Studies on the cutting management of grass-clover swards Part II. The effects of close cutting with either a gang mower or a reciprocating-knife mower on the yields from an established grass-clover sward

1. In an experiment conducted on an established perennial rye-grass/white clover sward close cutting was carried out over a 3-year period (1956–58), either with a lawn mower to simulate gang mowing or with a reciprocating-knife mower. The sward was cut either six or eight times in each season, and received 0 or 2 cwt. ‘Nitro-Chalk’/acre for each cut. 2. Swards cut with the gang mower yielded from 3·5 to 12·5% more herbage dry matter than swards cut with the reciprocating-knife mower and also gave a greater mean yield of crude protein. 3. The difference in dry-matter yield between swards cut with each of the mowers is attributed to the slightly closer cutting level of the gang mower having a greater inhibiting effect on flower development in the grasses and hence stimulating leaf production and increasing total yields. 4. In the second and third years of the experiment swards cut with the gang mower outyielded those cut with the reciprocating-knife mower by a proportionately greater amount when eight cuts rather than six cuts were taken in the season. 5. When no nitrogenous fertilizer was applied the proportion of broad-leaved weeds in the sward increased more rapidly over the 3-year period where the herbage was cut with the gang mower rather than the reciprocating-knife mower. This disadvantage of gang mowing did not apply where the fertility was maintained at a high level by applications of nitrogenous fertilizer. 6. It is concluded that the gang mower is a more suitable machine than the reciprocating-knife mower for close cutting on a field scale.