Response of superior grapevines to soil inoculation with some phosphorus solubilizing bacteria transformats

Abstract EN

During 2015 and 2016 seasons, laboratory and field experiments were carried out.

Laboratory experiment aimed to produce three transformats of solubilizing P bacterial from exposing wild Actinomyces sp.

to irradiation with Ultraviolet rays (UV) for one to five minutes.

All newly transformats were derived from bacillus megatherium var.

phosphaticum.

In the other filed experiment as a slow release P fertilizer i.e.

rock phosphate (19.3% P2O) besides any one of the previous three newly P transformats were used as a partial replacement of mineral P (MP) namely triple calcium superphosphate (37.5% P2O5) in Superior vineyards.

Results showed that using P at 50 to 75% mineral P, 25 to 50% Rock phosphate and any one of the produced P bacterial transformats (1,2 or 3) was very effective in enhancing leaf chemical components (chlorophyll a, b, total chlorophylls, total carotenoids as well as percentages cane total carbohydrates, N, P, K, Mg, Ca and S), berry set (%), yield and quality of the berries over the application of P as 100% mineral P or when P was added as 25% mineral P with 75% rock phosphate and any one of P microbial transformats.

The best P microbial transformats in terms of increasing growth characteristics, vine nutritional status, berry setting (%),yield and cluster aspects could be arranged, in descending order as follows transformats 3, 1 and 2(Bacillus megatherium var.

phosphaticum).

Quality of the berries was greatly improved in response to using transformats 3 and 2 and 1, in ascending order.

Using rock phosphate at 50% and P bacterial transformats 3 at 10 ml/vine as a partial replacement of 50 % mineral P fertilizer in Superior vineyards gave the best results with regard to the yield and fruit quality.