Morphological And Micromorphological Changes In The Structure Of A Rhodic Hapludox As A Result Of Agricultural Management [alterações Morfológlcas E Micromorfológicas Na Estrutura De Um Latossolo Vermelho Distroférrico Típico Decorrentes Do Manejo Agrícola]

In evaluation of soil quality for agricultural use, soil structure is one of the most important properties, which is influenced not only by climate, biological activity, and management practices but also by mechanical and physico-chemical forces acting in the soil. The purpose of this study was to evaluate the influence of conventional agricultural management on the structure and microstructure of a Latossolo Vermelho distroférrico típico (Rhodic Hapludox) in an experimental area planted to maize. Soil morphology was described using the crop profile method by identifying the distinct structural volumes called Morphologically Homogeneous Units (MHUs). For comparison, we also described a profile in an adjacent area without agricultural use and under natural regrowth referred to as Memory. We took undisturbed samples from the main MHUs so as to form thin sections and blocks of soil for micromorphological and micromorphometrical analyses. Results from the application of the crop profile method showed the occurrence of the following structural types: loose (L), fragmented (F) and continuous (C) in both profiles analyzed. In the Memory soil profile, the fragmented structures were classified as FptμΔ+tf and FmtΔμ, whose micromorphology shows an enaulic-porphyric (porous) relative distribution with a great deal of biological activity as indicated by the presence of vughs and channels. Lower down, from 0.20 to 0.35 m, there was a continuous soil volume (sub-type CΔμ), with a subangular block microstructure and an enaulic-porphyric relative distribution, though in this case more compact and with aggregate coalescence and less biological activity. The micromorphometrical study of the soil of the Memory Plot showed the predominance of complex pores in NAM (15.03%), FmtΔμ (11.72%), and FptμΔ+tf (7.73%), and rounded pores in CΔμ (8.21%). In the soil under conventional agricultural management, we observed fragmented structures similar to the Memory Plot from 0.02 to 0.20 m, followed by a volume with a compact continuous structure (CΔμ), without visible porosity and with few roots. In the MHUs under conventional management, reduction in the packing pores (40%) was observed, mainly in the continuous units (C). The microstructure had well-defined blocks, with the occurrence of planar pores and less evidence of biological activity. In conclusion, the morphological and micromorphological analyses of the soil profiles studied offered complementary information regarding soil structural quality, especially concerning the changes in pore types as result of mechanical stress undergone by the soil. © 2015, Revista Brasileira de Ciencia do Solo. All rights reserved.391205221Ball, B.C., In, S.P.A.P., Dane, J.H., Topp, C., Editors. Methods of soil analysis. Physical methods. Madison (2002) : Soil Science Society of America, pp. 1141-1158Bertol, I., Albuquerque, J.A., Leite, D., Amaral, A.J., Zoldan Junior, W.A., Propriedades físicas do solo sob preparo convencional e semeadura direta em rotação e sucessão de culturas, comparadas às do campo nativo (2004) R Bras Ci Solo, 28, pp. 155-163Bullock, P., Fedoroff, N., Jongerius, A., Stoops, G., Tursina, T., Babel, U., Handbook for soil thin section description (1985) Albrington: Waine ReserchCastro, S.S., Cooper, M., Santos, M.C., Vidal-Torrado, P., Curi, N., Marques, J.J., Guilherme, L., Alvarez, V., Micromorfologia do solo MG: Sociedade Brasileira De Ciência Do Solo, 2003, 3, pp. 107-164Cooper, M., Vidal-Torrado, P., Grimaldi, M., Soil structure transformations from ferralic to nitic horizons on a toposequence in southeastern Brazil (2010) R Bras Ci Solo, 34, pp. 1685-1699Curmi, P., Kerttzman, F.F., Queiroz Neto, J.P., Ringrose-Voase, A.J., Humpherys, G.S., (1994) Soil Micromorphology: Studies in Management and Genesis. Amsterdam: Elsevier, 22, pp. 569-579. , Developments in Soil ScienceDersigny, C., Guimarães, M.F., Visintin, T., Observação do estado estrutural e da repartição espacial do sistema radicular do milho cultivado num Latossolo Roxo In: Anais Do 8O Congresso Brasileiro E(1990) Sociedade Brasileira De Ciência Do Solo, p. 76Dexter, A.R., Soil physical quality. Part I. Theory, effects of soil texture, density, organic matter, and effects on root growth (2004) Geoderma, 120, pp. 201-214Drees, L.R., Karathanasis, A.D., Wilding, L.P., Blevins, R.L., Micromorphological characteristics of long-term no-till and conventionally tilled soils (1994) Soil Sci Soc am J, 58, pp. 508-517Doran, J.W., Microbial biomass and mineralizable nitrogen distributions in no tillage and plowed soils (1987) Biol Fertil Soil, 5, pp. 68-75Sistema brasileiro de classificação de solos. 3a ed (2013) Rio De JaneiroFregonezi, G., Brossard, M., Guimarães, M.F., Medina, C.C., Modificações morfológicas e físicas de um Latossolo argiloso sob pastagens (2001) R Bras Ci Solo, 25, pp. 1017-1027Gautronneau, Y., Manichon, H., (1987) Guide méthodique Du Profil CulturalGuimarães, R., Tormena, C.A., Alves, S.J., Fidalski, J., Blainski, E., Tensile strength, friability and organic carbon in an Oxisol under a crop-livestock system (2009) Sci Agric, 66, pp. 499-505Hakansson, I., Voorhees, W.B., Riley, H., Vehicle and wheel factors influencing soil compaction and crop response in different traffic regimes (1988) Soil till Res, 11, pp. 239-282Hallaire, V., Cointepas, J.P., Caractérisation de la macroporosité d’un sol de verger par analyse d’ image (1993) Agronomie, 13, pp. 155-164Imhoff, S., Silva, A.P., Tormena, C.A., Spatial heterogeneity of soil properties in areas under elephant-grass short duration grazing system (2000) Plant Soil, 219, pp. 161-168Juhász, C., Cooper, M., Cursi, P.R., Ketzer, A.O., Toma, R.S., Savanna woodland soil micromorphology related to water retention (2007) Sci Agric, 64, pp. 344-354Marques, S.R., Weill, M., Silva, L., Qualidade física de um Latossolo Vermelho, perdas por erosão e desenvolvimento do milho em dois sistemas de manejo (2010) Ci Agrotec, 34, pp. 967-974Pagliai, M., La Marca, M., Lucamante, G., Genovese, L., Effects of zero and conventional tillage on the length and irregularity of elongated pores in a clay loam soil under viticulture (1984) Soil till Res, 4, pp. 433-444Reynolds, W.D., Drury, C.F., Yang, X.M., Tan, C.S., Optimal soil physica quality inferred through structural regression and parameter interactions (2008) Geoderma, 146, pp. 466-474Santos, R.D., Lemos, R.C., Santos, H.D., Ker, J.C., Anjos, L., Manual de descrição e coleta de solo no campo. 6a ed (2013) Viçosa, MG: Sociedade Brasileira Da Ciência Do SoloSchaefer, C., Souza, C.M., Vallejos, M., Viana, J., Galvão, J., Ribeiro, L.M., Características da porosidade de um Argissolo Vermelho-Amarelo submetido a diferentes sistemas de prepare de solo (2001) R Bras Ci Solo, 25, pp. 765-769Shapiro, S.S., Wilk, M.B., An analysis of variance test for normality (Complete samples) (1965) Biometrika, 52, pp. 591-611Silva, A.P., Kay, B.D., Perfect, E., Characterization of the least limiting water range of soils (1994) Soil Sci Soc am J, 8, pp. 1775-1781(1993) Washington: Soil Conservation Service of United States:, 18. , HandbookSouza, Z.M., Marques Júnior, J., Cooper, M., Pereira, G.T., Micromorfologia do solo e sua relação com atributos físicos e hídricos (2006) Pesq Agropec Bras, 41, pp. 487-492Stoops, G., (2003) Guidelines for Nalysis and Description of Soil and Regolith Thin SectionsTamia, A., Moreau, R., Fortier, M.G., . Influence du travail du sol sur l’évolution physique d’un sol forestier ferralitique après défrichement motorisé (1999) Étude Gestion Sols, 6, pp. 27-39Tavares Filho, J., Ralisch, R., Guimarães, M.F., Medina, C.C., Balbino, L.C., Neves, C., Método do perfil cultural para avaliação do estado físico de solos em condições tropicais (1999) R Bras Ci Solo, 23, pp. 393-399Tavares Filho, J., Tessier, D., Characterization of soil structure and porosity under long-term conventional tillage and no-tillage systems (2009) R Bras Ci Solo, 33, pp. 1837-1844Thierfelder, C., Wall PC. Rotation in conservation agriculture systems of Zambia: Effects on soil quality and water relations (2010) Exper Agric, 46, pp. 309-325Xu, X., Nieber, J.L., Gupta, S.C., Compaction effects on the gas diffusion coefficients in soil (1992) Soil Sci Soc am J, 56, pp. 1743-1750Warrick, A.W., Nielsen, D., Spatial variability of soil physical properties in the field (1980) Applications of Soil Physics. New York: Academic Press, pp. 319-344. , In: , editorWeill, M., Sparovek, G., Estudo da erosão na microbacia do Ceveiro (Piracicaba, SP). II - Interpretação da tolerância de perd de solo utilizando a metodologia do índice de tempo de vida (2008) R Bras Ci Solo, 32, pp. 815-82