Quiñones et al.- Water quality using fuzzy logic. 144 UNIVERSIDAD DE NARIÑO e-ISSN 2256-2273 Rev. Cienc. Agr. July - December 2021 Volume 38(2): 144-156 Quiñones et al.- Water quality using fuzzy logic. 144 Potentialities and limitations of Planosols with distinct depths of diagnostic horizon Potencialidades y limitaciones de Planosoles en distintas profundidades de su horizonte diagnóstico Mirian Cristina Gomes Costa 1 ; Ricardo Espíndola Romero 2 ; Juciane Maria Santos Sousa Vieira 3 ; Raul Shiso Toma 4 ; Jaedson Cláudio Anunciato Mota 5 1 . Associate Professor, Ph.D. Universidade Federal do Ceará, Ceará, Brasil, mirian.costa@ufc.br. 2 . Titular Professor, Ph.D. Universidade Federal do Ceará, Ceará, Brasil, reromero@ufc.br 3 . Research, Ph.D. Universidade do Estado de Santa Catarina, Santa Catarina, Brasil, jucianemariass@ gmail.com 4 . Adjunct Professor, Ph.D. Universidade Federal do Ceará, Ceará, Brasil, raulstoma@ufc.br 5 . Associate Professor, Ph.D. Universidade Federal do Ceará, Ceará, Brasil, jaedson.mota@ufc.br Cite: Costa, M.C.G.; Romero, R.E.; Viera, J.M.S.S.; Toma, R.S.; Mota, J.C.A. (2021). Potentialities and limitations of Planosols with distinct depths of diagnostic horizon. Revista de Ciencias Agrícolas. 38(2): 144- 156. doi: https://doi.org/10.22267/rcia.213802.163 Received: May 05 2020. Accepted: August 13 2021. ARTICLE DATA ABSTRACT There is a variation in the depth of subsurface horizon of Planosols in semi- arid region, which may influence the agricultural potential and affect food production. The general aim of this study was to identify potentialities and limitations of two Planosols as a function of subsurface horizon depth. The adjacent profiles P1 and P2 were studied in Pentecoste (Ceará, Brazil). Morphological, physical, and chemical analyses were done aiming at soil characterization. Soil bulk density (BD), porosity, and penetration resistance (PR) were analyzed in a completely randomized split-plot design with four replicates to compare P1 and P2 and the horizons Ap and Btf. Btf was found at 62cm depth in P1 and at 18 cm depth in P2. Indicatives of water saturation were more evident in P2. The profile P1 showed lower hardness and higher friability, as well as higher acidity in subsurface (pH H2O from 4.4 to 4.7) and higher aluminum content (1.2cmol c kg -1 ). Both profiles were eutrophic and showed low contents of organic carbon (1.5 to 8.5g kg -1 ) and phosphorus (0.9 to 3.9mg kg -1 ). The sodium percentage in CEC was 9.1% in P1 and 5.5% in P2. Water retention increases in Btf compared with Ap was 7.3% in P2 and 2.7% in P1. Both profiles showed increase in BD in Btf, reaching 1.7g cm -3 , while PR was higher in P2 (1.5 MPa). There are potentialities and limitations common to both soil profiles, but P1 has more physical potentialities and more chemical limitations than P2. Key words: Soil classification; soil morphology; pedology; planic B soil horizon; tropical soils. RESUMEN Existe una variación en la profundidad del horizonte sub superficial de los Planosoles en la región semiárida, que pueden influenciar el potencial agrícola y afectar la producción de alimentos. En este estudio el objetivo general fue identificar las potencialidades y limitaciones de dos Planosoles en función de la profundidad de su horizonte sub superficial. Los perfiles adjacentes P1 y P2 fueron estudiados en Pentecoste (Ceará, Brasil). Con la finalidad de caracterizarlos fueron realizados análisis morfológicos, físicos y químicos. La Revista de Ciencias Agrícolas e-ISSN 2256-2273 https://doi.org/10.22267/rcia.213802.163 Research article: Other Agricultural Sciences Research article: Other Agricultural Sciences