engleski

The simulation model of winter wheat organic matter production

The computer model of winter wheat productivity was developed as a practical model for general analysis of production conditions and for yield prognosis at different climatic conditions in eastern Croatia by comparison of impact of meteorological changes, soil types and fertilization on growth, development and yield of winter wheat. The system elements included in model are plant (different plant organs), soil profile from top to root depth and environmental factors (temperature, light, water, nutrients). The model belongs to a class of environmentally (air temperature) driven empirical-mechanistic models with time increment. The program is composed of 5 hierarchy ordered modules: the main module for growth and development simulation, the modules for photosynthesis simulation, for emergence simulation, for soil moisture dynamic simulation and for the nutrient availability simulation. On the highest place in hierarchy are the PAR and temperature, followed by water and nutrients dynamics. Used meteorological daily data are as follows: air temperature, rainfall, cloudiness and the soil temperature. The simulation procedure: emergence (influenced by soil temperature and moisture), temperature coefficient (temperature influence on photosynthesis), leaf area index simulation, soil moisture dynamic simulation (influenced by rainfall), nutrient availability simulation (influenced by soil temperature and moisture), photosynthesis simulation (influenced by cloudiness and air temperature), organic matter allocation and plant organs mass increment, plant development stage simulation (influenced by aggregated air temperature). The simulation results are parameters of soil moisture, nutrients availability and growth and development dynamic. Considering used meteorological data, model is most sensitive to rainfall dynamics during vegetation and differences among the years, but the general conclusion is that use of average meteorological data (10 years) hide influence of arid or humid periods in some years on simulated yield.

simulation model ; winter wheat ; soil moisture ; precipitation ; temperature ; LAI

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