Effect of Natural and Bio-Fertilizers on Productivity and Quality of Table Beet (Beta vulgaris L.) Grown in Sandy Soil at Siwa Oasis, Egypt

El-Sayed, M. A. M, M.F. Attia and M. R, Hafez

A field experiment was conducted on table beet (Detrweet cv.) throughout two consecutive winter seasons of 2015/2016 and 2016/2017 in Khimisah experimental farm which is located at the latitude of 29°12' 34.5 N'', and the longitude of 25° 24' 2.56'' E., at Siwa Research Station, Matrouh Governorate, Desert Research Center, Cairo, Egypt. The field experiment was conducted in a randomized complete block design with split plot. The main factor was the mineral fertilizer (MF) at 62kgP2O5 + 100kgK2O/fed as calcium super phosphate (15.5% P2O5) + potassium sulfate (50%K2O) i.e. recommended dose (RD), 62kgP2O5 as rock phosphate (RP), 100kgK2O/fed as rock feldspar (RK) and RP+RK, while the sub main factor have been dedicated to the bio-fertilizers (BF) treatments i.e. without inoculation, with phosphate dissolving bacteria (PDB), with potassium solublizing bacteria (KSB) and PDB+KSB.

Results indicated that the most effective treatment was the interaction between (RP+RK) + (PDB+KSB) produced the highest significant values of growth, root yield and quality, beside available P and K in soil and their content and uptake by table beet plants as well as, the microbial densities and dehydrogenase activity in the rhizosphere of table beet. This treatment also resulted in the maximum total net profit and the maximum total benefit cost ratio "BCR" (i.e. total income/total cost) (4.32) as compared to the other treatments.

It can be concluded that the application of natural P and K rocks fertilizers in combination with P and K solubilizing bacteria in sandy soil such as Khimisah soil will increase soil available and plant uptake of nutrients, yield and quality close to those obtained by chemical phosphorus and potassium application. Thus, replacing these chemical phosphorus and potassium fertilizers by natural one will help in reducing environmental pollution, cheaper in price and produce safe human food especially in Siwa Oasis which is nature reserve.

Key words: Rock phosphate, Rock feldspar, P and K available and uptake, bio-fertilizers, table beet plant.