Research articles (Dept of Environmental Science)
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Kalabamu, F.T. (Elsevier Science Ltd. http://www.elsevier.com/locate/landusepol, NaN, 2000)[more][less]
Abstract: Since attainment of independence, almost every country in East and Southern Africa has introduced some kind of land reform aimed at reconciling indigenous land tenure practices and those introduced by colonial regimes. The reforms have centred on modi"cation of tenurial rules on access, ownership, administration and transfer of land rights coupled with land redistribution and/or restitution in some countries. With the exception of a few countries, such as Botswana, land reforms have largely remained on statute books with little to show on the ground. The paper gives an overview of land reforms in East and Southern Africa, taking Botswana as a case study. It notes that although Botswana has largely been successful in implementing land reforms, it is currently experiencing land tenure problems, especially in peri-urban settlements and inner city low-income areas, despite government's enhanced control over local land administrative structures. The paper ends with suggestions on how to contain the current problems. URI: http://hdl.handle.net/10311/1134 Files in this item: 1
Kalabamu_LUP_2000.pdf (1.757Mb) -
Meck, M.L.; Atlhopheng, J.; Masamba, W.R.L.; Ringrose, S.; Diskin, S. (Bentham Open, http://www.benthamscience.com/open/tomj/index.htm, NaN, 2011)[more][less]
Abstract: This study set out to establish the major minerals at Dorowa and determine which of those are likely to host metals that may leach into surface and groundwater. This study comes after a preliminary assessment of the water quality in the Save River downstream of the Dorowa phosphate mine in Zimbabwe showed an increase in conductivity, iron content, manganese content, nitrates and hardness when compared to those taken before the mining area. X-Ray Diffractometry (XRD) was used to establish the major minerals at Dorowa whilst Inductively Coupled Plasma Mass Spectrometry (ICP- MS) was used to establish the chemistry of the rocks. The results from this study show that the major minerals in the rocks around Dorowa are feldspars, pyroxenes, apatite, magnetite and calcite. The metals hosted by the rocks include Ag, As, Be, Cd, Co, Cu, Pb, Hg, Ni, Sb, Se and Zn. The study concludes that the minerals likely to host metals are calcite and apatite. Metal hosting is higher in apatite minerals than in calcite. Metal hosting by the other minerals observed in the study area is low. URI: http://hdl.handle.net/10311/1109 Files in this item: 1
Atlhopheng_OMJ_2011.pdf (848.6Kb) -
Dikinya, O.; Areola, O. (Springer, http://link.springer.com/, March NaN, 2010)[more][less]
Abstract: The use of treated urban wastewater for irrigation is a relatively recent innovation in Botswana and knowledge is still limited on its impact on soil heavy metal levels. The aim of this study is to analyze and compare heavy metal concentration in secondary wastewater irrigated soils being cultivated to different crops: olive, maize, spinach and tomato in the Glen Valley near Gaborone City, Botswana. The studied crop plots have been cultivated continuously under treated wastewater irrigation for at least 3 years. Most crop farms have sandy loam, loamy sand soils. Based on food and agriculture organization, heavy metal threshold values for crop production have been studied. Results showed that the wastewater irrigated soils in the Glen Valley have higher cadmium, nickel and copper than desirable levels, while the levels of mercury, lead and zinc are lower than the maximum threshold values recommended for crop production. The control sites show that the soils are naturally high in some of these heavy metals (e.g copper, zinc, nickel) and that crop cultivation under wastewater irrigation has actually lowered the heavy metal content. Comparing between the crops, mercury and cadmium levels are highest in soils under maize and decline linearly from maize to spinach to olive to tomato and control site. By contrast, concentrations of the other metals are at their lowest in maize and then increase from maize to spinach to olive to tomato and to control site. URI: http://hdl.handle.net/10311/1105 Files in this item: 1
ijest 2010 dikinya and areola.pdf (685.3Kb) -
Kizza, S; Areola, O (Academic Journals, November NaN, 2010)[more][less]
Abstract: This study investigated the influence of the accumulation of animal wastes on the soils of active kraal sites through time. This investigation involved the sampling and analysis of the soils of kraals that had been in use for periods ranging from 2 to over 45 years. Soil sampling and analysis were done both in the dry and wet seasons for comparative purposes. The properties of the kraal soils were compared with those of control sites. Samples were taken from 25 kraals categorized into 5 age (length of use) groups: < 5years; 6 - 10; 11 - 20; 21 - 40; > 40 years. The soils were sampled at two depths, 0 – 15 and 15 – 35 cm. Soil parameters analyzed included particle size distribution (%), bulk density (g/cm3), pore space (%), moisture content (%), pH in water and in potassium chloride solution, EC (μS/cm), organic matter (%), CEC (meq/100g), exchangeable bases: Ca++(cmolc/kg), Mg++(cmolc/kg), K+(cmolc/kg), Na+(cmolc/kg); nitrogen: NH4-N (mg/kg), NO3-N (mg/kg), TKN (%), and Olsen P (mg/kg). Results showed a direct correlation between length of active kraal utilization and impact of animal waste concentration on the soil with correlation coefficients as high as r = 0.99 and r = 0.95 for pH and OM respectively. Nutrient levels in kraal soils of all ages were significantly higher (P = 0.05) than those of the control site soils. Most nutrient elements showed increases ranging from about 2 - 30 times greater than in the control site soils. Soil nutrient levels were higher in the dry season than in the wet season. The nutrient enrichment in the kraals extended deep into the soil, at least, to the 35 cm depth. The organic and nutrient enrichments of the soils also had very positive effects on soil moisture and structural characteristics. However, this highly localized nutrient enrichment of kraal soils is detrimental to the long term sustainability of arid ecosystems and soil productivity. The nutrients concentrated in kraals have been harvested from the surrounding areas by grazing animals and transferred to the kraal sites. In a situation of sedentary kraaling that exists in semi arid lands of Botswana where rotation of kraal sites or the harvesting of animal manure from kraals for use as soil manure is not commonly practiced, the concentration of soil nutrients at scattered kraal spots causes an imbalance in the spatial pattern of soil and plant productivity in the arid land ecosystem. The entire ecosystem is made poorer by this phenomenon. Description: Full Length Research Paper URI: http://hdl.handle.net/10311/1095 Files in this item: 1
Kizza and 0Areola.pdf (293.8Kb) -
Meck, M.L.; Atlhopheng, J.; Masamba, W.R.L.; Ringrose, S. (Elsevier Science Ltd, http://www.elsevier.com/locate/pce, NaN, 2010)[more][less]
Abstract: The study set out to determine the weathering and dissolution of metal hosting minerals at Dorowa for purposes of deducing pollution potential to the nearby Save River. Phosphate rock is mined at Dorowa for the production of phosphate fertilizer. The major minerals found in the ring complex are feldspars, pyroxenes, apatite, magnetite and calcite. Chemical analysis established that the rocks are associated with metals that include copper, lead, zinc, cobalt, nickel, tin and cadmium. Among the many minerals present apatite and calcite host metals more than the other minerals due to their crystal structure. This study investigated the weathering and dissolution of these two minerals. Both apatite and calcite dissolve in natural environmental conditions prevalent at Dorowa. From the analysis the study concludes that the potential availability of metals trapped in the calcite and apatite structures is high. The understanding of weathering and dissolution of metal hosting minerals is important in predicting quality of water around the study area, because most villagers use the Save River as their primary drinking water source. URI: http://hdl.handle.net/10311/1021 Files in this item: 1
Atlhopheng_PCE_2010.pdf (758.1Kb)