Al-Gaadi Khalid A, Hassaballa Abdalhaleem A, Tola ElKamil, Kayad Ahmed G, Madugundu Rangaswamy, Alblewi Bander, Assiri Fahad
Precision Agriculture Research Chair (PARC), King Saud University, Riyadh, Saudi Arabia.
Department of Agricultural Engineering, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia.
PLoS One. 2016 Sep 9;11(9):e0162219. doi: 10.1371/journal.pone.0162219. eCollection 2016.
Crop growth and yield monitoring over agricultural fields is an essential procedure for food security and agricultural economic return prediction. The advances in remote sensing have enhanced the process of monitoring the development of agricultural crops and estimating their yields. Therefore, remote sensing and GIS techniques were employed, in this study, to predict potato tuber crop yield on three 30 ha center pivot irrigated fields in an agricultural scheme located in the Eastern Region of Saudi Arabia. Landsat-8 and Sentinel-2 satellite images were acquired during the potato growth stages and two vegetation indices (the normalized difference vegetation index (NDVI) and the soil adjusted vegetation index (SAVI)) were generated from the images. Vegetation index maps were developed and classified into zones based on vegetation health statements, where the stratified random sampling points were accordingly initiated. Potato yield samples were collected 2-3 days prior to the harvest time and were correlated to the adjacent NDVI and SAVI, where yield prediction algorithms were developed and used to generate prediction yield maps. Results of the study revealed that the difference between predicted yield values and actual ones (prediction error) ranged between 7.9 and 13.5% for Landsat-8 images and between 3.8 and 10.2% for Sentinel-2 images. The relationship between actual and predicted yield values produced R2 values ranging between 0.39 and 0.65 for Landsat-8 images and between 0.47 and 0.65 for Sentinel-2 images. Results of this study revealed a considerable variation in field productivity across the three fields, where high-yield areas produced an average yield of above 40 t ha-1; while, the low-yield areas produced, on the average, less than 21 t ha-1. Identifying such great variation in field productivity will assist farmers and decision makers in managing their practices.
对农田作物生长和产量进行监测是保障粮食安全和预测农业经济回报的重要环节。遥感技术的进步推动了农作物生长监测和产量估算进程。因此,本研究运用遥感和地理信息系统(GIS)技术,对沙特阿拉伯东部某农业区三个面积均为30公顷的中心支轴灌溉农田的马铃薯块茎产量进行预测。在马铃薯生长阶段获取了陆地卫星8号(Landsat-8)和哨兵2号(Sentinel-2)卫星图像,并从图像中生成了两个植被指数(归一化差异植被指数(NDVI)和土壤调节植被指数(SAVI))。基于植被健康状况绘制了植被指数图并将其划分为不同区域,据此设置分层随机采样点。在收获前2至3天采集马铃薯产量样本,并将其与相邻的NDVI和SAVI进行关联分析,进而开发产量预测算法并用于生成预测产量图。研究结果表明,对于陆地卫星8号图像,预测产量值与实际产量值之间的差异(预测误差)在7.9%至13.5%之间;对于哨兵2号图像,该差异在3.8%至10.2%之间。实际产量值与预测产量值之间的关系显示,陆地卫星8号图像的R2值在0.39至0.65之间,哨兵2号图像的R2值在0.47至0.65之间。本研究结果显示,这三块农田的田间生产力存在显著差异,高产区域平均产量超过40吨/公顷;而低产区域平均产量低于21吨/公顷。识别田间生产力的巨大差异将有助于农民和决策者进行农事管理。