A Study In Normalized Difference Vegetation Index Monitoring And Optimization Of Nitrogen Application With Different Levels Of Water And Nitrogen

The average nitrogen loss rate of wheat is between14%-55%. Therefore, in order to scientific and reasonable management of nitrogen, increasing nitrogen utilization efficiency, real time to understand and master the different growth stages of Winter Wheat in the important nutrition element foot or missing and agricultural information monitoring is very important.The trial begin at Xinji experiment station of Hebei in2007.The design of experiment have3irrigation treatments, under each of irrigation have4nitrogen levels. The use of hand-held Greenseeker active spectrometer monitor winter wheat on important growth period, study on the relationship of between winter wheat nitrogen nutrition and value of NDVI, according to the established model, and to validate the model, the different water and nitrogen content on the winter wheat photosynthetic rate, the ground biomass and plant total nitrogen content and affecting yield. The main results are as follows:1、The NDVI values of Reduction of water33%and traditional irrigation treatment were higher than the reduction of water67%in2009-2010years during growth period of winter wheat, including two seasons at jointing stage the average NDVI value of reduction of water33%treatment is higher maximum than reduction of water67%, average increased by4.2%; traditional irrigation treatment NDVI value is significantly higher than reduction of water67%at booting stage of2009years Winter Wheat, increased by6.7%.2009-2010two seasons at jointing stage, the average NDVI value of traditional nitrogen treatment is decreasing nitrogen in reducing nitrogen22%and44%respectively significantly higher7.9%and11.8%; In2009the average NDVI value of the booting stage of traditional nitrogen treatment and reducing nitrogen22%were more reducing nitrogen44%was higher than9.8%and6.2%.2、Reduction of water33%treatment of photosynthetic rate than reduction of water67%and traditional irrigation significantly increased5.5%and6.3%respectively in2009flowering stage, reduction of water33%and traditional irrigation on photosynthetic rate were higher than the water reducing67%increased7.4%and6.9%in2010flowering stage.Traditional irrigation level:2009-2010two seasons at filling stage between of traditional nitrogen and nitrogen reduction of22%has no significant difference, between of reducing nitrogen44%and no nitrogen has also no significant difference, but between of the two groups treatment before and after has significant difference.3、Determination of2009-2010year growth period of Wheat Strains and the nitrogen content of the grain, the results showed that:under the same irrigation level,3nitrogen treatment were significantly higher than that of no nitrogen, in the final grain nitrogen to nitrogen210kg/hm2is highest.The same level of nitrogen fertilization,2009-2010years the growth period of3irrigation treatments were not significantly difference between levels, but increased irrigation water and flowering water on booting two during grain filling stage of wheat3nitrogen treatment average Wheat Strains of nitrogen content increased by12.1%and14.8%, and the harvest period average grain nitrogen volume were increased by8.0%and6.1%.4、Under the same irrigation level,2009-2010years measured in growth period of excessive nitrogen (270Kg/hm2) on winter wheat aboveground biomass increased significantly; the two season harvest3irrigation levels under the traditional nitrogen (270kg/hm2) treatment of average aboveground biomass has2%drop than nitrogen reduction22%(210kg/hm2).The same level of nitrogen fertilization,2009grain filling period of traditional nitrogen levels than traditional irrigation water reducing67%increased25.9%,44%levels of reducing nitrogen water reducing33%and traditional irrigation treatments were more water reducing67%significantly increased33.3%and37.9%,2010although rise somewhat, but not significantly improved.5、Under the same irrigation level, the amount of nitrogen reached270kg/hm2was210kg/hm2with an average of3.2%drops. The same level of nitrogen fertilization, irrigation water and increase the flowering booting water+grouting water respectively to nitrogen application amount was210kg/hm2and150kg/hm2increase maximum, and rose water+flowering underwater N210kg/hm2(I2N210) combination of winter wheat grain yield the highest, thus increasing irrigation can properly reduce the maximum grain yield nitrogen fertilizer.6、2009-2010two during wheat growth period amount of nitrogen fertilizer and NDVI value and grain yield the relationship between respectively can use linear equation and curve fitting two (P<0.01,R2=0.3698), determines the maximum theoretical yield is7985kg/hm2, corresponding to the quantity of nitrogen fertilizer is217kg/hm2; suggested that the elongation stage and booting stage of winter wheat nitrogen nutrition diagnosis and as an important period of nitrogen nutrition diagnosis.7、Winter wheat nitrogen diagnosis based on NDVI model identifies the jointing stage and flowering stage critical NDVI values were0.5969,0.7561, if the actual value is below the critical value, that the lack of nitrogen in winter wheat, and have a significant impact on yield. The3irrigation gradient in winter wheat under nitrogen diagnosis model identifies the jointing stage and flowering stage critical NDVI values were:0.5974,0.6174,0.6263and0.7729,0.7746,0.7631,33%of which water irrigation in jointing stage under the recommended nitrogen with water67%and traditional irrigation significantly lower44.4%and28.7%.