Estimation of winter wheat nitrogen stress using the CERES crop model
2001
Zalud, Z. | Pokorny, E. | (Mendelova Zemedelska a Lesnicka Univ., Brno (Czech Republic)) | Stralkova, R. | Podesvova, J.
Deterministic crop growth CERES-Wheat model was used to estimate the relation between the nitrogen stress and grain yield of winter wheat (Samanta variety). Climatological, pedological, physiological and management data measured during three year experiment (1996-1999) form the database which was used for calibration of the crop model. Its evaluation was done by grain yield, length of growing season and total amount of nitrogen in biomass. The nitrogen stress for five growth stages was modelled for two treatments differing in the previous growth crop (treatment A with spring barley, treatment B with alfalfa). These stress values were correlated with index of production (yield) potential Z, which is computed as a ratio between potential and stressed (nutrient and water limited) yield. Its lowest value reached 72.3 % in 1997-1998 (treatment A), the highest value was 93.4 % in 1998-1999 (treatment B). Their statistic response (the coefficients of determinance varied between 0.6007 to 0.9686) describes the size of nitrogen stress in respect to grain yield. The dividing of growth period to five stages enables to estimate the time of nitrogen stress occurrence.
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