Random Forests for Global and Regional Crop Yield Predictions.
Accurate predictions of crop yield are critical for developing effective agricultural and food policies at the regional and global scales. We evaluated a machine-learning method, Random Forests (RF), for its ability to predict crop yield responses to climate and biophysical variables at global and regional scales in wheat, maize, and potato in comparison with multiple linear regressions (MLR) serving as a benchmark. We used crop yield data from various sources and regions for model training and testing: 1) gridded global wheat grain yield, 2) maize grain yield from US counties over thirty years, and 3) potato tuber and maize silage yield from the northeastern seaboard region. RF was found highly capable of predicting crop yields and outperformed MLR benchmarks in all performance statistics that were compared. For example, the root mean square errors (RMSE) ranged between 6 and 14% of the average observed yield with RF models in all test cases whereas these values ranged from 14% to 49% for MLR models. Our results show that RF is an effective and versatile machine-learning method for crop yield predictions at regional and global scales for its high accuracy and precision, ease of use, and utility in data analysis. RF may result in a loss of accuracy when predicting the extreme ends or responses beyond the boundaries of the training data.
School of Environmental and Forest Sciences, College of the Environment, University of Washington, Box 354115, Seattle, WA 98195, United States of America.
Jig Han
JH
Jeong
Department of Geographical Sciences, University of Maryland, College Park, MD, United States of America.|Crop Systems and Global Change Laboratory, USDA-ARS, Beltsville, MD 20705, United States of America.
Jonathan P
JP
Resop
Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, United States of America.|Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, United States of America.
Nathaniel D
ND
Mueller
Crop Systems and Global Change Laboratory, USDA-ARS, Beltsville, MD 20705, United States of America.
David H
DH
Fleisher
School of Environmental and Forest Sciences, College of the Environment, University of Washington, Box 354115, Seattle, WA 98195, United States of America.
Kyungdahm
K
Yun
Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, United States of America.
Ethan E
EE
Butler
Crop Systems and Global Change Laboratory, USDA-ARS, Beltsville, MD 20705, United States of America.
Dennis J
DJ
Timlin
Climate Change & Agroecology Division, National Institute of Agricultural Science, RDA, Suwon, Korea.
Kyo-Moon
KM
Shim
Institute on the Environment, University of Minnesota, St. Paul, MN 55108, United States of America.
James S
JS
Gerber
Crop Systems and Global Change Laboratory, USDA-ARS, Beltsville, MD 20705, United States of America.
Vangimalla R
VR
Reddy
School of Environmental and Forest Sciences, College of the Environment, University of Washington, Box 354115, Seattle, WA 98195, United States of America.
Soo-Hyung
http://orcid.org/0000-0003-3879-4080
SH
Kim
D018556:Crops, Agricultural; D000069550:Machine Learning; D008962:Models, Theoretical