Commercial Organic Fertilizer characteristics and fertilizer

management in intensive OGH

Dr. Kurt Möller

Universität Hohenheim, Stuttgart, Germany

Outline

• Introduction

• Soil nutrient status of organic greenhouses

• Nutrient balances

• Nutrient uptake by vegetable crops in comparison to nutrient supply by base fertilizers

• Characteristics of selected commercial organic fertilizers

• Conclusions

Principles of fertilization in organic farming

• Based on EC-regulations (834/2007; 889/2008) + regulations by farmers organizations

• Fertilization based on efficient cycling of nutrients and biological N2 fixation by legumes

• Off-farm inputs regulated by annexes in EC 889/2008

• No easily available mineral N and P fertilizers

• Growers organizations have additional restrictions (e.g. use of meat and bone meal, composts, etc.)

Definitions

• Base organic fertilizers

– bulky fertilizers applied often in huge amounts,

– mostly as base dressings before crop sowing/planting,

– low nutrient concentrations

– E.g. composts, solid farmyard manures, liquid slurries

• Complementary organic fertilizers

– listed in annex I of the EC regulation,

– may be applied as base or/and top dressing during the plants growth

– E.g. keratins, MBM, vinasse

EU-EGTOP (Expert Group for Technical Advice

on Organic Production) opinions on fertilization in

organic greenhouses

• greenhouse crops should be fertilized primarily from slow release organic fertilizer materials like compost and animal manures,

• ideally from certified organic sources,

• use of irrigation to flush surplus nutrients is not an acceptable practice consistent with the organic principles,

• When choosing the quantity and type of fertilizers, the nutrient balances must be taken into consideration to avoid salinization or leaching of nutrients.

Main kinds of “crop rotations” in organic

greenhouses in SW-Germany

Single/few early,

main, and late crops

Very diverse with several

early, main, and late crops

Previous crop kohlrabi lamb salad, winter

lettuce

kohlrabi, spinach,

radish, chive, lettuce,

endive, onions,

parsley

Main crop tomatoes, sweet

pepper, eggplant,

cucumber

tomatoes, cucumber, sweet

pepper, eggplant, runner

bean

Tomatoes, cucumber, sweet pepper,

eggplant, runner bean,

radish, spinach, roquette

Last crop/following

crop

no lettuce Lamb salad, lettuce , radish

Salatrauke, parsley,

chive, lettuce

N (greenhouses)

2 (Demeter) 11 (6 Bioland, 5 Demeter) 9 (4 Bioland, 5 Demeter)

„main crop

accentuated“

Field with

lowest level

0

20

40

60

o

o o

*

Open land

n = 24

Greenhouse

n = 10

c

*

* 151

227

Recommended

soil P level

Boxplot of plant available soil-P contents in organically cropped vegetable fields (von Fragstein et al. 2004)

mg

PC

AL/

10

0 g

so

il

Field with

highest level

Field with

lowest level

Field with

highest level

Soil available P and K contents in organically managed orchards in SW-Germany (n = 402)

8

R² = 0.47

0

20

40

60

80

0 10 20 30 40

mg

KC

AL/1

00 g

soil

mg PCAL/100 g soil

y = 1.72x + 8.66

K-deficit

P-deficit

optimal

range

(i

)

(ii

)

(iii)

(v

i)

(v)

(v)

PK

surplus

Soil available P- and K-concentration in organically managed greenhouses in SW-Germany (n = 22)

0

10

20

30

40

50

60

70

0 10 20 30 40 50 60

mg K

CA

L/1

00 g

soil

mg PCAL/100 g soil

PK surplus

range

P o

ptim

um

rang

e

K optimum range

pla

nt

avai

lab

le K

CA

L (m

g kg

-1)

Bioland N=11 N=11

Demeter level A (low) < 58 mg K kg-1

level B (adequate) 59 – 116 mg K kg-1

level C (moderate) 117 – 208 mg K kg-1

level D (high) 208 – 291 mg K kg-1

level E (very high) > 291 mg K kg-1

Levels of plant available soil K-concentration in organically managed greenhouses in SW-Germany (n = 22)

Pla

nt

avai

lab

le P

(m

g kg

-1)

level A (low) < 22 mg P kg-1

Level B (adequate) 22 – 40 mg P kg-1

level C (moderate) 41 – 87 mg P kg-1

level D (high) 88 – 148 mg P kg-1

Bioland N=11 N=11

Demeter

Number of greenhouses

Growers´ organization

Levels of plant available soil P-concentration in organically managed greenhouses in SW-Germany (n = 22)

Saldo = Input

• Base fertilizer

• Complementary

fertilizer

• Potting media

• Irrigation water

Output

• Yield of the

crops

• Removed crop

residues

-

N, P, K, S,

Mg, Ca, Na,

Cl

Calculation of nutrient budgets for 2010-2013

Nutrient Input-Output balances of organically managed greenhouses in SW-Germany (n = 22)

0

100

200

300

400

500

N P K Ca Mg S Na Cl

Base organic fertilizers

Complementary organic & mineral fertilizers

Outputs

kg

ha

-1/k

g C

aO

ha

-1

Liming

effect

460

-265

Potential nutritional disorders due to nutrient

excess and high soil pH

• Phosphorus – Lower micronutrient availability (Zn, Mn, etc.)

• Calcium: – antagonistic effects to K+, Mg+, Mn2+ and other micronutrients, etc. unbalanced nutritional composition

– calcium oxalate deposition under the skin: goldspot in tomatoes

• Sulfur: – reduced uptake of B and Mo antagonistic effects

– salinity,

– stronger product taste (glucosinulates)

• Sodium: – antagonistic effects to K+, Ca2+, Mg2+

– salinity,

– product quality (organic acids taste)

• High pH: – micronutrient deficiency (Zn, B, etc.)

– enhanced decomposition of the soil organic matter

Fertilizer strategies of bio-organical and bio-dynamic

managed greenhouses

B ioland Demeter

MV Min Max MV Min Max

dt ha - 1 a - 1 dt ha - 1 a - 1

Base fertilizer

Compost 52 0 156 641 0 810

Solid farmy. manure 1 20 0 520 769 0 1200

liquid slurry - - - 133 0 248

Green manures - - - 83 0 250

Complementary fertlizers

Faba bean meal - - - 78 0 110

Vicia meal - - - 6,2

Fertilizer

0 18,7

MALTaflor ® 26,8 0 36,4 - - -

Vinasse 20,0 0 27,8 5,2 0 15,6

Bioilsa ® 20,7 0 41,0 15,2 0 18,2

Horn 14,2 0 56,0 25,7 0 36,9

K 2 SO 4 6,9 0 12,0 0,8 0 2,3

Comparison of the nutrient input-output balances of organically

managed Bioland & Demeter greenhouses in SW-Germany (n = 22)

-250

-150

-50

50

150

250

350

450

550

650

N P K Ca Mg S Na Cl Liming

effect

Bioland Demeter

kg

ha

-1/k

g C

aO

ha

-1

0

100

200

300

400

500

600

700

N Bioland N Demeter Ca Bioland Ca demeter K Bioland K Demeter

Series1 Series2

N, C

a, K

(kg

ha

-1)

N Ca K

Bioland Demeter Bioland Demeter Bioland Demeter

Base

fertilizer

Comple-

Mentary

fertilizers

Growers organization

Total nutrient inputs and ratio of base and complementary

fertilizers for N, Ca and K in organically managed Bioland &

Demeter greenhouses in SW-Germany (n = 22)

0

20

40

60

80

100

120

140

160

180

P Bioland P Demeter Mg Bioland Mg Demeter

S Bioland S Demeter Na Bioland Na Demeter Cl Bioland Cl Demeter

Series1 Series2 Bioland Demeter Bioland Demeter Bioland Demeter Bioland Demeter Bioland Demeter

P, M

g, S

, Na,

Cl (

kg h

a-1)

Mg S Na Cl

Growers organization

P Base

fertilizer

Comple-

mentary

fertilizers

Total nutrient inputs and ratio of base and complementary

fertilizers for N, Ca and K in organically managed Bioland &

Demeter greenhouses in SW-Germany (n = 22)

Nutrient spectra of base fertilizers (after correction of long term

plant availability) in comparison to vegetable crop NPKS uptake P

su

pp

ly /

un

it N

su

pp

ly

0,0

1,0

2,0

3,0

4,0

5,0

6,0

Nitrogen Phosphorus Potassium Sulfur

Digestates Composts Animal manures

Nutrient transformations and flows in a manure

heap

oxic

reactions anoxic

reactions

Rain water

K leaching

P remains!!!!!

Relative P enrichment

Nutrient spectra of different (complementary)

organic fertilizers

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

N P

K

S

-

-20

0

20

40

60

80

100

0 5 10 15 20 25 30 35

meat meal, keratins, etc.

swine slurries, vinasse, rape-seed-expeller,

potato liquid, etc.

municipal compost

C/N ratio

N a

vaila

bili

ty (

%)

digestates from leftovers food industry

digestates from energy crops and urban organ. wastes

farmyard manure

Relationship of organic manure C/N-ratio and (apparent) N

availability in the year of application (Möller & Schultheiß 2014)

legume grist, alfalfa meal

y = -30.8Ln(x)+101

R² = 0.62

Neto-N-Mineralization of organic fertilizers at different

incubation temperatures (Kelderer et al. 2008)

digestates

Blood meal Meat meal Vinasse

Poultry manure

Biosol expeller Soja-expeller

Bioilsa 10 compost

0

10

20

30

40

50

60

0 14 60 0 14 60

8 °C 16 °C

Days of incubation

Net

o-N

-rel

ease

(%

)

high N-release, low Temp-Sensitivity:

high N-release, high Temp-Sensitivity :

Moderate N-release + low Temp-Sensitivity:

Moderate N release. + high Temp-Sensitivity:

What to do in open field????

24

R² = 0.47

0

20

40

60

80

0 10 20 30 40

mg

KC

AL/1

00 g

soil

mg PCAL/100 g soil

y = 1.72x + 8.66

K-deficit

P-deficit

optimal

range

(i

)

(ii

)

(iii)

(v

i)

(v)

(v)

PK

surplus

Nutrient spectra of different (complementary)

organic fertilizers

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

N P

K

S

What to do in Greenhouses???

0

10

20

30

40

50

60

70

0 10 20 30 40 50 60

mg K

CA

L/1

00 g

soil

mg PCAL/100 g soil

PK surplus

range

P o

ptim

um

rang

e

K optimum range

Nutrient spectra of base fertilizers (after correction of long term

plant availability) in comparison to vegetable crop NPKS uptake P

su

pp

ly /

un

it N

su

pp

ly

0,0

1,0

2,0

3,0

4,0

5,0

6,0

Nitrogen Phosphorus Potassium Sulfur

Digestates Composts Animal manures

Keratins

• key structural component of hair and nails,

• horn & hooves, feather, wool, hair meal,

• high N and S contents, and very low in P and K,

• rapid N mineralization & low P contents well suited

for use as corrective N fertilization in intensive

vegetable systems and in greenhouses.

• Deficiency:

– However: high S! increased salinity problems.

Meat and bone meal

• high in N and high N mineralization in the year of application often used as specific top dressing and corrective N fertilization in intensive vegetable systems,

• Deficiencies: – high P and low K contents, – not suited for use in intensive vegetable cropping

systems due to imbalanced nutrient spectrum increased imbalances in nutrient composition,

– not suited as complementary fertilizer to composts/solid farmyard manures as base fertilizers,

• best suitability to fertilize arable crops with high N demand (potatoes, cereals).

Vinasse

• high N, K and S contents and low P contents,

• high N mineralization in the year of

application,

• well suited for use in intensive vegetable

cropping systems including greenhouses,

• Deficiencies:

– high Na contents relevant when using in

greenhouses (salinity),

– High S contents relevant when using in

greenhouses (salinity),

Conclusions • Extremely high soil P (and K) levels in organic fields

cropped with (N-demanding) high value crops,

• Imbalances derived from base fertilization (e.g. N deficiency) resulted in new imbalances by application of complementary fertilizers (e.g. S excess),

• Risk of indirect negative impacts:

– high pH: micronutrient deficiency by immobilization,

– high P: micronutrient deficiency due to fixation,

– high S, Ca, etc.: soil salinity,

Conclusions • Base dressings:

– Manuring in intensive organic systems need a deep redesign (P & S budget surpluses, K deficits),

– composting is related to high gaseous N losses and potentially by N and K leaching losses the main nutrients required by vegetables,

– Composts are not suited as a major source of nutrients in high value crops with high N demand and soils without legume crops (BNF),

– one approach to overcome the problems is the use of digestates instead of composts.

Conclusions

• The higher the soil nutrient level, the lower the degree of freedom in the choice of fertilizers

• Congruence with basic organic ideas: – In GH it is impossible to get balanced nutrient input-output

relations with major amounts of composts or other slow release base fertilizer

– The current lobbing for restrictions in the use of complementary fertilizers/top dressings would increase the problem of nutrient imbalances

– Cl deficits combined with S excess KCl-fertilizer as alternative K source?

– Induced leaching to manage soil salinity?

– very intensive systems show the limitations and shortages of the concepts based on “feed the soil, and not the plant”

Thank you very much for your

attention

34