Dryland salinity occurs due to the replacement of deep-rooted perennial vegetation with shallow-rooted annual species.Long fallows in a cropping rotation can also be a cause.ryland salinity occurs due to the replacement of deep-rooted perennial vegetation with shallow-rooted annual species.
A baseball cap, sometimes also called snapback hat when worn as a fashion item, is a type of soft cap with a rounded crown and a stiff peak projecting in front.
By the mid 1970's (c1976) the headstock logo design changed to utilize a gold Martin style decal stating Sigma Guitars in script with Est. 1970 underneath in a smaller block font. The headstock shape was also modified, to be more deeply tapered and shaped to resemble their Martin brethren.hese rare, hard to find models were actually made in Japan and imported to, and guaranteed by Levin in Sweden. They cost more than the top of the range DR-41 at the time. They have a paper label stating Inspected and Guaranteed by Levin and Sigma Guitars est 1970 is inlaid on the headstock in abalone.