Pumpkin Yield and Weed Populations Following Annual Ryegrass

Abstract

ABSTRACT Sustainable production can sometimes be achieved with diversification of cropping patterns and by the use of disparate crops in rotation. Following a forage grass harvest for feed it may be possible to produce a cucurbit crop before it is time to reseed an overwintering grass cover crop. Pumpkins may be a crop that can be grown in rotation with grasses. Five annual Italian ryegrass varieties of varying maturity [“Shiwasuaoba” (early); “Miniamioba” and “Waseyutaka” (medium); “Marshall” and “Zorro” (late)] were established in the fall. In early summer of the following year the grasses were harvested, their yield determined, and the stubble left in place. The control was composed of winter wheat which was harvested in the spring and the stubble turned under and the soil maintained without cover. Seed of pumpkin, cv. ProGold 300, were sown into strips tilled in the ryegrass stubble or bare soil. Number and weight of pumpkins were determined. Weed cover in plots following pumpkin harvest was determined. Plots were seeded with the ryegrasses or wheat, with the procedures repeated over two years. Marketable number and yield of pumpkin were not affected by cover or year of planting and averaged 1,755 fruit/ha and 5.9 Mg·ha−1, respectively, over both years. The percent of pumpkin fruit of the expected size for this cultivar, >7.25 kg, was 41% in the first year and 26% in the second year. Approximately 68% of fruit from plants on bare soil, and 27% from plants on soil covered with ryegrass stubble, were >7.25 kg. Total weed cover was not different on bare soil between years (avg. 86%), and dicot weeds were greater in 2002 than 2003. Total weed cover in ryegrass plots averaged about 36% in 2002 and 93% in 2003. Dicot weed cover in ryegrass stubble plots were not different between years or ryegrass variety and averaged 32%. Monocot weed cover was significantly lower in 2002, 5%, than in 2003, 57%, regardless of cover. There is a need for additional studies in ryegrass-pumpkin rotation before recommendations can be made for its implementation in southeastern Oklahoma.