Soybean inoculation –important agricultural practice

➢ Soybean is among the most widely grown grain legumes and the thirdmost cultivated crop worldwide

➢ High-quality chemical composition of soybean seed (～ 40% protein, 20% oil)

➢ The cultivation area is expected toincrease due to the great economicimportance of soybean

Symbiotic nitrogen fixation (SNF)

soil N N min. fertilizers biological

SNF

Soybean (Glycine max.) + Bradyrhizobium

Soybean plants obtain nitrogen from three sources

➢ 58% of total soybean N uptake comes from SNF (38 to 78%) (Salvagotti et al., 2008)

➢ Selection of rhizobial strains with a high potential for N fixation,

competitiveness, adapted to the specific environmental conditions

Symbiotic nitrogen fixation (SNF)

➢ In Serbia soybean inoculation ̶ more than 35 years

IFVCNS

Soybean seed

Inoculants NS-NITRAGIN

For free

➢ Inoculation is an environmentally andeconomically justified agricultural practice

Symbiotic nitrogen fixation (SNF)

➢ Inoculation recommended as a regular soybean cultivation practice

✓When soybeans are grown on a field for the first time

✓When soybeans have not been grown on a field for 3-5 years

✓ Soil pH lower than 6 or higher than 8.5

✓ Less than 1% organic matter content

✓ Higher sand or clay percentage in soil

➢ Adverse environmental conditions affect the number and activity of nodule bacteria

• Could lose efficiency after a certain time under

variable environment conditions

Effect of inoculation and mineral N on soybean nodulation parameters

• Inoculation ̶ with B. japonicum(NS-Nitragin)

• Results ̶ the average of tree-year field experiments

0

10

20

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50

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90

0 N kgha¯¹ 30 N kgha¯¹ 60 N kgha¯¹ 90 N kgha¯¹

pla

nt-1

Nodule number

0,00

0,50

1,00

1,50

2,00

2,50

0 N kgha¯¹ 30 N kgha¯¹ 60 N kgha¯¹ 90 N kgha¯¹

mg

pla

nt-1

Nodule N content

0

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100

150

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250

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400

450

0 N kgha¯¹ 30 N kgha¯¹ 60 N kgha¯¹ 90 N kgha¯¹

mg

p

lan

t-1

Nodule dry matter mass

Effect of inoculation and mineral N on soybean nodulation parameters

0

10

20

30

40

50

60

70

0 N kgha¯¹ 50 N kgha¯¹ 150 N kgha¯¹ 250 N kgha¯¹

pla

nt-1

Nodule number

inoculated

noninoculated

0

50

100

150

200

250

300

350

400

0 N kgha¯¹ 50 N kgha¯¹ 150 N kgha¯¹ 250 N kgha¯¹

mg

pla

nt-

1

Nodule dry matter mass

• Experimental field - soybean wasn't grown for more than 10 years

0,00

0,50

1,00

1,50

2,00

2,50

3,00

0 N kgha¯¹ 50 N kgha¯¹ 150 N kgha¯¹ 250 N kgha¯¹

mg

pla

nt-

¹

Nodule N content

Effect of inoculation and mineral N on soybean plant parameters

0

2

4

6

8

10

12

14

16

0 N kgha¯¹ 50 N kgha¯¹ 150 N kgha¯¹ 250 N kgha¯¹

g p

lan

t -¹

Above-ground dry matter mass

inoculated

noninoculated

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500

600

700

800

0 N kgha¯¹ 50 N kgha¯¹ 150 N kgha¯¹ 250 N kgha¯¹

mg

pla

nt-

¹Above-ground N content

inoculated

noninoculated

Effect of inoculation and mineral N on soybean yield parameters

0

10

20

30

40

50

60

0 N kgha¯¹ 50 N kgha¯¹ 150 N kgha¯¹ 250 N kgha¯¹

Number of pods

inoculated

noninoculated

0

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100

150

200

250

0 N kgha¯¹ 50 N kgha¯¹ 150 N kgha¯¹ 250 N kgha¯¹

Mass of 1000 seeds

inoculated

noninoculated

Effect of inoculation and mineral N on soybean yield and seed protein content

30

32

34

36

38

40

0 N kgha¯¹ 50 N kgha¯¹ 150 N kgha¯¹ 250 N kgha¯¹

%Seed protein content

inoculated

noninoculated

2000

2200

2400

2600

2800

3000

3200

3400

3600

3800

0 N kgha¯¹ 50 N kgha¯¹ 150 N kgha¯¹ 250 N kgha¯¹

kg

ha

-¹

Grain yield

inoculated

noninoculated

Effect of inoculation and mineral N on soil microbiological parameters

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50

100

150

200

250

inoculated noninoculated inoculated noninoculated inoculated noninoculated inoculated noninoculated

0 N kg ha-1 50 N kg ha-1 150 N kg ha-1 250 N kg ha-1

CF

U g

-1 s

oil

Total microbial number x 10^7

Number of azotobacters x 10^2

Number of ammonifiers x 10^6

Number of N2 fixers x 10^6

Number of fungi x 10^4

Number of actinomycetes x 10^4

Improving SNF under drought stress conditions

➢ Drought is one of the major limiting factors in crop production

➢ 60% of legume production in the world occurs under coditions of drought

➢ SNF is extremely sensitive to drought stress

➢ To overcome negative effects of drought on nitrogen fixation, along with

plant selection it is necessary to select rhizobial strains that have higher

tolerance to water deficit

Improving SNF under drought stress conditions

➢ Resent researches are focused on the selection of rhizobial strains with increasedtolerance to drought stress and their impact on antioxidant defense system insoybean plants

enzymatic nonenzymatic

+ - + - + -0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

7 days drought

U/g

FW

Soluble peroxidase activity Inoculated-LEAF

Non-inoculated-LEAF

Inoculated-ROOT

Non-inoculated-ROOT

Inoculated-NODULES

Non-inoculated-NODULESleaf root

nodule

+ - + - + -0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

7 days drought

U/g

FW

Cell wall-bound peroxidase activity

root

nodule

leaf

Effect of inoculation on enzymatic antioxidative system

Effect of inoculation on nonenzymatic antioxidative system –

antioxidant capacity (ABTS •+) in plants

+ - + - + -0

0,2

0,4

0,6

0,8

1

1,2

7 days drought

µm

ol

TE

/g Inoculated-LEAF

Non-inoculated-LEAF

Inoculated-ROOT

Non-inoculated-ROOT

Inoculated-NODULES

Non-inoculated-NODULES

leaf root

nodule

Thank you for your attention