Production, composition and morphology of tall fescue and perennial ryegrass pastures grown with white and strawberry clover: A dissertation submitted in partial fulfilment of the requirements for the degree of Bachelor of Agricultural Science with Honours at Lincoln University

Abstract

Three pasture treatments were compared with either white clover (Trifolium repens L) (WC) or strawberry clover (Trifolium fragiferum L) (SC), to determine the extent to which total dry matter (DM) accumulation, seasonal growth pattern and plant morphology was manipulated over an eight month trial period (February to September, 2009). The pasture treatments were: summer active 'Advance' tall fescue (Festuca arundinaceaae Schreber) (A), winter active 'Flecha' tall fescue (F) and perennial ryegrass (Lolium perenne L) (PRG). A positive relationship was found between total DM production and grass species. Perennial ryegrass had the highest DM production (6,484 kg DM/ha) which differed to both tall fescue cultivars 'Advance' (4,816 kg DM/ha) and 'Flecha' (5,115 kg DM/ha). There was no difference in total DM production between cultivars of tall fescue. The winter active tall fescue had little effect on the overall seasonal distribution of forage supply compared with the summer active tall fescue and perennial ryegrass. On average white clover produced 63% more DM then strawberry clover over the eight month time period with grand means of (571 and 213 kg DM/ha), respectively. The relationship between DM production and the main effects (grass species and clover species) translated into a similar relationship for pasture composition. Higher DM producing grass pastures had similarly higher levels of grass as a percent of total composition and conversely lower levels of clover. The summer active tall fescue had the highest clover production (644 kg DM/ha) out of all three grass species sown. Faster tillering perennial ryegrass produced the highest average amount of tillers per plant (10.04), 49% more than 'Flecha' (5.10 tillers/plant) and 67% more then 'Advance' (3.34 tillers/plant). This had an inverse relationship with clover number, so as tiller number increased the number of clover plants declined. This impacted strawberry clover more then white clover, resulting in a lower production and composition of strawberry clover to white clover. Morphologically strawberry clover had fewer nodal roots then white clover, but had a larger tap root, possibly indicating a greater drought resistance. The results demonstrate that tall fescue and strawberry clover production were much lower than the industry 'standard' perennial ryegrass/white clover pasture for total herbage accumulation and seasonal distribution. However, significant interactions among sites reinforces the need to understand limitations to plant growth on a site-by-site basis, to select plants that match the environmental conditions, and to manage them appropriately to reach their growth potential. Future data collected from this continued study may illustrate the true potential of these alternative grass and clover species, due to the possibility of establishment difficulties impacting early on.