Salinity and Compost Amendment Impact on Al-Kaline Phosphate Activity in Rhizoshere of Tomato and Bean plants.

Abstract

The aim of this study is to investigate the activity of alkaline phosphatase (extracellular enzyme) in vertical and horizontal developing direc tions of rhizosphere (0-5 and 5-10) cm . The plots experiment is performed in College of Agriculture / University of Al-Qadissiya for the spring season 2013 ,the sandy loam soil is used to cultivate Tomato (Lycopersicon Esculentum mill) and Bean (Phaseolus Vulgaris L.) plants under salinity levels (without salinity , 6 , 8 and 10) dS.m-1 and compost levels (0,10 and 20)T.h-1 , their interactions completely randomized design (CRD) is used with six replicates, and the means of treatments are compared by L.S.D test 5% level . The results are summarized as : 1- The enzyme activity are increased with increasing of the adding compost level 20Ton.h-1 and its interactions with salinity levels . 2- The enzymes activity are varied in rhizosphere development directions and the plants are differ in the site of highest activity , the enzyme activity in horizontal rhizosphere development direction is higher than the vertical direction . 3- The enzyme activity in bean rhizosphere is higher than in Tomato rhizosphere in activity except of the alkaline phosphatase at all rhizoshere vertical and horizontal directions . 4- The high inhibitor percentage of enzyme activity is at the level of 10 dS.m-1 salinity and the lowest is at the 6 dS.m-1 . The inhibition percentage are increased in vertical direction of rhizosphere developing (5-10)cm in tomato plant. The adding compost levels are varied by increasing or decreasing of enzyme activity according to rhizosphere development and it sites ..