Influence of plant growth promoting rhizobacteria (PGPR ... - Eucarpia

Institute of Soil Science, Belgrade, Serbia
Influence of plant growth promoting rhizobacteria
(PGPR) on alfalfa, Medicago sativa L. yield
by inoculation of a preceding Italian ryegrass,
Lolium multiflorum Lam.
Dušica Delić 1 , Olivera Stajković-Srbinović 1 ,
Djordje Kuzmanović 1 , Nataša Rasulić 1 , Srboljub Maksimović 1 ,
Jasmina Radović 2 and Aleksandar Simić 3
1 Institute of Soil Science – Belgrade, Serbia
2 Institute for Forage Crops – Krusevac, Serbia
3 Faculty of Agriculture, University of Belgrade, Serbia
EUCARPIA 2011

Influence of plant growth promoting rhizobacteria on alfalfa, Medicago sativa L. yield by inoculation of
a preceding Italian ryegrass, . Lolium multiflorum Lam.
The aim of this study was to improve growth of Italian
raygrass and provide effective alfalfa nitrogen fixation
under unfavorable soil conditions.
The object of the study was to evaluate effects of a
preceding Italian ryegrass inoculation with PGPR on the
number of applied S. meliloti in the soil
as well as quality and quantity of Italian ryegrass as the
preceding crop and alfalfa as subsequent crop.
EUCARPIA 2011

Influence of plant growth promoting rhizobacteria on alfalfa, Medicago sativa L. yield by inoculation of
a preceding Italian ryegrass, Lolium multiflorum Lam.
PLANTS:
Alfalfa cultivar K-28
Italian ryegrass cultivar K-29t
MATHERIAL and METHODS
STRAINS:
Sinorhizobium meliloti: L3Si, 218, 207 and 4148ss:
Azotobacter vinelandi strain Av and Azotobacter chroococum strain
NDD
Enterobacter sp. strain E1
TREATMENTS: inoculated treatments and controls without
inoculation.
POT EXPERIMENT consisted of three parts:
• Inoculation of Italian ryegrass as preceding crop (in 2009)
• Determination of S. meliloti number after ryegrass cutting
• Inoculation of alfalfa as subsequent crop in comparison with
common inoculation of alfalfa (in 2010)
EUCARPIA 2011

Figure 1. Effect of bacterial inoculants on plant parameters of Italian ryegrass as preceding crop
SDW
mg pot -1
900
800
700
600
500
400
300
200
100
0
Av E1 Ao
NDD
L3Si 4148ss 207 218 Ø1 NØ
Bacterial strains
The highest average values of ryegrass shoot dry weight (SDW) were obtained in
inoculated treatments with A. vinelandi strain Av and S. meliloti strain 207 as well
as A. chroococum strain Ao NDD, 752.90, 701.20 and 658.15 mg pot -1 , respectively.
These results indicated that SDW was significantly influenced by inoculation with
these strains in respect to the other inoculated treatments and control-Ø.
EUCARPIA 2011
Total N
mg pot -1
40
35
30
25
20
15
10
5
0
SDW
Total N

Figure 2. Effect of previous crop seed inoculation on S. meliloti number in soil the following year
No of rhizobia
g-1 soil
100000
10000
1000
100
10
1
9500
3000
14000
140
L3Si 218 207 Ø3**
Number of
rhizobia
(MPN)
Rhizobial number determined after ryegrass cultivation was increased by 2-
10 times depending on rhizobial strains applied in respect to S. meliloti
number before sowing of ryegrass. This inoculation of ryegrass together
with subsequent alfalfa inoculation presented double inoculation of alfalfa.
EUCARPIA 2011

Figure 3. Effect of bacterial inoculants on plant parameters of alfalfa as subsequent crop
SDW
mg pot -1
6000
5000
4000
3000
2000
1000
0
L3Si 4148 207 218 Ø1 NØ
Bacterial strains
Total N
mg pot -1
Alfalfa double inoculation by the strains L3Si and 218 gave the
highest SDW, 4939.33 and 4216.30 mg pot-1, respectively.
Among alfalfa treatments without preceding crop, strain L3Si
had also the highest effectiveness expressed by SDW (4042 mg
pot -1 ) and total N content (137.04 mg pot -1 ), however
significantly lower than in double inoculated treatments with
the same strain.
200
180
160
140
120
100
80
60
40
20
0
SDW double
inoculation
SDW common
inoculation
Total N double
inoculation
Total N common
inoculation

Influence of plant growth promoting rhizobacteria on alfalfa, Medicago sativa L. yield by inoculation of
a preceding Italian ryegrass, Lolium multiflorum Lam.
CONCLUSIONS
Our results indicate that Italian ryegrass yield and N
assimilation was increased by inoculation with
A. vinelandi strain Av and S. meliloti strain 207.
Nevertheless, Italian ryegrass seed inoculation with S.
meliloti strains led to increased number of S. meliloti in soil
with its low density.
In addition, the year before alfalfa growing Italian ryegrass
seed inoculation with S. meliloti strain L3Si as well as 218
provided abundant number of these strains in the soil
and
together with alfalfa common inoculation influenced better
yield of alfalfa.
This alfalfa double inoculation shoud be applied in the soils
poor with S. meliloti or without it.
EUCARPIA 2011