دراسة تأثير التثبيت البيولوجي للكثبان الرملية المتحركة على الخصائص الفيزيائية والكيميائية للتربة في وادي زبيد، سهل تهامة- اليمن

Abstract

This work aims to study of effect of the biological fixation on physical and chemical properties of soil, it was conducted in the zabid valley, located at southern Tihama (Yemen), six sites were studied (AL Mukhayriyan, AL Shubayta, Kadf Ruma, AL Rawiyah, Auan, AL Maghras). soil samples were taken from each site from biological fixation dunes (from under the trees) and form null dunes at the same site. These samples were analyzed at Institute National of Agronomy in Tunnies. Several properties were compared for each site, soil texture, hydraulic conductivity, bulk density, field capacity, wilting permanent point, porosity, organic matter, N, P, K, and ph. The results showed that an improvement in the physical and chemical properties of the soil under biological fixation, compared to null dunes, this improvement has been influenced by density of the plantations. The local species such as acacia (Acacia tortilis, A. ehernbergiana), Palanits aegyptiaca and zyziphus-spina cristi are more adapted to growth on the sand dunes. We have observed that the forest plantations were deterioration, the local population has been negative impacted by overgrazing, logging or cutting. The biological fixation of the mobile dunes at Tihama plain need more studies and research for development and improvement of work mechanisms and positive effects on the stability ecosystem.