Investigation of soil quality (health) in commercial production of rooibos tea (Aspalathus linearis) in the Western Cape, South Africa

Smith, Jacobus Francios Naude (2014-04)

Thesis (MScAgric)--Stellenbosch University, 2014.

Thesis

ENGLISH ABSTRACT: The global demand for rooibos tea (Aspalathus linearis) has steadily increased over the past five years thanks to the increased awareness of its health benefits, while rooibos tea production has decreased. If this trend continues, rooibos producers will be unable to meet the world demand. What makes rooibos a particularly challenging crop to grow is the fact that it is a sensitive fynbos species, adapted to low soil nutrient conditions, which can only be cultivated in a niche area of the Western and Northern Cape regions of South Africa. The farmers are under great pressure due to increasing production costs and environmental laws which restrict the establishment of new rooibos fields in fynbos areas. The only way for farmers to meet the demand will have to be by increasing their tea yields and quality while using the same area of land. To date, very little research has been conducted to help the producers. Rooibos farmers report that yields decline dramatically over time since the clearing of the natural fynbos vegetation. It was hypothesized that this decrease in production is most likely related to changes in soil quality (health) and ecology. Thus, the aim of this study was to examine soil (chemical, physical and microbiological properties) and plant quality parameters in cultivated rooibos fields of various ages and adjacent, rooibos stands in pristine fynbos. The results will be used to diagnose the decline in rooibos production and suggest amendment strategies to improve commercial rooibos production. Experimental sites were selected in the Clanwilliam district, at the two oldest (Nardouwsberg and Seekoeivlei) of the six main rooibos producing areas. Virgin fynbos, young rooibos fields (2 years) and older rooibos fields (20-60 years) were selected as sampling sites.

AFRIKAANSE OPSOMMING: Die wêreld se vraag na rooibostee (Aspalathus Linearis) het konstant oor die afgelope vyf jaar toegeneem, omdat rooibostee geassosieer word met ʼn gesonde leefstyl. Daar word egter tans ʼn afwaartse neiging in tee-oeste en rooibostee-produksie waargeneem. Indien die tendens voortgaan soos tans, sal rooibostee-produsente nie aan die wêreldvraag kan voldoen nie. ‘n Verdere uitdaging van rooibostee-produksie is dat dit ʼn sensitiewe fynbos-plant is wat aangepas is om op gronde te groei wat laag in voedingstowwe is en slegs in klein areas in die Wes- en Noord-Kaap geproduseer kan word. Faktore soos toenemende koste en omgewingsvriendelike wette stel groter uitdagings aan boere. Om sukses te behaal, is boere verplig om hul tee-opbrengs per hektaar en tee-kwaliteit te verbeter. Daar is nog min navorsing gedoen om die produsente te help. Rooibosteeboere het opgemerk dat die produksie gewoonlik drasties afneem na die eerste 5-jaar plantsiklus op nuut skoongemaakte fynbosgronde. Die hipotese is dat die afname in produksie grotendeels toegeskryf kan word aan die veranderinge in grondkwaliteit (gesondheid) en ekologie. Die doel van die studie is dus om die grond- (chemiese, fisiese en mikrobiologiese eienskappe) en plantkwaliteit parameters in gevestigde rooiboslande en aanliggende onversteurde fynbos-areas te ondersoek. Uiteindelik sal die resultate gebruik word om die afname in rooibosteeproduksie te diagnoseer en verskillende regstellende behandelings voor te stel om sodoende volhoubare bestuurstrategieë te verseker om die kommersiële rooibostee-produksie te verbeter. Eksperimentele areas (Nardouwsberg en Seekoeivlei in die Clanwilliam –distrik) is in twee van die ses hoof rooibostee-produserende areas uitgesoek. Nuwe fynbosareas, jong rooibosteelande (2 jaar) en ouer rooibosteelande (20 – 60 jaar) is uitgekies om monsters te neem. Grondmonsters en een-jaaroue plantmonsters is in drievoud by elke area geneem.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/86737
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