Theme 2-2: Forage Production and Utilization--Poster Sessions
Description
Using results from official variety testing in Sweden, long-term changes (1964-2018) in total annual dry matter (DM) yield for pure stands of red clover (Trifolium pratense) and timothy (Phleum pratense) were analysed and compared for two Swedish trial site areas: a central area (59.6-61.5°N) and a southern area (55.5-57.0°N). All trials were managed using a standard protocol, with only minor changes over time. On average for all varieties of timothy in the trials, there was an increase of 91.6 kg ha-1 in total DM yield in the first harvest year, probably due to genetically improved varieties, increasing from two to three cuts and a changing climate. For red clover, there was a lower yearly increase of 45.9 kg ha-1 in total DM yield in the first harvest year. Four-fold larger variation in red clover yield was seen in the second half of the study period (after 1993) compared with the first, possibly due to a more fluctuating climate, particularly in winter, and more overwintering damage. In timothy, the variation in yield over the entire period was more stable, but still increased by around 80 % in the second half of the period compared with the first. For the most frequently included timothy variety, SW Kämpe II, which was present in trials between 1965 and 2001, total DM yield in the first harvest year (96.8 kg ha-1 ) was similar to the trial mean over the period for all timothy varieties. For the most frequently included red clover variety, Hermes II (present 1955-1996), total DM yield in the first harvest year increased by 33.2 kg ha-1 , i.e., less than the trial mean for that species.
Included in
Long-Term Changes in Dry Matter Yield in Variety Trials of Forage Species in Sweden
Using results from official variety testing in Sweden, long-term changes (1964-2018) in total annual dry matter (DM) yield for pure stands of red clover (Trifolium pratense) and timothy (Phleum pratense) were analysed and compared for two Swedish trial site areas: a central area (59.6-61.5°N) and a southern area (55.5-57.0°N). All trials were managed using a standard protocol, with only minor changes over time. On average for all varieties of timothy in the trials, there was an increase of 91.6 kg ha-1 in total DM yield in the first harvest year, probably due to genetically improved varieties, increasing from two to three cuts and a changing climate. For red clover, there was a lower yearly increase of 45.9 kg ha-1 in total DM yield in the first harvest year. Four-fold larger variation in red clover yield was seen in the second half of the study period (after 1993) compared with the first, possibly due to a more fluctuating climate, particularly in winter, and more overwintering damage. In timothy, the variation in yield over the entire period was more stable, but still increased by around 80 % in the second half of the period compared with the first. For the most frequently included timothy variety, SW Kämpe II, which was present in trials between 1965 and 2001, total DM yield in the first harvest year (96.8 kg ha-1 ) was similar to the trial mean over the period for all timothy varieties. For the most frequently included red clover variety, Hermes II (present 1955-1996), total DM yield in the first harvest year increased by 33.2 kg ha-1 , i.e., less than the trial mean for that species.
