Spatial and Temporal Variability of Spring Barley Yield and Quality Quantified by Crop Simulation Model

Nitrogen fertilization is the most critical agronomic input affecting barley production and farm profitability. The strict quality requirements for malting barley are challenging to achieve for farmers. In addition, soil variability and weather conditions can affect barley yield and quality. Thus, the objectives of this study are to (a) quantify the variability of soil properties, and (b) use spatial data in a crop simulation model, quantifying the impacts of climate-soil interactions on the barley crop yield and grain quality. Based on historical yield maps, a commercial field was divided into different yield stability zone levels. The Decision Support System for Agrotechnology Transfer model was used to evaluate soil and crop spatial data. The bulk density affected the soil water content and soil mineral N and hence the crop-growing conditions in each yield stability zone. Our observed and simulated results showed that 120 kg N ha(-1) is the optimal rate to increase grain yield while still keeping within the grain N% requirements for malting quality. This study shows the great value of integrating crop modeling with on-farm experimental data for improving understanding of the factors which affect site-specific N fertilization of barley.