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Typescript, etc. / Digitized by Kansas State University Libraries

LD2668 .T4 1941 F41 / Master of Science

Thesis (MSc. (Agricultural Economics)) -- University of Limpopo, 2014 / Maize is the most important crop in South Africa, being both the major feed grain for livestock and the primary staple food crop for the majority of the South African population. Furthermore, the maize industry contributes substantially to employment, manufacturing, foreign exchange and food security. The importance of maize in contributing to national growth is critical; this makes it meaningful to investigate the nature of maize farmers’ production decisions. This study quantifies the supply response of maize farmers to price and non-price factors in South Africa using econometric techniques. The non-price factors considered in this study are rainfall, technology and market policy. A modified Nerlovian partial adjustment model was applied on historical time series data spanning from 1980-2012 to estimate the supply response of maize in South Africa. To deal with the expected problems associated with time series data the study adopted several diagnostic tests. Results indicate a short-run supply elasticity of 0.49 and a long-run supply elasticity of 0.65, signifying that maize farmers are less sensitive to price changes. The results confirm that non-price factors seem to have more effect on maize supply in South Africa. These findings coincide with those obtained in supply response studies for field crops conducted in other developing African countries. The study also showed that non-price factors such as, rainfall, technology and market policies have a positive impact on maize production. Given the findings, the study recommends policies that focus more on non-price factors as a means of stabilising maize production. The study also recommends that Industry stakeholders and policymakers should find means to integrate the significant relationships between non-price factors and production output into future decisions and marketing policies to safeguard a healthy, growing and sustainable maize industry in South Africa. Key words: Maize supply response, Nerlovian partial adjustment model, price factors, non-price factors.

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Increasing maize production in Trinidad & Tobago could reduce imports and lessen dependency on foreign markets for food and feed. A review of large maize development projects and a survey of maize farmers on small landholdings indicated that mechanized production of maize grain is technically and economically impractical. Maize is normally grown and harvested in the green immature stage by small-scale farmers as a fast, easy, and relatively profitable sideline vegetable crop. An imported hybrid and an improved local landrace (ICTA Farm Corn) yielded more green maize than a Mexican-bred locally-distributed variety, following early (June) rainy season plantings. Hybrid and local unimproved open-pollinated maize were grown with two levels of weed control and with two levels of fertilizer application following late (November) rainy season plantings. For commercial carnival season production of green maize on productive soils in Trinidad, the purchase of imported hybrid seed is economically justifiable, but high inputs into weed control and fertility management may not be needed. A consumer preference study of the main varietal types eaten as boiled ears indicated panelists could not discern differences when seasoned with Creole seasoning, but preferred yellow, large-eared varieties when not seasoned. In a series of 11 variety trials on Inceptisolic and Ultasolic soils in Trinidad, imported hybrids and ICTA Farm Corn consistently yielded greater than 9 other varieties. Grid mass selection for ear weight and ear size was carried out in ICTA Farm Corn. Green maize ear length (1.9% cycle$ sp{-1}$), width (1.5% cycle$ sp {-1}$), and ear weight (2.4% cycle$ sp{-1}$) increased linearly with selection, leading to increases in green marketable (4.4% cycle$ sp{-1}$), green total (3.0% cycle$ sp{-1}$), and grain yield ha$ sp{-1}$ (4.3% cycle$ sp{-1}$). Phenotypic correlations indicated high levels of association between grain yield and both green marketable ear weight (r = 0.91

Development and functioning of arbuscular mycorrhizal (AM) symbiosis in the soil-plant system are required in sustainable agriculture. AM development of maize genotypes and uptake of nutrients as influenced by soil P levels were studied. Several experiments were conducted both in the greenhouse and in the field. / In greenhouse trials, pasteurized substrates were inoculated with Glomus intraradices as mycorrhizal treatments. Mycorrhizal development varied widely among maize hybrids and inbreds. Leafy normal stature (LNS) had the highest root colonization and shoot:root ratio and was the most responsive to AM fungi. Mycorrhizal development was generally reduced at high soil P and micronutrient levels. The percentage of root colonization was correlated with the ratio of plant tissue N/P only when soil N level was intermediate. Mycorrhizal plants increased uptake of Zn and Cu only at low P and low micronutrient levels, but decreased Mn uptake at higher micronutrient level. / In field trials, soil fumigation was used to eliminate AM fungi in control plots. Again LNS was most responsive to indigenous AM fungi, closely followed by Non-leafy normal stature (NLNS). Mycorrhizae increased uptake of K, Ca and Mg only when these nutrients and available P were low in soil. Correlations between extraradicular hyphae and plant concentrations of K, Ca and Mg suggested that uptake of K was more dependent on extraradicular hyphae than uptake of Ca and Mg. Total P uptake was higher in plots where the AM symbiosis was not repressed, but soil available P was not always reduced. / There is potential for development of mycorrhiza efficient maize hybrids performing well under low input management in sustainable agriculture.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1990. / Includes bibliographical references (leaves 338-348) / Microfiche. / xx, 348 leaves, bound ill. (some col.) 29 cm