Abstract:Para estudos de movimento da água no solo tornam-se imprescindíveis o conhecimento de suas propriedades físicas e hidráulicas e suas correlações. Ambas as propriedades têm importância fundamental no armazenamento e transporte de água, tal como, também, de nutrientes e no controle da infiltração, sendo influenciadas pelas condições de superfície do solo. Neste contexto buscou-se realizar, com o presente estudo, a caracterização físico-hídrica de solos de duas bacias experimentais (Jatobá e Mimoso/Pesqueira, PE)… Show more
“…Sediment fraction measurements in rivers and streams are challenging and by sampling them, the sediment transport can be better understood (da Silva et al 2012). Additionally, soil erosion and SE estimations can be improved by enhancing model calibrations (Almagro et al 2019).…”
Section: Main Findings and Advancesmentioning
confidence: 99%
“…REHISA is composed of eight federal universities from the Northeast region (UFPB, UFRN, UFCG, UFAL, UFPE, UFRPE, UFC and UFCG) and one state agency (FUNCEME). This partnership aims to create and improve instrumentation and monitor experimental basins, and address particular issues present in the Northeast region, including (a) anthropogenic changes that affect land cover and the hydrological cycle; (b) evaporation and sedimentation in dams (typically small and used for human supply); (c) evapotranspiration and interception in Caatinga vegetation (small trees and shrubs); (d) infiltration and subsurface flow in soils that are poor in nutrients, sandy and very shallow; and (e) surface water movement due to scarce precipitation (usually below 800 mm) (REHISA 2004, Santos et al 2011, Oliveira et al 2012, Silva et al 2012, Coutinho et al 2014, Figure 1. Number of publications by year (2009 found in a Scopus database search using the following terms: "experimental watershed," "experimental basin," "experimental catchment," "representative watershed," "representative basin," "representative catchment," and "field hydrology."…”
In-situ hydrological monitoring is essential for a proper decision-making process and modelling. Efforts have been made in Brazil to carry out field activities at the basin scale, but how complete and comprehensive are those studies? Where are they located? How long have they been carried out? What are the main findings? To answer these questions, an overview of experimental monitoring basins in Brazil is presented, listing their geographical locations, monitored variables, operational status, monitoring periods and main publications. We identified 60 monitored sites, spread across most Brazilian biomes, with an average monitoring period of 12 years. However, some publications from these monitoring studies are not fully accessible to the international community. Field hydrology activities in Brazil contribute to a better understanding of hydrological processes in humid and semiarid regions and inform us about the impacts of land-use change on water quality and quantity.
“…Sediment fraction measurements in rivers and streams are challenging and by sampling them, the sediment transport can be better understood (da Silva et al 2012). Additionally, soil erosion and SE estimations can be improved by enhancing model calibrations (Almagro et al 2019).…”
Section: Main Findings and Advancesmentioning
confidence: 99%
“…REHISA is composed of eight federal universities from the Northeast region (UFPB, UFRN, UFCG, UFAL, UFPE, UFRPE, UFC and UFCG) and one state agency (FUNCEME). This partnership aims to create and improve instrumentation and monitor experimental basins, and address particular issues present in the Northeast region, including (a) anthropogenic changes that affect land cover and the hydrological cycle; (b) evaporation and sedimentation in dams (typically small and used for human supply); (c) evapotranspiration and interception in Caatinga vegetation (small trees and shrubs); (d) infiltration and subsurface flow in soils that are poor in nutrients, sandy and very shallow; and (e) surface water movement due to scarce precipitation (usually below 800 mm) (REHISA 2004, Santos et al 2011, Oliveira et al 2012, Silva et al 2012, Coutinho et al 2014, Figure 1. Number of publications by year (2009 found in a Scopus database search using the following terms: "experimental watershed," "experimental basin," "experimental catchment," "representative watershed," "representative basin," "representative catchment," and "field hydrology."…”
In-situ hydrological monitoring is essential for a proper decision-making process and modelling. Efforts have been made in Brazil to carry out field activities at the basin scale, but how complete and comprehensive are those studies? Where are they located? How long have they been carried out? What are the main findings? To answer these questions, an overview of experimental monitoring basins in Brazil is presented, listing their geographical locations, monitored variables, operational status, monitoring periods and main publications. We identified 60 monitored sites, spread across most Brazilian biomes, with an average monitoring period of 12 years. However, some publications from these monitoring studies are not fully accessible to the international community. Field hydrology activities in Brazil contribute to a better understanding of hydrological processes in humid and semiarid regions and inform us about the impacts of land-use change on water quality and quantity.
“…In the Caatinga, investigation of this subject is still rare. On the scale of watersheds in the semiarid region of Brazil, relevant research can be cited, however, with greater focus on sedimentological processes, such as Antonino et al (2004); Figueiredo et al (2016); Rodrigues et al (2009);Montenegro and Ragab (2010;; Neves et al (2010); Costa et al (2013); Silva, Montenegro and Santos (2012); Souza et al (2011).…”
-Soil is an important water compartment into a watershed scale, mainly due to its role in providing water to plants and to the influence of antecedent moisture on the runoff initiation. The aim of this research is to assess the permanence of water effectiveness in the soil under preserved-vegetation constraints in the Caatinga biome, in the semiarid northeastern Brazil. For this purpose, hourly soil moisture measurements were collected with TDR and analyzed between 2003 and 2010 for three soil-vegetation associations in the Aiuaba Experimental Basin. The results showed that in nine months per year soil moisture was below wilting point for two associations, whose soils are Chromic Luvisol and Haplic Lixisol (Abruptic). In the third association, where the shallow soil Lithic Leptosol prevails, water was found non-effective four months per year. A possible reason for the high water permanence in the shallowest soil is the percolation process, generating sub-surface flow, which barely occurs in the deeper soils. In situ observations indicates that the long period of soil moisture below the wilting point was not enough to avoid the blooming season of the Caatinga vegetation during the rainy periods. Indeed, after the beginning of each rainy season, there is a growth of dense green vegetation, regardless of the long period under water shortage.Keywords: Wilting point. Soil. Semiarid environment.PERMANÊNCIA DA EFETIVIDADE DA ÁGUA NA ZONA DE RAÍZES NO BIOMA CAATINGA RESUMO -O solo é um dos compartimentos de água de maior importância em uma bacia hidrográfica. A vegetação depende majoritariamente da água retida pelo solo para atender às suas demandas; e o início do escoamento superficial depende fortemente da umidade inicial do solo. Este estudo teve como objetivo avaliar a permanência da efetividade da água no solo sob condições de vegetação preservada no bioma Caatinga, Semiárido do Nordeste brasileiro. Para isso, foram analisados dados horários de umidade do solo através de sensores TDR obtidos entre os anos de 2003 e 2010 para três associações solo-vegetação presentes na Bacia Experimental de Aiuaba. Os resultados indicam que, durante nove meses ao ano, a água no solo encontra-se abaixo do ponto de murcha permanente para duas associações, cujos solos são Argissolo Vermelho-Amarelo e Luvissolo Hipocrômico. Na terceira associação, cujo solo é raso (Neossolo litólico), a água encontra-se não efetiva durante quatro meses ao ano. Avalia-se que a maior permanência de água neste solo dê-se pela limitação de percolação profunda, induzindo o escoamento sub-superficial; o que não se verifica nos solos mais profundos. Verificou-se in situ que o longo período de umidade abaixo do ponto de murcha permanente não comprometeu a vida das espécies da Caatinga. Após o início de cada período chuvoso, observa-se o crescimento de uma densa massa de vegetação, apesar do longo período sob estresse hídrico.Palavras-chave: Ponto de murcha permanente. Solo. Semiárido.
“…A condutividade hidráulica do solo saturado sofre influência de atributos do solo tais como: estrutura, textura, homogeneidade, massa específica do solo, massa específica das partículas, porosidade total e macro e micro porosidade (Trevisan et al, 2009), manejo, e o teor de matéria orgânica (Silva et al, 2012). A curva de retenção de água no solo expressa a relação entre o potencial mátrico e a umidade do solo (Nascimento et al, 2010a), sendo uma característica específica de cada solo (Beutler et al, 2002).…”
O objetivo deste trabalho foi desenvolver funções de pedotransferência com base em atributos físico-hídricos do solo, para estimar a retenção de água e condutividade hidráulica. O trabalho foi realizado em área com cultivo de café Conilon (Coffea canephora Pierre) irrigado e submetido à subsolagem na linha no plantio. Amostras indeformadas foram coletadas na linha (P1) e na entrelinha (P2) da cultura na camada de 0-0,80 m, para determinação da curva de retenção de água e condutividade do solo utilizando-se o permeâmetro de Guelph. As funções de pedotransferência apresentaram subestimativas para os potenciais 0,-500 e-1500 kPa e de-6,-10,-33 e-100 kPa, respectivamente, nos P1 e P2. No P2 o erro médio relativo percentual para os potenciais foi de 8,42%, maior que no P1 (4,87%), resultando em maior erro nas estimativas de alturas de água armazenadas no solo. A curva de retenção de água para solo subsolado pode ser estimada com erro menor que 5% a partir dos atributos argila, volume total de poros, macroporosidade, microporosidade e densidade do solo, além de condutividade hidráulica pela fração de argila do solo. Para solo não subsolado a curva de retenção pode ser estimada com erro menor que 9% pelo volume total de poros e macro e microporos e a condutividade hidráulica pela fração de areia grossa.
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