بررسي تغييرات ويژگي هاي فيزيكوشيميايي و ميكرومورفولوژي خاك جنگل هاي طبيعي تبديل شده به شاليزارها در منطقه فومنات گيلان

Physico-Chemical and Micro-Morphological Changes in Paddy Soils Converted from Forest in Foomanat Region, Gilan

A vast area of Iranian forests plain near the Caspian Sea have been converted into paddy soils. The special management practices required for rice cultivation have changed the physico-chemical and micro-morphological properties of these soil. During the course of this study, it was intended to show these changes taken place in foomanat region. An adjacent pair of pedons in the forest land and paddy field in this area was selected. Morphological and physico-chemical studies were carried out. Microscopical studies on the thin sections and finally comparison between the pair of pedons were performed. These changes in physico-chemical soil properties mainly included decrease in soil organic matter, change in volume and type of voids, creation of reducing conditions, soil aggregates, and damage of its structure. Micro-morphological changes included impregnative diffuse sesquiocidic nodules, friargillan infillings and subsequently producing the condition for fragipan formation. Therefore, in this region, conversion of forest soils to paddy soils provided special soil properties, which make it impossible to carry out reforestation even with the original species.