Soil health assessment in desertified drylands in Brazil

• Grant number: 24/03722-1
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2024
• End date: February 28, 2027
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Maurício Roberto Cherubin
• Grantee: Antonio Yan Viana Lima
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 21/10573-4 - Center for Carbon Research in Tropical Agriculture (CCARBON), AP.CEPID
• Associated scholarship(s): 25/04487-9 - From degradation to restoration: microbial shifts and carbon cycling in Brazilian drylands, BE.EP.DR

Abstract

Dryland degradation creates hardships for millions of people worldwide. Brazilian drylands are characterized by extensive land use changes to subsistence agriculture, leading to soil degradation and desertification. Desertification leads to soil health (SH) degradation, but several regenerative practices (e.g., grazing exclusion, cover crops, reforestation), may stop and even revert this process, restoring SH in the Brazilian drylands. However, there is a lack of scientific studies quantifying the impacts of desertification on SH and the potential of regenerative techniques to restore SH in Brazil's Desertification Nuclei. This type of information is crucial for developing science-based strategies and public policies to combat desertification and reduce the region's vulnerability to climate change and food insecurity. This project aims to quantify the SH of the four Brazilian Desertification Nuclei (located in Iraçuba-CE, Cabrobó-PE, Gilbués-PI, and Cariris Velhos-PB) by evaluating areas under native vegetation, advanced stage of desertification (i.e., degraded), and restoration. In each Desertification Nucleus, the experimental design consists of three experimental plots (50 m x 50 m) in those three different scenarios (native vegetation, advanced stage of degradation, and restoration practices). A standardized soil sampling protocol was performed in all studied areas, totaling 108 soil samples for the 0-10 cm depth (i.e., 4 nuclei x 3 land uses x 3 plots (repetition) x 3 composite samples per plot). Soil analysis will include: i) Chemical indicators: pH, EC, N-Total, H+Al, P, K+, Ca2+, Mg2+, Al3+, and base sum, V%, CEC, and m%; ii) Physical indicators: total sand, silt, clay, moisture, bulk density, stability of the wet aggregate and water infiltration; iii) biological analysis will be conducted to quantify total organic carbon, microbial biomass C and N, and determine the activity of the enzyme's urease, ²-glucosidase, acid phosphatase, and arylsulfatase. Metatranscriptomics will be employed to analyze the RNA extracted from the soil samples and construct metabolic pathways related to C cycle. SH will be assessed by integrating chemical, physical and biological indicators using Soil Management Assessment Framework (SMAF). The Normalized Difference Vegetation Index will be used to evaluate vegetation conditions in the study areas. Statistical analyses will be conducted to analyze the data, including tests for variance, normality, and the use of nested ANOVA and Tukey's test for significance determination. We expected to evaluate and compare the effectiveness of strategies to combat desertification and restore degraded areas in Brazilian drylands, considering SH indicators and the impact on C stocks, providing insights to promote public policies to combat desertification.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

LIMA, ANTONIO YAN VIANA; CHERUBIN, MAURICIO ROBERTO; GRESCHUK, LUCAS TADEU; MUNIZ, GABRIEL DE ALMEIDA MORI; CAVALCANTE, DOUGLAS MONTEIRO; PEREIRA, ARTHUR PRUDENCIO DE ARAUJO. Mapping soil health research in the Brazilian Semiarid region: a bibliometric approach. EXPERIMENTAL AGRICULTURE, v. 60, p. 18-pg., 2024-12-02. (24/03722-1, 21/10573-4)