Importance of soil moisture and temperature on the growth of improved pasture on the Northern Tablelands of New South Wales

Abstract

A simple model for predicting pasture growth from climatic data was developed and tested against experimental data.

The model was used to analyse climatic data from a 24-yr period (1950–1973) to elucidate the relative importance of soil moisture and temperature on the growth of improved pastures on the Northern Tablelands of New South Wales, and to predict the year-to-year variations in total pasture growth.

Predicted yearly dry matter production varied between extremes of 5000 kg ha^-1 yr^-1 in 1965 and 14,000 kg ha^-1 yr^-1 in 1971.

Soil moisture was the major factor limiting pasture growth from the beginning of October until the end of May, and temperature was the major limiting factor from the end of May to early October. During May and October there was a period when both factors had a similar probability of being the most limiting factor. Variations in soil moisture caused greater within-year variability in pasture growth than temperature except in April and September when variability caused by temperature equalled that caused by soil moisture. The significance of these effects is discussed.