Associations Between Attributes of Nitisols and the Climate of the Southern Coast of Pernambuco

Abstract

-Nitisols are livelihood sources of agricultural and socio-economic development in several underdeveloped countries worldwide, including Brazil. Brazilian Nitisols are usually associated with basaltic rocks found in the Southern and Southeastern regions of the country. However, Nitisols derived from basalt also occur on the southern coast of Pernambuco state, a region under full urban, agricultural, and industrial development. Aiming to understand the relationship between climate and attributes of Nitisols from the southern coast of Pernambuco, we performed morphological descriptions, physical and chemical analyzes, iron selective extraction, and soil mineralogy (sand, silt, and clay) for three basaltic soil profiles along a land slope. The results suggest a strong weathering of the profiles due to climate conditions, besides a great loss of basic cations and xanthization process, resulting in the natural genesis of acric Nitisols with yellowish coloration, which has not been yet cataloged for this soil order in the Brazilian taxonomic system. In addition, there is a variation for physical attributes of Nitisols along the slope.Keywords: Tropical soils. Soil-environment relationship. Xanthization process. ASSOCIAÇÕES ENTRE OS ATRIBUTOS DE NITOSSOLOS E O CLIMA DA COSTA SUL DE PERNAMBUCORESUMO -Os Nitossolos dão suporte ao desenvolvimento agrícola e socioeconômico de muitos países subdesenvolvidos do mundo, incluindo o Brasil. Os Nitossolos brasileiros estão geralmente associados às rochas basálticas das regiões Sul e Sudeste. Entretanto, Nitossolos derivado de basalto também ocorrem na costa sul de Pernambuco, uma região em pleno desenvolvimento urbano, agrícola e industrial. Objetivando compreender as relações entre o clima e os atributos dos Nitossolos da costa sul de Pernambuco, foram realizadas descrições morfológicas, análises físicas e químicas, extrações seletivas de ferro e a determinação da mineralogia das frações areia, silte e argila de três perfis derivados de basalto ao longo de uma vertente. Os resultados demonstram que o clima da região implica em forte intemperização dos perfis, em grande perda de bases e favorece o processo de xantização, resultando na singular gênese de Nitossolos com matizes amarelados e caráter ácrico, fato que até o momento ainda não foi catalogado para esta ordem no sistema taxonômico brasileiro. Os resultados também demonstram a variação dos atributos físicos dos Nitossolos ao longo da vertente.Palavras-chave: Solos tropicais. Relação solo-ambiente. Processo de xantização.

Genesis and Classification of Nitisols from Volcano-Sedimentary Lithology in Northeastern Brazil

“…Soils with a nitic horizon are predominantly derived from basic to intermediate rocks Vidal-Torrado, 2000, 2005;Cooper et al, 2010;Santos et al, 2013;Soil Survey Staff, 2014;De Wispelaere et al, 2015), including the Nitossolos of the Cabo Basin (Oliveira et al, 2004;Neves et al, 2018;). In contrast to the studies mentioned and to P1 and P2 of the present study, the P3 profile (footslope), in addition to basalt, is formed from sedimentary rocks richer in SiO 2 , since the blocks and the matrix of the conglomerate package present a typical granitic composition (Alheiros and Ferreira, 1989), contributing to an unusual formation of Nitossolo associated with acidic and basic rocks.…”

“…The smectite in P3 may be related to complex conglomerates, since they may be intercalated with argillites and shales of the Cabo Basin (Mabesoone and Alheiros, 1988;Alheiros and Ferreira, 1989 by Oliveira et al (2004) and Neves et al (2018) for not identifying 2:1 minerals in the clay fraction.…”

“…According to the soil surveys carried out by Brasil (1972) and Araújo Filho et al (2000), the main orders of soils that occur along the southern coast of Pernambuco are Argissolos (Acrisols; Lixisols), Latossolos (Ferralsols), Nitossolos (Nitisols), and Gleissolos (Gleysols). Previously, studies have been performed in the abovementioned region with Nitossolos (Oliveira et al, 2004;Neves et al, 2018), which are always formed from the basaltic alteration of the Ipojuca Formation, classified as Nitossolo Vermelho and Nitossolo Háplico, typically presenting a kaolinitic and oxidic mineralogy in addition to low levels of exchangeable Al 3+ .…”

“…Basic and intermediate rocks are widely documented as the parent lithology for soils with a nitic horizon (Cooper and Vidal-Torrado, 2000;Cooper et al, 2010;Melo et al, 2010;Soil Survey Staff, 2014;De Wispelaere et al, 2015). The Nitossolos developed from basalt throughout Brazil (Brasil, 1972;Santos Filho et al, 1978;Araújo Filho et al, 2000;Tremocoldi, 2003;Oliveira et al, 2004;Neves et al, 2018) generally present values of Fe 2 O 3 (sulfuric digestion) above 18 % and are classified as Nitossolos Vermelhos or Brunos (Santos et al, 2013). However, for Nitossolos Háplicos, neither the ferric nor the allytic character have been predicted to date (Santos et al, 2013).…”

“…The southern coast of Pernambuco is inserted in areas of dissected plateaus. In addition to the close relationship between parent material and soil properties (Brilhante et al, 2017;Neves et al, 2018), the relief plays a key role in pedodiversity, since along the slopes, there may be mixtures of parent materials, conditioning the formation of soil with peculiar properties. It is possible to find the occurrence of Nitossolos distinct from those previously studied in other regions of Brazil (Cooper and Vidal-Torrado, 2000;Ferreira et al, 2003;Silva et al, 2009;Melo et al, 2010) The southern coastal region of Pernambuco, in addition to the estuarine environments, is formed by the Atlantic forest ecosystem, the natural vegetation of which is practically nonexistent.…”