The role of topography, soil, and remotely sensed vegetation condition towards predicting crop yield
byT.E.Franz, S. Pokal, J.P. Gibson, Y. Zhou, H. Gholizadeh, F. A. Tenorio, D. Rudnick, D. Heeren, M.F. McCabe, M.G. Ziliani, Z. Jin, K. Guan, M. Pan, J. Gates, B. Wardlow
Year:2020DOI:10.1016/j.fcr.2020.107788
Extra Information
Field Crops Research, Vol. 252,p. 107788, (2020)
Abstract
Foreknowledge of the spatiotemporal
drivers of crop yield would provide a valuable source of information to
optimize on-farm inputs and maximize profitability. In recent years, an
abundance of spatial data providing information on soils, topography,
and vegetation condition have become available from both proximal and
remote sensing platforms. Given the wide range of data costs (between
USD $0−50/ha), it is important to understand where often limited
financial resources should be directed to optimize field production. Two
key questions arise. First, will these data actually aid in better
fine-resolution yield prediction to help optimize crop management and
farm economics? Second, what level of priority should stakeholders
commit to in order to obtain these data? Before fully addressing these
questions a remaining challenge is the complex nature of spatiotemporal
yield variation. Here, a methodological framework is presented to
separate the spatial and temporal components of crop yield variation at
the subfield level. The framework can also be used to quantify the
benefits of different data types on the predicted crop yield as well to
better understand the connection of that data to underlying mechanisms
controlling yield. Here, fine-resolution (10 m) datasets were assembled
for eight 64 ha field sites, spanning a range of climatic, topographic,
and soil conditions across Nebraska. Using Empirical Orthogonal Function
(EOF) analysis, we found the first axis of variation contained 60–85 %
of the explained variance from any particular field, thus greatly
reducing the dimensionality of the problem. Using Multiple Linear
Regression (MLR) and Random Forest (RF) approaches, we quantified that
location within the field had the largest relative importance for
modeling crop yield patterns. Secondary factors included a combination
of vegetation condition, soil water content, and topography. With
respect to predicting spatiotemporal crop yield patterns, we found the
RF approach (prediction RMSE of 0.2−0.4 Mg/ha for maize) was superior to
MLR (0.3−0.8 Mg/ha). While not directly comparable to MLR and RF the
EOF approach had relatively low error (0.5–1.7 Mg/ha) and is intriguing
as it requires few calibration parameters (2–6 used here) and utilizes
the climate-based aridity index, allowing for pragmatic long-term
predictions of subfield crop yield.
Keywords
Maize and soybeanyieldspatiotemporal krigingStatisticsRemote sensing