Estimating water application efficiency for drip irrigation emitter patterns on banana

Sci. agric. (Piracicaba, Braz.)

Filho

2015

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Spatial and temporal variability of soil water extraction from the root zone affect soil water balance determination. The number of sensors installed in the root zone in studies addressing water balance is still set arbitrarily. This study provided an investigation of the water extraction process by banana (Musa spp.) roots by (i) determining the variability of water extraction from the banana tree root zone, (ii) detecting differences in the estimation of evapotranspiration (ET) by the soil water balance method when the number of soil profiles monitored in the roots zone varies, (iii) and; determining the minimum number of Time Domain Reflectometry (TDR) probes needed to obtain ET precision and accuracy similar to that determined by a drainage lysimeter. The field experiment was conducted in Cruz das Almas, in the state of Bahia, Brazil, where a drainage lysimeter was installed on a banana plantation. The water extraction in the banana root zone was quantified by the water content variations monitored in 72 points by TDRs, with measurements at 15-min intervals. The variability of water extraction in the banana root zone was medium to high. The range of variability affects the reliability of the crop evapotranspiration calculation by the soil water balance method. To prevent an overestimation of banana evapotranspiration, the water extraction in the soil profile must be monitored with at least 16 TDR probes installed at a minimum distance of 0.9 m and a minimum depth of 0.7 m.

Section: Et Variation With Different Numbers Of Radial Distances (R 1mentioning

confidence: 99%

Water extraction variability in the banana root zone affects the reliability of water balance

Sci. agric. (Piracicaba, Braz.)

Filho

2015

Self Cite

“…However, root water extraction may vary in space and time regardless of root concentration (Clothier and Green, 1994;Silva et al, 2009;Javaux et al, 2008;Raza et al, 2013). This variability has been studied by Silva et al (2015) for banana crop and the authors reported that it is necessary at least 16 time domain reflectometry (TDR) probes to be installed at a minimum distance from plant of 0.9 m and a minimum soil depth of 0.7 m to prevent an overestimation of banana crop evapotranspiration.…”

Section: Introductionmentioning

confidence: 99%

Water extraction and implications on soil moisture sensor placement in the root zone of banana

Sci. agric. (Piracicaba, Braz.)

Filho

et al. 2018

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ABSTRACT:The knowledge on spatial and temporal variations of soil water storage in the root zone of crops is essential to guide the studies to determine soil water balance, verify the effective zone of water extraction in the soil and indicate the correct region for the management of water, fertilizers and pesticides. The objectives of this study were: (i) to indicate the zones of highest root activity for banana in different development stages; (ii) to determine, inside the zone of highest root activity, the adequate position for the installation of soil moisture sensors.

“…Several studies have used time-domainreflectometry (TDR) to estimate the water flow in unsaturated soils (Wessolek et al, 2008;Silva et al, 2009;Selle et al, 2011;Baram et al, 2012;Séré et al, 2012). In this case, the procedures to use the TDR technique being well-known, the percolation levels can be calculated without the predetermination of the hydraulic properties.…”

Section: Introductionmentioning

confidence: 99%

Estimation of water percolation by different methods using TDR

2014

Rev. Bras. Ciênc. Solo

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Detailed knowledge on water percolation into the soil in irrigated areas is fundamental for solving problems of drainage, pollution and the recharge of underground aquifers. The aim of this study was to evaluate the percolation estimated by time-domain-reflectometry (TDR) in a drainage lysimeter. We used Darcy's law with K(θ) functions determined by field and laboratory methods and by the change in water storage in the soil profile at 16 points of moisture measurement at different time intervals. A sandy clay soil was saturated and covered with plastic sheet to prevent evaporation and an internal drainage trial in a drainage lysimeter was installed. The relationship between the observed and estimated percolation values was evaluated by linear regression analysis. The results suggest that percolation in the field or laboratory can be estimated based on continuous monitoring with TDR, and at short time intervals, of the variations in soil water storage. The precision and accuracy of this approach are similar to those of the lysimeter and it has advantages over the other evaluated methods, of which the most relevant are the possibility of estimating percolation in short time intervals and exemption from the predetermination of soil hydraulic properties such as water retention and hydraulic conductivity. The estimates obtained by the Darcy-Buckingham equation for percolation levels using function K(θ) predicted by the method of Hillel et al. (1972) provided compatible water percolation estimates with those obtained in the lysimeter at time intervals greater than 1 h. The methods of Libardi et al. (1980), Sisson et al. (1980) and van Genuchten (1980) underestimated water percolation.