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Effect of nitrogen supply on maize yield. II. Field and model analysis
- Muchow, R.C., Sinclair, T.R.
- Agronomy journal 1995 v.87 no.4 pp. 642-648
- Zea mays, growth models, mathematical models, simulation models, crop yield, nitrogen fertilizers, soil fertility, nitrogen content, nutrient uptake, grains, Northern Territory
- Experiments investigating the yield response of maize (Zea mays L.) to applications of fertilizer N are generally analyzed empirically. While the nature Of the yield response can be characterized, information on the effects of various components influencing the soil and crop N budgets are unresolved. The objective of this study was to examine the results of a series Of N fertility experiments with the aid of a mechanistically based crop model. The experiments resulted in grain yields ranging from 99 to 1102 g m-2, and these yields were well simulated by the model (r2 = 0.97). Under high fertility conditions, temperature and solar radiation interception explained the variation in yield among environments. Under low fertility conditions, mineralization of soil organic N was especially important in explaining yield variations among environments. Management practices preceding the experimental crops were hypothesized to have large effects on the N availability in the soil, and consequently influence observed and simulated yields. Sensitivity tests confirmed the importance of defining the initial soil organic N levels in simulating crop growth and yield when there is little or no applied N fertilizer.