Crops are growing rapidly and questions regarding expected end-of-season yields and soil water and nitrogen (N) status in the fields become very timely. A group of faculty, researchers, farm managers, and students from Iowa State University have developed a free, publicly available online platform (http://crops.extension.iastate.edu/facts/) to provide answers to these questions. The project is called FACTS (Forecast and Assessment of Cropping sysTemS) and provides real-time information that includes ground-truth measurements and predictions for 20 combinations of crops and management practices for six sites covering major soil and climatic conditions across Iowa (Fig. 1).
Fig. 1. Locations of the experimental sites where 20 site-crop-management replicated treatments are monitored. Three of the six sites have tile drainage. Blue circles are locations with tile drainage and red circles are locations without tile drainage.
The FACTS project takes a “systems approach” to forecast and evaluate cropping systems performance and has two main goals: 1) to provide real-time information to help farmers make decisions and 2) ground-truth model predictions and improve the science behind predictive tools. The team consists of experts on cropping systems modeling (Archontoulis, Dietzel), soil nitrogen dynamics and water quality (Castellano, Helmers), climatology (Vanloocke, Herzmann), crop production, management and extension (Licht, Archontoulis), statistics, visualization tools and web programming (Vanderplas, ISU Biology IT). The approach to forecasting cropping systems performance includes use of a) mechanistic cropping systems model (APSIM) to simulate crop growth, soil dynamics, and soil-crop-weather interactions; b) actual, historical, and forecasted weather information from NDFD and CFS models; c) frequent soil, crop, weather measurements; and d) advanced statistical and visualization tools to disseminate the information.
The forecast tool within the FACTS platform provides the following real-time information per category:
- Daily rain, GDD, maximum and minimum temperature per treatment that includes actual and forecasted weather data
- Benchmark weather data to show how the 2016 year compares with historical years
- Water and nitrogen
- Soil water and nitrate measurements, simulations and forecasts for 0-1, 1-2 and 2-3 feet soil depth
- Crop water and nitrogen uptake measurements, simulations and forecasts
- Crop and staging
- End-of-season yield predictions as % of historical or in actual units (bu/acre) that include best case scenario, median prediction and worst case scenario
- Crop staging together with days and magnitude of frost and heat stress
- Compare yields, rain, GDD, soil nitrogen status, crop N and water uptake values across 20 corn and soybean treatments located at 6 sites
- Environmental and economic variables will be added towards the end of season
Some highlights from the June 13, 2016 forecast:
- Most of the studied corn and soybean treatments have expected yields of 0 to 10% above historical average value as of June 13, 2016 (Fig. 2). Corn yields in southeast Iowa are predicted to be below average because of minimal precipitation since planting (Fig. 3). Corn yield predictions at northeast and southwest Iowa seem to be higher than other regions. Note that the above predictions change with time as the weather changes.
- Most of the corn plots are around V6 stage, a critical stage as the potential kernel number per ear is determined around that stage. Any stress at this time period will reduce the potential kernel number. High temperatures might become an issue.
- Most of the soybean plots are around the V3-V4 stage
- The soil nitrate profile (0-3 feet depth) is adequate for this time of year. In the coming days, soil nitrate pools will decline because the crop will take up nitrogen from the soil at high rates of about 5 lbs of N per acre per day.
- The 2016 weather so far compared to the previous years is: a) hot, with above average temperatures in all regions; b) dry, with below average precipitation in central and southeast Iowa; and c) wet, with above average precipitation in northeast and southwest Iowa.
Figure 2. Yield predictions as percent difference from historical average. The historical average is calculated by averaging 36 simulations performed for each system. Each simulation uses 2016 management and genotype and a different weather year (1980–2016). Details about the management can be found here: /facts/experimental-sites
Figure 3. Cumulative rainfall (inches) since planting for each crop. Details about the management can be found here: /facts/experimental-sites
Figure 4. Soil nitrate profile as predicted on June 13, 2016. Details about the management can be found here: /facts/experimental-sites
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