Edible fynbos plants : a soil types and irrigation regime investigation on Tetragonia decumbens and Mesembryanthemum crystallinum

Tembo-Phiri, Chimwemwe (2019-04)

Thesis (MScConsEcol)--Stellenbosch University, 2019.

Thesis

ENGLISH ABSTRACT: Fynbos’ rich biodiversity has been a source of much economic activity with its beautiful wild flowers and world-famous Proteas. Additionally, the medicinal and health benefits of rooibos and honey bush have enormous market value all over the world. Despite the importance of Fynbos as a biome, the value of its edible species as agronomic resources has been neglected. A two-part study having an agronomic and social component was conducted at the Welgevallen Experimental Farm (WEF, Stellenbosch University) and the Sustainability Institute (SI, Lyndoch, Stellenbosch), respectively. The aim of the agronomic study was to determine the performance of Tetragonia decumbens (dune spinach) and Mesembryanthemum crystallinum (sout slaai) in relation to soil type and watering regime trials. A completely randomised design was used for the water trial having four treatments (no watering as a control, 25 %, 50% and 80% pot water holding capacity) and the soil trial having three treatments (dune sand from Kommetjie beach as a control, sandy soil from the SI, and loamy soil from WEF). Though the water treatments had no significant effect (p > 0.05) on the agronomic performance of dune spinach and sout slaai, the results suggested that the 25% and 50% water treatment levels are sufficient for growth of dune spinach and sout slaai when grown in the soil in which they naturally occur. Results from the soil regime trial indicated significant increases in agronomic performance of dune spinach and sout slaai among soil treatments, except the number of dune spinach runners and sout slaai leaf pairs. It was concluded that agronomic performance can be improved significantly when dune spinach and sout slaai are planted in more fertile sandy soils and well aerated loamy soils. For the social study, an indigenous food tasting event was organised at which a survey was administered to 24 respondents that primarily assessed their acceptance of the two edible fynbos species as alternative vegetables and nutrition sources. A cooked and raw version of each vegetable was tasted by each participant. The cooked version (smoortjie) of dune spinach, elicited a statistically significant median increase in acceptability compared to the, dune spinach salsa, exact p = 0.035. The sout slaai smoortjie did not generate a statistically significant median increase in acceptability compared to the sout slaai salsa, exact p = 0.092. It was found that the ‘overall acceptance of dune spinach vegetable’ was positively correlated to the ‘overall acceptance of sout slaai vegetable’, r(23) = 0.504, p = 0.01. There was no association between consumption intent and overall acceptance of the two indigenous vegetables, r(23) = 0.362, p = 0.082. However, there was a strong positive association between the respondent’s overall acceptance of the two indigenous vegetables and their purchasing intention, r(23) = 0.698, p < 0.001. The most important reason for purchasing these indigenous vegetables that emerged was the frequency of general vegetable shopping and desire to eat the vegetables. These reasons were closely followed by the availability on the market and price of the dune spinach and sout slaai.

AFRIKAANSE OPSOMMING: Fynbos se ryk biodiversiteit is ’n bron van baie ekonomiese aktiwiteite met sy pragtige veldblomme en wêreldbekende Proteas. Daarbenewens het die medisinale en gesondheidsvoordele van rooibos en heuningbos geweldige markwaarde oor die hele wêreld heen. Ten spyte van die belangrikheid van Fynbos as ’n bioom, is die waarde van sy eetbare spesies as agronomiese hulpbronne verwaarloos. ’n Tweeledige studie met beide ’n agronomiese en gemeenskap komponent is onderskeidelik by dieWelgevallen proefplaas (WPP, Stellenbosch Universiteit) en die Volhoubaarheidsinstituut (VI, Lynedoch, Stellenbosch) gedoen. Die doel van die agronomiese studie was om die agronomiese prestasie van Tetragonia decumbens (duinspinasie) en Mesembryanthemum crystallinum (soutslaai) te bepaal tydens proewe met verskillende tipes grond and hoeveelhede water. ’n Ten volle lukrake ontwerp met drie behandelings en ’n kontrole is gebruik vir die waterproef; geen water as kontrole, en 25 %, 50% en 80% van die potgrond se waterhoudingskapasiteit. Die grondtipe proef het twee behandelings en een kontrole gehad: kus (duin) sand van Kommetjie-strand as kontrole, sandgrond van die VI en leemgrond van WPP. Alhoewel die waterbehandelings geen beduidende effek (p > 0.05) gehad het op die agronomiese prestasie van duinspinasie en soutslaai nie, het die resultate aangedui dat die 25% en 50% waterhoudingskapasiteit voldoende is vir die groei van duinspinasie en soutslaai in die grond waarop hulle natuurlik voorkom. Die grondtipe proef het ’n aansienlike toename in agronomiese prestasie van duinspinasie en soutslaai gewys. Grondanalise het aangedui dat beide spesies die vermoë het om marginale grond te verbeter. Daar is bevind dat agronomiese prestasie aansienlik verbeter kan word wanneer duinspinasie en soutslaai in meer vrugbare sanderige grond geplant word. Wat die gemeenskapstudie betref, is ’n inheemse-kos proegeleentheid gereël waar 24 respondente aan ’n opname deelgeneem het wat hoofsaaklik hul aanvaarding van die twee eetbare Fynbossoorte as alternatiewe groentes en voedingbronne beoordeel het. ’n Gekookte (smoortjie) en rou (salsa) weergawe van elke groente is geproe. Die duinspinasie smoortjie het ’n statisties beduidende mediane toename in aanvaarbaarheid in vergelyking met die duinspinasie salsa verkry, presiese p = 0, 035. Die soutslaai smoortjie het nie ’n statisties-betekenisvolle mediane verhoging in aanvaarbaarheid in vergelyking met die soutslaai salsa genereer nie, presiese p = 0, 092. Daar is bevind dat die ‘algehele aanvaarding van duin-spinasiegroente’ positief gekorreleer is met die ‘algehele aanvaarding van soutslaai groente’, r(23) = 0.504, p = 0.01. Daar was geen verband tussen verbruiksvoorneme en algehele aanvaarding van die twee inheemse groente nie, r(23) = 0.362, p = 0.082. Daar was egter ’n sterk positiewe verband tussen die respondent se algehele aanvaarding van die twee inheemse groente en hul aankoopvoorneme, r(23) = 0.698, p < 0.001. Die belangrikste rede vir die aankoop van hierdie inheemse groente wat na vore gekom het, was die gereëldheid van algemene groente aankope en behoefte om die groente te eet. Hierdie redes is gevolg deur die beskikbaarheid op die mark en prys van die duinspinasie en soutslaai.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/105974
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