Browsing by Author "Moeletsi, M'aseapa Mookho Violet."

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Nitrogen and phosphorus release and potential fertiliser effects of biogas slurry on spinach yield.
(2018) Grootboom, Lunga Sincerely.; Muchaonyerwa, Pardon.; Tsubo, Mitsuru.; Tesfai, Mohammed.; Moeletsi, M'aseapa Mookho Violet.
Use of organic waste to produce biogas aids in waste management and produces organic residue, biogas slurry (BGS), with appreciable quantities plant nutrient and potential to improve soil productivity. Feedstock and retention time during anaerobic digestion influence the quality and fertilizer value of the biogas Slurry. The objective of the study was to determine the release nutrients of biogas slurry, its potential as nitrogen (N) source and effects of co-application with chemical fertilizer (CF) on spinach yields and soil chemical parameters. Samples of biogas slurry, produced from cattle dung, and cattle manure (CM) were collected from Qwa-qwa, in the Free State Province of South Africa. The samples were analysed for pH, electrical conductivity (EC), total carbon (C), nitrogen, phosphorus (P), exchangeable bases and trace elements. Dried biogas slurry and cattle manure were applied to Avalon and Hutton soils at 0, 1, 2 and 3% (w/w). Then moistened to field capacity moisture, and incubated for 8 week, with periodic moisture correction. Destructive sampling was used to collect soil samples at 0, 1, 2, 4 and 8 weeks and the samples were analysed for pH, electrical conductivity, ammonium and nitrate-nitrogen, available phosphorus and exchangeable bases. Three glasshouse experiments were conducted to determine the fertiliser value of BGS for spinach (Spinacia oleracea) grown for 8 weeks. In the first experiment, biogas slurry was compared with chemical fertilizer and cattle manure as nitrogen sources at 100 kg N/ha in the Avalon soil. The second experiment involved application of biogas slurry and cattle manure at increasing nitrogen application rates of 0, 100, 150, 200 and 250 kg N/ha in Avalon soil. While the third experiment involved co-application of biogas slurry with chemical fertilizer at 0/100, 40/60, 60/40 and 100/0 kg N/ha (BGS/CF) in Avalon and Hutton soils. Soil pH increased with increasing application rate on both soils, during incubation. The 1% application rate showed the least pH increase for Hutton soil, which was significantly higher by 1.89% for cattle manure and 3.70% for biogas slurry than the control at week 8. Ammonium-N declined by 73.6% in Avalon compared to the 36.7% in Hutton soil at 3% BGS NH4-N within 2 weeks, then increased steadily up to week 8 at all application rates for both soils. On the other hand, nitrate-nitrogen declined for biogas slurry and increased for cattle manure, with increasing application rate after 2, 4 and 8 weeks of incubation in both soils. Available phosphorus increased with increasing rate of both biogas slurry and cattle manure especially up to two weeks of incubation in soils. Spinach dry matter yield were comparable between biogas slurry (4.04 g/pot) and cattle manure (3.40 g/pot) as a nitrogen sources, even though greater nutrient uptake and soil residual fertility occurred in BGS treatment. Increasing application of biogas slurry and cattle manure increased spinach dry-matter (DM) accumulation significantly from 100 up to 150 kg N/ha by 32.9% for biogas slurry and 23.1% for cattle manure, beyond that rate there was no notable variation. Higher nutrient uptake was observed at 150 kg N/ha, which supports the higher yields. However, biogas slurry co-application with chemical fertilizer had no synergistic effect and increasing application rate showed no significant improvement in dry matter yield and nutrient uptake. The findings of the study implied that the fertiliser value of biogas slurry was similar to cattle manure and subsequent crop could benefit from residual fertility after biogas slurry and cattle manure.
Primary school teachers' understanding and interpretation of problem-solving : how it is promoted in science lessons, why and why not?
(2005) Moeletsi, M'aseapa Mookho Violet.; Malcolm, Clifford Keith.
This study explores how Lesotho primary school teachers understand and interpret problem-solving (PS) and how they teach and support it. Observation schedules and semi-structured interviews were used to collect data from classrooms, teachers and learners. The findings revealed that teachers have considerable understanding of (PS) and value it but are not teaching it. Teachers attribute this to their lack of knowledge, the difficult conditions in their schools, policy constraints (such as assessment) and their own habits and behaviours. However, the data also indicated that teachers, with support, can successfully design and teach appropriate lessons in their schools, raising issues about their knowledge, beliefs, identity and structures.
Runoff simulation using the SWAT model for flood frequency analysis and design flood estimations in the Luvuvhu River catchment, South Africa.
(2018) Thavhana, Mulalo Precious.; Moeletsi, M'aseapa Mookho Violet.; Savage, Michael John.
Abstract available in PDF file.