RELATIONSHIPS BETWEEN COVER PERFORMANCE AND DATE OF FALL-SEEDING WHERE WINTER RYE WAS BROADCAST INTO A STANDING POTATO CROP

Winter rye was broadcast into a potato crop just after topkilling with the object of avoiding post-harvest delays in establishing a winter ground cover. Rye treatments were interseeded (i) at intervals of 1 d for up to 10 d before potato digging, without post-harvest tillage and (ii) just after digging and preparatory seedbed tillage as a comparative standard. Generally, cover performance of rye, measured as plant count, tiller count or dry mass of plants showed significant (P < 0.05) increase with decreasing days to potato digging up to 3 or 4 d before digging. There was no sacrifice of rye cover using this interseeding approach compared with traditional post-(potato) harvest seeding in a prepared seedbed. Seeding 3-4 d before potato harvest is recommended on the basis of superior fall plant count, spring tiller count and shoot dry mass, and winter survival indices on either of these days.