% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@INPROCEEDINGS{Brogi:1008374,
      author       = {Brogi, Cosimo and Bogena, Heye Reemt and Pisinaras,
                      Vassilios and Köhli, Markus and Dombrowski, Olga and
                      Hendricks-Franssen, Harrie-Jan and Panagopoulos, Andreas and
                      Huisman, Johan Alexander and Babakos, Konstantinos and
                      Chatzi, Anna},
      title        = {{P}otential and limitations of cosmic-ray neutron sensors
                      for irrigation management in small fields},
      reportid     = {FZJ-2023-02320},
      year         = {2023},
      abstract     = {Given the expected increase of droughts related to climate
                      change, soil moisture (SM) monitoring will likely become
                      essential for farmers as it helps to reduce water
                      consumption while mitigating crop losses. Cosmic-Ray Neutron
                      Sensing (CRNS) is a promising SM monitoring method that is
                      based on the negative correlation between fast neutrons
                      originating from cosmic radiation and SM content. As CRNS
                      integrates SM over a large radius of ~130-210 m with a
                      penetration depth of ~15-85 cm, it has advantages over
                      point-scale and remote-sensing methods. However, it is yet
                      unclear how well CRNS can monitor areas with complex SM
                      heterogeneity, such as small irrigated fields. In this
                      study, two CRNS equipped with a novel gadolinium oxide
                      thermal shielding were installed in two small (~1.2 ha)
                      irrigated apple orchards located in the Pinios Hydrologic
                      Observatory (Greece). Each CRNS was supported by an Atmos41
                      all-in-one climate station, by water meters measuring
                      irrigation timing and amounts, and by a network of 12
                      wireless SM measurement nodes (SoilNet) that monitored SM at
                      5, 20 and 50 cm depth. The results showed that the CRNS was
                      sensitive to the weekly irrigation events, but that it
                      showed a general underestimation of the magnitude of SM
                      fluctuations caused by the irrigation, which resulted in a
                      RMSE of 0.058 cm3 cm-3. To better understand these results,
                      we used the URANOS model to simulate neutron transport for a
                      CRNS placed in the centre of a square irrigated field of
                      varying dimensions (0.5 to 8 ha). The simulation results
                      showed that CRNS can be used to monitor irrigation in fields
                      as small as 0.5 ha in certain SM conditions and that a
                      gadolinium-based thermal shielding provides the best
                      monitoring results due to the much-reduced detection of
                      thermal neutrons. Nonetheless, a considerable number of
                      detected neutrons (above $60\%)$ can originate outside the
                      target field if the irrigated field is small, and in such
                      cases a CRNS may not be able to clearly distinguish
                      irrigation from SM variations in the surroundings. In an
                      attempt to correct for such SM variations not related to
                      irrigation, an additional SoilNet node was installed outside
                      one of the two irrigated apple orchards in September 2021.
                      By combining the results of neutron transport simulations
                      with the information provided by this additional SoilNet
                      node, a correction of CRNS-derived SM was developed that
                      better captures both timing and magnitude of SM changes
                      (RMSE reduced to 0.031 cm3 cm-3). These results show that
                      the combination of real-world studies with neutron transport
                      simulations can help to establish CRNS as a reliable tool in
                      irrigation management.},
      month         = {Jun},
      date          = {2023-06-12},
      organization  = {EGU Galileo Conference, A European
                       vision for hydrological observations
                       and experimentation, Napoli (Italy), 12
                       Jun 2023 - 15 Jun 2023},
      subtyp        = {Other},
      cin          = {IBG-3},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {2173 - Agro-biogeosystems: controls, feedbacks and impact
                      (POF4-217) / DFG project 357874777 - FOR 2694: Large-Scale
                      and High-Resolution Mapping of Soil Moisture on Field and
                      Catchment Scales - Boosted by Cosmic-Ray Neutrons
                      (357874777)},
      pid          = {G:(DE-HGF)POF4-2173 / G:(GEPRIS)357874777},
      typ          = {PUB:(DE-HGF)24},
      doi          = {10.5194/egusphere-gc8-hydro-51},
      url          = {https://juser.fz-juelich.de/record/1008374},
}