Location: Small Grain and Food Crops Quality Research
Project Number: 3060-21650-002-033-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2022
End Date: Dec 31, 2025
Objective:
1. Measure water use by peas, lentils, cowpeas, wheat, millet, and corn and determine how the addition of pulse crops into the rotations could affect the water footprint and water use efficiency of both dryland and irrigated cropping systems;
2. Monitor the impact of pulses on soil carbon sequestration and soil health;
3. Evaluate the impact of peas, lentils, and cowpeas on plant N concentrations, residual soil N, nodule and rhizosphere community composition, and plant-rhizobia interactions;
4. Complete a cradle-to-farmgate life cycle analysis of pulses produced in each rotation to identify opportunities to reduce greenhouse gas emissions and water use;
5. Quantify the economic impact of adding pulses to cropping systems to verify whether they could be economically sustainable; and
6. Evaluate the impacts of incorporating pulses in U.S. diets at varying levels on environmental and nutritional outcomes.
Approach:
The goal of this project is to quantify the potential of pulse crops (specifically, dry peas, lentils, and cowpeas) to improve environmental and economic sustainability through incorporation into both dryland and irrigated wheat rotations in semi-arid and arid climates. The project will utilize crop rotations of three-years, with each crop represented in each year in two different parts of Colorado (semi-arid, dryland rotations in eastern Colorado and arid, irrigated rotations in western Colorado). Several sustainability parameters (water, carbon, nitrogen, and economics) will be measured and applied to a thorough life cycle analysis and a dietary impact analysis. The three rotations in the dryland cropping system will be wheat-corn-fallow (WCF), wheat-corn-millet (WCM) and wheat-corn-cowpea (WCP). We will determine the moisture utilization of each crop and each cropping system by monitoring precipitation and using the neutron attenuation method. We will also measure yield and grain protein levels and calculate water use efficiency for each system. For research in western Colorado, we will utilize two drip irrigated cropping systems and introduce lentils and peas as a winter fallow replacement. The two winter crop rotations will be wheat-pea-lentil (WPL) and wheat-fallow-corn (WFC). Soil health indicators will be evaluated every year immediately after harvest in the surface 0-15 cm. We will include a suite of soil health parameters that reflect key soil functions including bulk soil density, wet aggregate stability, and permanganate oxidizable carbon (C) as well as C and nitrogen (N) in particulate organic matter and mineral-associated pools. In the field studies, we will measure plant N concentration (at harvest for each crop) and residual soil N following harvest to 60 cm deep. To develop new knowledge on peas, lentils, and cowpeas related to understanding the nodule and rhizosphere microbial community composition, a greenhouse study will be conducted using two distinct soils collected from field sites where pulse crops have been previously grown. We will determine: 1) rhizobial species present in each pulse crop, 2) rhizobial species that might contribute to the presence of specific N forms in the plant and the soil, and 3) rhizobial species that contribute to pulse root traits. A comparative, cradle-to-farm gate attributional life cycle analysis (LCA) will be performed to estimate the greenhouse gas emissions, water use, land use, and energy use of the pulses produced in each crop rotation. We will investigate the effect of pulse crop rotations on farm profitability and risk by developing a moment-based approach to characterizing the production system returns that explores the role played by higher moments of the net return distribution. We will complete a consequential LCA of the impacts of substituting chicken with pulses on dietary carbon, water, land, and energy footprints at three dietary pulse inclusion levels.
