Author
 |
Skaggs, Todd |
|
Poss, James |
|
Shouse, Peter |
|
Grieve, Catherine |
|
Submitted to: Vadose Zone Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/10/2006 Publication Date: 6/21/2006 Citation: Skaggs, T.H., Poss, J.A., Shouse, P.J., Grieve, C.M. 2006. Irrigating forage crops with saline waters 1. volumetric lysimeter studies. Vadose Zone Journal. 5:815-823. Interpretive Summary: The disposal of agricultural drainage waters into surface waters or onto lands leads to salinization and degraded soil and water quality. In regions lacking outlets for agricultural drainage disposal, the recycling of drainage waters for irrigation is increasingly seen as a viable management option. Modeling could potentially assist in the design of management practices for drainage reuse operations, but data are lacking about the accuracy of simulations of root water uptake under the dynamic, saline field conditions that are encountered in reuse systems. This study used a volumetric lysimeter system to gather data on the production of forage crops with saline drainage waters. The data will benefit scientists, engineers, and growers involved in the design and management of agricultural drainage reuse operations. Technical Abstract: In regions lacking outlets for agricultural drainage disposal, the recycling of drainage waters for irrigation is increasingly seen as a viable management option. Modeling could potentially assist in the design of management practices for drainage reuse operations, but data are lacking about the accuracy of simulations of root water uptake under the dynamic, saline field conditions that are encountered in reuse systems. This study used a volumetric lysimeter system to examine, within the context of drainage reuse management systems, relationships between irrigation water salinity, irrigation depth, forage crop biomass production (alfalfa and tall wheatgrass), evapotranspiration (ET), drainage depth, and drainage water quality. Findings include: (1) ET rates in the volumetric lysimeters were very high owing to clothesline and oasis effects; (2) the relationship between ET and yield differed from what has been reported in literature, possibly due to higher evaporation rates in abundantly watered, salt stressed treatments that had reduced canopy cover; (3) the salt tolerance exhibited by tall wheatgrass and alfalfa differed from what has been reported in the literature: the observed threshold salinity for tall wheatgrass was significantly lower than reported, whereas the threshold for alfalfa was higher; (4) leaching fractions varied greatly in response to both irrigation depth and irrigation water quality; (5) drainage water quality and depth varied in response to temporal variations in evapotranspiration. In a companion paper, the data are evaluated against a simulation model considered for use in the design of reuse management practices. |
