Detecting Recent Crop Phenology Dynamics in Corn and Soybean Cropping Systems of Kentucky
Detecting Recent Crop Phenology Dynamics in Corn and Soybean Cropping Systems of Kentucky
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DOI：
10.3390/rs13091615
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发表时间：
2021-04
期刊：
影响因子：
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通讯作者：
Yanjun Yang;B. Tao;L. Liang;Yawen Huang;C. Matocha;Chad D. Lee;M. Sama;B. El-Masri;W. Ren
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作者：
Yanjun Yang;B. Tao;L. Liang;Yawen Huang;C. Matocha;Chad D. Lee;M. Sama;B. El-Masri;W. Ren
准确的物候信息对于监测作物发展、预测作物产量和增强应对气候变化的应变能力至关重要。采用基于曲线变化的NDVI(归一化差异植被指数)时间序列的动态阈值方法，对典型气候过渡带肯塔基州2000-2018年的玉米和大豆播种收获期进行了研究。我们将基于卫星的估计与地面观测进行了比较，并对研究期间的作物物候阶段进行了趋势分析，以分析它们与气候变化和作物产量的关系。结果表明，玉米和大豆的播期分别推迟了0.01天和0.07天/年。玉米收获期也以每年0.67天的速度推迟，而大豆的提前收获期则以每年0.05天的速度提前。玉米生长季以每年0.66天的速度显著增加，大豆以每年0.12天的速度缩短。敏感性分析表明，播种期对前期温度较为敏感，而采收期与整个生长季的温度呈显著正相关。就气候变化因素而言，只有夏季降水增加与肯塔基州玉米收割日期推迟在统计上相关。进一步分析表明，玉米产量的增加与收获期推迟(1.37BU/亩/天)和生长季延长(1.67BU/亩/天)显著相关。我们的结果表明，季节性气候变化(如夏季降水)是影响作物物候趋势的主要因素，特别是在研究期间肯塔基州的玉米收成。我们还强调了改变作物物候在限制作物生产方面的关键作用，这需要进一步努力优化作物管理实践。
Accurate phenological information is essential for monitoring crop development, predicting crop yield, and enhancing resilience to cope with climate change. This study employed a curve-change-based dynamic threshold approach on NDVI (Normalized Differential Vegetation Index) time series to detect the planting and harvesting dates for corn and soybean in Kentucky, a typical climatic transition zone, from 2000 to 2018. We compared satellite-based estimates with ground observations and performed trend analyses of crop phenological stages over the study period to analyze their relationships with climate change and crop yields. Our results showed that corn and soybean planting dates were delayed by 0.01 and 0.07 days/year, respectively. Corn harvesting dates were also delayed at a rate of 0.67 days/year, while advanced soybean harvesting occurred at a rate of 0.05 days/year. The growing season length has increased considerably at a rate of 0.66 days/year for corn and was shortened by 0.12 days/year for soybean. Sensitivity analysis showed that planting dates were more sensitive to the early season temperature, while harvesting dates were significantly correlated with temperature over the entire growing season. In terms of the changing climatic factors, only the increased summer precipitation was statistically related to the delayed corn harvesting dates in Kentucky. Further analysis showed that the increased corn yield was significantly correlated with the delayed harvesting dates (1.37 Bu/acre per day) and extended growing season length (1.67 Bu/acre per day). Our results suggested that seasonal climate change (e.g., summer precipitation) was the main factor influencing crop phenological trends, particularly corn harvesting in Kentucky over the study period. We also highlighted the critical role of changing crop phenology in constraining crop production, which needs further efforts for optimizing crop management practices.