Developing A Rice Precise Cultivation Management Model For Different Planting Methods

Developing a model is very meaningful for rice precise cultivation management across different planting method,which could improve cultivation management in precision,quantification and digitalization.The existing research data and expert knowledge were used as the basis of modeling.The system analysis principle and mathematical modeling technology were used in the modeling process.The quantitative relationship between different planting methods,ecological environment,cultivar types,and cultivation management were analyzed and refined,and the model parameter algorithms were integrated.Aiming at different planting methods and cultivars,the suitable sowing and transplanting dates,planting density and nitrogen fertilizer management models were developed.The models will be validated by independent dataset collected from literatures,meanwhile the field experiments’ data were used to test the effect of the planting dates designed by models.this new rice model system can accurately design the suitable planting dates,planting density and nitrogen fertilizer strategy for farmers in different rice production zones and cultivars.This work can act as a technical approach to achieve high yield and efficiency for rice precision farming.Sowing and transplanting dates of rice are currently susceptible to climate warming.Previous studies have suggested that an effective and simple way to mitigate the effects of global warming is to adjust sowing dates.In this study,planting method,fertilizer and water management,photoperiod,day length,solar altitude angle,latitude,and cultivar factors were added in the simulation model developed by Feng et al.A model was developed to design the suitable planting date for diverse varieties across different planting methods.The models will be validated by independent dataset collected from literatures.Field experiments were conducted in three ecological sites to further validate the practices designed by model.The model precisely designed suitable sowing and transplanting dates under most scenarios with RMSE,R2 and EF.Compared with local experts’ practices,the planting dates designed by this model system showed a 0.8%-5.5%increase in grain yield and higher precise and adaptability in the field experiments.Planting density is an important factor affecting tillering in rice.The optimal population structure should be designed to achieve high yield.In this study,the related factors that affect the seeding rate were analyzed systematically,and the seeding rate algorithm was developed before sowing rice nursery.The planting density model was developed by integrating the "n-3" law of synchronously emerging of tiller with leaf,LAImax algorithm and logistic equation of tiller number.Rice cultivars are classified by European distance.In this study,the cultivar,planting method and nursery were added to the planting density model.Data from literatures and field experiments were used to validate the planting density model under different scenarios.The verification results showed that the model accurately designed suitable planting density demonstrated by R2,RMSE,P（t）and EF.Compared with local experts’ practices,the planting dates designed by this model system showed a 0.66%～17.73%increase in grain yield and higher precise and adaptability in the field experiments.Scientific and reasonable N fertilizer management is beneficial to reducing fertilizers,cutting costs,and reducing pollution.Based on the principle of comprehensive balance of farmland nutrients,this study analyzed the factors affecting nitrogen utilization systematically.In this study,the advantages of ratio algorithm and coefficient correction algorithm are integrated to optimize the algorithm of nitrogen use efficiency.The nitrogen fertilizer management model was developed by integrating the soil water heat carbon and nitrogen simulation model,modified double exponential model and soil modifying coefficient model.The field experiments’ data were used to test the effect of the nitrogen fertilizer practice designed by the model.Compared with local experts’ practices,the nitrogen fertilizer practice designed by the model showed a 0.15%～18.98%increase in grain yield and higher precise and adaptability in the field experiments.