title: The design and implementation of the leaf area index sensor.
abstract: The quick and accurate acquisition of crop growth parameters on a large scale is important for agricultural management and food security. The combination of photographic and wireless sensor network (WSN) techniques can be used to collect agricultural information, such as leaf area index (LAI), over long distances and in real time. Such acquisition not only provides farmers with photographs of crops and suggestions for farmland management, but also the collected quantitative parameters, such as LAI, can be used to support large scale research in ecology, hydrology, remote sensing, etc. The present research developed a Leaf Area Index Sensor (LAIS) to continuously monitor the growth of crops in several sampling points, and applied 3G/WIFI communication technology to remotely collect (and remotely setup and upgrade) crop photos in real-time. Then the crop photos are automatically processed and LAI is estimated based on the improved leaf area index of Lang and Xiang (LAILX) algorithm in LAIS. The research also constructed a database of images and other information relating to crop management. The leaf length and width method (LAILLW) can accurately measure LAI through direct field harvest. The LAIS has been tested in several exemplary applications, and validation with LAI from LAILLW. The LAI acquired by LAIS had been proved reliable.
authors.affiliation: College of Global Change and Earth System Science, Beijing Normal University, No.19, XinJieKou Wai Street, HaiDian District, Beijing 100875, China. lixh@bnu.edu.cn.|Joint Center for Global Change Studies, Beijing 100875, China. lixh@bnu.edu.cn.|State Key Laboratory of Remote Sensing Science, Jointly Sponsored by the Institute of Remote Sensing and Digital Earth of Chinese Academy of Sciences and Beijing Normal University, No. 20 Nouth, DaTun Road, ChaoYang District, Beijing 100101, China. lixh@bnu.edu.cn.
authors.forename: Xiuhong
authors.initials: X
authors.lastname: Li
authors.affiliation: College of Global Change and Earth System Science, Beijing Normal University, No.19, XinJieKou Wai Street, HaiDian District, Beijing 100875, China. toliuqiang@bnu.edu.cn.|Joint Center for Global Change Studies, Beijing 100875, China. toliuqiang@bnu.edu.cn.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Chinese Research Academy of Environment Sciences, No.8, DaYangFang, AnWai, ChaoYang District, Beijing 100012, China. yangrj@craes.org.cn.
authors.forename: Rongjin
authors.initials: R
authors.lastname: Yang
authors.affiliation: College of Global Change and Earth System Science, Beijing Normal University, No.19, XinJieKou Wai Street, HaiDian District, Beijing 100875, China. hjzhang89@126.com.
authors.forename: Haijing
authors.initials: H
authors.lastname: Zhang
authors.affiliation: College of Global Change and Earth System Science, Beijing Normal University, No.19, XinJieKou Wai Street, HaiDian District, Beijing 100875, China. llbsh123@163.com.
authors.forename: Jialin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: College of Global Change and Earth System Science, Beijing Normal University, No.19, XinJieKou Wai Street, HaiDian District, Beijing 100875, China. celcugb@163.com.
authors.forename: Erli
authors.initials: E
authors.lastname: Cai
mesh_terms: D018556:Crops, Agricultural; D017753:Ecosystem; D004784:Environmental Monitoring; D018515:Plant Leaves / Q000033:anatomy & histology* / Q000254:growth & development; D058998:Remote Sensing Technology; D059015:Wireless Technology