Masters Degrees (Agronomy)

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Browsing Masters Degrees (Agronomy) by Subject "Bambara groundnut -- Growth -- South Africa"

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    Use of biostimulants to assess the production of the underutilised legume, Bambara groundnut
    (Stellenbosch : Stellenbosch University, 2021-03) Zidubule, Siphiwo; Phiri, Ethel E.; Mothapo, Palesa Natasha; Stellenbosch University. Faculty of AgriSciences. Dept. of Agronomy.
    ENGLISH ABSTRACT: Underutilised crops are an important part of local diets but have not been fully adopted in modern agriculture. Often, they are cultivated in marginal lands with low, if any, nutrients. The need for underutilised crop research becomes apparent not only because a big portion of plant based human food is mainly derived from a limited number of staple crops. With the threat of global warming and associated more extreme weather, and indirect impacts such as crop diseases, reliance on a few crops is a major challenge to food and nutritional security. Moreover, existing deficiencies of key vitamins and minerals pose a serious constraint to livelihoods, more especially in rural areas. Bambara groundnut (Vigna subterranea (L) Verdc.) is one of the crops that could be used to increase food production. With a reported high drought tolerance, Bambara groundnut is cultivated across Africa, but its full potential has not been realised and its agronomic performance scantily documented. Therefore, two greenhouse experiments, using two landraces of Bambara groundnut, were conducted at the Welgevallen experimental farm, Stellenbosch University, Stellenbosch. The aim was to investigate the effect of different biostimulants on the growth performance of Bambara groundnut. The specific objectives were to: (1) Evaluate the effect of different biostimulants on agronomic plant performance, (2) Assess the effects of biostimulants on the nutritional composition of Bambara groundnut seeds. The study consisted of five treatments (untreated control, chicken manure fertiliser, Kelpak®, humic substance and Moringa leaf extract, n=6 replicates each), conducted in a tunnel production system. Biostimulant treated plants reached 50% flowering significantly earlier that the control and fertiliser treated plant. Plants treated with Kelpak® showed significantly higher plant height, larger leaf area, and higher leaf dry matter relative to control and other treatments. Treatment with humic substance and Moringa leaf extracts resulted in higher yield parameters, number of pods per plant, 100-seed weight, and total seed yield were the highest in humic substance treated plants followed by Moringa leaf extract. Therefore, the humic substance showed the highest harvest index percentage relative to the other treatments. Of the three biostimulants treatments, Kelpak® treated plants produced the lowest seed yield. Using multiple linear regression we found that variation in total seed yield could be explained by the input of treatment, particularly humic substance and Moringa. Kelpak® was found to not have a significant effect on seed yield but rather on plant height and dry shoot mass, indicating better suitability to growing leafy vegetables than grain. The nutrient composition was improved under Moringa and humic substance treatment, meaning that these two factors not only improved plant growth and productivity but maintained the nutritional composition of Bambara. Therefore, biostimulant application positively influenced Bambara groundnut growth, development, and yield without compromising the nutritional content of the crop seeds. Therefore, biostimulants alongside appropriate levels of fertilization may be used to enhance the production of Bambara groundnut crops, and other underutilised and neglected crops. However, the results need to be validated by investigating the remaining landraces of Bambara groundnut. Keywords: Bambara groundnut, biostimulants, underutilised crops, landraces.