A Study On The Lodge Of Winter Wheat By Remote Sensing Monitor

The wheat is one of the major crops in our country,and the planting area where planting the winter wheat is accounted for 84~90 present of the total area. Shandong province has a long history of agriculture and is one of major wheat producing areas,has the highest land rate in the country and high reclamation rate. In the cultivation process,the wheat is vulnerable threatened by stripe rust,pest disasters,lodging,drought and water-logging,freezing,etc. But in resent years,the yield of wheat keeps going up. The water,fertilizer,height,pest and disease are no any more to be the obstacles for high yield of wheat,but the lodging of wheat become to the obstacle. The remote sensing research monitoring for lodging wheat has an important research value for the agricultural department,which guide the agricultural production (cultivation and management, harvesting machinery arrangements, etc), disaster assessment after the wheat lodged.The object of this study is that we get the spectral reflectivity data through the spectrometer monitor the area where the wheat was lodged,set up a method that can dynamic monitor the lodging wheat with the right time and the remote sensing images of the target area. We proceeded from reality,manual simulation the situation of wheat lodging,used the spectrometer to monitor the spectral reflectivity data of lodging wheat,summarized the change characters with the remote sensing image data,provided an important basis to dynamic monitor.In this paper,we discussed the time and severity of wheat lodging. We simulated the situation of wheat lodging,measure the spectral reflectivity data of the wheat which lodged in different time and different severity,and analyzed the data with the ViewSpecPro soft. We analyzed the figure of wheat spectral reflectivity curve,then summarized the change characters and impact factors of spectral reflectivity value from the change of plant components,time,chlorophyll content. We researched the change of first derivative and vegetation index of the lodging wheat,summarized the change characters of spectral reflectivity value of lodging wheat. We chose the PRISM data and the AVNIR-2 data which were got by the ALOS satellite to be our data source through compared with several remote sensing data. We located the target area with the ALOS satellite image data,analyzed the change characters of remote sensing image information and compared the change information of the lodging wheat in the remote sensing image with the spectral reflectivity data,summarized the change characters of spectral reflectivity data and remote sensing image information when wheat lodged.From that analyzed the spectral reflectivity data and remote sensing image data,we summarized the change characters of spectral reflectivity value and the pixel value of remote sensing image after the wheat lodged:(1)The spectral reflectivity value was increased in the visible band and near-infrared band when the wheat lodged in filling stage,and the spectral reflectivity value was increased when the lodging angle increased;the spectral reflectivity value of wheat which lodged in early filling stage had the same change characters in the same time which had the same lodging angle and lodged in middle filling stage;when the filling stage ended and the maturity stage began,the spectral reflectivity value of wheat which was lodged in the later filling stage was greater than the value of wheat which were lodged in early or middle filling stage;the spectral reflectivity value were changed over time whether the wheat was lodged or not lodged and had basically same change characters,the spectral reflectivity value had no change in the visible band and frequency decreased in the near-infrared band when the wheat was in the filling stage;the difference is that the spectral reflectivity value decreased steadily with the normal wheat but decreased smaller and smaller with the lodging wheat in the near-infrared band;the first derivative of the wheat spectral reflectivity data were more pronounced the change characters of spectral reflectivity curve after the wheat lodged.(2)The information of remote sensing image show that the change characters of lodging wheat image pixel value were consistent with the normal wheat,the value of red band was the lowest and the value of near- near-infrared band was the highest;the image pixel value were increased in both of red and near-infrared bands in the target area where the wheat was lodged,the change was obvious in near-infrared band;the change of image pixel value was contact with the lodging angle in different target area,the image pixel value were increased when the lodging angle increased.(3)The spectral reflectivity value has the same change characters with the pixel value of remote sensing image,they were both increased in red and near-infrared bands,the value-added in near-infrared band were both greater than in red band,the rate of increase were directly proportional to the lodging angle,the spectral reflectivity value and pixel value of remote sensing image were increased when the lodging angle increased. In this paper,we use the remote sensing image which has a high spatial resolution. Then analyze the pixel value of remote sensing image information of the target area in location,compare the spectral reflectivity value with the pixel value of remote sensing image where the wheat was lodged. The study found that we can use the change characters of the pixel value of remote sensing image of target area to dynamic monitor the time of wheat lodged and the degree of affected,predict the production loss,provide correct information for the agriculture department quickly. This paper provide strong basis for that it can be carried out come true that the remote sensing dynamic monitor the area where the wheat lodged.