Diagnosis Of N Nutrient Status Of Crop Using Digital Image Processing Technique

In this thesis, the experiment was conducted in Luancheng suburb where winter wheat and summer corn are planted. The possibility of using digital image analysis method for plant N status diagnosis was studied, and the standard method of digital image acquisition and saving was established. In addition, aerial true color and infra-red images analysis method, which combined with soil and plant N rapid test, was studied for N recommendation in a large scale.And the color parameter indexes of wheat canopy images at effect of water and fertility was studied. The main results are as follows:1,The digital image processing technique could be used of N status detection of winter wheat. The results show significant inverse relationships between greenness intensity and canopy total N, SPAD readings, plant nitrate concentration and nitrate N content in 0⁹0 cm soil at jointing stage and booting stage. Compared with other seven green index of plant canopy, the normalized greenness intensity G/(R+G+B) was much better because of its better correlations with canopy total N, SPAD readings, plant nitrate concentration and soil N supply. In booting stage,the correlations are not so significant as those in jointing stage. The jointing stage is crucial period with G/(R+G+B) as the index for the N nitrogen diagnosis using digital image processing technique.In the 6-leaf stage, color parameter indexes of B/(R+G+B), G/B, R/B, B/L are significantly linearly correlated with N application level, leaf SPAD, stem sap nitrate concentration, plant total N content and nitrate N content in 0⁹0 cm soil (P<0.01). And B/(R+G+B) presents most significant correlation, and B/L is next to it. In 10-leaf stage, the correlations are not so significant as those in 6-leaf stage. The results suggest that it is feasible to use digital image processing technique to diagnose N nutrient statues of summer corn. The 6-leaf stage is crucial period with B/(R+G+B) as the index for the N nitrogen diagnosis using digital image processing technique.2,For taking digital image of wheat canopy in field, the angle between digital camera and ground could be 30～60°.The G/(R+G+B) from three kinds of cameras have certain relevance and its pixels.3,Field digital image analysis method combined with soil and plant rapid test could be used for N fertilization recommendation. According to the winter wheat jointing stage nitrate content .According to this equation can on winter wheat jointing stage to recommend fertilization. When deficit of N supply,ertilization recommendation is 100¹50 kg ( N )·hm^-2 , when N supply , ertilization recommendation is 50¹00 kg(N)·hm^-2,When excessive N supply,ertilization recommendation is 0⁵0kg(N)·hm^-2。Field digital image analysis method combined with soil and plant rapid test could be used for N fertilization recommendation. According to summer corn 6 leaf stage nitrate in fertilizer, According to this equation of summer corn 6 leaf stage to recommend fertilization. When deficit of N supply,ertilization recommendation is 230kg(N)·hm^-2,when N supply,ertilization recommendation is 180²30 kg(N)·hm^-2,When excessive N supply,ertilization recommendation is 150¹80kg(N)·hm^-2。4,In couple effect of water and fertility, on the digital image colour of income data data analysis parameters.The result is that diagnosis of N nutrient status of wheat using digital imageprocessing technique in couple effect of water and fertility. And the relationships between color parameter indexes of wheat canopy images and N application level, wheat yield were determined. The results show that color parameter indexes are significantly linearly correlated with N application level and wheat yield. In couple effect of water and fertility color parameter indexes was little different at the different water. Namely the variety that measures along with N application level, under the different humidity condition of the color parameter has certain regulation.When amount of nitrogen was low, the function of humidity was negative when the function of humidity was positive, while high N application level.