Effect of temperature and litter quality on decomposition rate of Pinus patula needle litter

AbstractThis study examined the mass loss and CO2 production from Pinus patula (Schlecht et Cham) leaf litter collected from fertilized plots in the Mpumalanga Province. Litter decomposition increased with increasing temperature. Warming between 15 and 18°C significantly increased the amount of CO2 emissions from the litter. Mass loss positively correlated with temperature levels. Nitrogen fertilizer applications had significant effects on litter decomposition rate but a minor effect on litter nitrogen quality. Litter quality was not a strong predictor of decomposition rates implying temperature is the major factor influencing the decomposition rate of Pinus patula needle litter. Results of this study are consistent with the hypothesis that the rate of nutrient cycling in non-limiting environments will increase, due primarily to an increase in litter decomposition as a result of increased temperatures

Boundaries and Bridges: the influence of James Cooksey Culwick on the development of the teaching and learning of music in nineteenth century Ireland

James Cooksey Culwick (1845-1907) was born in England. Trained as chorister and organist in Lichfield Cathedral, he moved to Ireland at twenty- one and remained until his death in 1907. Although his reputation as scholar, musician and teacher was acknowledged widely during his lifetime - he received an honorary doctorate from University of Dublin (1893) - little is known about the contribution he made to music education. This paper addresses this gap in the literature and argues that it was Culwick's singular achievement to pay attention to music pedagogy at secondary level, by recognizing that music could be seen as a serious career option for girls, and by providing resources for teachers which emphasised the development of an 'art-feeling' in pupils of all abilities. In addition, he considered Irish music as an art which had significance as music first, and Irish music second, and advocated a 'laudable tolerance' for opposing views on matters of cultural identity to Ireland at the end of the nineteenth century

Reading tea leaves worldwide: decoupled drivers of initial litter decomposition mass‐loss rate and stabilization

The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large‐scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass‐loss rates and stabilization factors of plant‐derived carbon, using the Tea Bag Index (TBI). The stabilization factor quantifies the degree to which easy‐to‐degrade components accumulate during early‐stage decomposition (e.g. by environmental limitations). However, agriculture and an interaction between moisture and temperature led to a decoupling between initial mass‐loss rates and stabilization, notably in colder locations. Using TBI improved mass‐loss estimates of natural litter compared to models that ignored stabilization. Ignoring the transformation of dead plant material to more recalcitrant substances during early‐stage decomposition, and the environmental control of this transformation, could overestimate carbon losses during early decomposition in carbon cycle models

Biological processes as indicators of sustainable plantation forestry : evidence for sustainable plantation forestry

This paper discusses the use of an ecosystems approach in the management of plantations and the concept of plantations in providing goods and services. Ecological indicators are compared for the CIFOR and South African systems. The CIFOR system focuses on three criteria, which involve the maintenance of a) biodiversity, b) ecosystem function and c) genetic variation. The South African system has chosen six criteria: a) the protection of natural forests, b) conservation of biodiversity, c) conservation of ecosystem structures and processes, d) protection of forests from fire, pests, diseases and alien plants, d) maintenance of production potential and e) the conservation of soil and water resources. Ideas are presented on indicators and measures, which may be useful in the sustainable management of nutrient cycling, yield production, pest outbreaks and water use and quality. Indices of nitrogen mineralization rates, soil carbon stocks and ongoing mensuration of biomass are key measurements. Under global change conditions it is predicted that the outbreaks of pests will be more severe and the industry must be prepared to invest in appropriate monitoring and technologies. It is emphasized that a framework needs to be provided into which the indicator measures can be placed. This would best be accomplished by the simultaneous development of a number of relatively simple ecosystem and plant-physiological based models. Southern African Forestry Journal No.195 2002: 57-6

Nutritional sustainability of Eucalyptus plantations : a case study at Karkloof, South Africa : evidence for sustainable plantation forestry

The nutritional sustainability of a short-rotation Eucalyptus grandis plantation system was evaluated in a trial located at Karkloof, KwaZulu-Natal, South Africa, by determining nutrient pools and fluxes. Nutrient pools in the forest floor and biomass (above- and below-ground) were assessed by destructive sampling. The size of nutrient pools in the soil that approximate to readily available and potentially available fractions was estimated from chemical extractions. An approximate nutrient input-output budget was constructed. The study has shown that large nutrient pools occur in the forest floor and below-ground biomass when compared to most short-rotation eucalypt cropping systems overseas. The readily available soil pools are moderately large (100 to 800 kg ha-1) when compared to similar systems in the tropics (Brazil & Congo). The potentially available nutrient pools are particularly rich in potassium (2.5) and magnesium (1.1 t ha-1). This indicates that the system is well buffered against nutrient depletion in the short and long term. Estimates of nutrient fluxes revealed that fertilization and mineral weathering constitute small inputs, while atmospheric deposition makes a major contribution to the system (95% of total N inputs, 92% of total Ca and Mg and 82% of total K inputs). Sizeable nutrient losses were caused by slash burning (N), leaching (Ca & Mg), and both wood harvesting and firewood collection (N, K & Ca). The management regime and intensity of operations both have a pronounced effect on nutrient fluxes to and from the system, and hence, the net balance of the budget was calculated for different management regimes at representative intensities. Net fluxes were positive or near zero for most elements in the absence of firewood collection or slash burning and changed to losses of between ca. 5 to 10 kg ha-1 a-1 per individual nutrient when slash burning was incorporated in the regime. Despite the increases in nutrient loss with more intensive management, the indices of nutritional sustainability for all regimes tested still indicated a stable system with respect to nutrition. Nutritional sustainability has been gauged by other researchers using the ratio (nutrient export in harvesting) / (available nutrient pool size). An index of nutritional stability (pINS) is proposed, based on the negative logarithm of the ratio (net nutrient loss) / (nutrient pool) where the nutrient pool can be readily available soil pools or (long term) potentially available system pools. Although this index has intensive data requirements, it evaluates management intensity effects as well as the ";buffer capacity"; of the system more rigorously than previously proposed indices. Southern African Forestry Journal No.195 2002: 63-7

The impact of the addition of Eucalyptus grandis wood chips on nitrogen availability in plantation soils: scientific paper

The impact of plantation residues, as a result of clearfelling, on nutrient availability in plantation systems, as well as the difficulties during subsequent planting and harvesting, should be considered in the development of plantation management strategies. The aim of this experiment was to determine if the addition of stump wood chips would result in the immobilisation of nitrogen. Soil from two plantations, one of the Kranskop soil form (0,57% nitrogen) and one of the Hutton soil form (0,23% nitrogen), were analysed in a laboratory experiment for changes in nitrogen availability. Soils were amended with wood chips and varying amounts of nitrogen fertilizer. Inorganic nitrogen was measured after 14,60 and 90 days of aerobic incubation. Net mineralisation rates, regardless of treatment or soil, ranged between -24,98 and +2,53 mg nitrogen / g soil / day, over the 3-month incubation period. Immobilisation of nitrogen was found to occur in those treatments that received the highest nitrogen additions. Addition of wood chips on their own did not alter the nitrogen availability patterns. However, it was observed that wood chips, together with high levels of additional nitrogen, resulted in an extended period of release of nitrogen in these plantation soils. Southern African Forestry Journal No.196, 2003: 9-1

Influence of irrigation and fertilisation on early growth of Eucalyptus grandis

No Abstract Available Discovery and Innovation Vol.15(3&4) 2003: 213-22

Prescribed under-canopy burning in Pinus patula plantations of the Mpumalanga highveld: The effects of fire on tree growth

The effect of controlled undercanopy burning on tree growth has been studied under 16-year-old Pinus patula trees in Mpumalanga. Three fire intensity treatments and a control “no-burn” treatment, were applied to 1 ha plots. Average fuel depth was 42cm with a mean fuel load of 14.3 tons/ha. Fuel load was reduced by 15%, 30% and 60% in the three intensity burns. Fire intensity parameters were calculated using the BEHAVE fire behaviour prediction and fuel modeling system. Fireline intensity was predicted to be 134, 277 and 761kW/m for low, medium and high intensity experimental burns, respectively. Bark scorch height was found to be significantly greater in the plots under the high intensity burn treatment than in the low and medium intensity treatments. Most trees experienced scorch damage to between 0 and 40% of the crown volume. There was a significant negative effect on tree growth after a period of 36 months in the high intensity burn treatment. A low level (3 dead trees in sample of 360) of mortality occurred. This study showed clearly that undercanopy burning, at a low intensity, could significantly reduce fuel loads without resulting in decreased tree growth. It is recommended that this approach should be explored at an operational scale.Keywords: Pinus patula, prescribed burning, growth, fire intensity Southern African Forestry Journal No. 204 2005: 3-1

Drought Characterization and Trend Detection Using the Reconnaissance Drought Index for Setsoto Municipality of the Free State Province of South Africa and the Impact on Maize Yield

The reconnaissance drought index (RDI) for the Setsoto municipality of the Free State province in South Africa was calculated for the period between 1985 and 2019 at 3 month (October–December), 6 month (October–March), and 12 month (October–September) intervals. Rainfall and minimum and maximum temperature data from four weather stations (Clocolan, Ficksburg, Marquard, and Senekal) were used for this study to characterize drought using “DrinC” software together with the Mann Kendall test with Sen’s slope to detect drought trends and the rate of change. Extreme, severe, and moderate droughts were recorded for all the stations, with RDIs ranging from −3.6 to −1.0 at different temporal scales. The years 1991, 1994, 2006, 2011, and 2015 were highlighted using the RDI 3, 6, and 12 month calculations. Results showed that the yield decreased either in the year of the drought or in the subsequent year, due to the exact timing of the low-rainfall events in the season and soil moisture storage. Yields were low, on average 2.5 tons ha−1 year−1, with high variability. Optimal growing conditions are essential in the early part of the season, October–December, for maximizing yield; if droughts are experienced at this time then the yield is more greatly impacted than if the droughts occur later in the season. Spatial analysis shows a large variability of drought patterns across the Municipality, over the years, with the 3 month RDI values giving a more detailed picture of this variability than the 6 and 12 month RDI values

A Systemic Analysis of the Environmental Impacts of Gold Mining within the Blyde River Catchment, a Strategic Water Area of South Africa

Exploratory modelling of the impact of gold mining on groundwater in a strategic water area of South Africa was undertaken. A systems dynamics (SD) model was developed to simulate the impact of gold mining on water quality, focusing on groundwater contamination risk, within the context of competing developmental priorities around water resource development and the socio-economic gains from gold mining. The model also identified interventions to minimise the impacts by the year 2040. The study area was the Blyde River Catchment (BRC), which is part of the Olifants Water Management Area in South Africa. This area is an important contributor, currently and in the future, to freshwater flows and groundwater in the Olifants River Catchment, which is one of South Africa’s most economically important catchments. The model development process included a causal loop diagram­–based problem conceptualisation, followed by the drawing of stock-flow diagrams and the determining of model parameters based on a combination of background literature, data from environmental impact assessments, and from the national Department of Water and Sanitation. The model showed the potential environmental risks of gold mine wastewater production and interventions to minimise these risks. The most effective intervention identified to reduce the risk of groundwater contamination was the development and use of synthetic-lined tailings dams. The baseline simulation result of sulphate loading of 5430 t/year can be reduced by 3070 t/year to give a simulated sulphate load of 2270 t/year in 2040 using this intervention. In comparison, the simulated wastewater recycling intervention only reduced the sulphate load to 4630 t/year and the wastewater treatment interventions to 3420 t/year. This project contributes to the exploratory modelling of an understudied region of the Olifants River Catchment that is a crucial provider of freshwater flows to the Olifants, which is threatened by increasing gold mining in the upper BRC. The SD model highlighted the importance of protecting the dolomitic aquifers in the BRC for the long term sustainability of the catchment, which is particularly important if groundwater development occurs