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

Abstract

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.

Management of trickle irrigation for banana: Hydrodynamic processes and sensor placement at the root zone

“…The ideal regions of sensor placement found was up to 0.75 m, from the pseudo-stem and up to 0.33 m deep, towards the microsprinkler for treatment T1; up to 0.80 m from pseudo-stem and up to 0.48 m deep for treatment 2; and up to 0.83 m from pseudo-stem towards the micro-sprinkler, and up to 0.55 m deep for treatment 3. These results are in agreement with those proposed by Silva et al (2018), who applied the concept of Time Stable Representative Proposition (TSRP) and found two patterns of water uptake for banana crops as a function of the developmental stages: one characterizes the initial and vegetative growth stage, when the effective water extraction occurs up to the distance of 0.70 m from the plant, and the other characterizes the flowering and fruit growth stages, when the effective extraction occurs up to 0.90 m from and T3) and drip (T4 and T5) T1 -Micro-sprinkler, 70 L h -1 and one emitter for four plants located in one lateral line between two plant rows; T2 -Micro-sprinkler, 53 L h -1 and one emitter for four plants located in one lateral line between two plant rows; T3 -Micro-sprinkler, 35 L h -1 and one emitter for four plants located in one lateral line between two plant rows; T4 -Dripper, 4 L h -1 and one lateral line per plant row with on-line emitters spaced 0.7 m apart; T5 -Dripper, 4 L h -1 and two lateral lines per plant row with on-line emitters spaced 0.7 m apart * -Significant at p ≤ 0.05 by F test T1 -Micro-sprinkler, 70 L h -1 and one emitter for four plants located in one lateral line between two plant rows; T2 -Micro-sprinkler, 53 L h -1 and one emitter for four plants located in one lateral line between two plant rows; T3 -Micro-sprinkler, 35 L h -1 and one emitter for four plants located in one lateral line between two plant rows; T4 -Dripper, 4 L h -1 and one lateral line per plant row with on-line emitters spaced 0.7 m apart; T5 -Dripper, 4 L h -1 and two lateral lines per plant row with on-line emitters spaced 0.7 m apart Table 2. Distances from plant and soil depth for placement water content or potential sensors in the root zone of banana crops the plant.…”

“…These results may be used with confidence, since the sensor placement region in the soil recommended in this study are within the limits reported by Silva et al (2009), who determined positioning of sensors for banana crops irrigated by micro-sprinklers under sub-humid climate and recommend the range of 0.10 and 0.80 m from the pseudo-stem, up to the depth of 0.25 m. Moreover, the recommended range of distance and depth are within the limits reported by Coelho et al (2010), who proposed an ideal zone to placing sensors in soils with banana crops irrigated by four drippers per plant of 0.50 m from pseudo-stem and up to 0.35 m deep. Regarding the percent distribution of water extraction relative to soil depth, two patterns of soil water extraction distribution were also found by Silva et al (2018): the first characterizes the initial and vegetative growth stages, when the effective water extraction occurs up to depth of 0.30 m, and the second characterizes the flowering and fruit growth stages, when the effective water extraction reaches the depth of 0.40 m.…”

“…The effective root depth and distance (Sant' Ana et al, 2012) combined with the effective root-extraction depth and distance have been recommended as limits for sensor placement in irrigation systems (Santos et al, 2005;Coelho et al, 2007). However, root uptake varies with time and space in the effective root zone (Silva et al, 2018). Thus, the effective root zone for sensor placement also depends upon the crop type, soil type, irrigation system, and age of plants (Coelho et al, 2007).…”

Analysis of the Variability in Soil Moisture Measurements by Capacitance Sensors in a Drip-Irrigated Orchard

“…Therefore, the optimal choice of sensor location will depend on the intended usage. Some authors [ 78 ], in a study on banana crops, established that the optimal position of the sensors for irrigation scheduling purposes varied according to the crop growth stage. Other authors [ 57 , 75 , 79 ] used two or more depths to monitor SWC.…”

Monitoring water content changes in a soil profile with TDR-probes at just three depths - How well does it work?

“…irrigation scheduling) data on water content changes in the soil are required. The efficient use of water resources also depends on the accuracy of the measured soil water content (Lozoya et al, 2016;Silva et al, 2018).…”