Agricultural Research,Education and Extension Organization Iranian Journal of Soil Research 2228-7124 22 2 2009 02 19 Investigation the Effects of Salinity and Soil Phosphorus on Respiration, Microbial Biomass and Phosphatase Activities in the Rhizosphere of Berseem Clover (Trifolium alexandrinum L.) Investigation the Effects of Salinity and Soil Phosphorus on Respiration, Microbial Biomass and Phosphatase Activities in the Rhizosphere of Berseem Clover (Trifolium alexandrinum L.) 217 223 127000 10.22092/ijsr.2009.127000 FA M. Ghollarata Researcher Fayez Raiesi Associate Professor, Shahr-e Kord University H. Nadian Associate Professor, Molla Sani-e Ahvaz University Journal Article 2006 10 02 In order to investigate the effects of salinity and soil phosphorus on respiration, microbial biomass and phosphatase activities in the rhizosphere of berseem clover (<em>Trifolium alexandrinum </em>L.), an factorial experiment was arranged in a randomized complete block design with four levels of salinity (S₁= 0.12, S₂= 2, S₃= 6 and S₄= 10 dS/m) and two levels of phosphorus (P₁= 10 and P₂= 30 mg/kg ) from KH₂PO₄ sources with four replications under greenhouse conditions. Different levels of salinity were produced by NaCl, MgCl₂, Na₂SO₄ and MgSO₄ with weight proportional 2, 1, 1 and 1 respectively. The traits such as Soil respiration, Substrate-Induced Respiration (SIR), Microbial biomass and activities of Acid and Alkaline phosphatase enzymes in the rhizosphere of berseem clover were measured. The salinity was applied using saline water with the above- mentioned electrical conductivities. The results show that an increase in soil phosphorus increases soil respiration but decreased microbial biomass, SIR and acivities of acid and alkaline phosphatase. All measured traits were reduced with an increase in salinity.  In order to investigate the effects of salinity and soil phosphorus on respiration, microbial biomass and phosphatase activities in the rhizosphere of berseem clover (<em>Trifolium alexandrinum </em>L.), an factorial experiment was arranged in a randomized complete block design with four levels of salinity (S₁= 0.12, S₂= 2, S₃= 6 and S₄= 10 dS/m) and two levels of phosphorus (P₁= 10 and P₂= 30 mg/kg ) from KH₂PO₄ sources with four replications under greenhouse conditions. Different levels of salinity were produced by NaCl, MgCl₂, Na₂SO₄ and MgSO₄ with weight proportional 2, 1, 1 and 1 respectively. The traits such as Soil respiration, Substrate-Induced Respiration (SIR), Microbial biomass and activities of Acid and Alkaline phosphatase enzymes in the rhizosphere of berseem clover were measured. The salinity was applied using saline water with the above- mentioned electrical conductivities. The results show that an increase in soil phosphorus increases soil respiration but decreased microbial biomass, SIR and acivities of acid and alkaline phosphatase. All measured traits were reduced with an increase in salinity.  https://srjournal.areeo.ac.ir/article_127000_7c9a091ac0529de63488c95b7c75c18d.pdf