- Agronomic: corn, millet, peas (field, cowpeas), sorghum (milo), sorghum sudangrass, soybeans, sunflower, forage sorghum, cover crops
- Crop Production: cover crops, cropping systems, crop rotation, double cropping, no-till
- Education and Training: extension
- Farm Business Management: budgets/cost and returns
- Natural Resources/Environment: biodiversity, carbon sequestration
- Production Systems: dryland farming
- Soil Management: soil quality/health
Farmers throughout the Corn Belt may want to consider diversifying traditional corn and soybean-based rotations to increase agronomic sustainability and to spread financial risks associated with low market prices of corn and soybean. An alternative is a more diverse crop rotation using field pea (FP) (short-season grain crop) followed by cover crops (CC), forages (F), or short-season crops (SC). Field peas are planted mid-March and harvested in early-July providing the window of opportunity to extend the growing season by double cropping. Potential benefits include reduced tillage, fertilizer and herbicide inputs, minimize soil erosion and compaction, increase the efficiency of cropping system water use, build up soil organic matter, suppress weeds and pests, and reduce nitrate leaching. The objectives of this project were to: (1) quantify the rotational costs and economic returns of FP-CC/F/SC as compared to corn-soybean rotation; and (2) evaluate soil nutrient dynamics, water use and total plant biomass provided by FP-CC/F/SC.
The study was conducted at the University of Nebraska-Lincoln Southeast Research and Extension Center Nebraska near Mead, NE in 2018 and 2019 as randomized complete block design. Field peas were planted in March and harvested early-July followed by the planting of short-season grain crops, forages, and cover crops. Short season grain crops included corn, soybean, sunflower, grain sorghum, and proso millet. Forages included sudangrass and forage sorghum, and cover crops were winter-sensitive and winter-hardy. Aboveground biomass was collected for forages and cover crops, and grain yield for the short season grain crops. Soil samples were collected after harvest, in March 2019. Corn grain yield in 2019, planted following FP-SCs/Fs/CCs rotation were evaluated.
Forage sorghum, sudangrass, cover crops winter-sensitive and winter hardy reached 13000, 7860, 3851 and 4187 kg ha-1 of dry weight, respectively. Corn, soybean, sunflower, grain sorghum, and proso millet grain yields were 1720, 697, 1930, 5996 and 1933 kg ha-1. Corn, soybean, and sunflower were frost-killed before reaching maturity. The principal component analysis showed that SCs are associated with soil nitrate levels and Fs and CCs with soil organic carbon and soil respiration. Nitrate levels in the soil profile were reduced by 40 % when Fs and CCs were grown as compared to SCs. There were no differences in corn grain yield following FP-CC/F/SC rotation. Grain sorghum, proso millet, forage, and cover crop production showed the highest potential to be used as a double crop with field pea as an alternative crop rotation in eastern Nebraska.
Farmers will be able to: (1) identify the circumstances upon which replacing corn or soybean with FP-CC/F/SC will be economically viable and how using such a system can improve soil nutrient cycling and other ecosystem services; (2) select best-suited cover crop, forage, or short season crop following field pea for double cropping to diversify their corn-soybean crop rotation and spread production risks; and (3) improve their economic well-being, quality of life, and professional inquiry of issues related to environmental stewardship and long-term sustainability.