基于光谱探测的小麦精准追肥机设计与试验

为了实现小麦生长过程中的实时变量追肥,使用近地光谱探测技术,设计了大田实时变量追肥机。追肥光谱监测系统实时获取作物冠层归一化植被指数,结合追肥策略计算出当前的目标施肥量,采用测速和测距法反馈肥料流量信息,并根据追肥机实际行进速度,实时调整追肥量,实现精准变量追肥。试验结果表明,田间小麦长势存在空间差异性,冠层的归一化植被指数可以解析此差异性;追肥机追肥控制精度达到90%以上,可以满足精准追肥的要求;变量追肥比定量均匀追肥增施氮肥28 kg/hm2左右。

Design and Experiment of Variable Rate Fertilizer Applicator Based on Crop Canopy Spectral Reflectance

This variable rate fertilizer applicator based on crop canopy real-time spectral information (normalized differential vegetation index) was designed to realize real-time variable fertilization in the field. By accessing the real-time normalized differential vegetation index via six spectrum sensors, and the speed of the tractor via velocity measuring system, the expert system of applicator could ascertain the rate of fertilizer based on the fertilization algorithm. The expert system of applicator adjusted fertilizing to attain precision fertilization according to the feedback fertilizer flow. The system design, working principle and experiments of the applicator were explained. The experimental results indicated that the inherent spatial variability of wheat growth within a field was considerable, and wheat canopy normalized differential vegetation index could resolve this difference. The fertilization precision could reach above 90%, and variable rate fertilizer applied more nitrogen (28kg/hm2) than quantitative fertilization. Therefore, the control system of the rate fertilizer applicator was favorable, and the applicator could achieve precise fertilization in the precision agriculture.