http://www.nrn-lcee.ac.uk

Sêr Cymru National Research Network for Low Carbon, Energy and Environment (NRN-LCEE) Lecture Series

Why soils are key to the sustainable intensification of agriculture in the face of climate change

R Jane RicksonProfessor of Soil Erosion and Conservation

Cranfield Soil and AgriFood InstituteSchool of Energy, Environment and AgriFood

November 11th 2015

Why soils are key to the sustainable intensification of agriculture

Outline of the talk

• The global challenges ahead

• The importance of soil in sustainable intensification

• Threats to soils, their functions and sustainable intensification

• Soil management research for sustainable intensification

Courtesy of Professor Karl Ritz

The global challenges ahead

1. Can 9 billion people be fed [and housed and transported] equitably, healthily and sustainably?

2. Can we cope with future demands for water?

3. Can we provide enough energy to supply the growing population coming out of poverty?

4. Can we mitigate and adapt to climate change?

5. Can we do all of this and reverse declining biodiversity and loss of ecosystems

Sir John Beddington, Chief Scientific Advisor to HM Government

The global challenges ahead: the need for sustainable intensification

Food Security (the 5 ‘As’)

Available Supply – quantity and reliability

Affordable Economics

Accessible Geography and economics

Appropriate Quality, cultural norms, changing diets

Adequate Diet, health, nutrition

• Definition of food security: “all people, at all times, have physical, social and economic access to sufficient, safe, and nutritious food which meets their dietary needs and food preferences for an active and healthy life” (FAO 1996)

• 94 - 97% of all food originates from terrestrial environments (FAOSTAT, 2011)

• Global food production must increase by 3% annually to 2030

• Linked to social unrest and political turmoil

The global challenges ahead: the need for sustainable intensification

How to achieve this, given:

• Finite amount of land

Whole apple

% Planet earth

3/4 74% Water1/4 26% Land1/8 13% Uninhabitable to

humans1/8 13% Habitable

3/32 10% Only suitable for non arable land

1/32 3% Suitable for arable < 1/32 peel Topsoil

74%

13%

9%

3%

-

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

1961 1965 1969 1973 1977 1981 1985 1989 1993 1997 2001 2005 2009 2013

Area of agricultural land ('000 hectares) (FAOSTAT)

Agricultural area

Arable land andPermanent cropsArable land

Permanent crops

The global challenges ahead: the need for sustainable intensification

How to achieve this, given:

• Finite amount of land• Competition with other land uses

– biofuels, urban development, infrastructure

Area (000 ha) under maize (forage, biogas and grain) in the UK (Source: Maize Growers Association, pers. comm.)

Photos courtesy of Nicola Geeson

The global challenges ahead: the need for sustainable intensification

How to achieve this, given:

• Finite amount of land• Competition with other land uses

– biofuels, urban development, infrastructure

• Increasing competition for water supplies

• ‘Yield plateau’ – poor yield response to higher fertiliser use

UK national average wheat yields 1980-2011. Knight et al., 2012.

The global challenges ahead: the need for sustainable intensification

How to achieve this, given:

• Finite amount of land• Competition with other land uses

– biofuels, urban development, infrastructure

• Increasing competition for water supplies • ‘Yield plateau’ – poor yield response to

higher fertiliser use• Limited (affordable) energy resources• Decreasing labour supplies (rural

depopulation)• Climate change and weather variability

(and impacts on water management, crop production and land degradation)

SO MAYBE THE ANSWERIS IN THE SOIL???

The importance of soil for sustainable intensification

• “….And what do you do for a living?”

• Expressions / sayings about soil

– ‘mud’ used in a figurative sense meaning worthless or polluting (16th century)

– ‘mudslinging’

– ‘His (her) name is mud (Mudd)’

– Connotations of the word “soil”

• Soil science (and art)

The importance of soil for sustainable intensification

• Healthy soils are able to "sustain plant and animal productivity”...and much, much more……

• Direct links with sustainability (economic, environmental and social pillars)• Human health and wellbeing (Millennium Ecosystem Assessment)• Individuals’ and national economic status

Ecosystem goods and services delivered by soil Examples

Provisioning of material goods and services

Agricultural production (food, fibre, fodder, fuel) Water storage and suppliesLand for development (residential, industry, infrastructure)

Regulation of ecosystem processes

Flood control (water storage)Carbon storage (CO2 emissions: mitigate climate change)

Cultural, non-material services Landscape aestheticRecreation / amenity, protection of heritage

Supporting services Habitats, biodiversitySoil formation

“The thin layer of soil covering the earth's surface represents the difference between

survival and extinction for most terrestrial life.”

Doran and Parkin, 1994.

The importance of soil for sustainable intensification

What makes a healthy soil?

Soil Quality“the capacity of soil to function, within natural or managed ecosystem boundaries, to sustain plant or animal productivity, maintain or enhance water quality, and support health and human habitation” ….or more simply “the capacity of soil to function” or “fitness for use”

Karlen et al., 1997

Soil Health“Maintenance of the quality (physical, biological and chemical) and quantity of soil relative to the requirements of human and biological systems, including food, fuel and material production, carbon sequestration and water regulation, so that the provision of soil ecosystem services is sustainable”

InnovateUK Knowledge Transfer Network (Environmental Sustainability) website: https://connect.innovateuk.org/web/in-situ-land-remediation/at-a-glance-soil-health

The importance of soil for sustainable intensification

Soil quality and health are related to soil properties:

– Physical (texture, depth, structure, porosity, density, water holding capacity, infiltration rate, stability: aggregates and mass)

– Biological (flora and fauna e.g. seed bank and micro-biota)

– Chemical (nutrients, carbon, pH)…and interactions between them: soil as a complex ‘system’

How do we know we’ve got there? Concept of ‘Soil Quality Indicators’ (SQIs)

http://moradi.lawr.ucdavis.edu/Research.php

ORGANICMATTER

BIOTA

NUTRIENTS STRUCTURE

WATERBIOTA

Soil health: the pivotal 5

Threats to soils, their functions and sustainable intensification

As identified in the EU Thematic Strategy for Soil Protection (2006)

• Estimated 12 million hectares of agricultural land are lost to soil degradation every year.

Threats to soils, their functions and sustainable intensification

Example: Soil erosion in England & Wales

Wind erosion Tillage erosion

Co-extraction with root crops and farm machinery Water

Typical erosion rate range (t ha-1 year-1) 0.1 – 2.0 0.1 – 10.0 0.1 – 5.0 0.1 – 15.0

Land use affectedArable,

upland, some pasture

Arable ArableArable, pasture, upland

Exported off field Yes No Yes Yes

Comparison of the magnitude of soil loss for different erosion processes (Owens et al., 2006). N.B. Rate of soil formation ≈ 1 t ha-1 year-1 (Verheijen et al., 2009)

Processes of soil erosion in the UKSoil erosion in the UK

Threats to soils, their functions and sustainable intensification

• Irreversible loss of a natural resource / asset? e.g. loss of soil depth due to erosion

• Yield decline (quantity, quality and reliability; e.g. 20 million tonnes of grain per annum; UNCCD, 2011)

• Costs (e.g. reseeding, nutrient replacement)

• True impacts on food production currently masked by unsustainable inputs?– Irrigation– Chemical fertilisers

The importance of soil management in sustainable intensification

1. Enhance productivity (quantity, quality and reliability of marketable yield)

– Improve uptake of water and nutrients by roots– Reduce pests / diseases / weeds

2. Control soil degradation– Erosion; diffuse pollution; compaction; losses of C, organic

matter and habitats; salinisation; acidification

3. Concept of “sustainable intensification”– Producing more (quantity/ quality/ reliability of marketable

yield) with less environmental impact / damage

1 + 2 = 3

Aim: “To maintain a fertile seedbed and root zone, whilst retaining maximum resistance to soil degradation”

ORGANICMATTER

BIOTA

NUTRIENTS STRUCTURE

WATERBIOTA

Soil health: the pivotal 5

Soil erosion, Bedfordshire

Soil management practices for sustainable intensification

1. Soil cultivation and tillage

2. Crop agronomy

3. Soil (organic) amendments+ 14 minutes rainfall

Soil management practices for sustainable intensification

1. Soil cultivation and tillage

a) Conventional v conservation practices

(reduced tillage, minimum till, strip tillage, zero till – maintain good seed bed, organic matter, soil structure, soil biology)

+ 14 minutes rainfall

Courtesy of Professor Karl Ritz

Soil management practices for sustainable intensification

1. Soil cultivation and tillage

a) Conventional v conservation practices (reduced tillage, minimum till, strip tillage, zero till – maintain good seed bed, organic matter, soil structure, soil biology)

b) Timeliness of operations soil moisture content when trafficking – erosion and compaction risks?

c) Depth of operationsplough pan formation?effects on biota?

d) Direction of operations (up/down on steep, marginal land)

A case study:Optimising soil disturbance and use of mulches for erosion and runoff control

Dr. Joanne Niziolomski

Shallow soil disturbance (175 mm), both with and without straw mulch (6 t ha-1).

Winged tine Narrow with two shallow leading tines Modified para-plough

Field trial treatments

Soil disturbance field trial resultsTotal runoff volume (l)

– Straw mulch always reduced runoff – MPP with straw reduced total runoff significantly (p<0.05) compared

with all other treatments.

0

100

200

300

400

500

600

700

Non-SSD NSLT MPP WT

Tota

l run

off (

l)

Shallow soil disturbacne typeNo shallow Narrow tine shallow Modified Winged tine soil disturbance leading tine para-plough (Niziolomski, 2015)

Soil management practices for sustainable intensification

2. Use of crop agronomy for better soil management– Rotations– Cover and companion cropping– Break crops (deep rooting species)– Nutrient replenishment (e.g. N fixing legumes)– Grass waterways (erosion and runoff control)

N.B. CAP reform and ‘greening’ rules

CropRoot Type

Root traits expected to improve soil structure

Wheat DFibrous vigorous deep roots

Rye D Deep fibrous roots

Oats D Aggressive deep roots

Italian ryegrass

FFibrous root system

Lucerne EDeep and aggressive rooting

Phacelia FProlific root system but more confined to surface

Fodder radish

TTap root, long and extensive root hairs on laterals

Chicory T Tap root

Sweet clover

EVigorous and extensive multi-order lateral branching,

Field bean E Large, strong roots

Lupin E Tap root

(Ritz, 2014)

Root morphology of cover crops

T D F ET D F E

Radish Mustard

Turnip Rape

PhD study (Agnese Mancini): Cover crops for soil erosion and runoff control in forage maize

Case study: Use of grassed waterways for sediment control

Case study: Use of grassed waterways for sediment control

Soil management practices for sustainable intensification

3. Soil (organic) amendments– Green manures (cover cropping)– Composts– Mulches– Sewage sludge– Digestate from AD plants

Increase organic matter content, carbon, soil biota

Improve soils structure and resilience

Effects will be specific to materials used and sites (weather, soil type, etc)

http://www.biogen.co.uk/The-Biogen-Difference/The-Closed-Loop

Case study:Application of organic waste to restore soil health and productivity of a degraded soil

Benedict Unagwu

Increase cropyield?

Poultry manure

Mushroom compost

PAS compost (green waste)

Anaerobic digestate

Improve Soil Quality Indicators (SQIs)?

Vertical bars denote standard error. MC = Mushroom compost; AD_SW = Anaerobic digestate solid waste, PAS = PAS 100:2005 Quality Protocol compliant compost; PM = Poultry manure.

Results: Post-incubation soil analysis

• At 10 t/ha & 30 t/ha, AD_SW & PM > control • At 30 t/ha, MC > control

Amendment effects on maize height and biomass

32

control

10 t ha-1 PM

At 3 weeks after planting

10 t ha-1 MC

At tasseling (9 weeks after planting)

Why soils are key to the sustainable intensification of agricultureTake home messages

• Food production has to increase by 3% per annum on finite land resources

• Healthy soils deliver multiple ecosystem goods and services, but can be irreversibly degraded

• Soil conservation can improve soil productivity and control degradation processes

• Cost effectiveness of practices will be site specific and must fit into current farming practices – socio-economic context– infrastructure / machinery– farmer psychology / behaviour

• Ultimate goal is economically, socially and environmentally acceptable food production

= “sustainable intensification”

ORGANICMATTER

BIOTA

NUTRIENTS STRUCTURE

WATERBIOTA

In conclusion…..

“The challenge for global agriculture is to grow more food, on

not much more land, using less water, fertiliser and pesticides

than we have historically done.”

Sir John Beddingtonformer UK Government Chief Scientific Adviser.

‘The answer is in the soil……’

Thank you for your attention

Professor Jane Rickson j.rickson@cranfield.ac.uk

+44 1234 750111 ext. 2705