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Effect of different nitrogen sources and growth media on water use of blueberry cultivated under shade net
Author(s)
Mshweshwe, Asemahle
Date Issued
2026
Type
master thesis
Publisher
Cape Peninsula University of Technology
Abstract
Globally blueberry (Vaccinium spp.) production has rapidly increased in recent years, driven by consumers' increased demand for this nutritious fruit. This study investigated the interactive effects of different N sources and soilless growth media on water use, growth, yield, and quality of blueberry. A pot experiment was carried out in polythene bags under a white shade net. Three nitrogen sources: ammonium sulphate [(NH4)2SO4] (N 21.1%), calcium nitrate [Ca (NO3)2] (N 16.6%), and urea (H2NCONH2) (N 46%) were applied to two soilless substrates growth media (100% coir and a combination of 80% coir: 20% zeolite) in a randomized complete block design. Growth, fruit yield, and berry quality parameters were measured. Our results showed that treatment with NH4 + and 100% coir yielded higher values for most growth parameters, chlorophyll content index, proanthocyanidin, as well as the availability of macro and micronutrients in the soilless substrate. The 100% coir treatment favours early shoot expansion due to superaeration and root expansion, and the addition of zeolite to coir reduced water demand by the test plants. The retention of NH4 + by the 20% zeolite treatment was not beneficial to the blueberry plants, hindering chlorophyll content accumulation and photosynthesis. These results suggest that a further investigation into the influence of different zeolite levels on blueberry production cultivated using pots. The application of NH4 + enhances fruit size and weight, primarily by enhancing the process of photosynthesis through higher N and chlorophyll content in leaves, and ultimately improving nutrient assimilation and nutrient use efficiency.
Additional information
Thesis (MAgric)--Cape Peninsula University of Technology, 2026
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Asemahle_Mshweshwe_230407862.pdf
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