Slide 21.   Surface sealing in furrows is often a problem in the Ord River area, because of the combined effects of sodium (in some cases) and intermittent rainfall.  PAM used in the furrows can stabilize soil against sealing, but unless PAM was sprinkler applied to the raised ridges or beds between furrows, it cannot prevent the effects of soil washing from these areas onto the treated furrows.  Once canopy growth has become sufficient, the erosion from the ridges ceases to be a problem, and PAM treatment of furrows after final cultivation, will usually provide several weeks of good soil protection.