scholarly journals Three-dimensional monitoring of soil water content in a maize field using electrical resistivity tomography

2012 ◽  
Vol 9 (7) ◽  
pp. 8535-8578 ◽  
Author(s):  
L. Beff ◽  
T. Günther ◽  
B. Vandoorne ◽  
V. Couvreur ◽  
M. Javaux

Abstract. A good understanding of the soil water content (SWC) distribution at the field scale is essential to improve the management of water, soil and crops. Recent studies proved that electrical resistivity tomography (ERT) opens interesting perspectives in the determination of the SWC distribution in 3 dimensions (3-D). We conducted this study (1) to check and validate the sensitivity of ERT for monitoring SWC distribution in a maize field during the late growing season; and (2) to investigate how maize plants and precipitations affect the dynamics of SWC distribution. We used time domain reflectometry (TDR) measurements to validate ERT-inverted SWC values. We also calculated the evolution of water mass balance to check whether ERT was capable of giving a reliable estimate of soil water stock evolution. We observe that ERT is able to give the same average SWC as TDR (R2 = 0.98). In addition, we showed that ERT give better estimates of the water stock than TDR thanks to its higher spatial resolution. The high resolution of ERT measurements also allows the discrimination of SWC heterogeneities. The SWC distribution shows that alternation of maize rows and inter-rows is the main influencing factor of the SWC distribution. The drying patterns are linked to the root profiles, with drier zones under the maize rows. During small dry periods, the SWC decrease occurs mainly in the two upper soil horizons and in the inter-row area. At the opposite, precipitations increase the SWC mostly under the maize rows and at the upper soil layer. Nevertheless, the total amount of rainfall during the growing season is not sufficient to modify the SWC patterns induced by the maize rows. During the experimental time, the SWC redistribution hardly occurred from maize rows to the inter-rows but lateral redistribution from the inter-row to the maize rows induced by potential gradient generates SWC decrease in the inter-rows area and in the deeper soil horizons.

2013 ◽  
Vol 17 (2) ◽  
pp. 595-609 ◽  
Author(s):  
L. Beff ◽  
T. Günther ◽  
B. Vandoorne ◽  
V. Couvreur ◽  
M. Javaux

Abstract. A good understanding of the soil water content (SWC) distribution at the field scale is essential to improve the management of water, soil and crops. Recent studies proved that Electrical Resistivity Tomography (ERT) opens interesting perspectives in the determination of the SWC distribution in 3 dimensions (3-D). This study was conducted (i) to check and validate how ERT is able to monitor SWC distribution in a maize field during the late growing season; and (ii) to investigate how maize plants and rainfall affect the dynamics of SWC distribution. Time Domain Reflectometry (TDR) measurements were used to validate ERT-inverted SWC values. Evolution of water mass balance was also calculated to check whether ERT was capable of giving a reliable estimate of soil water stock evolution. It is observed that ERT was able to give the same average SWC as TDR (R2 = 0.98). In addition, ERT gives better estimates of the water stock than TDR thanks to its higher spatial resolution. The high resolution of ERT measurements also allows for the discrimination of SWC heterogeneities. The SWC distribution showed that alternation of maize rows and inter-rows was the main influencing factor of the SWC distribution. The drying patterns were linked to the root profiles, with drier zones under the maize rows. During short periods, with negligible rainfall, the SWC decrease took place mainly in the two upper soil horizons and in the inter-row area. In contrast, rainfall increased the SWC mostly under the maize rows and in the upper soil layer. Nevertheless, the total amount of rainfall during the growing season was not sufficient to modify the SWC patterns induced by the maize rows. During the experimental time, there was hardly any SWC redistribution from maize rows to inter-rows. Yet, lateral redistribution from inter-rows to maize rows induced by potential gradient generates SWC decrease in the inter-row area and in the deeper soil horizons.


2007 ◽  
Vol 6 (2) ◽  
pp. 123-132 ◽  
Author(s):  
Joerg Rings ◽  
Alexander Scheuermann ◽  
Kwasi Preko ◽  
Christian Hauck

2019 ◽  
Author(s):  
Benjamin Mary ◽  
Luca Peruzzo ◽  
Jacopo Boaga ◽  
Nicola Cenni ◽  
Myriam Schmutz ◽  
...  

Abstract. This paper presents a time-lapse application of electrical methods (Electrical Resistivity Tomography – ERT – and Mise-à-la-Masse – MALM) for monitoring plant roots and their activity (root water uptake) during a controlled infiltration experiment. The use of non-invasive geophysical monitoring is of increasing interest as these techniques provide time-lapse imaging of processes that otherwise can only be measured at few specific spatial locations. The experiment here described was conducted in a vineyard in Bordeaux (France) and was focused on the behaviour of two neighbouring grapevines. The joint application of ERT and MALM has several advantages. While ERT in time-lapse mode is sensitive to changes in soil electrical resistivity and thus to the factors controlling it (mainly soil water content, in this context), MALM uses DC current injected in a tree stem to image where the plant-root system is in effective electrical contact with the soil at locations that are likely to be the same where root water uptake (RWU) takes place. Thus ERT and MALM provide complementary information about the root structure and activity. The experiment shows that the region of likely electrical current sources produced by MALM does not change significantly during the infiltration study time in spite of the strong changes of electrical resistivity caused by changes in soil water content. This fact, together with the evidence that current injection in the soil produces totally different patterns, corroborates the idea that this application of MALM highlights the active root density in the soil. When considering the electrical resistivity changes (as measured by ERT) inside the stationary volume of active roots delineated by MALM, the overall tendency is towards a resistivity increase, which can be linked to a decrease in soil water content caused by root water uptake. On the contrary, when considering the soil volume outside the MALM-derived root water uptake region, the electrical resistivity tends to decrease as an effect of soil water content increase caused by the infiltration. The results are particularly promising, and the method can be applied to a variety of scales including the laboratory scale where direct evidence of roots structure and root water uptake can help corroborate the approach. Once fully validated, the joint use of MALM and ERT can be used as a valuable tool to study the activity of roots under a wide variety of field conditions.


SOIL ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 95-114 ◽  
Author(s):  
Benjamin Mary ◽  
Luca Peruzzo ◽  
Jacopo Boaga ◽  
Nicola Cenni ◽  
Myriam Schmutz ◽  
...  

Abstract. This paper presents a time-lapse application of electrical methods (electrical resistivity tomography, ERT; and mise-à-la-masse, MALM) for monitoring plant roots and their activity (root water uptake) during a controlled infiltration experiment. The use of non-invasive geophysical monitoring is of increasing interest as these techniques provide time-lapse imaging of processes that otherwise can only be measured at few specific spatial locations. The experiment here described was conducted in a vineyard in Bordeaux (France) and was focused on the behaviour of two neighbouring grapevines. The joint application of ERT and MALM has several advantages. While ERT in time-lapse mode is sensitive to changes in soil electrical resistivity and thus to the factors controlling it (mainly soil water content, in this context), MALM uses DC current injected into a tree stem to image where the plant root system is in effective electrical contact with the soil at locations that are likely to be the same where root water uptake (RWU) takes place. Thus, ERT and MALM provide complementary information about the root structure and activity. The experiment shows that the region of likely electrical current sources produced by MALM does not change significantly during the infiltration time in spite of the strong changes of electrical resistivity caused by changes in soil water content. Ultimately, the interpretation of the current source distribution strengthened the hypothesis of using current as a proxy for root detection. This fact, together with the evidence that current injection in the soil and in the stem produces totally different voltage patterns, corroborates the idea that this application of MALM highlights the active root density in the soil. When considering the electrical resistivity changes (as measured by ERT) inside the stationary volume of active roots delineated by MALM, the overall tendency is towards a resistivity increase during irrigation time, which can be linked to a decrease in soil water content caused by root water uptake. On the contrary, when considering the soil volume outside the MALM-derived root water uptake region, the electrical resistivity tends to decrease as an effect of soil water content increase caused by the infiltration. The use of a simplified infiltration model confirms at least qualitatively this behaviour. The monitoring results are particularly promising, and the method can be applied to a variety of scales including the laboratory scale where direct evidence of root structure and root water uptake can help corroborate the approach. Once fully validated, the joint use of MALM and ERT can be used as a valuable tool to study the activity of roots under a wide variety of field conditions.


Soil Science ◽  
2010 ◽  
Vol 175 (10) ◽  
pp. 469-473 ◽  
Author(s):  
Zhaoqiang Ju ◽  
Xiaona Liu ◽  
Tusheng Ren ◽  
Chunsheng Hu

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