Stephen Briggs

…..Organic Advice That Counts

Optimising N for Cereal Production

• Formed in 2001

• Organic specialists

• 14 consultants (Arable, Horticulture, Soil,

livestock, Business management, Food processing/

branding, Adding value, Land management,

Conservation, Marketing, Training, Research)

• 420+ Organic farmers on 350,000ac +

• SB Farms 270ac Cambs & Rutland

Stephen

Briggs

Ric Bowers

Isobel Wright

Gareth Jones

Dan Powell

Sam Franklin Lois Philipps

Graham

Collier

Lynn Briggs

Mike Tame

Andrew Head

Alison Smythe

Dominic

Watts

Ian Knight

Manure use

Farm Waste or Valuable Resource?

Source segregated

green waste

High quality composting

Monitor & Manage

Sewage Sludge ?.....an on-going debate

Typical Total nutrient contents of

livestock manures (fresh weight)

FYM

DM

%

N

Kg/t

P

Kg/t

K

Kg/t

Mg

Kg/t

Cattle 25 6.0 3.5 8.0 0.7

Pig 25 7.0 7.0 5.0 0.7

Layer 30 16.0 13.0 9.0 2.2

Table poultry 60 30.0 25.0 19.0 4.2

Slurry

Dairy 6.0 2.0 1.0 2.5 0.5

Source : Managing Manure on Organic Farms ADAS EFRC 2002

FYM Use on Arable crops

• Apply prior to cultivations (Aut. & Spring)

• Ensure rapid incorporation to minimise losses

• Apply slurry/poultry FYM in spring only

• Slurry can be used to „top-dress‟ crops

• Ensure good aeration to combat weed seeds

• Applications limited to 170kg N/ha/yr

• Large FYM applications can reduce clover contents in green manures

Mixed arable/Livestock rotation – Manure additions

Grass/clover

Grazed Grass/clover

Silage &

Grazed

Wheat

Beans

Spring Barley

Not US

A.Silage? N, P, K

N, P, K

N, P, K

FYM or

Compost N

N

P, K

N

Manure added

Optimising N Management in

Organic All-Arable Systems ?

All Arable systems

Current organic arable systems

•Characterised by a ‘ley’ arable systems

•Highly cyclic ‘rotations’

•Nutrient rich and nutrient poor

•Economic cash crops tempered by no

income from fertility building phases

•Fertility building success is key

•Cash flow implications

5 cash crops : 1 clover

4 cash crops : 2 clovers

Stockless arable rotation – Fertility building

S Barley

U S

Clover ? Clover

Green manure

W Wheat

Vetch

Green manure

Spring Oats

N, P, K

N, P, K

FYM or

Compost

N

N

N

Fertility building - The key to the whole system ……

But which legume?

Legume / green manure

choices ?

All Arable systems

Wheat / Lupin Pea / Oat Wheat / Beans

BI-Crop ?

Undersowing

AGROFORESTRY

Use N fixing trees?

Forage Legumes

White clover Trifolium repens

Red clover Trifolium pratense

Crimson clover Trifolium incarnatum

Subterranean clover Trifolium subteranneum

Alsike clover Trifolium hybridum

Persian clover Trifolium resupinatum

Egyptian clover Trifolium alexandrinum

Lucerne/alfalfa Medicago sativa

Winter/common vetch Vicia sativa

Summer/goar vetch Vicia lathyroides

Hairy vetch Vicia hirsuta/villosa

Kidney vetch Anthyllis spp

Sanfoin Onobrychis viciifolia

Large birdsfoot trefoil Lotus pedunculatus

Birdsfoot trefoil Lotus corniculatus

Trefoil/black medick Medicago lupulina

White lupin Lupinus alba

Yellow lupin Lupinus luteus

Blue lupin Lupinus angustifolius

Grain legumes

Field peas Pisum sativum

Fodder (grey) pea Pisum arvense

Field bean Vicia Fabia

French /pinto bean Phaseolus vulgaris

Soya bean Glycine max

Lentil Lens culinaris

Other legumes

Galega, Goats rue Galega orientalis

Chickling vetch, sweet pea Lathyrus spp.

White Sweet clover Melilotus alba

Chickpea Cicer arietinum

Black bean Castanospernum australe

Cut & mulch

how often ?

impact on N

1 or 2 year Leys

OF0316 Developing improved guidance

for the use of fertility building crops

A DEFRA funded project – OF0316

- High Mowthorpe Yorks

- Duchy College Cornwall

- Bedford

OF0316 Developing improved guidance

for the use of fertility building crops 2002 - 2006

A: Red clover/grass mixture (herbage cut & removed)

B: Ryegrass only (herbage cut and removed)

C: Red clover/grass mixture (herbage cut & mulched)

D: Ryegrass only (herbage cut and removed; herbage

from treatment A spread onto this plot)

-All with and without FYM

Novel legume investigations

OF0316 Developing improved guidance for the use of

fertility building crops – Project Team Mark Shepherd ADAS Gleadthorpe

Gillian Goodlass ADAS H. Mowthorpe

Steve Cuttle IGER Trawgoed

David Hatch IGER North Wyke

Stephen Briggs Abacus Organic

John King ADAS Cambridge

Stephen Roderick Duchy College

Matching rates of mineralisation of

soil N & uptake by crop

Jan Feb Mar Apr May Jun Jul Aug Sep Oct

Nit

rog

en

Uptake

Mineralisation

Predicting N supply

mineral-N

(1)

mineral-N

(2)

Soil-N

(0)

Soil-N

(2)

Soil-N

(1)

crop N

N losses

manures

residues

Factors affecting N

accumulation

• Legume species and cultivar

• Yield, persistence, rate of establishment, spatial variability

• Environment, soil nutrient status (P,K,Mg) etc

• Mineral N supply…….

Predicting N fixation

0 100 200 300 400 500 600

kg N/ha/year

Red clover (silage)

Lucerne (silage)

Field bean (grain crop)

Forage peas

White clover/grass (grazed)

Lupin (grain crop)

Vetch (cut & mulched)

Soya (grain crop)

White clover/grass (silage)

Provisional ranges for quantities of N fixed and remaining after harvest

N fixed

N after harvest

(including roots)

Source : OF0316 – Adas, Abacus Organic, Duchy College, IGER

N release & utilisation

harvest

Soil N

Legume

Crop 1 Crop 2

harvest

losses

N mineralisation

losses losses

Year O Year 1 Year 2

manure

Factors affecting N ‘release’

• soil type

• soil organisms

• aeration

• climate

• nature of residues (C:N, fresh residues v SOM)

• management of green material

Green manure incorporation

& Impact on Nitrogen availability

• Decomposition stimulates microbial activity and soil N release

• N available to the following crop – when?

• The C:N ratio influences decomposition rate

• Young green material with C:N ratios of 15 -rapid breakdown & N release

• Residues with mid-20’s a C:N ratio - soil N readily available as they decompose

• Older more “woody” material with a C:N ratio of 80 – slow breakdown & N release

Material C: N ratio

Soil microorganisms 7

Soil organic matter (SOM) 10 – 12

Clover 13

Compost 15

Grazing Rye 36

Maize stems 60

Wheat straw 80

Fresh sawdust 400

• Potential to use different green manures (alone or

in combination) with differential decomposition

rates to influence soil N release to better match

growing crop demand

Field experiments to determine

N accumulation under fertility building crops

Harvesting plots

DM yield 2004

0

2

4

6

8

10

12

14

16

Clover cut and

remove

Clover cut and

remove

Grass cut and

remove

Grass cut and

remove

Clover cut and

mulch

Clover cut and

mulch

Grass cut and

mulched w ith

clover

Grass cut and

mulched w ith

clover

w ith w ithout w ith w ithout w ith w ithout w ith w ithout

tota

l D

M y

ield

(t/

ha

)

cut 3

cut 2

cut 1

Clover mulched on grass plot- Yorkshire & Cornwall

Source : OF0316 ADAS, Abacus Organic, Duchy College, IGER research funded by DEFRA

FYM FYM FYM FYM

Yields higher on plots containing clover

Clover Clover Grass Grass

N offtake 2004

0

50

100

150

200

250

300

350

400

Clover cut and

remove

Clover cut and

remove

Grass cut and remove Grass cut and remove Clover cut and mulch Clover cut and mulch Grass cut and

mulched wit h clover

Grass cut and

mulched wit h clover

wit h wit hout wit h wit hout wit h wit hout wit h wit hout

No

ffta

ke (

kg

/ha)

cut 3

cut 2

cut 1

Source : OF0316 ADAS, Abacus Organic, Duchy College, IGER research funded by DEFRA

N offtake much higher when clover present

Grass Clover Clover Grass

N Fixation 2004 ADAS yr 2 (3 cuts)

Treatments N Sources No FYM FYM

B N taken off from soil 69 110

D N taken off from soil + mulch 191 196

D-B N from mulch 122 85

A N from soil+fixation 282 317

A-B N from fixation 214 207

C N from soil+fixation+ mulch 354 342

C-D N fixation in presence of mulch 163 146

(A-B)-(C-D) Loss in fixation caused by mulch 51 61

A Red clover/grass (cut & removed)

B Grass only (cut & removed)

C Red clover/ grass (mulched)

D Grass only (mulched with cuttings from A)

Source : OF0316 ADAS, Abacus Organic, Duchy College, IGER research funded by DEFRA

Kg/N/ha Kg/N/ha

Soil/Crop Fractionation Nitrogen (kg/ha)

0

50

100

150

200

250

300

350

1 2 3 4 5 6

site

kg

N /

ha

clover

grass

litter/stubble

roots

vetch

Source : OF0316 ADAS, Abacus Organic, Duchy College, IGER research funded by DEFRA

Most of the N is in the Soil – but significant amounts in foliage

It all starts & ends in the soil

THE „SOIL FOOD WEB‟ OF A LIVING SOIL

Estimated 15 million species on the planet (1-1.5 million classified)

Number of species in the soil………?

Size Organisms Numbers (per g)

Biomass (kg/ha-fresh)

SMALL Bacteria 100 million 1600 V Actinomycetes 2 million 1600 V Fungi 0.2 million 2000 V Protozoa 30,000 380 V Microalgae 25,000 320 V Nematodes 1.5 120 V Earthworms 1 per kg 800

LARGE Arthropods, Ascari & Molluscs

1-200

Typical numbers & biomass of soil biota

• Keep it simple

• Make best use of Manures – manage and store well

• Plan crop rotations

• Compost use

• Undersowing & Bi-crops

Conclusions

• Fertility implications from different green manures

• C:N ratio :Consider for subsequent N release

• Match : Green manure breakdown

characteristics to N requirement and time of

uptake of subsequent cash crops

• Soil is the key……subterranean farming

Conclusions

Charles Darwin, 1881

The plough is one of the most ancient and most valuable of mans

inventions; but long before man existed, the land was regularly ploughed, and continues to be thus ploughed by earthworms.