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RESEARCH ARTICLE

Factors affecting the growth of kikuyu. II. Water supply

GJ Murtagh

Australian Journal of Agricultural Research 39(1) 43 - 51
Published: 1988

Abstract

The influence of water supply on the growth of a kikuyu (Pennisetum clandestinum) pasture was estimated from field measurements of growth rate. A model was used to separate the confounded effects on growth of light interception, temperature, nitrogen and water supplies, and maintenance respiration. Water supply for growth was expressed as a function of both the soil water content and evaporative demand (potential evapotranspiration). The growth of kikuyu was very sensitive to water supply. On a wet soil (soil water potential > -20 kPa), an evaporative demand above 3.2 mm day-1 slowed growth. With optimum temperatures and a sward yield which gave the best balance between light interception and rate of maintenance respiration, a low evaporative demand of 2 mm day-1 reduced growth rates only when the soil water potential was less than - 134 kPa. However, with a medium-high evaporative demand of 5 mm day-1, growth was reduced by 39% on a wet soil, and ceased at a soil water potential of - 101 kPa.

https://doi.org/10.1071/AR9880043

© CSIRO 1988

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