Webinar-Soil electrical conductivity: Managing salts for sustained high yields

[@michelbisson6645]

so what do you recommand to correct salt content?

[@METERGroup]

Hi Michel, thanks so much for reaching out! You can get answers to your application questions by emailing [e-mail]. Our scientists will get back to you shortly with all the answers you need to your technical questions. Have a great day!

[@cpfglobalagronomics6162]

I have a question for Dr Campbell...the chart "Salt Concentration vs. EC and Osmotic Potential" in this presentation suggests that 1 dS/m EC has the equivalent osmotic potential of -40 kPa. Plant response to soil salinity 0-2 dS/m is considered "negligible" in this range but according to the chart, at 2 dS/m plants would experience an osmotic potential of -80 kPa, which is quite dry soil in addition to the effect of matric potential, the two of which are additive. This makes no sense to me. Further, between 2 and 4 dS/m EC, growth "may be restricted" according to published tables, but the osmotic potential a plant would experience at 4 dS/m would be a dangerously dry -160 kpa even at field capacity? I suspect I'm missing something here but can't tell what it is.

[@METERGroup]

Thanks for the question! Your analysis seems correct but understanding of potential impact of various water potentials on plant performance seems more extreme than I’ve experienced in our work. We’ve given a few virtual seminars on plant performance at various water potentials. In potatoes, for example, a water potential getting close to the accepted -1,500 kPa showed reduction in yield toward 25%. In turfgrass, water potentials approaching -500 kPa correlated with plants stopping water uptake in a coarse sand. From these experiments, a water potential of -140 kPa would indicate to me a slightly-less than optimal water condition but not something that would endanger the plant. For more discussion on water potential ranges for plants, watch this webinar: metergroup.com/webinars/soil-moisture-why-water-content-cant-tell-you-everything-you-need-to-know/. Still, having an osmotic potential of -140 kPa before adding in a soil matric potential does raise the risk of plant stress (and possible salt toxicity) considerably, especially if the osmotic potential level remains undetected. Hope that helps.

[@cpfglobalagronomics6162]

@@METERGroup Thanks for replying to my comment. I don't know anything about potatoes or turfgrass, but corn is a water-demanding crop requiring careful attention to matric potential in the effective root zone to raise the yield curve. In arid and semi-arid environments salt accumulation is an ever-present concern as well as coastal areas affected by salt water intrusion. Water potential from -20 to -100 is the agronomic range for most crops, with maximum allowable depletion roughly half that. How do you factor in osmotic potential?

[@METERGroup]

Dr. Gaylon Campbell will be giving a virtual seminar on this material soon - he even has a graph in the presentation related to yield loss in corn related to salinity. You can register for the live webinar here: metergroup.com/webinars/using-the-salt-balance-to-irrigate-more-efficiently/