The effect of varying row spacing and seeding density within rows of the perennial grass component of a mixed sward

Abstract

With a Phalaris tuberosa L.–Trifolium subterraneum L. association, seeding the grass in widely spaced rows in 1950 increased the total productivity of the pasture over the first 6-year period (1951–1956) by comparison with normal 7 in. row seeding. The annual production was greater in four years and did not differ significantly in the other two. At first the increased yield was due to annual species, mostly T. subterraneum, exploiting the larger inter-row environment. This was followed by greater production of perennial grass in the wide row treatments. It is suggested that this was the result of greater availability of soil nitrogen provided by symbiotic fixation. Reducing the sowing rate, by halving the seeding density within rows, had no effect on the yield per acre of any of the species in the pasture.