基于无人机遥感影像的冬小麦氮素监测

精准氮素管理是一项提高作物氮肥利用效率的有效策略,利用无人机遥感技术精确估测小麦氮素状况是必要的。试验在山东省乐陵市科技小院实验基地进行,利用八旋翼无人机搭载Mini-MCA多光谱相机于2016年获取冬小麦4个关键生育时期(返青期、拔节期、孕穗期、扬花期)冠层多光谱数据,同步获取地上部植株样品并测定其生物量、吸氮量、氮营养指数,及成熟期籽粒产量,根据各关键生育期与全生育期分别构建植被指数与农学参数回归分析模型,评估基于无人机遥感影像的冬小麦氮素营养诊断潜力。结果表明:基于无人机遥感影像能够较好地估测冬小麦氮素指标(R2为0.45~0.96),决定系数随着生育期推移而逐渐增大。拔节期、孕穗期和扬花期估产效果接近且具有很好的估测能力,扬花期DATT幂函数模型对小麦氮营养指数的解释能力最强(R2=0.95)。因此,以多旋翼无人机为平台同步搭载多光谱相机对冬小麦有较好的氮素诊断潜力,可利用估测结果指导精准氮肥管理。

Nitrogen Monitoring of Winter Wheat Based on Unmanned Aerial Vehicle Remote Sensing Image

Accurate nitrogen (N) management is a promising strategy to improve crop N use efficiency. It is important to accurately estimate the state of wheat nitrogen by unmanned aerial vehicle (UAV) remote sensing. The experiment was arranged in science and technology yard base in Laoling City, Shandong Province. The eight-rotor UAV was used to carry a Mini-MCA multispectral camera and collect the wheat canopy spectral data about four key stages (returning green stage, elongation stage, booting stage and flowering stage) of growth and development in 2016. Meanwhile, winter wheat samples of biomass, nitrogen uptake and nitrogen nutrient index were collected and measured synchronously. Grain yield was measured in mature stage. In critical stages and whole stage of different vegetation, indexes and agronomy parameters regression analysis models were established to assess winter wheat nitrogen nutrition diagnostic potential based on UAV remote sensing image. The results showed that it had better estimation of winter wheat nitrogen index (R2 was 0.45~0.96) based on UAV remote sensing image and the decision coefficient was gradually increased with the elapse of growth period. And those in elongation stage, booting stage and flowering stage were similar and had better ability for yield estimation. DATT power function model was the most powerful to explain the wheat nitrogen nutrition index (R2 was 0.95) in flowering stage. Therefore, the platform for multiple UAV rotorcraft synchronization carrying multi-spectral camera had better nitrogen diagnosis potential for winter wheat and it can be used to guide the precise nitrogen fertilizer management.