EFFECTS OF ROW SPACING AND SEEDING RATES ON SEED YIELD IN RED CLOVER, ALSIKE CLOVER AND BIRDSFOOT TREFOIL

The effects of various row spacings and seeding rates on seed yield and certain seed yield components, viz, florets per head, seed set, seeds per pod, were studied on single seedings with three successive seed crops of red clover (Trifolium pratense L.), alsike clover (T. hybridum L.), and birdsfoot trefoil (Lotus corniculatus L.). Alsike clover and birdsfoot trefoil produced the highest yields at the narrow 15-cm spacing with successive decreases to the 60-cm spacing. The taller-growing and later-blooming, single-cut red clover was slightly more adaptable to varying spacings with the highest yields at 30- and 45-cm spacings, and slightly lower yields at the 15- and 60-cm spacings. All three crops competed successfully with weeds at the narrow spacings (15 and 30 cm). All three crops were able to compensate within limits in the 2nd and 3rd seed yr for differences in stand caused by different seeding rates. Seeding rates of 2.2 and 4.5 kg/ha were most favorable. Certain components of yield, e.g., florets per inflorescence, percent seed set, and seeds per pod, did not vary within years and are primarily affected by rainfall, soil fertility, pollinator populations and favorable pollinating weather. Differences in seed yields were attributable to total production of flower heads or racemes.