Potential production of grass and clover monocultures in a mediterranean-type environment — an experimental approach

Abstract

Monocultures of Lolium rigidum cv. Wimmera and Trifolium subterraneum cv. Woogenellup were established at four densities and mown at three contrasting heights over a 5 month period. Heavy applications of fertilizer were applied to eliminate nutrient deficiencies. Dry matter yields and leaf areas were measured before and after the 3-weekly defoliations, and shoot numbers before the defoliations. Growth rate was related to leaf area index (LAI) in all but one of the sampling periods. Maximum growth rates were proportional to light energy, and the average efficiency of conversion was 4.5% for the clover and 5.5% for the grass. Total herbage yields as high as 17.3 t ha-1 were obtained from the grass, and up to 16.4 t ha-1 from the clover. The results are discussed in relation to the differential ability of grass and clover to exploit the environment. The grass was leafier and had more shoots, but it is thought that clover intercepted more of the incident light at low LAI. The results indicate that potential yields would be reduced at the low LAI values associated with an efficiently utilized pasture.