|Ayars, James - Jim|
Submitted to: National Salinity Engineering Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/14/2004
Publication Date: 11/9/2004
Citation: Christen, E.W., Hornbuckle, J.W., Ayars, J.E. 2004. Methodology to assess the performance of subsurface drainage salinity control.. National Salinity Engineering Conference Proceedings. Engineers Australia, Engineering Salinity Solutions, pp 21-25. Interpretive Summary: This paper describes a methodology used to monitoring the impact of leaching on soil salinity over a 3 year period and then this information to describe the potential impact on grape development and yield. An initial salinity survey was done using an EM-38 electrical conductivity meter. This was followed with annual surveys for the next 2 years. Leaching was done after the first survey to prepare the site for grapevines. The subsequent surveys were used to characterize the effect of leaching and to evaluate the potential for crop growth. The cropping potential was based on the crop salt tolerance as characterized by the Maas-Hoffman threshold values and the existing soil salinity. The resulting maps showed a high degree of correlation between good growth and low salinity as measured by the EM-38. This procedure is an inexpensive and quick method to characterize the economic impact of drainage. It can also be used to guide subsequent leaching events to minimize subsurface drainage.
Technical Abstract: The performance of subsurface drainage systems is rarely evaluated after installation either for physical or financial performance. Moreover, assessments are rarely made regarding the completion of salinity reclamation and hence the need to move to a reduced drainage requirement. This paper provides a methodology based upon electromagnetic (EM) soil salinity survey to provide a temporal and spatial analysis of the effectiveness of subsurface drainage. This spatial assessment allows assessment of the efficacy of the drainage system, in terms of uniformity of reclamation and time to reclamation, and provides important data that can be used to instigate differential management of the subsurface drains. This may be to use controlled drainage to reduce salt loads and hence reduce salt loads requiring disposal. Using the EM surveys and plant salinity tolerances, maps of relative yield are produced and total yield per field estimated. This provides the basis for financial performance assessment of the subsurface drainage system.