Salinity

Salinity affects the respiration and photosynthesis of rice. It decreases biological N2 fixation and soil nitrogen mineralization. Its other effects on rice growth include;

• reduced germination rate
• reduced plant height and tillering
• poor root growth
• increased spikelet sterility

The major cause of salinity or sodicity include;

• poor irrigation practice or insufficient irrigation water in seasons/years with low rainfall
• high evaporation; Salinity is often associated with alkaline soils in inland areas where evaporation is greater than precipitation.
• increased level of saline groundwater
• salt water intrusion in coastal areas (e.g., Mekong Delta)

 

How to identify (symptoms)

• tips of affected leaves turn white
• pale, yellow or yellow-white patches as a result of chlorosis appear on some leaves
• plants stunting and reduced tillering
• patchy field growth

How to manage

• Grow salt-tolerant varieties by contacting your local agricultural office
• In rice-upland crop system, change to double rice-cropping if sufficient water is available and climate allows.
• Submerge the field for 2-4 weeks before planting rice. Leach the soil after planting under intermittent submergence to remove excess salt. 
• Collect and store low saline rainwater for irrigation of dry-season crops (eg., by establishing resevoirs)
• In coastal areas prevent intrusion of salt water.
• Use fertilizers efficiently.