New Zealand Journal of Botany abstract

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Nutritional requirements of Clematis vitalba L. (old man's beard)

L. J. HUME*
C. J. WEST**
H. M. WATTS+

DSIR Land Resources
Private Bag
Lower Hutt, New Zealand
*Present address: Centre for Maori Studies and Research, P.O. Box 56, Lincoln University, Canterbury, New Zealand.
**Present address: Department of Conservation, P.O. Box 743, Invercargill, New Zealand.
+Present address: Reserve Bank, The Terrace, Wellington, New Zealand.

Abstract  The nutritional requirements of the naturalised vine, Clematis vitalba, were investigated in order to determine soil factors which might restrict its growth. Topsoil samples (0-10 cm), collected from 19 sites where C. vitalba has naturally established in New Zealand, had moderately acid to near neutral pH values, high to very high percentage base saturation, and medium to very high concentrations of the exchangeable cations Ca, Mg, and K, but tended to have low plant-available P and phosphate-extractable sulphate concentrations. Extractable-Al concentrations were very low. Profile descriptions at these sites showed that almost all soils were being or had been rejuvenated by alluvium, colluvium, or tephra. The soils had few physical impediments to root growth, so plants were readily able to exploit the soils and their nutrients.

In a glasshouse experiment, growth of C. vitalba increased with increasing rate of lime (CaCO3) and with increasing rate of applied P. Greatest growth in these conditions was associated with: pH = 4.7; exchangeable Al = 4.6 me./100 g; 0.02M CaCl2-extractable Al = 3.5 mg/g; and Olsen P = 56 mg/g. Death of plants was associated with: pH = 3.7; exchangeable Al = 12.6 me./100 g; 0.02M CaCl2-extractable Al = 107 mg/g; and Olsen P = 5.0 mg/g. The response to lime was to high pH and/or low Al concentrations rather than to high concentrations of Ca, indicating that C. vitalba is not a calcicole. Plant growth was found to be more closely correlated with CaCl2-extractable Al concentrations than to pH or exchangeable Al concentrations. In a second (subtractive nutrient) experiment, growth of C. vitalba was reduced by low concentrations of soil N, P, Ca, S, and micronutrients. The depression in growth in the minus micronutrient treatment appeared to be caused by low plant Mn concentrations, or possibly by high Fe concentrations as a result of the lower Mn concentrations. Despite very low concentrations of K and Mg in the soil, significant growth responses to the addition of these elements were not obtained. The addition of Fe was found to depress root growth.

The growth and spread of C. vitalba may be restricted by extremely acid soil conditions and by very low concentrations of N, P, Ca, S, and possibly Mn in the soil. However, it does not appear to be unusually sensitive to soil acidity or nutrient deficiencies.

Keywords  Clematis vitalba; old man's beard; pH; soil nutrients; growth

New Zealand Journal of Botany, 1995, Vol. 33: 301-313

0028-825X/95/3303-0301 $2.50/0 (c) The Royal Society of New Zealand 1995

PDF file of entire paper: medium quality (726K); (scanned from paper original: notes about this process)

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