GROWTH ANALYSIS OF MAYWEED CHAMOMILE (ANTHEMIS-COTULA) INTERFERENCE IN PEAS (PISUM-SATIVUM)

Destructive growth analysis of field replacement series experiments wi th mayweed chamomile and dry field peas was used to determine the comp etitive relationship between the two species. Mayweed chamomile produc ed similar amounts of leaf area and dry weight per plant in a dry year and a wet year. On the other hand, dry field peas produced 20% more l eaf area and 100% more dry weight per plant in the wet year compared t o the dry year. Height, leaf area, and dry weight of peas reached maxi mum between bloom and pod-set, and then declined. Height and dry weigh t of mayweed chamomile increased steadily throughout the growing seaso n. Mayweed chamomile leaf area reached a maximum at the beginning of f lower stem elongation. Initially, the relative growth rate of mayweed chamomile was about three times greater than the rate for peas, but by 40 to 48 d after planting, rates were similar for both species. Relat ive yields and relative crowding coefficients for dry weight showed th at peas were 3 to 20 times more aggressive than mayweed chamomile. Res ults of these experiments show that mayweed chamomile is a weak compet itor against peas, but because it continues to grow after peas senesce , it could interfere with crop harvest.