LTER experiences and relationship to long-term trials in Africa

Professor Sieg SnappDept Crop and Soil SciencesKBS, Michigan State University

The mission of the LTER Network: Knowledge and predictive understanding necessary to conserve, protect, and manage the nation's ecosystems, their biodiversity, and the services they provide.

LTER sites share a common commitment to long-term research in core areas:

• Pattern and control of primary production

• Spatial and temporal distribution of populations

• Pattern and control of organic matter accumulation

• Patterns and movements of inorganic inputs through soils ground- and surface waters

• Patterns and frequency of disturbance

Kellogg Biological StationKBS LTER Site @ MSU

• Central QuestionTo what extent can we manage field crops

with biology rather than chemistry?– without sacrificing high yields…

KBS Long-Term Ecological Research (LTER) Site

Annual Crops (Corn - Soybean - Wheat) Conventional tillage High No-till Low-input with legume cover Organic with legume cover

Perennial Crops Alfalfa Poplar trees

Successional Communities Early successional old field Mid successional old field Late successional forest Low

Ecosystem Type Management Intensity

KBS LTER Site Layout

Cropping Systems in RCBD (n=6blocks with 7 1-ha plots)

Successional Systems in landscape, same soil series, n=3

Block 5

Main Cropping System Experiment KBS-LTER

Cropping Systems

Treatments

T1 Conv. &

T2 No-till:

C-S-W

T3 Low input &

T4 Organic

Cr-S-Wrc

r=rye winter coverrc=red clover cover

Major Research Areas at the KBS LTER Site

• Microbe-soil-plant interactions that control soil nutrient availability

• Insect predator-prey relationships that control pest populations

• Competition among weeds and crops for limiting resources

• Drivers of soil carbon status and greenhouse gas mitigation

• Agronomic yield and valuation of other ecosystem services provided by agriculture

MethodologyManagement:LTER executive committee (Robertson chair + 6 co-PI scientists)Agronomic committee (Snapp chair + scientists, extension and farmers)manage cropping systems by protocols updated each season

Measurements: - Developed LTER-cross site synthesis on measurements in the late 1980s-LTER book publication (Robertson et al., 1998) -LTER-KBS website under review process, 2011- Document consistent approaches to monitor soil and plant primary productivity (aboveground), soil nutrient cycling (nitrogen), moisture dynamics, soil C, GWP

New management approach 2011: Manage by objective, prevailing farming norms for T1 conventional and no-till, and biology to replace chemical inputs for T3 & T4.

10

Drains on Broadbalk

Learning from The Broadbalk Experiment

11

Unmanured, continuous wheat

Continuous wheat: FYM PK+144 kg N

1st wheat in rotation: FYM+96 kg N Best NPK

Red R

ostock

Broadbalk management and wheat yield: Updates based on prevailing norms

Red C

lub

Squ. Mas

ter

Red Sta

ndard

Squ. Mast

er

Cappel

le D

esp.

Flander

s

Brim

stone

A

pollo

H

erew

ard

Introduction of: liming fungicides fallowing herbicides

LTER Energy Balance (GJ ha-1 y-1)

System Energy Required

Energy Yield

Ratio

Conven-tional

7.1 72.7 10

No-Till 4.9 78.5 16

Low Input 5.1 66.9 13

Organic 4.8 53.1 11

LTER Row Crop 17 years Gelfand et al. EST 2010

Source: Syswerda, et al. in review.

Nitrate Loss from KBS Cropping Systems 1996-2007

Annual Crops

PerennialUnmanaged

LTER C Sequestration

Annual CropsConventional Tillage 1.00 1.01No-Till 1.24 1.20 Organic with cover 1.09 1.19

Cropping System Soil Carbon in Topsoil

%C8y

Perennial CropsAlfalfa 1.30 1.38 Poplar 1.40 1.46

%C17y

LTER Row Crop 17 years Snapp et al. 2010

Permag. OxidCarbon (POXC)

-Meta-analysis ofrelationship to MB,physical C fractions

Culman et al., 2012 SSSAJ

Cross-Site LTER Syntheses Long-term Intersite

DecompositionExperiment (LIDET)

Parton et al. 2006 Science 315: 361

Lotic Intersite Nitrogen Experiment (LINX)

Mulholland et al. 2008 Nature 452:202

Suding et al. 2005 PNAS 102: 4387

Productivity Diversity Traits Network (PDTNet)

Q (L/s)1 10 100 1000

U ( g

N m

-2 s

-1)

0.001

0.01

0.1

1

10

100 r2 = 0.58

NO3 conc (gN/L)0.1 1 10 100 100010000

0.001

0.01

0.1

1

10

100

GPP (gO2/m2/d)0.01 0.1 1 10 100

0.001

0.01

0.1

1

10

100

alpha (s-1)1e-6 1e-5 1e-4 1e-3 1e-2 1e-1

0.001

0.01

0.1

1

10

100

Controls on total NO3 uptake

Systems evaluation – Malawi case study

Snapp et al., 2010 PNAS

Maize vs Maize-Glir Intercrop N fert.

Southern Malawi ICRAF

Beedy et al., 2009 AEE

Next steps?Single (electronic) database and uniform methods protocolsInternational registries:

http://ltse.nicholas.duke.edu/www.ilternet.edu/

‘Visioning’ to develop multidisciplinary projects and cross-site synthesis

Link to environmental monitoring and modellingLink to international LTERsPromote wider use; methods review; and continuity planning (support long-term trial management)Student exchange and capacity building

Linkages to Long-term experiments in Africa

1. Methods

2. Cross-site synthesis- Student exchange and capacity building

3. Core ‘common’ research questions:e.g., drivers and processes involved in sustainable intensification