Effectiveness of combined thermophilic composting and vermicomposting on biodegradation and sanitization of mixtures of dairy manure and waste paper

Thermophilic composting is commonly used for the treatment of organic wastes or for production of organic/natural fertilizers. Vermicomposting (V) is also increasingly becoming popular. These two techniques have their inherent advantages and disadvantages. In this study, vermicomposting and a combination of thermophilic composting and vermicomposting were compared as ways of sanitizing and biodegrading dairy manure and waste paper mixtures with C:N ratios of 30 and 45. Wastes with a C:N ratio of 30 proved more suitable for both vermicomposting and combined thermophilic composting and vermicomposting as their composts were more stabilized and with higher nutrient contents than composts made from wastes with a C:N ratio of 45. Both vermicomposting and combined compostingand vermicomposting were effective methods for the biodegradation of dairy manure and paper waste mixtures with C:N ratio of 30 but the latter was more effective in the biodegradation of waste mixtures with a C:N ratio of 45. Combining therrmophilic composting and vermicomposting eliminated the indicator pathogen Escherichia coli 0157 from the final composts whereas vermicomposting only managed to reduce the pathogen population

Effects of sheep kraal manure on growth, dry matter yield and leaf nutrient composition of a local amaranthus accession in the central region of the Eastern Cape Province, South Africa#

Indigenous vegetables that supply abundant amounts of protein, vitamins, calories and minerals could alleviate problems of malnutrition, in developing countries. Amaranthus is one such vegetable that could be domesticated and cultivated but information on its fertility requirements is scanty. A dry-land field experiment was therefore conducted to study the effects of sheep kraal manure application rates on growth, fresh and dry matter yields, nutrient uptake and grain yield of one of the Amaranthus accessions that grow in the wild in the Eastern Cape. The treatments were sheep kraal manure rates rangingfrom 0 to 10 t/ha and an NPK {2:3:4(30) + 0.5% Zn} fertiliser as a positive control at 150 kg/ha. Low manure rates (.2.5 t/ha) resulted in plant heights and fresh matter yields which were comparable to those in the unfertilised control, whereas higher rates (5 and 10 t/ha) and NPK fertiliser gave greater plant heights and higher yields at both 30 and 60 days after transplant (DAT) (

Effects of sheep kraal manure on growth, dry matter yield and leaf nutrient composition of a local Amaranthus accession in the central region of the Eastern Cape Province, South Africa

Indigenous vegetables that supply abundant amounts of protein, vitamins, calories and minerals could alleviate problems of malnutrition, in developing countries. Amaranthus is one such vegetable that could be domesticated and cultivated but information on its fertility requirements is scanty. A dry-land field experiment was therefore conducted to study the effects of sheep kraal manure application rates on growth, fresh and dry matter yields, nutrient uptake and grain yield of one of the Amaranthus accessions that grow in the wild in the Eastern Cape. The treatments were sheep kraal manure rates ranging from 0 to 10 t/ha and an NPK {2:3:4(30) + 0.5% Zn} fertiliser as a positive control at 150 kg/ha. Low manure rates (≤2.5 t/ha) resulted in plant heights and fresh matter yields which were comparable to those in the unfertilised control, whereas higher rates (5 and 10 t/ha) and NPK fertiliser gave greater plant heights and higher yields at both 30 and 60 days after transplant (DAT) (p<0.05). At 30 DAT, manure application rates of ≥2.5 t/ha and the NPK fertiliser treatment, produced greater shoot dry-matter yields (≥29.35 g/plant) than the unfertilised control (17.11 g/plant). Uptake of N and P in the leaves increased with increase in manure application rate with N uptake reaching a maximum of 308 mg N /plant at a manure rate of 2.5 t/ha which corresponded with the maximum dry matter yield of 45.97 g/plant. There was no effect of manure rate or fertiliser on residual soil N and Ca, whereas P, K, Mg and Zn were increased (p<0.005). The findings suggested that ≥2.5 t/ha sheep kraal manure could result in growth, nutrient uptake and yield comparable to 150 kg/ha NPK fertiliser for the Amaranthus accession used in this work.Keywords: Amaranthus accession, sheep manure, dry matter yield, nutrient composition, residual nutrient

Inoculation effects of two South African cyanobacteria strains on aggregate stability of a silt loam soil

Two South African cyanobacteria strains (coded 3g and 7e) of the genus Nostoc were evaluated for  improvement of the aggregate stability of a silty loam soil with low organic C content and compared with  Nostoc strain 9v isolated from a Tanzanian soil. The soil was either cropped with maize or non-cropped and  inoculated with the three strains in a glasshouse. After 42 days, the aggregate stability based on mean weight  diameter (MWD) and fragment size distribution were determined by fast wetting, wet stirring and slow  wetting methods. Inoculation of the soil with strains 3g and 7e improved the soil’s MWD and increased its  proportion of large aggregates, particularly in the cropped soil. The opposite was the case for aggregates in soils inoculated with the reference strain 9v. Strain 3g resulted in greater improvement of MWD estimated by fast wetting, while strains 7e and 9v improved aggregate stability estimated by wet stirring. Improvement of aggregate stability was more related to exocellular polysaccharide (EPS) content than organic C. The results suggest that indigenous strains with high potential for EPS production could improve the soil structural  stability of degraded soils in South Africa.Key words: Aggregate stability, exocellular polysaccharides, indigenous cyanobacteria, mean weight diameter

Effect of Cry1Ab Protein on Rhizobacterial Communities of Bt-Maize over a Four-Year Cultivation Period

Background: Bt-maize is a transgenic variety of maize expressing the Cry toxin from Bacillus turingiensis. The potential accumulation of the relative effect of the transgenic modification and the cry toxin on the rhizobacterial communities of Btmaize has been monitored over a period of four years. Methodology/Principal Findings: The accumulative effects of the cultivation of this transgenic plant have been monitored by means of high throughput DNA pyrosequencing of the bacterial DNA coding for the 16S rRNA hypervariable V6 region from rhizobacterial communities. The obtained sequences were subjected to taxonomic, phylogenetic and taxonomicindependent diversity studies. The results obtained were consistent, indicating that variations detected in the rhizobacterial community structure were possibly due to climatic factors rather than to the presence of the Bt-gene. No variations were observed in the diversity estimates between non-Bt and Bt-maize. Conclusions/Significance: The cultivation of Bt-maize during the four-year period did not change the maize rhizobacterial communities when compared to those of the non-Bt maize. This is the first study to be conducted with Bt-maize during such a long cultivation period and the first evaluation of rhizobacterial communities to be performed in this transgenic plant using Next Generation Sequencing

Pedology: AGS 221

Pedology: AGS 221, degre/diploma examination November 2009

Soil Taxonomy: AGS 322

Soil Taxonomy: AGS 322, degree examination November 2009

Introduction to Soil Science: AGS 211

Introduction to Soil Science: AGS 211, degree examination January 2011

Plant Nutrition & Soil Fertility: AGS 321

Plant Nutrition & Soil Fertility: AGS 321, examination Jan 2010

Pedology: AGS 221

Pedology: AGS 221, supplementary examination January 2011