Mapping of C and P based on mineralogy estimated by Vis-NIR-SWIR

Author(s)

Kathleen Fernandes Braz

• Document type: Doctoral Thesis
• Press: Jaboticabal. 2021-07-28.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2021-03-10
• Advisor: José Marques Júnior

Abstract

The irrational use of land has caused imbalances throughout the ecosystem. The influence on other components of the environment, such as water, air and the biogeochemical cycles of the elements, is already notorious. The present work aimed to estimate the C and P stocks in soils of the Planalto Ocidental Paulista, from the mineralogy of the clay fraction given by diffuse reflectance spectroscopy, and to establish and map specific management areas. The study area was the Planalto Ocidental Paulista, which occupies about 13 million ha. 600 samples were collected to perform physical, mineralogical and spectral analyses. The mineralogy, chemistry, particle size and physics of soils, C and P stocks, and C isotopes were evaluated in stratified samples, based on the geology, geomorphology and pedology of the area. All data were subjected to statistical and geostatistical analyses. The results obtained allowed to obtain the reference values of C and P stock, based on the mineralogical composition of the soil. Basalt soils have the highest C contents and element stocks when compared to sandstone soils. Sandstone soils in highly dissected landscape forms had the highest P stocks, followed by basalt soils. It is possible to generate C and P stock maps, and C content maps from different mathematical analyses. Machine learning allows good estimation of C contents for different geologies. These results will allow planning for the definition of specific management areas for the purpose of conserving natural resources. It is possible to achieve this goal using sensors such as the spectrum, which allow the quantification of a large sample number, in a fast, practical, cheap and less polluting way. (AU)

• FAPESP's process: 17/05477-0 - Kaolinite and gibbsite minerals in the characterization and mapping of stock of C and P in the soils of the Western paulista plant
• Grantee: Kathleen Fernandes Braz
• Support Opportunities: Scholarships in Brazil - Doctorate