https://vital.seals.ac.za/vital/access/manager/Index en-us 5 https://vital.seals.ac.za/vital/access/manager/Repository/vital:71911 Wed 27 Mar 2024 10:39:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:62724 Wed 22 Mar 2023 11:40:43 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:52002 Wed 19 Oct 2022 14:21:27 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:28265 Wed 13 Mar 2024 14:17:24 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10495 Wed 12 May 2021 23:47:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10678 Wed 12 May 2021 23:17:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:20556 Wed 12 May 2021 22:55:14 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10666 Wed 12 May 2021 22:54:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10656 Wed 12 May 2021 22:42:47 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:33432 Wed 12 May 2021 22:40:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:35348 Wed 12 May 2021 22:34:59 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10423 Wed 12 May 2021 22:17:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10504 Wed 12 May 2021 20:21:45 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10419 Ni > Cu > Fe > Mg. The mass of metal ions that accumulated on one gram of clinoptilolite as determined from the isotherms was calculated to be 6.16 mg/g for lead and 0.74 mg/g for copper. Data from the lead equilibrium studies were fitted into Langmuir and Freundlich equations and linear regression was used to calculate linearity coefficients for the isotherms. The results showed that the removal of lead ions by clinoptilolite is complex as both monolayer and multilayer adsorption occurs on a heterogeneous surface.]]> Wed 12 May 2021 19:56:33 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10498 Wed 12 May 2021 19:54:14 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10611 Wed 12 May 2021 19:47:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10590 Wed 12 May 2021 19:44:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:29965 Wed 12 May 2021 19:28:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:31131 Wed 12 May 2021 19:16:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:8324 Wed 12 May 2021 19:10:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10661 Wed 12 May 2021 19:09:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:20494 Wed 12 May 2021 18:55:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:29439 Wed 12 May 2021 18:50:12 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27124 Wed 12 May 2021 18:44:27 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10460 Wed 12 May 2021 18:40:35 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10399 Wed 12 May 2021 18:39:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27039 Wed 12 May 2021 18:21:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:21055 Wed 12 May 2021 18:12:23 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:20403 Wed 12 May 2021 18:01:49 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:33029 10 and TPI between -1 and 1. Landslides are less pronounced on slope zones where slope gradient is <15˚ and >45˚, profile curvature <0, TWI <8 and >18, SPI <10 and TPI >1. Deep soil profiles ranging between 2.5 and 7 meters are a major characteristic of the study area. Soils are characterized by clay pans at a depth ranging between 0.75 and 3 meters within the profiles. The study area is dominated by clay texture, except for the uppermost surface horizons, which are loamy sand. All surface horizons analysed had the percentage of sand, silt and clay ranging from 33 to 55%, 22 to 40% and 10 to 30% respectively. In the deeper horizons, sand was observed to reduce drastically to less than 23%, while clay increased to greater than 50%. The clay content is very high in the deeper horizons exceeding 35%. By implication, such soils with a very high clay content and plasticity index are considered as Vertisols, with a profound influence in the occurrence of landslides. The top soil predominantly contains more quartz, while subsurface horizons have considerable amounts of illite/muscovite as the dominant clay minerals, ranging from 43% to 47 %. The liquid limit, plasticity index, computed weighted plasticity index (PIw), expansiveness (ɛex) and dispersion ranging from 50, 22, 17, 10 and 23 to 66, 44,34,54 and 64, respectively also have strong implications for landslide occurrence. Landslides are not normally experienced during or immediately after extreme rainfall events but occur later in the rainfall season. By implication, this time lag in landslide occurrence and rainfall distribution, is due to the initial infiltration through quartz dominated upper soil layers, before illite/muscovite clays in the lower soil horizons get saturated. Whereas forest cover reduced from 40 % in 1985 to 8% in 2015, cultivated land and settlements increased from 16% and 11% to 52% and 25% respectively during the same period. The distribution of cultivated land decreased in lower slope sections within gradient group < 15˚ by 59%. It however increased in upper sections within gradient cluster 25˚ to 35˚ by over 85% during the study period. There is a shift of cultivated land to the steeper sensitive upper slope elements associated with landslides in the study area. More than 50% of the landslides are occurring on cultivated land, 20% on settlements while less than 15 % and 10% are occurring on grassland and forests with degraded areas respectively. Landslides in Kigezi highlands are triggered by a complex interaction of multiple- factors, including dynamic triggers and ground condition variables. Topographic hollows are convergence zones within the landscape where all the parameters interact to cause landslides. Topographic hollows are therefore potential and actual landslide sites in the study area. Characterized by deep soil horizons with high clay content dominated by illite/muscovite minerals in the sub soils and profile concave forms with moderately steep slopes, topographic hollows are the most vulnerable slope elements to landslide occurrence. The spatial temporal patterns of landslide occurrence in the study area has changed due to increased cultivation of steep middle and upper slopes. Characterized by deep soil horizons with high clay content dominated by illite/muscovite minerals in the sub soils and profile concave forms with moderately steep slopes, topographic hollows are the most vulnerable slope elements to landslide occurrence. The spatial-temporal patterns of landslide occurrence in the study area has changed due to increased cultivation of steep middle and upper slopes. A close spatial and temporal correlation between land use/cover changes and landslide occurrence is discernible. The understanding of these topographical, pedological and land use/cover parameters and their influence on landslide occurrence is important in land management. It is now possible to identify and predict actual and potential landslide zones, and also demarcate safer zones for community activities. The information generated about the area’s topographic, pedological and land cover characteristics should help in vulnerability mitigation and enhance community resilience to landslide hazards in this fragile highland ecosystem. This can be done through designating zones for community activities while avoiding potential landslide zones. It is also recommended that, tree cover restoration be done in the highlands and the farmers encouraged to re-establish terrace farming while avoiding cultivation of sensitive steep middle and upper slope sections.]]> Wed 12 May 2021 17:50:51 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10492 Wed 12 May 2021 17:49:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10510 Wed 12 May 2021 17:48:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10481 Wed 12 May 2021 17:40:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10465 Wed 12 May 2021 17:26:49 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:29331 Wed 12 May 2021 17:22:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36921 Wed 12 May 2021 17:12:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10473 Wed 12 May 2021 17:10:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10494 Wed 12 May 2021 16:38:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10496 Wed 12 May 2021 16:32:05 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10604 300 cm) Rhizophora trees at Mngazana Estuary. Mortality of Avicennia marina individuals (51-150 cm) was related to tree density indicating intraspecific competition and self thinning. Selective harvesting of particular size classes of Rhizophora mucronata was recorded when comparing length of harvested poles (~301 cm) and the size class distribution of individuals. Taking into account the differences in growth rate for each size class for this species it will take approximately 13 years to attain a height of 390 cm which is the height at which trees are selected for harvesting at this estuary. This is 2.6 times slower than those individuals growing in Kenya. The feasibility of harvesting is dependent on the growth rate of younger size classes to replace harvested trees as well as the rate of natural recruitment feeding into the population. Different harvesting intensity scenarios tested within a matrix model framework showed that limits should be set at 5 percent trees ha-1 year-1 to maintain seedling density at > 5 000 ha-1 for R. mucronata. However harvesting of Bruguiera gymnorrhiza should be stopped due to the low density of this species at Mngazana Estuary. Harvesting of the tallest trees of Avicennia marina can be maintained at levels less than 10 percent ha-1 year-1. Effective management of mangrove forests in South African is important to maintain the current state, function and diversity of these ecosystems. Management recommendations should begin with determining the freshwater requirements of the estuaries to maintain the mouth dynamics and biotic communities and deter the harvesting of (whole) adult trees particularly those species that do not coppice. Further management is needed to ensure that forests are cleared of pollutants (plastic and industrial), and any further developments near the mangroves should be minimized.]]> Wed 12 May 2021 16:26:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10677 Wed 12 May 2021 16:26:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10479 Wed 12 May 2021 16:16:37 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10744 Wed 12 May 2021 16:14:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10634 Wed 12 May 2021 16:11:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27880 Wed 12 May 2021 15:59:39 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10489 Wed 12 May 2021 15:51:55 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10311 Wed 12 May 2021 15:44:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:40895 Wed 12 May 2021 15:06:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:40527 Wed 12 May 2021 14:59:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:41622 Wed 12 May 2021 14:54:09 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:40893 Wed 12 May 2021 14:47:45 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:40259 Wed 12 May 2021 14:33:56 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:41615 Wed 12 May 2021 14:17:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:40849 Wed 12 May 2021 13:47:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:43426 Wed 07 Jul 2021 21:22:59 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:56013 Tue 06 Sep 2022 14:34:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:43883 Tue 03 Aug 2021 10:18:39 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:46026 Tue 01 Feb 2022 13:06:45 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30786 Thu 13 May 2021 13:38:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36926 Thu 13 May 2021 12:45:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10394 Thu 13 May 2021 08:12:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:36658 Thu 13 May 2021 07:26:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10338 Thu 13 May 2021 07:01:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10485 Thu 13 May 2021 07:00:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:26925 Thu 13 May 2021 06:52:01 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10535 Thu 13 May 2021 06:44:42 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:20832 Thu 13 May 2021 06:31:05 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:34048 Thu 13 May 2021 05:53:12 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10486 Thu 13 May 2021 05:47:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10388 Thu 13 May 2021 05:44:33 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:31347 Thu 13 May 2021 05:31:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:27842 Thu 13 May 2021 05:19:03 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10422 Thu 13 May 2021 04:46:28 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10459 Thu 13 May 2021 04:00:48 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:28900 Thu 13 May 2021 03:48:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:11093 Thu 13 May 2021 03:35:04 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:35265 Thu 13 May 2021 02:59:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10563 Thu 13 May 2021 02:27:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:34124 Thu 13 May 2021 02:13:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:20659 Thu 13 May 2021 01:58:36 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10514 Thu 13 May 2021 01:50:06 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:20378 Thu 13 May 2021 01:48:33 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10455 Thu 13 May 2021 01:40:42 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:30945 Thu 13 May 2021 01:27:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10368 99.9 % certainty) potential in two of the semi-organic mixtures formulated while the organic mixture showed a relatively good growth rate as compared to the control (pure tap water). According to statistical analysis (ANOVA) comparison, two of the semi-organic mixtures performed considerably better than the two commercial samples evaluated. Potential benefits profoundly associated with these nutrient mixtures as compared to similar liquid fertilizer products on the market is that most nutrients are chelated and dissolved in solution. Also, the mixtures contain all necessary nutrients including plant growth substances required for healthier plant growth. The most important socioeconomic impact is the value addition to the technology chain in the citrus industry. The use of fluid fertilizers in significant quantities is less than twenty years old. Nevertheless, growth has been so rapid that in South Africa demand for mixed liquid fertilizer has greatly increased from 90 000 tons NPK & blended micronutrients in 1955 to more than 600 000 per annum tons today (Report 41/2003, Department of Minerals and Energy). The liquid fertilizers market is sparsely specialized with major competitors like Omnia, Kynoch and Foskor supplying more than 50 % of the market demand. Amongst the nutrient mixtures formulated, mixture one is an NPK (1-1-2) based nutrient mixture containing both secondary nutrients (0.5 % Mg & 1.0 % Ca) and seven micronutrients (0.1 % Fe, 0.05 % Cu, 0.05 % Zn, 0.05 % Mn, 0.02 % B, 0.0005 % Mo and 0.0005 % Co). The composition of this mixture offers the formula a potential to be used as a general purpose (all stages of plant growth) fertilization mixture in view of its balanced composition (containing all essential plant nutrients). Mixture two contains essentially the micronutrients and in higher concentrations (0.3 % Fe, 0.3 % Cu, 0.1 % Zn, 0.2 % Mn, 0.02 % B, 0.0005 % Mo and 0.0005 % Co) as compared to mixture one except for boron, molybdenum and cobalt. The concentration of the micronutrients contained in this mixture is adequately high which offers a potential for it to be used in supplementing nutrition in plants with critical micronutrient-deficient symptoms. Mixture three is very similar to mixture two (1.0 % Fe, 0.05 % Cu, 0.05 % Zn, 0.05 Mn, 0.05 % B, 0.0005 % Mo and 0.0005 % Co) except that the concentrations of all seven micronutrients are considerably less than those of contained in mixture two. However, the concentration of iron in this mixture is as high as 1.0 %. The mixture has a potential to be used in high iron-deficient situations. Mixture four is an organic formula with relatively low nutrient concentrations (NPK-0.02-0.02-1, 0.27 % Mg, 0.02 % Ca, 0.008 % Fe, 0.26 % Cu, 0.012 % Zn, 0.009 % Mn). Nevertheless, this mixture is appealing for organically grown crops where the use of chemicals is prohibited by standards. These lemon juice-based nutrient mixtures were further characterized and tested for stability and storability over a period of eight weeks. This study revealed no major change in the physical quality (colour, pH and “salt out” effect). The basic formulation methodology is a two-step procedure that involves filtration of the lemon juice to remove membranous materials, mixing at ambient temperature and stabilization of the nutrient mixtures. However, for the organic nutrient formula mix, filtration follows after extraction of nutrients from plant materials using the lemon juice.]]> Thu 13 May 2021 01:15:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:37044 Thu 13 May 2021 01:13:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10320 Thu 13 May 2021 00:57:54 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:35505 Thu 13 May 2021 00:55:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:11071 Thu 13 May 2021 00:49:22 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:20495 Thu 13 May 2021 00:28:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:38922 Thu 13 May 2021 00:25:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10581 Thu 13 May 2021 00:21:32 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:35351 Thu 13 May 2021 00:00:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:46022 Thu 03 Feb 2022 13:55:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:54397 Sat 06 Aug 2022 21:37:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:72779 Mon 27 May 2024 13:13:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:37113 Mon 22 Aug 2022 15:05:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:45688 Fri 28 Jan 2022 11:06:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:62815 Fri 24 Mar 2023 15:08:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:40468 Fri 15 Mar 2024 12:24:52 SAST ]]>