Estimating soil total nitrogen in smallholder farm settings using remote sensing spectral indices and regression kriging

Xu, Y and Smith, S E and Grunwald, S and Abd-Elrahman, A and Wani, S P and Nair, V D (2018) Estimating soil total nitrogen in smallholder farm settings using remote sensing spectral indices and regression kriging. Catena (TSI), 163. pp. 111-122. ISSN 03418162

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Abstract

Mapping soil nutrients can help smallholder farmers identify soil nutrient status and implement site-specific soil management schemes. In the past, Digital Soil Mapping has seldom been utilized to guide soil nutrient management in smallholder farm settings in South India. The objective of this research was to analyze the spatial resolution effects of different remote sensing images on soil total nitrogen (TN) prediction models in two smallholder villages, Kothapally and Masuti in South India. Regression kriging (RK) was used to characterize the spatial pattern of TN in the topsoil (0–15 cm) by incorporating spectral indices with different spatial resolutions. The results suggested that soil moisture, vegetation, and soil crusts can contribute to the conservation of soil TN in both study areas. Soil prediction models with different spatial resolutions showed a similar spatial pattern of soil TN. The results also demonstrated that the effect of very fine spatial remote sensing spectral data inputs does not always lead to an increase of soil prediction model performance. A RapidEye-based (5 m) soil TN prediction model had lower prediction accuracy than a Landsat 8-based (30 m) soil TN prediction model in Masuti. WorldView-2/GeoEye-1/Pleiades-1A-based (2 m) soil TN prediction models had the highest prediction accuracy in both study areas. The spectral indices based on new bands of WorldView-2 such as coastal, yellow, red edge, and new near infrared bands had relatively strong correlations with soil TN. The utilization of Very High Spatial resolution images such as WorldView-2 in Digital Soil Mapping could improve soil model performance and spatial characterization. Remote sensing-based soil prediction models have high potential to be widely applied in smallholder farm settings.

Item Type: Article
Divisions: Research Program : Asia
CRP: UNSPECIFIED
Uncontrolled Keywords: Digital Soil Mapping, Remote sensing, Smallholder farms, GIS, South India, Soil total nitrogen, Spatial resolution, Soil nutrients mapping
Subjects: Others > Digital Soil Mapping
Others > GIS Techniques/Remote Sensing
Others > Soil
Others > Soil Science
Depositing User: Mr Ramesh K
Date Deposited: 19 Apr 2018 05:24
Last Modified: 19 Apr 2018 05:24
URI: http://oar.icrisat.org/id/eprint/10600
Official URL: http://dx.doi.org/10.1016/j.catena.2017.12.011
Projects: UNSPECIFIED
Funders: UNSPECIFIED
Acknowledgement: This work is supported by the grant award no. 1201943 “Development of a Geospatial Soil-Crop Inference Engine for Smallholder Farmers” EAGER National Science Foundation and Research Foundation for Youth Scholars of Beijing Technology and Business University. The soil analysis was performed in the soil laboratory at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) in Patancheru/Hyderabad, India. We thank Christopher M. Clingensmith at University of Florida, and other ICRISAT staff members and villagers of Kothapally for support in field sampling. We also thank Yiming Xu's PhD committee member Dr. Thomas K. Frazer for his commitment and guidance. A matching assistantship for Yiming Xu was provided by the School of Natural Resources and Environment, University of Florida, and the China Scholarship Council.
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