Cover Crops for Improving Nitrogen Use Efficiency in a Semiarid Irrigated Forage Rotation

View the project final report

Commodities

• Agronomic: corn, sorghum sudangrass

Practices

• Animal Production: feed/forage
• Crop Production: conservation tillage, cover crops, crop rotation, no-till, nutrient cycling, nutrient management
• Education and Training: participatory research
• Production Systems: agroecosystems
• Soil Management: nutrient mineralization, soil analysis, soil quality/health

Livestock production contributes to >40% of the agricultural economy in New Mexico. High yield and quality of forage provide the foundation for the success of the livestock-based economy. However, there is a challenge for sustaining forage-based agriculture in the southwestern region because of low water and nutrient use efficiency.

Forage crops require a large quantity of nutrients, specifically nitrogen (N). High N application rates in irrigated forage production systems can lead to N loss through leaching and runoff. Cover cropping can increase N-use efficiency by improving N recycling in the cover crop-integrated forage production system. Enhanced knowledge of N-movement in the soil profile under fallow and cover crops will help optimize N management and minimize the environmental risk associated with N leaching. Synchronizing N release from cover crop residues can reduce the N-requirement of forage crops and increase farm profitability.

We propose to evaluate the effects of diverse cover crop mixes on crop N-use efficiency in an irrigated forage corn-sorghum rotation system. Soil water samples from soil profiles will be monitored once a month for inorganic N content. Cover crops and forage biomass, and their quality will also be estimated. Research findings will be shared with growers through farmer's field day, extension workshop, regional conference, and extension article publication. The project will address the knowledge gap regarding the cover cropping benefits in the forage production system. We expect the project to motivate the forage growers to adopt cover cropping to increase agricultural productivity and improve soil health.

Research Objectives

1. Estimate the soil inorganic N content using deep-profile water samples in a cover crop-integrated forage production system.
2. Determine crop yield and N-use efficiency of forage crops.

Education/outreach Objectives

1. Disseminate the project results to the local growers and the general audience (researchers, educators, students, and policymakers).