Thandiwe Nleya, John Rickertsen, and Bruce Swan. South Dakota State Univ., 1905 Plaza Blvd., Rapid City, SD 57702, United States of America
The adoption of no-till cropping systems has allowed for diversification of the traditional winter wheat-fallow rotation in western South Dakota. The changes in the rotation have fueled demand for information on alternative crops suited for production in the region. Field pea (Pisum sativum) is well adapted to western South Dakota growing conditions. Field pea cultivars are currently being evaluated for adaptation and yield, and agronomic packages for the crop are being developed. The cost of field pea seed is high, creating interest among growers and researchers on yield response of different pea varieties to plant population and implications on economic returns. A field pea plant population study was conducted with four field pea varieties planted at six plant populations ranging from 250,000 to 860,000 plants per hectare. The objectives were 1) to determine the effect of plant population on growth and yield of four field pea varieties, and 2) to determine the plant population required for optimum yield in western South Dakota. Yield increased significantly with increase in plant population with the highest yield obtained at the highest population density of 860,000 but with no significant differences in yield among the top three plant populations.