不同株型品种冬小麦NDVI 变化特征及产量分析

Changes in NDVI and yield of winter wheat cultivars with different plant types

  • 摘要: 冬小麦不同株型品种和灌溉类型是影响产量遥感估测的重要因素, 对二者的实时监测可以提高产量的估测精度。结合遥感数据(MODIS 数据)与非遥感数据(GPS 数据和外业调查资料), 研究了不同株型品种冬小麦在水、旱地条件下归一化差值植被指数(NDVI)的动态变化特征, 分析了不同生育时期NDVI 与产量之间的关系。结果表明: 冬小麦不同株型品种间NDVI 随生育时期的变化具有明显一致性, 呈“小-大-小”变化趋势; 拔节期至孕穗期不同株型品种冬小麦NDVI 差异显著, 披散型品种高于紧凑型品种, 该时期为准确识别冬小麦株型的最佳时期。水、旱地同一种株型的冬小麦品种在整个生育时期NDVI 均值差异较显著, 均表现为水地冬小麦高于旱地冬小麦, 尤以抽穗初期最为明显。水旱地冬小麦不同生育时期NDVI 与产量相关性均以抽穗初期为最高, 但用抽穗初期和灌浆期NDVI 与产量的复合回归方程进行产量预测比用抽穗初期NDVI 与产量的回归方程效果好, 旱地冬小麦尤为明显。

     

    Abstract: Plant type and irrigation scheme are key influencing factors of real-time yield estimation and monitoring of winter wheat in precision farming. In this paper, MODIS remote sensing data were used in combination with GPS and ground-truth non-remote sensing data to determine the dynamics of normalized difference vegetation index (NDVI) of winter wheat cultivars with different plant types under irrigation and non-irrigation conditions. The relationship between NDVI and yield of different winter wheat cultivars in different growth stages was then analyzed. Results showed the trends in NDVI with developmental stages of different wheat cultivars were same, following a low-high-low curve. There were obvious differences in NDVI from jointing to booting stages for different cultivars, and NDVI for cultivars with horizontal plant types was higher than that for cultivars with erect plant types. It implied that the jointing-to-booting stage was the best period for identifying plant types of winter wheat cultivars. Even for the same cultivar, mean NDVI was obviously different at each growth stage for irrigated and non-irrigated lands. NDVI for irrigated winter wheat was higher than that for non-irrigated winter wheat, with a notable difference especially at the early heading stage. At early heading stage, NDVI was strongly correlated with yield in irrigated and non-irrigated lands. However, regression equation based on NDVI both in the early heading and filling stages gave better prediction for wheat yield than that based on NDVI only in the early heading stage. This was especially the case for non-irrigated wheat fields.

     

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