Monitoring On Winter Wheat N, P Nutrition And Rice Pb Pollution Based On Canopy Multi (Hyper)-Spectrum

Nitrogen and Phosphorus are necessary elements for crops' growth. Nitrogen is important for the organic matter formation of crops. Organic matter that affects the chlorophyll synthesis composes organic parts of crops. The content of N is one of important indices for monitoring crops developmental information and the estimation of yields and quality. As Phosphorus of several kinds takes part in many metabolisms of plants, its significance is represented in crops' high yields and preserving varietals merits. The amounts of N fertilizer and P fertilizer application are enormous, however, farm fertilization need a quick, brief and satisfying way of diagnosing crops' N and P nutrition. The application of N fertilizer and P fertilizer is one of important cultivating measures for wheat widely planted in China. Experience of farmers' cultivating is the primary direction to the application of N fertilizer and P fertilizer, which will cause the unreasonable application of N fertilizer and P fertilizer. N and P nutrition could not be met because of the less application so that crops ' growth is restrained and the yields decrease and the merits decline; the excessive application will lead to crops' later maturation and waste of resources and pollution in fields such as soil hardening, water excessive nourishment. Traditional diagnosis of crops' nutrition including appearance diagnosis, chemical diagnosis and chlorophyll apparatus diagnosing depend greatly on experience and are affected by crop variety and developmental stage and the growth surroundings to some extent. The analyzing process is cockamamie because of great workload and causes damages to plants because of taking fresh samples. So the traditional means are limited in the agricultural extension of great scale and a new and more scientific method need be searched and developed to acquiring crops' growth information quickly and conveniently.Along with the progress of human beings' activities, especially the development of modern industry, the environmental pollution is increasingly serious and caused a series ofsocial effects of pollution. The heavy metal pollution in soil is more and more serious in China. Soil would fail in the ability of supplying nitrogen because the heavy metals in soil hold back the materialization of N. Plumbum seriously restrains the plants absorption of N, P, and K and decreases the efficiency of these nutrients' re-transportation in plants, which causes the level of matters and metabolism abnormal. Pb restrains the some enzymatic activity in the photosynthesis and the formation of chlorophyll, which decreases the efficiency of photosynthesis. Through the food chain Pb enters plants and animal bodies and ultimately endangers the human health. So eliminating the pollution of heavy metals from the headstreams is urgent affair. As well as the monitoring and diagnosis of N and P nutrition, monitoring heavy metals pollution needs a quick, brief and satisfying methodThe spectral reflectance of plant has obvious features. Different plants, the same plant of different growth stages, plants of normal growth, and plants invaded by the lake of elements or other factors of surroundings has different spectral reflectance. With the deepening of remote sensing application in agriculture, people have found that the spectral feature of plants is affected by its physiological characteristic, which decided the absorption, transmission and reflectance of light and the physiological characteristic of plants reflect the growing status of crops. Therefore, the difference of characteristics of spectrum can be used to monitor crops' growth status. On the basis of remote sensing, this analysis method need short time, need no numerous chemical analyses and would not damage plants. With a high level of automation, the process of crop spectral analysis is simple and can quickly acquire information.In this study multi-spectral radiometer (MSR-16R) was used to measure the spectrum of wheat canopy leaves managed by several levels of N, P fertilizer. The sensitive bands were searched from the analysis of wheat canopy spectrum, their transformation and agro-parameters, which conduces to find the relationship among the contents of N and P of crops, ultimate yields and canopy functional leaves' spectrum. All the work is done to ascertain the abundant or lack of N and P of crops, then to adopt relative agricultural measures to enhance crops' quality and increase ultimate yields. Furthermore, by building the crops' spectrum data base and a spectral estimation and monitoring model of crops' N and P nutrition, this study can supply gist and reference for remote sensing monitoring used in precision agriculture of great scale.