A Fundamental Research of Remote Sensing Application on Precision Fertigation

To meet the urgent need for precision agricultural management, the study integrated 'area information' from remote sensing with the 'spot information' of the ground. A forecast study of agricultural precision variables, including fertigation and agricultural yield was conducted on scales of county, farm and paddy field. Based on spectral data and crop growth model assimilation, a method for precision variable-rate fertilization and benefit evaluation of crop was proposed. A winter wheat growth monitoring and yield forecast model based on hyperspectral data remote monitoring and crop growth model was established. The study established a remote monitoring model of winter wheat grain protein based on crop nitrogen translocation and water stress, providing a scientific basis for wheat classification and acquisition, processing and value-adding. Through measures such as providing thematic maps and remote sensing monitoring reports, the research has enhanced the application of spatial information technology in crop production layout, precise fertilization and decision-making of variable irrigation. The practice of the research has been promoted in provinces like Heilongjiang, Jilin, Hebei, Henan, Shandong, Jiangsu, Hunan and other major grain-producing areas in China, as well as in Beijing.

(1) A remote monitoring technology system for precision nutrient management was established to achieve a real-time diagnosis and variable control of crop nutrients.

A diagnostic model based on crop nitrogen/pigment ratio was established, which was combined with crop growth model and crop planting expert system to achieve a real-time nutrient diagnosis, fertilization decision-making and variable control in field and area scales. Incorporating with the spatial variation characteristics and mapping of soil nutrients, a technology system for monitoring and evaluating the spatial and temporal changes of farmland soil for agricultural sustainable development was built. The quantitative precision strategy for organic fertilizer, nitrogen, phosphorus, potassium and other nutrients management in agricultural land was formulated and fertilization zoning on agricultural land in county scale was conducted.

(2) A remote monitoring technology system for precision management of farmland moisture was established, and a remote sensing model for drought monitoring and loss assessment system were also proposed.

       The correlations between crop growth, yield, grain protein content, soil and crop moisture were clarified through water stress experiment. A remote sensing model for crop yield and quality monitoring based on water stress was thus established to guide the decision of variable rate irrigation. A remote sensing model of farmland drought monitoring and a disaster loss assessment system were constructed, providing technical support for regional drought relief.