The findings revealed that variability in storing C under different scenarios of water availability exists among the wheat genotypes studied. Also, the residues of different wheat residues exhibit potential of sequestering more C into the soil thus improve soil fertility.
Soil organic carbon, glomalin related soil protein and related physical properties after 15 years of different management practices in a subtropical region of South Africa.
(2019) Mubekaphi, Caroline.; Nciizah, Adornis Dakarai.
Soil aggregation is an important mechanism, which plays a significant role in soil fertility as it decreases soil erosion and mediates air permeability, water infiltration, and nutrient cycling. Aggregation depends on a variety of aggregate binding agents, including carbon and its fractions, interrelating concurrently at different spatial scales. However, biologically active fractions of organic matter, such as microbial biomass carbon (MBC) and water-extractable organic carbon (WOC) could better reflect the changes in soil quality. Recent studies have highlighted the existence of a thermostable, water-insoluble soil glycoprotein operationally referred to glomalin-related soil protein (GRSP) that is crucial for preserving SOC. However, the relationship between SOM fractions and GRSP, and effects of different land uses on these parameters and relationships in humid environments are not clearly understood. The study sought to determine the relationships between soil organic carbon fractions, GRSP and aggregate stability under different management practices. The study was conducted on a farm located in the south-east of Howick, in the uMgungundlovu District Municipality, KwaZulu Natal province of South Africa. Soil samples were collected at 0-5, 5-10, 10-20 and 20-30 depths from three management practices i.e. long-term no till (NT), conventional tillage (CT), and native Forest (F). The native forest soils served as the control. Glomalin was assayed. The soils were further analysed for Ca, Mg, K, and Na, microbial biomass carbon (MBC), water soluble organic carbon (WSOC), soil bulk density (BD). Interaction between land-use and soil depth had significant effects on SOC content. There was general decrease in SOC as depth increased for all management practices except for no till, where no significant differences were observed in SOC across the four soil depth layers. The interaction between land-use and soil depth had significant effects (p < 0.05) on both easily iii extractable (EE-GRSP) and total (T-GRSP) glomalin related soil proteins. The NT treatment had the lowest concentration of EE -GRSP than the other two treatments in the 0-5 cm depth whilst no differences among the management practices at deeper soil layers were observed. The concentration of T-GRSP for soils under forest and NT tended to decrease with depth, while in CT the 10-20 and 20-30 cm depths had higher concentrations than the 0-5 and 5-10 cm depths. Land use also had significant effects (p < 0.05) on soil aggregate stability. Soils under Forest were the most stable with an MWD of just over 3, whilst soils under Conventional Tillage had the lowest MWD value of 1.24. The observed aggregate stability was significantly influenced by GRSP as evidenced by a significant positive relationship between both EE-GRSP (R2 = 0.72) and T-GRSP (R2 = 0.82). Therefore, management practices that mimic natural forest favour the accumulation of SOC and T-GRSP and should be widely adopted.
Analysis of global gully characteristics and the impacts of gabions and grass on sediments and carbon storage.
(2018) Dube, Hastings Bangani.; Muchaonyerwa, Pardon.; Chaplot, Vincent A. M.
Abstract available in PDF file.
Reforestation effects of a former sugarcane land on soil fauna invertebrate community and enzyme activity.
(2017) Mnembe, Sibusisiwe Jenifer.; Chivenge, Pauline.; Mafongoya, Paramu L.
Abstract available in PDF file.
Assessing the effect of in-field rainwater harvesting on soil physico-chemical properties and crop yield in comparison with the traditional farmers’ practice.
(2017) Khuzwayo, Mduduzi.; Zengeni, Rebecca.; McCosh, Jon Stuart.
Most communal farmers in South Africa rely on rain-fed agriculture. However, the country is experiencing rainfall variability as well as low soil fertility. These are major limiting factors to food production especially since South Africa is dominated by a semi-arid climate. It is for this reason that rural communities must optimally utilise their limited water reserves. Rainwater harvesting (RWH) technologies are amongst possible alternatives to maximise agricultural crop production. The aim of this study was to assess the effect of in-field rainwater harvesting on selected soil physico-chemical properties and maize crop yield in comparison with the traditional farmer practice. The study was conducted in homestead gardens in Kwa-Zulu Natal (KZN) province, under Msinga local municipality and in Eastern Cape Province (EC), under Tsolo local municipality. The study was set up at five homestead gardens namely Madosini, Beya, Mjali, Quvile and Sokhombe in the Eastern Cape and three field trials in Kwa-Zulu Natal (Mntungane, Xoshimpi and Mxheleni). It was designed as randomised complete block design, that compared in-field rainwater harvesting (contour ridges) with the traditional farmer practice (control) over two seasons (2013/14 and 2014/2015). Data was collected for soil chemical and physical properties as well as for crop grain and dry matter yields. Soil samples were collected at 0 - 10, 10 - 20 and 20 - 30 cm depths for analysis of soil pH, exchangeable bases, micronutrients and aggregate stability, and for analysis of bulk density at 0 -10 cm. These samples were collected at planting (2013) and at harvesting (2015). Gravimetric soil moisture content was periodically monitored at different stages of maize growth (planting, vegetative growth, tasselling and harvesting) in 2015. Biomass and grain yield were determined at harvest. Results showed that rainwater harvesting improved soil moisture content, aggregate stability, grain and dry matter yields. No clear trend was observed on the effect of rainwater harvesting on exchangeable bases, soil pH and micronutrients across all study sites in Kwa-Zulu Natal and Eastern Cape. It was therefore recommended that rainwater harvesting be used by resource constrained rural farmers who are experiencing unfavorable precipitations to improve crop yields and soil productivity.
Factors affecting phosphorus requirements for the soils of South African Sugar Industry.
(2016) Poswa, Lwazi Zukisa.; Muchaonyerwa, Pardon.; Miles, Neil.; Manson, Alan David.
Abstract available in PDF file.
Indigenous knowledge systems available to conserve soil and water and their effects on physico-chemical properties on selected smallholder farms of KwaZulu-Natal.
(2017) Vilakazi, Bonginkosi Samuel.; Zengeni, Rebecca.; Mafongoya, Paramu L.
Most of rural South Africa is semi- arid, experiencing a variable climate with extreme events such as droughts, floods or thunderstorms. In spite of this, communal farmers develop indigenous strategies to cope with these extremes in order to sustain agricultural production. The aim of the study was to document indigenous strategies that smallholder farmers in Bergville and uMsinga, in KwaZulu Natal use to predict weather, conserve soil and water in an effort to improve crop yields. Data was gathered through a baseline survey, which was supplemented with laboratory analyses to evaluate the physio-chemical properties of soil under different conservation practices in both areas. The baseline survey was carried out in sixteen villages, (eight villages each from uMsinga and Bergville). Information was gathered through 5 key informant interviews, 8 focus group discussions and 200 household questionnaires in each area. Soil characterisation was also done in the same sixteen villages by sampling from six conservation techniques namely zero and minimum tillage, intercropping, contour ploughing, fallowing and ridge/furrow planting, which were compared with conventional tillage. Soil samples were collected at 0-20, 20-40 and 40- 60 cm depth, then analysed for total C, N, P, pH, bases, EC, organic C, exchangeable Al and particle size distribution using standard laboratory techniques. Aggregate stability and bulk density were determined at 0-20 cm depth only by collecting aggregates and soil cores respectively. Results showed that Bergville and uMsinga farmers rely on crop and livestock farming, home industries, poultry farming, salaries and social grants for income. Farmers also believe that the climate has been changing over the years through temperature rises and more erratic rain. They use indigenous indicators such as wind and cloud patterns, animal and bird behaviour, shape of the moon and position of the sun to predict weather. To cope with extreme weather, farmers rely on rainmakers and traditional healers in drought years, open drainage pathways to drain excess water during floods, burn incense to quell thunderstorms and lightning, then use the aloe plant, ashes and cow dung to control pests and diseases. Farmers also use drought tolerant crops (sorghum / millet), varieties (yellow maize) to cope with dry spells; and practices such as intercropping and crop rotation to sustain soil productivity. To conserve soil and water, farmers use raised beds, mulching, early maturing crops, furrows & ridges, earth dams and animal manure in the gardens; while contour farming, zero tillage, fallowing, terraces and animal manure are used in the fields. Techniques such as zero tillage, terraces, furrow/ridge, raised bed and mulching were adopted from science. Whereas fallowing, contour ploughing, manure addition, earth dams and rainwater harvesting are IKS. In uMsinga most farmers still prefer their indigenous methods. Whereas in Bergville, farmers prefer scientific methods. Zero, minimum and conventional tillage treatments improved soil properties (bases, P, OC and aggregate stability) at Bergville whereas at uMsinga intercropping, contour ploughing and furrow / ridge performed better. The clay fraction did not have much influence on the performance of the techniques. In uMsinga, silt had more impact since it enhanced soil pH, Ca and K availability. High soil pH enhanced availability of bases (Ca, Mg and Na) particularly at Bergville, but negatively correlated with Al. Soil moisture enhanced availability of Mg, Na, P and C: N at but had a negative correlation with K. Whereas in Bergville, soil moisture positively correlated with OC but was negatively correlated with Na. Correlation results showed that there was no relationship between the different particle size fractions and tillage techniques. As a result, the higher performing techniques do not have their performance influenced by textural fraction. It was recommended that farmers in Bergville adopt zero and minimum tillage since they improved soil properties in the field. In uMsinga, intercropping and contour ploughing would be better soil quality enhancers than conventional tillage in the field, while the furrow/ridge is of more benefit in the gardens.
Chemical characteriistics, fertilizer value and escherichia coli and salmonella composition of vermicomposted sewage sludge.
(2016) Mashologu, Busisiwe.; Muchaonyerwa, Pardon.
Abstract available in PDF file.
Elemental composition and fertiliser value of different types of human hair in South Africa.
(2016) Malepfane, Ntwanano Moirah.; Muchaonyerwa, Pardon.
Abstract available in PDF.
Rapid biomax thermophilic composting effects on quality, nutrient release and fertiliser value of chicken litter composts.
(2016) Mawonga, Thamsanqa.; Muchaonyerwa, Pardon.
Large accumulation of organic waste produced from intensive animal production systems pose challenges for disposal and direct land application of these materials adversely affect the environment. Composting aids to reduce waste volume and produce a stable product, rich in nutrients, that is valuable for soil fertility improvement. The Biomax system has been developed as a system to rapidly compost organic wastes at 70-80 oC in a 24 h period. The stability, quality and fertiliser value of the compost needs to be understood. Considering the high temperatures involved it would be essential to establish whether or not the addition of the enzyme is entirely necessary in the process. The objectives of this study was to determine effects of the Biomax composting time and enzyme addition on chicken litter compost stability, quality, nutrient release, in soils, and dry matter yield and nutrient uptake of spinach. Biomax composts were produced from mixtures of chicken litter and other organic wastes with (W) and without (N) the BM1 enzyme. Compost samples were collected after 1, 6, 12, 18 and 24 h of composting, and analysed for pH, EC, total C, N, and P, exchangeable bases, trace elements, fulvic and humic acids and Escherichia coli and Salmonella spp. An incubation study was carried out with final composts (after 24 h of composting) applied to soil at 0, 1, 2 and 3 % (w/w) and destructive sampling was done after 0, 7, 14, 28, 42 and 56 days of incubation. The samples were analysed for pH, mineral N, available P, and bases. A glasshouse experiment was also conducted using the final compost produced with the BM1 enzyme. The compost was applied as the nitrogen source to 3 kg soil at 0, 2.5, 5, 10 and 20 t/ha and spinach (Spinacia oleracea) grown for eight weeks. The pH of compost with the BM1 enzyme decreased with composting time while the one without the enzyme increased between 1 and 12 h. Total C, electrical conductivity (EC), carbon to nitrogen ratio (C:N) and humification ratio (HR) were not affected by composting time for both composts. Total N increased up to 18 h of composting and became constant afterwards for both composts. Pathogenic organisms E. coli and Salmonella species were not detectable in all composts irrespective of composting time. In the incubation study NH4-N levels initially were similar statistically for all rates of both composts, except for soil treated with 1% of compost with the enzyme, which had lower NH4-N than that amended with 3% of the compost without the enzyme. Levels of soil NO3-N showed rapid increase in all treatments including control between 14 and 28 days of incubation and remained constant thereafter. The amount of available P was higher in soil treated with 3 % of both composts. There was no differences in spinach tissue nitrogen concentrations among the different application rates of Biomax compost. Spinach dry matter yield and N uptake improved with addition of compost. The findings of this study implied that the Biomax system is not effective in stabilising chicken litter into compost but it effectively sterilizes the organic waste materials and that the resultant composts rapidly release nutrients at sufficient rates to improve dry matter yield and nutrient uptake of spinach. Keywords: Biomax compost, mineralisation , nutrient composition, plant nutrient uptake, spinach (Spinacia oleracea).

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