As a quick demonstration to estimate crop yield levels at regional-scale with various management assumptions, this post describes how crop systems models can be used to assess yield gap of rainfed maize due to the limited supply of soil nitrogen. This methodology can help researchers to find what is the most critical factor that limits crop yield productivity in a given environment condition and how to address the constraint.
Crop systems models are often used to assess the potential yield of crops with or without certain types of constraints. As a quick and rough demonstration, this simulation result describes potential yields of rainfed maize with and without soil nitrogen constraint simulated for 50 years. The long-term average yield difference due to the soil nitrogen constraint was considered as the rainfed maize yield gap, assuming the potential and actual yield levels is defined by nitrogen availability in soils (In reality, there are many more types of constraints to be considered, such as soil nutrients other than nitrogen, pest/disease/weed, and variability of water; This post describes a simple proof-of-concept). The simulation was conducted at 5 arc-minute grids and aggregated over time (50-year average) and space (HCADMIN v1.0).
- Model: CERES-Maize 4.5-beta
- Crop: Maize
- Cultivar: Medium maturity generic (990002)
- Weather: CRU-Mashup v1.0.2
- Soil: HC.SOL v1.0
- Years: 1955-2004
- Reporting unit: HCADMIN v1.0
https://hc.box.net/shared/nklxay3bsx (Shapefile format)