YIELD AND COMPENSATORY GROWTH OF LUCERNE FOLLOWING SIMULATED WINTER-KILL

Lucerne (Medicago sativa L.) sown at 2.8-11.2 kg ha-1 in spring was th inned in the autumn by digging plants from alternate 15- or 30-cm leng ths of row. Both thinning treatments decreased the subsequent year sta nd density by 34%. Yields the following year were reduced by 24 and 17 % for the 15- and 30-cm treatments respectively, and the next year by 10% for both treatments. Thinning effects were similar at all sowing r ates. During the year following thinning, plants did not grow larger i n response to the thinning. Thus, development of compensatory growth b y lucerne plants following sudden stand thinning is slow.