Monitoring Winter Wheat Population Dynamics Using an Active Crop Sensor
WU Jun-hua1, YUE Shan-chao1, HOU Peng1, MENG Qing-feng1, CUI Zhen-ling1, LI Fei1, 2*, CHEN Xin-ping1
1. College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China 2. College of Ecology and Environmental Science, Inner Mongolia Agricultural University, Huhhot 010019, China
Abstract：Tiller density plays an important role in attaining optimum grain yield and applying topdressing N in winter wheat. However, the traditional approach based on determining tiller density is time-consuming and labor-intensive. As technology advances, remote sensing might provide an opportunity in eliminating this7 problem. In the present paper, an N rate experiment and a variety-seeding and sowing dates experiment were conducted in Quzhou County, Hebei Province in 2008/2009 to develop the models to predict the amount of winter wheat tillers. Positive linear relationships between vegetation indices and tillers were observed across growth stages (R2, 0.25～0.64 for NDVI; 0.26～0.65 for RVI). The validation results indicated that the prediction using NDVI had the higher coefficient of determination (R2, 0.54～0.64), the lower root mean square error (RMSE, 260～350 tillers m-2) and relative error (RE, 16.3%～23.0%) at early growth stages of winter wheat. We conclude that active GreenSeeker sensor is a promising tool for timely monitoring of winter wheat tiller density.
