ABSTRACT The least limiting water range (LLWR) has been extensively determined, but evaluating if LLWR can indeed indicate soil physical stress on plant growth is still a controversial issue. In this study, we used the Hydrus-1D hydrological model to simulate root water uptake (RWU) to analyze if RWU and LLWR are correlated under stress conditions. The LLWR was determined in a sandy-loam Ultisol and a clayey Oxisol. In both soils, RWU extracted by plants (leaf area index set as 3) […]

ABSTRACT Water and oxygen deficiencies in the soybean crop cultivated on lowland soils are an important topic of research. The objective of this study was to investigate changes in water and oxygen supply and soybean yield caused by soil management in lowland soils. A soybean crop was grown under four soil conditions: no-tillage (NT), chiseling (CH), ridge tillage on no-tillage (NTR), and ridge tillage on chiseling (CHR). Soil bulk density, total porosity, macro- and microporosity, air permeability, and saturated hydraulic […]

A cassava crop is often exposed to more than one period of water deficit during the growing season. The objective of this study was to verify if there is a difference in the FTSW (fraction of transpirable soil water) threshold for transpiration and leaf growth in cassava plants subjected to one or two periods of water deficit. Two experiments with cassava (Fepagro RS 13 cultivar) were conducted. Treatments were four soil water regimes subdivided into two periods, period 1 (P1) […]

Water is vital for plants. A reduction in water availability may affect crops transpiration and leaf growth. The objective of this study was to determine the response of transpiration and leaf growth to the fraction of transpirable soil water (FTSW) in two potato clones (an old and a new) adapted to Southern Brazil. Three experiments were carried out under a plastic shelter in Santa Maria, RS, Brazil, using two potato clones, an old (‘Macaca’) and a new (‘SMINIA793101-3’). Two of […]

Evaluating plant root capacity in extrating water from the soil is important for transpiration modeling and to understand crop growth and yield and soil water and nutrient balance. Aiming to test a macroscopic root water extraction model based on the microscopic process description, an experiment was described in which the root system of plants penetrated different soil layers with contrasting hydraulic properties. Four lysimeters containing two physically divided compartments were built and filled with material of two soils with different […]

Wheat is the main winter crop in Rio Grande do Sul State, Brazil, and the calculation of soil water balance is an important element in simulation models for crop growth, development and yield. The objective of this study was to improve the water balance estimation in soil under wheat by two modified models. The soil water content was measured by the gravimetric method during the growing season of two wheat cultivars sown on three dates in Santa Maria, RS, Brazil. […]

Water is a critical component of plant metabolism, and a reduction in soil water availability may affect crop growth, development and yield. The objective of this study was to quantify the influence of soil water deficit on transpiration and on some growth (plant height and stem diameter) and development (main stem leaf number) parameters of Eucalyptus grandis (Hill ex Maiden) and E. saligna (Smith) seedlings. For this purpose, a greenhouse experiment was conducted at the Federal University of Santa Maria, […]