Evaluation of soil water storage in native forest and eucalyptus areas

Abstract

In the region of the Paraíba do Sul river valley in the State of São Paulo, Brazil, pasture areas have been replaced by eucalyptus plantations, which can modify the dynamics of water in the soils of the region. The objective of this work was to evaluate the behavior of water in a Red-Yellow Latosol in two vegetative coverings, a six-year-old eucalyptus plantation, and a native forest, in the process of regeneration which began twenty years ago. The study was developed in the Una River basin from June 2009 to April 2011. The soil water potential was measured by 96 sensors (Watermark ™) at the depths of 20, 60 and 120 cm. The Available Water Capacity (AWC) and weekly residual soil storage for each layer were calculated. It was observed that the three layers reacted to the processes of rainfall and evapotranspiration and that there was a difference between the storage of water in the soil in the eucalyptus and native forest areas. There was no water restriction in the studied period; however, the variations in native forest storage were smoother than the variations occurring for eucalyptus. In the mean of the whole period and for the three layers, the storage in the native forest and eucalyptus were 88% and 64% of Available Water Capacity (AWC = 183 mm), respectively. These results show the native forest water conservation capacity in watersheds. Palavras-chave: bacias hidrográficas, tensiômetro, uso da água, floresta.

Climatic zoning for eucalyptus cultivation through strategic decision analysis

“…However, it is important to emphasize the need for additional studies with other factors (edaphic and specific legislation), as well as the analysis of environmental and socio economic impact of the expansion of eucalyptus forests. According to Targa et al (2017), the environmental impact analysis is necessary due to the discussion related to the availability of water in watersheds with extensive areas planted with eucalyptus. Arguello et al (2010) report that socioeconomic impacts include job supply, rural exodus and income generation for small-and medium-sized farms.…”

Os benefícios ambientais do plantio de eucalipto: revisão de literatura

“…Para isso existem tecnologias e manejos florestais que devem e necessitam serem empregados como forma de combater os efeitos negativos das perdas de solo em razão da erosão hídrica (Cândido et al, 2014). Targa et al (2017), através do seu estudo afirma que a área de mata nativa teve maior capacidade de armazenamento (88% do máximo) de água no solo do que a área de eucalipto (64% do máximo) nas três profundidades (0 -20 camadas de cm; 20-60 cm e 60-120 cm), durante o período de estudo. Corroborando com os outros autores que afirmam que o eucalipto consome menos água quando comparado com outros plantios, e por fim, não seca o solo.…”

Water balance in soil covered by regenerating rainforest in the Paraíba Valley region, São Paulo, Brazil

“…These electrodes are connected by wiring to a voltage meter that transforms the reading of electrical resistance into soil water potential, measuring accurately from 0 to -200 kPa. The details of this monitoring system can be seen in Paula et al (2013) and Targa et al (2017).…”

“…The matrix potential of soil water (Ψm) in the rainforest areas of the Paraíba Valley generally does not exceed 200 kPa, as determined by Salemi et al (2012); Paula et al (2013) and Targa et al (2017). Therefore, in this study, water-retention curves for each soil layer in both soil saturation and natural drought conditions was obtained inside containers based on 30-day weighing of WatermarkTM sensor readings (Pohl, 2017).…”

“…In addition, in the Vale do Paraíba region, some studies in a basin of eucalyptus reforestation indicated soil losses below tolerance levels (0.08 mg per ha per year) in Argissolo Ranzini and Lima, 2002). When monitoring soil water -storage in the Paraiba Basin, Targa et al (2017) revealed that at the end of 24 months the area with rain forest retained 88% of the maximum water storage-capacity in the soil, and that in eucalyptus only 64% of this capacity was reached.…”