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

Abstract

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.

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

“…The only exception was observed in the vegetative growth stage, in one of the four soil profiles, and only for depths z = 0.1 m and z = 0.5 m, where the highest mean deviations were also observed (Figure 2A). This fact should be related to a higher growth rate of banana roots at this stage (Silva et al, 2015). roots (Steudle and Frensch, 1996;Barrowclough et al, 2000;Watt et al, 2008;Draye et al, 2010).…”

“…The data were obtained from the same experiment in study of Silva et al (2015). Thus, edaphoclimatic conditions, lysimeter installation and assembly, construction and installation of TDR probes, soil water content monitoring, irrigation system and management, planting and cultivation practices of the banana crop, and experimental period are the same as those used in the study previously mentioned.…”

“…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. Soulis et al (2015) used several numerical experiments and investigated the effect of soil moisture sensors positioning on irrigation efficiency, revealing that irrigation efficiency varied considerably among the different sensor positions investigated.…”

Soil water storage variability in a three-dimensional analysis in the root zone of irrigated melon

“…Detailed understanding on the spatial-temporal variation of soil water storage in the root zone of crops can promote recommendations, as well as the effective root depth for water uptake, promoting accuracy in the irrigation depth calculation (Silva et al 2015;Silva et al 2018).…”

Three-Dimensional Water Extraction in the Root Zone of Drip-Irrigated Tomato

“…Studies have shown the existence of variability of water extraction in the root zone of various crops (JAVAUX et al, 2008;COELHO FILHO, 2009;SRAYEDDIN;DOUSSAN, 2009;DABACH;SHANI;LAZAROVITCH, 2016). In a study with the banana crop Silva, Coelho and Coelho Filho (2015) observed that spatial variability of water extraction (WE) affects the crop evapotranspiration (ET) estimate through SWB. However, in the case of short-cycle crops it is still a hypothesis the claim that the WE variability can affect the precision and accuracy of the ET estimates by SWB.…”