Rotational Benefits, Planting Timing, and Seeding Rate Evaluation of Field Pea in Semi-Arid Cropping Systems Across the High Plains of Western Nebraska

Field pea (Pisum sativum L.) is a cool season annual legume that is grown for production of edible seed or forage. Agronomic and rotational challenges exist for semi-arid growing regions in western Nebraska that challenge the profitability of many dryland cropping systems in wester Nebraska. This research is focused on improving agronomic recommendations of seeding rates and timing of crop establishment to improve yield responses for producers while evaluating the effectiveness of replacing chemical summer fallow with field pea to improve soil health, increase water conservation, and increase land productivity with an intensified crop rotation. The effect of planting date and seeding rate were evaluated with three different planting dates. Each planting date included five seeding rates at four locations throughout western Nebraska over two years. Planting date did not influence grain yield response while plant population did influence grain yield. Planting dates displayed different response curves within a site-year. Optimal plant population changed with different site-years and planting dates. Optimal plant population results from specific site-years and across western Nebraska over the two year experiment suggests that maximum partial net return is achieved between 70-109 plants m-2. The rotation study was evaluated by comparing chemical summer fallow and field pea as treatments in a wheat-corn-fallow cropping system at two locations in western Nebraska over two cycles. Soil water content, soil fertility, field pea yield, and subsequent winter wheat yield was recorded throughout the experiment. Incorporation of field pea did not change winter wheat yield compared to chemical summer fallow. Field pea did improve sustainability parameters at both locations at certain sampling dates but did not result in permanent ecological improvements following harvest of winter wheat. Advisor: Cody F. Creec