Relations between Microtopography and Soil N and P Observed by an Unmanned Aerial Vehicle and Satellite Remote Sensing (GF-2)
Relations between Microtopography and Soil N and P Observed by an Unmanned Aerial Vehicle and Satellite Remote Sensing (GF-2)
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DOI：
10.15244/pjoes/116608
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发表时间：
2020-10
影响因子：
1.8
通讯作者：
Hezhen Lou;Xiaoyu Ren;Shengtian Yang;F. Hao;Mingyong Cai;Yue Wang
中科院分区：
文献类型：
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作者：
Hezhen Lou;Xiaoyu Ren;Shengtian Yang;F. Hao;Mingyong Cai;Yue Wang
地形对于土壤养分流失和关键源区的识别具有重要意义。以往的研究主要采用大规模采样的方法，在粗尺度上探讨地形与土壤养分（尤其是氮、磷）的关系。然而，在微地形尺度上的关系仍然不清楚。本研究整合无人机（UAV）与卫星遥感（GF-2）资料，建立两个新的指数- NDVI（N）与NDVI（P）。结果表明，高NDVI（N）值的像元在水田中更多地分布在低海拔梯度上，而在旱地中则相反。在高（低）高差等级上，旱地（水田）的NDVI（P）值大（小）值像元较多。旱地各海拔梯度的平均NDVI（N）在0.25-0.33之间，平均NDVI（P）在0.47-0.61之间。水田各海拔梯度的NDVI（N）和NDVI（P）平均值分别为0.24-0.32和0.31-0.43。微地形可以重新分配土壤中的氮和磷的空间，因为它改变了灌溉和降雨的流动方向和侵蚀的泥沙流动。此外，土壤N和P在农田土壤中同时累积。
Topography is important for soil nutrient loss and critical source area (CSA) identification. Previous studies have primarily used mass soil sampling to explore the relations between topography and soil nutrients (especially N and P) at the coarse scales. The relations at the microtopographic scale, however, remain unclear. This study integrated unmanned aerial vehicle (UAV) and satellite remote sensing (GF-2) data to create two new indices – NDVI(N) and NDVI(P). Results revealed more pixels with high NDVI(N) values distributed across low elevation difference grades in paddy land; however, this was reversed for dry land. There were more NDVI(P) pixels with large (small) values at high (low) elevation difference grades in the dry land (paddy land). In dry land, the average NDVI(N) was in the range of 0.25-0.33, and NDVI(P) was in the range of 0.47-0.61 for each elevation grade. In paddy land, the average NDVI(N) and NDVI(P) values for each elevation grade were in the range of 0.24-0.32 and 0.31-0.43, respectively. Microtopography can redistribute N and P spatially within the soil because it changes the direction of flow from irrigation and rainfall and of sediment flow from erosion. Furthermore, soil N and P accumulate simultaneously in the soil of agricultural land.