Effect of time of sowing on irrigated pastures in south-eastern Queensland

Abstract

Irrigated pastures can be established from February, April or· June plantings but April and June gave the most consistent results. Total emergence of the sown species was the most satisfactory from April and June plantings (30 and 40 plants per sq. ft. respectively.) February plantings were only fairly satisfactory (23 plants per sq. ft.) while September plantings gave very poor emergence (12 plants per sq. ft.).
Weeds were troublesome in September and February plantings, the average numbers emerging over the three years being approximately 24 and 27 plants per sq. ft. respectively. Only moderate amounts emerged in April (13 plants per sq. ft.) and June plantings (8 plants per sq. ft.). The planting mixture containing the larger amount of ryegrass tended to suppress the early growth of weeds.
Details of growth rates and botanical composition at the first harvest and trends in composition over a full year from the planting time for the 1956 season are given. The green yield for the year was significantly higher in the February planting. A marked difference in composition developed between February and September plots on the one hand and April and June plots on the other, the former plots reverting essentially to a simple white clover and paspalum pasture while the latter plots retained fairly high proportions of the other sown grass species with ryegrass as the dominant grass.
When additional factors such as soil preparation and weed problems are considered, the best recommendation is that the final soil preparation for planting should be done as soon after the beginning of April as weather and soil conditions permit, with planting taking place wen before September.