RESPONSE OF TWO SEEDLESS GRAPEVINE CULTIVARS GROWN ON SANDY CALCAREOUS SOIL TO SOME PHOSPHATE DISSOLVING BACTERIA TREATMENTS

Abstract

High pH level in Egyptian sandy calcareous soils (soil of Sedmant Al-Gabl -Beni Suef Governorate) led to fix the soluble phosphorus to insoluble form such as tricalcium phosphate.In this study, two grapevine cvs Early Superior and Superior were treated with phosphorien as a source of phosphate dissolving bacteria "Bacillus megatherium" at 20g/vine once, twice or thrice addition for three consecutive seasons namely 2012/2013, 2013/2014 and 2014/2015.The study showed that, vines treated with phosphorien significantly increased the leaf area and shoot length especially in the third season.Application of phosphorien resulted in a significant effect on leaf mineral contents especially NPK as compared with untreated vines.Neither Superior nor Early Superior showed significant differences in magnesium contents for the three experimental seasons and calcium for the first and second seasons, whatever the number of applications.Yield per vine significantly increased as a result of phosphorien treatments in both cultivars especially was for the vines received phosphorien three times.The response of berries chemical content to phosphorien application was much more remarkable than those of physical properties, except those of cluster weight.However, T.S.S and reducing sugars were significantly increased as a result of phosphorien treatment in both cultivars.An obvious decrease in total acidity was noticed due to the use of phosphorien, this increment was more remarkable for the Superior cultivar.The investigated treatment had no negative effect on the overall quality characteristics of berries.To overcome soil Phosphorus fixation problem and to stimulate growth and fruiting of Superior and Early Superior grapevines growing under sandy calcareous soil, application of phosphorien at rate of 20 g/vine three times a yearly is highly recommended.