Effect of mixed
inoculants of phosphate solubilizing bacteria and Azotobacter chroococcum in the Papa
“Criolla” var. Yema de Huevo (Solanum phureja) crops
Faccini, G[1];
Garzón, S1; Martínez, M2;Varela, A[2]
2 Grupo de
Biotecnología Ambiental e Industrial, Lab. Microbiología
Ambiental y de Suelos. Facultad de Ciencias.1Carrera de
Bacteriología.
Pontificia Universidad
Javeriana. Cra. 7 No. 43-82 of. 111 Bogotá, Colombia
4 isolates of PSB (Pseudomonas cepacia, Xanthomona maltophilia,
Enterobacter cloacae and Acidovorans
delafieldii, called before P. delafieldii) and 4 of Azotbacter chroococcum,
isolated from previous works (Martínez, A and Moreno, A, 1996; Cuenca, D
and González, A, 1996) were chosen. They didn’t show antagonism
among themselves, by means of in vitro tests made on GISA medium (PSB-Azotobacter modified medium).
A dual inoculum was made with the 8 isolates in 4.6 L of sterile GISA
broth, which was in continous aireation. This dual inoculum was taken to a
field sample where seeds of “criolla” potato var. Yema de Huevo (Solanum
phureja) were planted in 15 threshing floor
that at the same time were divided in 5 treatments, each one with 3 repetitions
(T1: negative control; T2: NPK 10:30:10 100%; T3: NPK 10:30:10 50% + 20 L/Ha of
the dual inoculum; T4: 20 L/Ha of the dual inoculum and T5: NPK 10:30:10 50%).
120 days after,
the statistics analyses showed that in height of the stem, dry weight of the
root, number of tubers and soil available phosphorus, there were significant
differences between the treatments. In the rest of variables, there were no
differences between them.
With the a posteriori test of Tukey, it was possible to determine that
with chemical fertilization with or without dual inoculum, the height of the
stem, the fresh weight of plants, fresh weight of leafes and tubers, the
results were significantly greater than with the other treatments. The dry
weight of roots, and the soil available N, showed better results with the
inoculation of 50% of the inoculum + 50% of chemical fertilizer. The number of
tubers showed better results with 100% of the fertilizer.
A
dual inoculum of PSB and Azotobacter chroococcum like the one that was used in this research, will mantain the
production (Ton/Ha) of “criolla” potato var. Yema de Huevo (Solanum
phureja) similar to the production in
cultivations with 100% NPK fertilization only, and at the same time contribute
on the reduction of costs in about 7.4%, wich have favorable implications in
economical and environmental levels.