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ARS Home » Pacific West Area » Pendleton, Oregon » Columbia Plateau Conservation Research Center » Research » Research Project #443563

Research Project: DSSAT Winter Pea Model Development

Location: Columbia Plateau Conservation Research Center

Project Number: 2074-21600-001-003-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Oct 1, 2022
End Date: Jun 30, 2025

The objective of this project is to cooperatively develop a plant growth model for winter peas using the DSSAT modeling platform. Sub-objectives include: 1) conducting field studies to collect plant growth and development data under varied environmental conditions; 2) parameterizing the CROPGRO model using the field data and relevant information mined from the scientific literature; 3) publish the model parameters and model adaptation process in the peer-reviewed literature; and 4) add the CROPGRO-Winter Pea model to the DSSAT platform. This agreement is structured annually and is expected to be renewed for a total project period of three years. In the second year, the focus is on sub-objectives 1 and 2.

Sub-objective 1: Field studies Field studies will be established at three sites (Starvation, Bafus, and Adams) in Eastern Oregon for two years each. The experimental treatments at each site will include three winter pea varieties (MiCa, Klondike, Austrian Winter Pea) and wheat. The plots will be monitored and data will be collected monthly during slow fall and winter growth, then every two weeks during rapid spring and summer growth. Observations of the timing of key phenological growth stages will be made. Data will be collected on main-stem plant node numbers, canopy height, and canopy width. Plants in each plot will be dug up to check for the presence of nodules on pea roots. If nodules are present, they will be collected and counted in the field, then cleaned, dried, and weighed in the lab. Plant growth measurements will be taken by hand-harvesting 1-m2 areas of the crop in each plot. Total aerial biomass production, and dry weight of individual plant components (i.e. leaf, stem, and reproductive), will be determined. The biomass component samples will be ground to a fine powder, then analyzed for total N concentration. Once maturity is reached, the same sampling procedure will be used, but additional measurements will be added to derive seed yield and yield component information (i.e. seed weight per m2, seeds per pod, pods per plant, 1000-seed weight, seed protein). Soil moisture measurements will also be made. Sub-objective 2: Model parameterization Observed growth and yield data will be aggregated from the two years of pea experiments at the three sites. The observed data will be entered into the typical time-series and final harvest files of DSSAT. Weather and soil data will be entered into appropriate weather and soil files. The species, ecotype, and cultivar files of the CROPGRO model will be modified based on: 1) available scientific information on tissue composition and the cardinal temperature relationships that drive photosynthesis, respiration, leaf area expansion, progress to flowering/reproductive, rate of pod addition, and rate of seed growth; 2) comparison of simulated to observed growth dynamics, and subsequent calibration of species and cultivar parameters needed to reproduce the growth dynamics of the pea cultivars. The optimization methodologies will minimize the root mean square error and maximize the D-statistic for the different crop growth variables. Calibration of parameters will involve both manual and Bayesian optimization. Based on prior experience with adaptation of the model’s read-in files for species, ecotype, and cultivar for other legumes, FORTRAN code modification is not anticipated. Sub-objective 3: Model publication We anticipate addressing this sub-objective in the third project year. The paper will describe the adaptation process as well as illustrating successful simulations. Sub-objective 4: Add winter pea module to DSSAT We anticipate addressing this sub-objective in the third project year.