Total organic carbon, aluminium and iron in bulk samples and aggregate size fractions of a sandy clay loam humic soil under sugarcane relative to native forest in northern KwaZulu-Natal, South Africa.

The distribution of total aluminium (Al) and iron (Fe) and organic carbon (TOC) in aggregate fractions gives an insight into the dynamics of these elements in soil. This study determined the effects of over 30 years of sugarcane cultivation, compared to adjacent native forest, on Al, Fe and TOC in bulk soil and aggregate fractions within the 100 cm depth of a sandy clay loam humic soil. Samples were separated into large macro-aggregates: LM (>2000 μm), small macro-aggregates: SM (250-2000 μm), micro-aggregates: M (250-63 μm) and silt + clay: SC (<63 μm) fractions.

Characteristics and liming potential of biochar types from potato waste and pine-bark.

Large amount of wastes are burnt or left to decompose on site or at landfills where they cause air pollution and nutrient leaching to groundwater. Waste management strategies that return these food wastes to agricultural soils recover the carbon and nutrients that would otherwise have been lost, enrich soils and improve crop productivity. This study characterised biochar produced by pyrolysis of potato peels (PP), cull potato (CP) and pine bark (PB) at 350 and 650°C.

Land use and site effects on the distribution of carbon in some humic soil profiles of KwaZulu-Natal, South Africa.

Land use effects on the stocks of soil organic carbon (SOC) are generally based on the topsoil. Although subsoil horizons have lower concentrations, they contain a significant amount of SOC which may be more strongly protected than that in the topsoil layers. Analysis of SOC storage must therefore include the whole profile in respect of climate change mitigation.

Short-term effects of selected organic fertilizer sources on carbon dioxide fluxes and soil quality.

Biogas slurry (BGS) has potential as an organic nutrient source, and understanding its effect on carbon (C) exchange in soils is important for clarifying the contribution of organic amendments to soil fertility and the C budget globally. This study evaluated the effect of BGS, cattle manure (CM), and chemical fertilizer (CF) on carbon dioxide (CO ) fluxes, microbial biomass C, and β-glucosidase activity during the 2016-2017 and 2017-2018 maize (Zea mays L.) seasons, covering December-May, in South Africa.

Sorption of Selected Heavy Metals with Different Relative Concentrations in Industrial Effluent on Biochar from Human Faecal Products and Pine-Bark.

The removal of heavy metals from effluents at source could reduce contamination of soil and water bodies. A batch sorption experiment was performed to determine the effects of feedstock of biochars pyrolysed at increasing temperature on sorption capacities of Cu, Cr and Zn from industrial effluent and aqueous solutions. Sewage sludge, latrine faecal waste and pine-bark biochars were used.

Biomass, Nitrogen Uptake and Content of Depends on Strength of Swine Lagoon Water.

Studies focusing on manipulation of growth conditions for duckweed to promote biomass for crop nutrient supply, are scarce. The effects of swine lagoon water (SLW) concentration and its replenishment and harvest regimes on selected properties of were investigated. Dry matter and average growth rate of were not affected by SLW replenishment periods, whereas the properties decreased with increasing concentration of SLW.

Vermicomposting manure-paper mixture with igneous rock phosphate enhances biodegradation, phosphorus bioavailability and reduces heavy metal concentrations.

In organic soil fertility management, rock phosphate (RP) is gaining momentum as an acceptable phosphorus source, though much of this P is not bioavailable for plant uptake, particularly in igneous RP. This study evaluated the nutrient solubilization, biodegradation and heavy metal concentration when cow dung - waste paper mixture amended with increasing rates of igneous RP was vermicomposted with . The cow dung was optimized to a C/N ratio of 30 using waste paper and amended with RP to provide 0%; 2%; 4% and 8% of elemental phosphorus on a dry w/w basis.

Decomposition of Wolffia arrhiza residues rapidly increases mineral nitrogen and decreases extractable phosphorus in acidic soils.

While nutrient loads from anthropogenic sources upset aquatic ecosystem balance, Wolffia arrhiza (duckweed) has capacity to purge nutrient-rich water if continuously harvested. The nutrients accumulated in biomass have potential as soil fertility amendments. The objective of this study was to determine changes in release of nitrogen (N) and phosphorus (P), and the fate of P in soils after duckweed biomass amendment.

Complementary nutrient effects of separately collected human faeces and urine on the yield and nutrient uptake of spinach (Spinacia oleracea).

A glasshouse experiment was conducted to evaluate the combined use of separately collected human faeces and urine as fertilizer for spinach (Spinacia oleracea) production. Seven human faeces N : urine N combinations (1 : 7 to 7 : 1) each supplying 200 kg N ha(-1) were evaluated along with sole human faeces, sole urine, inorganic fertilizer and an unamended control. Complementary application of the two resources, human faeces and urine, increased fresh and dry matter yields only in treatments having high proportions of urine.

Effects of a precomposting step on the vermicomposting of dairy manure-waste paper mixtures.

Thermophilic composting is being promoted as a means of sanitizing waste materials prior to vermicomposting. The precomposting duration is, however, critical to the success of the vermicomposting phase as it affects worm biomass. This study evaluated the effectiveness of different precomposting periods (0, 1, 2, 3 and 4 weeks) on the sanitization and vermicomposting of dairy manure-waste paper mixtures.

Evaluation of human urine as a source of nutrients for selected vegetables and maize under tunnel house conditions in the Eastern Cape, South Africa.

The introduction of ecological sanitation (ECOSAN) toilets in South Africa has created opportunities for safer sanitation and recycling of human excreta, as fertilizers, in rural and peri-urban areas. A study was carried out to evaluate the fertilizer value of human urine (0 to 400 kg N ha(-1)) for maize and tomato, compared to urea, in a tunnel house. Dry matter yield of both maize and tomato, harvested at 9 and 10 weeks after planting, respectively, increased with increasing N rate (both as urine or urea) up to 200 kg N ha(-1).