Simulatingin situammonia volatilization losses in the North China Plain using a dynamic soil‐crop model

Abstract

Ammonia (NH 3 ) volatilization is an important N loss pathway in intensive agriculture of the North China Plain (NCP). Simulation models can help to assess complex N and water processes of agricultural soil-crop systems. Four variations (Var) of a sub-module for the deterministic, process-based HERMES model were implemented ranging from simple empirical functions (Var 3 and 4) to process-oriented approaches (Var 1 and 2) including the main processes of NH 3 volatilization, urea hydrolysis, nitrification from ammonium-based N fertilizer, and changes in soil solution pH. Ammonia volatilization, plant growth, and changes in ammonium and nitrate pools in the soil over several winter wheat-summer maize double-crop rotations at three locations in the NCP were simulated. Results were calibrated with two data sets (Dongbeiwang 1, Shunyi) and validated using two data sets (Dongbeiwang 2, Quzhou). They showed that the ammonia volatilization sub-module of the HERMES model worked well under the climatic and soil conditions of N China. Although the simpler equations, Var 3 and 4, showed lower deviations to observed volatilization across all sites and treatments with a mean absolute error (MAE) of 1.8 and 1.4 in % of applied N, respectively, compared to process-oriented approaches, Var 1 and 2, with a MAE of 2.2 and 1.9 in % of applied N, respectively. Environmental conditions were reflected better by the process-oriented approaches. Generally, simulation results were satisfying but simulated changes in topsoil pH need further verification with measurements.

A new urease-inhibiting formulation decreases ammonia volatilization and improves maize nitrogen utilization in North China Plain

“…The calibrated DTM has been shown to be well-suited for NH 3 measurements in multi-plot trials, and has been widely used around the world404142. Briefly, four chambers (total surface area approx.…”

“…A calibrated Dräger-Tube Method (DTM) was adopted to measure NH 3 loss, which is a dynamic chamber technique adjusted to actual meteorological conditions (e.g., temperature, wind speed) by an empirical calibration equation 8 . The calibrated DTM has been shown to be well-suited for NH 3 measurements in multi-plot trials, and has been widely used around the world 40 41 42 . Briefly, four chambers (total surface area approx.…”

Quantifying nitrogen loss and water use via regionalization and multiple‐year scenario simulations in the North China Plain

“…Therefore, nitrogen uptake can be limited under dry conditions. Selected model parameters and model applications within the same study region can be found in Michalczyk et al (2014Michalczyk et al ( , 2016. For regional modeling in the current study, HERMES was interfaced with GIS data via linking (Hartkamp et al, 1999).…”

“…A summer maize season (beginning/mid of June to end of September) prior to the simulation period was used for initialization. The model was set up with plant parameters based on a calibration and validation across winter wheat-summer maize crop seasons of experimental field data in previous studies in Quzhou County (Michalczyk et al, 2014(Michalczyk et al, , 2016. Initial values for soil water and mineral N (N min ) content were estimated based on experiments on farmers' fields.…”

“…Additionally, a model‐based, soil type specific, continuous 31‐year simulation study on N fertilizer recommendation and water management on county scale using multiple data sources is an innovative approach to identify best management practice for a winter wheat–summer maize double‐cropping system in the NCP. In order to perform such an integrative approach, the HERMES model was used in the current study ( Kersebaum and Beblik , 2001), which has already widely been tested in Europe ( Herrmann et al., 2005; Palosuo et al., 2011; Rötter et al., 2012; Hlavinka et al., 2014; Kollas et al., 2015; Salo et al., 2016; Yin et al., 2017), Canada ( Kersebaum et al., 2008), the USA ( Malone et al., 2017), and China ( Michalczyk et al., 2014, 2016), as it can operate with minimal data inputs and simulates water and N dynamics satisfactorily.…”