IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...

17 th International Congress on Nitrogen Fixation
Fremantle, Western Australia
27 November – 1 December 2011
Title Effect of nitrogen, phosphorus, magnesium and calcium nutrition on plant growth and levels
of macronutrients in the honeybush tea plant, Cyclopia longifolia (Vogel l.)
Authors Buhlebelive Mndzebele 1 and FD Dakora 2
Poster Board Number 25
1 Department of Crop Sciences, Tshwane University of Technology,
2 Department of Chemistry, Faculty of Science, Tshwane University of Technology
Cyclopia longifolia (Leguminosae) is endemic to the fynbos of the Cape Floristic Region of South Africa.
Together with eight other Cyclopia species, C. longifolia is used for making Honeybush tea, a herbal beverage
that is contributing to the South African economy. However, the effect of nutrient supply on plant growth, and the
concentration, and amounts of major minerals are not well understood in this legume. Because the shoots are
harvested annually as tea, establishing nutrient requirements for this species is necessary to minimize nutrient
mining. The aim of this study was to assess plant growth, as well as the concentration and amounts of major
elements in C. longifolia supplied with N, Mg, Ca and P as ammonium nitrate, magnesium chloride hexahydrate
and calcium chloride dehydrate dipotassium and hypophosphate at four levels (i.e. 0, 5, 25 and 50 mM). About
100 mL of each nutrient concentration was applied per plant at three months interval for 9 months. Plants were
harvested at 300 days after treatment in the field trial. Shoots were oven-dried (60 º C), weighed, and ground to
fine powder (0.85 mm) for tissue analysis using inductively coupled plasma-mass spectrometry. The data
showed that supplying of N, Mg, Ca and P to C. longifolia increased biomass and the concentration, and
amounts of major nutrients in plant tissue. The provision of N to C. longifolia induced uptake and accumulation of
N, P, Mg, Ca and Na in the field. Phosphorus supply also led to higher tissue concentrations of N, P, Ca, Mg and
Na just as the addition of Mg increased the concentration of Mg, P, Ca and Na in C. longifolia. Applying Ca to C.
longifolia plants also caused the accumulation of Ca, P, Mg and Na in shoots, but decreased N concentration
and content in field experiments. These data suggest that a moderate supply of N, P, Mg and Ca to C. longifolia
can stimulate plant growth and accumulation, and thus increase tea yields in farmers‟ fields.
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2011