Simulating field-scale variability and precision management with a 3D hydrologic cropping systems model

Abstract

Effective variable-rate nitrogen (N) management requires an understanding of temporal variability and field-scale spatial interactions (e.g. lateral redistribution of nutrients). Modeling studies, in conjunction with field data, can improve process understanding of agricultural management. CropSyst-Microbasin (CS-MB) is a fully distributed, 3-dimensional hydrologic cropping systems model that simulates small (10 s of hectares) heterogeneous agricultural watersheds with complex terrain. This study used a highly instrumented 10.9 ha watershed in the Inland Pacific Northwest, USA, to: (1) assess the accuracy of CS-MB simulations of field-scale variability in water transport and crop yield in comparison to observed field data, and (2) quantify differences in simulated yield and farm profitability between variable-rate and uniform fertilizer applications in low, average and high precipitation treatments. During water years 2012 and 2013 (a ''water year'' refers to October 1st through the following September 30th, where a given water year is named for the calendar year on September 30th), the model simulated surface runoff with a NashSutcliffe efficiency (NSE) of 0.7, periodic soil water content (comparison to seasonal soil core measurements) with a root mean square error (RMSE) B0.05 m 3 m -3 , and continuous . Simulated uniform N management resulted in 0-35 kg ha -1 greater field average yield in comparison to variable-rate management. The savings in fertilizer costs under variable-rate N management resulted in $23-$32 ha -1 greater field average returns to risk. This study demonstrated the capacity of CS-MB to further understanding of simulated and observed field-scale spatial variability and simulated crop response to low, medium and high annual precipitation.

Can agriculture technology improve food security in low- and middle-income nations? a systematic review

“…1 = 3 times a week within 52 weeks. 2 = 1 time a week within 52 weeks: the number of times the machine is unable to work Ward et al 76 Rules and regulations A = guidelines that prevent the efficient utilization of AT devices on the farmland. B = guidelines that do not relate to agricultural farming 0 = complex guidelines.…”

Cycles‐L: A Coupled, 3‐D, Land Surface, Hydrologic, and Agroecosystem Landscape Model

“…The conceptualization, development and evaluation of spatially‐distributed models (e.g., PALMS, PALMScot, SWAT‐MODFLOW, and CS‐MB) have primarily focused on hydrology (e.g., Kim et al., 2008; Molling et al., 2005), or crop yield and hydrology (e.g., Booker et al., 2015; Ward et al., 2018). A comprehensive evaluation of spatially‐distributed models encompassing multi‐state observations of hydrology, crop yield, and water quality has not been reported.…”

“…The SWAT-MODFLOW model was also coupled with the RT3D groundwater solute reactive transport model (Wei et al, 2019). Ward et al (2018) introduced CropSyst-Microbasin (CS-MB), a spatially-distributed and 3-D hydrologic cropping system model, which added the subsurface lateral flow of the Soil Moisture Routing model to CropSyst. The model was tested in a 10.9-ha watershed growing rainfed wheat in the Inland Pacific Northwest, USA, showing promising potential to simulate field-scale spatial variability of water distribution and grain yield.…”