CROPPING SYSTEMS FOR PERENNIAL RYEGRASS SEED PRODUCTION .1. MINIMUM TILLAGE ESTABLISHMENT OF ROTATION CROPS IN STUBBLE WITHOUT BURNING

Viability of alternative crops in a monoculture grass seed cropping sy stem will be enhanced if minimum tillage establishment through grass s eed stubble is successful without burning. Our objective was to compar e agronomic performances of red clover (Trifolium pratense L.), white clover (T. repens L.), meadowfoam (Limnanthes alba L.), and pea (Pisum sativum L.) when drill-seeded in the stubble of a third-gear perennia l ryegrass (Lolium perenne L.) seed crop, with and without burning stu bble. Four held experiments were conducted during a 6-yr period on a W oodburn silt-loam (fine-silty, mixed, mesic Aquultic Argixerolls) soil in western Oregon. Ryegrass stubble was either propane-burned or was not burned before drill-seeding the rotational crops. In one experimen t, a rotary strip-till drill was also compared with a no-till drill fo r establishing white clover in perennial ryegrass stubble. Burning the stubble enhanced spring growth of red clover; however, forage and see d yields in the first crop year were 47 and 66% higher, respectively, for the nonburned than the burned treatments. There were no difference s among treatments for forage and seed yields of red clover in the sec ond crop year. Treatments did not affect dry matter or seed production of white clover and spring pea. Meadowfoam forage and seed yields wer e 26 and 24% lower, respectively, for the nonburned than the burned tr eatments. We concluded that burning stubble before seeding may be adva ntageous for winter annual seed crops that mature during the spring or early summer months. However, burning stubble is not beneficial, or m ay be disadvantageous, for crops that mature during the late summer in areas such as Oregon with a Mediterranean climate. The no-till drill was superior to the strip-till drill far establishing white clover in perennial ryegrass stubble regardless of stubble management method.