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The Global ETD Search service is a free service for researchers
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Showing 21 to 22 of 22 (0.026 seconds)Spelling suggestions: "subject:"born browth"" "subject:"born bgrowth""
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Environmental impact of household solid waste disposal practices on plant growth in rural areas of KwaZulu-Natal : a case study of uThukela District MunicipalityKhumalo, Sabelo A. 02 1900 (has links)
The absence or unavailability of solid waste disposal facilities and service in rural areas of the UThukela District Municipality (UTDM) compelled residents to adopt many disposal practices. This included open burning of waste, which leaves residues in the form of waste ashes. Some heavy metal and hazardous substances remain active in these waste ashes. In this study, the impact of Solid Waste Disposal Practices (SWDP) on the environment was investigated by evaluating the effect of waste ashes on plant growth. The research was directed towards the evaluation of the environmental impact of solid waste disposal practices by households in these rural areas of KwaZulu-Natal (South Africa), on the growth of Zea Mays (Maize) plants. Rural maize farmers dominate the district of UTDM because it is a good agricultural area with great potential for high rainfall in summer, moderate temperatures, good soil and moderate slopes. The method selected to achieve research objectives was the evaluation of the influence of waste ashes, as by-products of SWDP, on plant growth. This was achieved by, determining soil fertility; collecting household solid waste from different rural families to determine the composition (including already burnt ash, plastic ash and wood ash; analysing the chemical composition of traditional ashes collected from sites where it was burnt (waste ashes); applying the evaporation pan test; mixing waste ashes and other additives with soil in planting pots in equal parts; planting Zea Mays in winter and summer; and lastly, monitoring and measuring agronomic parameters of plant growth on a regular basis. The selected additives to the in situ soil were fertilizer, compost, waste ash, plastic ash and wood ash. Pots with soil only (no additive added) served as control. The findings revealed that plants exposed to wood, waste and plastic ash struggled to grow when compared to plants grown with fertilizer, compost and soil only. The impact of all waste ashes on plant growth was negative in both seasons and some of the agronomic parameters were unable to sprout during the course of plant growth. The chemicals found after analysing the waste ashes included some of the heavy metals that remained active after burning. These were left behind in the environment. Consequently, it was concluded that household solid waste disposal practices in rural areas should be reviewed urgently, as they affect plant growth negatively. Recommendations were provided. / Environmental Sciences / M. Sc. (Environmental Science)
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INVESTIGATION OF CORN YIELD IMPROVEMENT FOLLOWING CEREAL RYE USING STARTER NITROGEN FERTILIZERHouston L Miller (7830965) 20 November 2019 (has links)
Cereal rye (CR), the most common and effective nitrogen (N) scavenging
cover crop option in the Midwest, is often utilized in cropping systems to
reduce nitrate loss for environmental benefits. To increase environmental
efficiency in Midwest corn cropping systems, we must increase the overall
adoption of CR. However, due to the yield reduction potential (6%) for corn
planted after CR termination, CR is primarily recommended before soybean. To
increase CR adoption, we must develop adaptive fertilizer management practices
that achieve competitive grain yields relative to cropping systems where CR is
not adopted. Therefore, the objectives of this study are to determine (1) the
effect of CR and starter nitrogen rate on corn growth and nitrogen content. (2)
the optimum starter nitrogen rate to achieve agronomic optimum corn yield
following CR. (3) the impact of phosphorus (P) at starter on plant growth,
nitrogen content, and yield with the inclusion of CR. For our study, five
starter N rates were applied in a 5x5 cm band to both CR and non-CR plots,
concentrations ranged from 0-84 kg N ha<sup>-1 </sup>in 28 kg N ha<sup>-1</sup>
intervals. Total N applied was the same for each treatment, relative to its
location, and was split between starter N at planting and sidedress applied at
growth stage V6 relatively. Although CR termination took place at least two
weeks before planting, CR decreased corn grain yield at one of three locations
by an average of 8%, nitrogen recovery efficiency (NRE) by 27%, and R6 total N content
by 23%, relative to the conventional control (non-CR 0N), when no starter N was
applied. At one of three locations, starter N rates of 56 kg N ha<sup>-1</sup>,
56 kg N ha<sup>-1 </sup>plus 17 kg P ha<sup>-1</sup>, and 84 kg N ha<sup>-1</sup>
increased corn grain yield, in CR plots, and 56 kg N ha<sup>-1</sup> plus 17 kg
P ha<sup>-1</sup> increased corn grain yield in non-CR plots. Phosphorus increased
corn grain N content at growth stage R6 in one of three locations and did not
impact corn grain yield at all locations. We conclude that the inclusion of
starter N at planting has the potential to increase agronomic productivity in
CR corn cropping systems in soil environments with a high capacity to
mineralize soil N. However, further research is required to refine our starter
N results to find an optimum starter N rate to apply before planting corn
following CR.
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