Research On Knowledge Model For Barley Cultivation Management

Based on the relationship between growth and environmental factors in barley, the models were constructed systematically to select the barley area and crop the barley,the models were on the design, and the models were controlled dynamicly .The validations were made in the different genotypes, sowing dates and N rates.In accordance with the decision points of the climate and the characteristics of the barley, the models were constructed to select the barley area and crop the barley.The models were with special consideration of the effects of temperature , planting patterns and variety.Based on physiological development time, the models were constructed systematically to control dynamicly . The model includes the bearing process model of barley ,the model of growth target ,the model of nutrient target and the model of controlling fertiliser nitrogen.By calculating the physical development time ( PDT )of the apical and phenological development stages in barley, the bearing process model of barley can get the forecast date of the developmental stage. The validation showed that the absolute prediction errors for development stages were generally less than 6 d, and the root mean square errors (RMSEs) were 0.6 ~ 2.9 d in Yangzhou in 2007~2009 years. The models reflected an enhancement in mechanism, explanation and prediction.Based on the experimental observation and quantitative analysis, the model of leaf area index (LAI) in barley was constructed by two nonlinear equations, with the maximal value of per plant leaf area as genetic parameter. The model represented the influence of nitrogen and temperature on leaf growth, and solved how two nonlinear equations joined. The validating results showed that the absolute prediction error ranges for LAI were 0.007~1.468, and the RMSEs were 0.229～0.718. The absolute prediction error ranges for dry matter weight were 0.002～0.264 kg?m-2, and the RMSEs were 0.019～0.143 kg?m-2.Some assumptions were made during the nitrogen accumulation process in barley as following. ( 1) Before anthesis, the nitrogen absorbed from soil was distributed to various organs according to certain proportions. (2) After anthesis, the absorbed nitrogen from the soils all was used for the grain protein formation. (3) After anthesis, the nitrogen stored in leaf, stem and spike starts to remobilize to the grain. Based on these assumptions, the dynamic models of nitrogen accumulation were constructed by relationship between dry matter accumulation and the nitrogen accumulation. In the model, the complex process of nitrogen remobilization after anthesis was simplified. The validating results showed that the absolute prediction error ranges for nitrogen accumulation in barley were 0.030～3.300 g?m-2and the RMSEs were 0.645～1.568 g?m-2.In the nitrogen absorption and remobilization model after anthesis, the relationship between leaf nitrogen remobilization and the leaf area index were described with exponential functions. Based on physiological development time,the model to predict 1000- grain weight was constructed.