Evaluation of Drainage from Passive Suction and Nonsuction Flux Meters in a Volcanic Clay Soil under Tropical Conditions Export

@article{citeulike:481239, abstract = {Root zone drainage measurements are needed to improve fertilizer management in areas where agriculture may be impacting groundwater supplies. We present results of field tests where drainage was measured with two types of suction (resolution of 0.16 and 1.6 mm tip-1) and a nonsuction (resolution of 0.22 mm tip-1) water flux meter (WFM). The soil was a microstructured weathered volcanic ash located on a coral atoll subject to intense rainfall and located in the Kingdom of Tonga. Our objectives were to evaluate water flux measurements by comparing them with (i) simple water balance estimates of cumulative fluxes, (ii) cumulative fluxes deduced from soil moisture content changes, and (iii) simulated fluxes using HYDRUS-1D. Soil hydraulic properties were obtained at five soil depths. During the 60-d evaluation period rainfall totaled 340 mm. The WFMs were installed in duplicate using disturbed soil. The consistency of the shape of the drainage curves measured with the WFMs, those derived from soil moisture changes, and those obtained with modeling led us to conclude that soil disturbance during WFM installation did not severely influence measurements. This was attributed to the strong microaggregation and disturbance introduced by plowing. Water balance and HYDRUS model estimates of drainage corresponded well with the measurement by nonsuction WFMs. Suction WFMs overestimated drainage, possibly due to flow convergence created by wick and divergence barrier lengths being not properly sized for the observed flow conditions. After the evaluation period some of the WFMs failed to respond. Nevertheless, flux meters are seen as promising tools to provide remote and continuous measurement of root zone drainage.}, author = {van der Velde, M. and Green, S. R. and Gee, G. W. and Vanclooster, M. and Clothier, B. E.}, citeulike-article-id = {481239}, citeulike-linkout-0 = {http://dx.doi.org/10.2136/vzj2005.0011}, citeulike-linkout-1 = {http://vzj.scijournals.org/cgi/content/abstract/4/4/1201}, comment = {includes mention of water flux meter manufacturers Decagon and Slade}, day = {16}, doi = {10.2136/vzj2005.0011}, journal = {Vadose Zone J}, keywords = {edaphology, flux, soil, vadose, water, zone}, month = {November}, number = {4}, pages = {1201--1209}, posted-at = {2006-01-26 04:36:05}, priority = {0}, title = {Evaluation of Drainage from Passive Suction and Nonsuction Flux Meters in a Volcanic Clay Soil under Tropical Conditions}, url = {http://dx.doi.org/10.2136/vzj2005.0011}, volume = {4}, year = {2005} }

TY - JOUR ID - citeulike:481239 L3 - citeulike-article-id:481239 N2 - Root zone drainage measurements are needed to improve fertilizer management in areas where agriculture may be impacting groundwater supplies. We present results of field tests where drainage was measured with two types of suction (resolution of 0.16 and 1.6 mm tip-1) and a nonsuction (resolution of 0.22 mm tip-1) water flux meter (WFM). The soil was a microstructured weathered volcanic ash located on a coral atoll subject to intense rainfall and located in the Kingdom of Tonga. Our objectives were to evaluate water flux measurements by comparing them with (i) simple water balance estimates of cumulative fluxes, (ii) cumulative fluxes deduced from soil moisture content changes, and (iii) simulated fluxes using HYDRUS-1D. Soil hydraulic properties were obtained at five soil depths. During the 60-d evaluation period rainfall totaled 340 mm. The WFMs were installed in duplicate using disturbed soil. The consistency of the shape of the drainage curves measured with the WFMs, those derived from soil moisture changes, and those obtained with modeling led us to conclude that soil disturbance during WFM installation did not severely influence measurements. This was attributed to the strong microaggregation and disturbance introduced by plowing. Water balance and HYDRUS model estimates of drainage corresponded well with the measurement by nonsuction WFMs. Suction WFMs overestimated drainage, possibly due to flow convergence created by wick and divergence barrier lengths being not properly sized for the observed flow conditions. After the evaluation period some of the WFMs failed to respond. Nevertheless, flux meters are seen as promising tools to provide remote and continuous measurement of root zone drainage. IS - 4 JF - Vadose Zone J EP - 1209 TI - Evaluation of Drainage from Passive Suction and Nonsuction Flux Meters in a Volcanic Clay Soil under Tropical Conditions VL - 4 SP - 1201 KW - edaphology KW - flux KW - soil KW - vadose KW - water KW - zone N1 - includes mention of water flux meter manufacturers Decagon and Slade AU - van der Velde, M AU - Green, SR AU - Gee, GW AU - Vanclooster, M AU - Clothier, BE PY - 2005/11/16/ UR - http://dx.doi.org/10.2136/vzj2005.0011 ER -