|Grattan, Stephen - DEPT LAWR, UC DAVIS, CA|
|Zeng, Linghe - USSL, UC RIV CO-OP|
|Scardaci, Steven - UC CO-OP EXT, COLUSA|
|Roberts, Stacy - AGRON & RANGE SCI, DAVIS|
Submitted to: California Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 9, 2002
Publication Date: November 1, 2002
Citation: Grattan, S.R., Zeng, L., Shannon, M.C., Scardaci, S.C., Roberts, S.R. 2002. Rice is more sensitive to salinity than previously thought. California Agriculture. 56(6):189-195. Interpretive Summary: Researchers from the University of California and the USDA-Agricultural Research Service (ARS) have gathered rather strong evidence which suggests that salinity is reducing rice yields in several locations within Colusa and Glenn counties. By monitoring the salinity in various fields, these researchers found that the electrical conductivity (EC) of the soil and field water increased in some areas with increasing distance from the water inlet. EC of the water was the best indicator of the salinity hazard which increased as salt concentration increased in the water. This salinity reduced crop yield. Literature indicates that rice is sensitive to salinity, particularly during the seedling stage. Therefore, irrigation management practices should be adopted to minimize salinity during these critical growth stages.
Technical Abstract: Studies conducted in the field by the University of California and controlled greenhouse conditions by the USDA-ARS indicate that rice is more sensitive to salinity than current guidelines suggest. This information is particularly important to a number of rice growers in Colusa and Glenn counties who have experienced salinity problems after adopting closed water management practices to reduce the loading of pesticides into the Sacramento River. Experiments have shown that an average seasonal salinity in excess of 1.9 dS/m, expressed as the electrical conductivity of the field water, can reduce grain yields. Salinity had a negative impact on a number of yield components including stand establishment, panicles/plant, tillers/plant, spikelets/plant, sterility, individual grain size and even delayed heading. Growth stages that were most sensitive to salinity were during seedling establishment and between the 3-leaf and panicle initiation stages. Therefore, irrigation management practices should be adopted to minimize salinity during these critical growth stages.