Development and evaluation of RZWQM2-P: A model for phosphorus management in tile-drained agricultural fields

A rising environmental concern, phosphorus (P) loss from agricultural fields via surface runoff or sub-surface drainage ends up in freshwater bodies (river, lakes), where it causes widespread algal blooms and water quality degradation. Recent studies suggest that agricultural fields fitted with artificial tile drainage system contribute heavily to these P losses. Simulation models could help to measure and manage the agricultural P losses and inform prudent management decisions to mitigate this problem in a time saving and cost-effective way. Computer simulation models for this purpose are presently lacking, particularly for tile drained agricultural fields. Accordingly, the present study was undertaken to develop a computer simulation model to simulate P loss from a tile drained agricultural field through different hydrological pathways. A state-of-the-art algorithm to simulate the fate and transport of P in tile-drained agricultural systems is proposed, tested and incorporated into the RZWQM2 model, to take advantage of its hydrologic and agricultural management subroutines — thereby yielding the RZWQM2-P model. Structured according to Jones et al., (1984) with updates and modifications prescribed by Vadas, (2014), the RZWQM2-P model features dedicated manure and fertilizer P pools to simulate P dynamics arising from their application. To simulate daily P absorption/desorption among the P pools, a dynamically changing rate factor is applied rather than a constant rate factor. Tile drainage dissolved reactive P (DRP) and particulate bound P (PP) loss are estimated according to Francesconi et al., (2016) and Jarvis et al., (1999), respectively. Losses of DRP and PP through surface runoff are simulated according to Neitsch et al., (2011) and McElroy et al., (1976), respectively. The RZWQM2-P model’s capacity to simulate the DRP and PP loss from an agricultural field through surface runoff and tile drainage was evaluated using two sets of observed P loss and water flow data collected from subsurface-drained fields under a corn-soybean rotation on a clay loam soil in southwestern Ontario, Canada. For both cases, the RZWQM2-P model performed satisfactorily (NSE > 0.50, PBAIS within ±30%, IoA >0.75). A sensitivity analysis of the RZWQM2-P’s input parameters was conducted to facilitate the application of the model by users like agricultural managers and environmental stakeholders. The sensitivity analysis found the simulation of RZWQM2-P’s P loss depends on many parameters; however, macroporosity was the preeminent parameter in simulation of all form of P losses. The DRP loss through surface runoff was most sensitive to the P extraction coefficient, and PP loss through surface runoff was mainly governed by the parameters of the Universal Soil Loss Equation. Tile flow DRP and PP losses were most sensitive to the plant P uptake distribution parameter and the soil detachability coefficient. The newly developed RZWQM2-P model is a capable tool for the simulation of P losses from an agricultural field, particularly for the tile-drained fields, however, it requires skilled and computationally demanding modelling

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.