Submitted to: Journal of Sustainable Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 21, 2004
Publication Date: January 15, 2006
Citation: Russo, V.M., Kindiger, B.K., Webber III, C.L. 2006. Pumpkin yield and weed populations following annual ryegrass. Journal of Sustainable Agriculture. 28:85-96. Interpretive Summary: Diversifying production practices can include use of sequential rotation of crops on the same land. In Oklahoma grass winter cover crops are often planted in the fall and harvested in late-spring to early-summer of the next year. Pumpkin is a vegetable crop that could be planted after grass. Five annual Italian ryegrasses with different maturities, 'Shiwasuaoba' (early); 'Miniamioba' and 'Waseyutaka' (medium); and 'Marshall' and 'Zorro' (late), were cut and followed in rotation with the pumpkin cv. ProGold 300 planted using minimum till practices into the stubble. The control was comprised of winter wheat which was harvested in the spring with the stubble turned under, and the soil maintained without cover. Pumpkin yields were determined, and following harvest of pumpkins, weed cover in plots were determined. Pumpkin yield was only 5.9 Mg/ha averaged over two years. About one-third of the pumpkin fruit exceeded 7.25 kg, the expected fruit size as advertized by the provider. Weed cover was not affected by the type of ryegrass or the control. Additional work needs to be conducted before pumpkin can be recommended for production in rotation with ryegrass in Oklahoma.
Technical 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 comprised 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 1755 fruit/ha and 5.9 Mg/ha, 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. Approx. 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.