Research On Variable-rate Fertilizer Application Technology And Its Applying System In Precision Agriculture

In our country, there are many problems on application of chemical fertilizer especially Nitrogen, such as inefficient application, pollution to environment. In order to solve these problems, we must develop precision variable rate application.There are many achievements in research on control system of variable rate fertilizer applicator at home and abroad. In spite of good performance foreign system cost highly and is based on their country own conditions such as climate and soil so as to spread in our country inapplicable While systems developed by domestic researchers have several shortcomings such as machinery complexity, apt to be affected by physical characters of fertilizers and high cost price.The rapid development of remote sensing technology and its deeper application in precision agriculture lead to more development of its in variable rate application. The normalized difference vegetative index is one important coronal fabric index of crops, which has important affects on colony light distributing, light using and yield. It is discovered in beginning experiments of this research that the normalized difference vegetative index (NDVI) of winter wheat in its rising period and lifting period is correlative with yield remarkably so as to be used to direct variable rate application of fertilizers.In order to overcoming these shortcomings of domestic systems, this paper explores a kind of fertilizer technology that is based on NDVI to estimate potential yield and crop absorption conditions of Nitrogen to determine the most effective application amount of Nitrogen, and develops a real time automatic variable rate applicator which applies liquid fertilizers and bases on remote sensing technology and controlling of Programmed logic controller. This system uses without-damage testing technology, i.e. a kind of NDVI measure instrument based on optical principle, to real-timely detect growing conditions of winter wheat during their growing, and by which estimates potential yield of winter wheat, and make corresponding decisions on fertilizer to realize variable rate application.