Biological soil quality as a factor of efficient resource utilization in organic farming systems. Andreas Fließbach, Paul Mäder January 2005

Transcription

1 Biological soil quality as a factor of efficient resource utilization in organic farming systems Andreas Fließbach, Paul Mäder January 2005

2 Biological soil quality a factor of efficient resource utilization The green revolution and its impact on agriculture and the environment Efficiency of production in farming systems of the DOK long-term trial in Switzerland The role of soil quality in sustainable farming systems

3 The Green Revolution PROGRESS: Crop Yield increase Fertilizer Input Pesticide Input Weed Control Breeding and GMO Heavy Machinery Larger Fields Specialization REACTION: Monocultures Nutrient loss Residues, Leachates Loss in Diversity Loss in Varieties Compaction Erosion Mixed farming: internal cycling of nutrients

4 Strategy of organic farming: Package of actions Optimising technique (crop rotation, soil management, fertilisation) Choice of cultivar, Inter- and Intracropping Induced resistance Plant protection Bio-Control Antagonists Prediction modelling Optimising landscape

5 How sustainable is organic farming? DOK long-term experiment, Therwil, Switzerland 8 treatments 3 crops 4 replicates 96 plots at 100m 2 N M D 1 D 2 O 1 O 2 K 1 K 2 D 1 D 2 O 1 O 2 K 1 K 2 K 1 K 2 N M O 1 O 2 N M K 1 K 2 D 1 D 2 D 1 D 2 O 1 O 2 N M D: Bio-dynamic O: Bio-organic K: Integrated M: Integrated no manure N: unfertilized 1: low fertilization intensity (0.7 livestock units/ha) 2: normal fertilization intensity (1.4 livestock units/ha)

6 DOK trial - the farming systems Organic Conventional (integrated) N bio-dynamic bio-organic Konventional Mineral composted FYM rotted FYM mixed FYM Mineral and slurry and slurry and slurry Mechanical weed control Indirect disease control rockdust NPK NPK Biocontrol for pests Insecticides (thresholds) Herbicides (thresholds) Fungicides (thresholds) Biodynamic copper- plant growth regulators preparations sulphate

7 Farmers and Researchers work hand in hand

8 DOK-trial: Crop rotation Potatoes Winterwheat (catch crop) Soybeans (catch crop) Maize Winterwheat Grassclover Grassclover Soil tillage and chosen varieties are identical. In last years seeds of varieties are chosen that are available in organic (untreated) and conventional (treated with fungicides and insecticides) form.

9 DOK trial - Input of nutrients 125% relative input (CONFYM=100%) 100% 75% 50% 25% 0% Nt Nmin P K organic matter BIODYN BIOORG CONFYM CONMIN

10 DOK trial Yield ( ) 120% 100% relative yield (CONFYM=100%) 4.4 t ha t ha t ha -1 80% 60% 40% 20% 0% Winter wheat Potatoes Grass-clover BioDyn BioOrg ConFYM ConMin

11 Intensity: Cereal yields in organic and conventional equal yields organic yield (t/ha) Lautenbach er Hof Darmstadt DOK FAM F Järna Apelsvoll Ensmad Nagele NL CWS Neuhof WSG conventional yield (t/ha) Piorr and Werner (1998) extended

12 Life cycle assessment for a whole crop rotation BIOORG vs. CONFYM winter wheat red beets winter wheat barley potatoes grassclover grassclover average Resource use waste + land use GWP + + acidification eutrophication soil toxicity yield diff. (%) Alföldi et al., Ökologie & Landbau 118 (2001)

13 On-farm Research Did anybody see the farmer?

14 Soil - a complex living system a b c d e f Ants Earthworms Rhizobia Fungi Actinomycetes Bacteria Reganold et al., (1990)

15 DOK: soil organic matter trend 20 Soil organic matter (g Corg kg -1 ) NOFERT CONMIN BIODYN BIOORG CONFYM

16 DOK: SOM change between 1978 and Soil organic matter change (kg Corg ha -1 ) NOFERT CONMIN BIODYN1 low fertilization intensity BIOORG1 CONFYM1 normal fertilization intensity BIODYN2 BIOORG2 CONFYM2

17 DOK: Soil microbial biomass carbon Long-term average ( ) Soil microbial biomass (kg Cmic ha -1 ) d NOFERT CONMIN d BIODYN a BIOORG b CONFYM Calculated for 0-20cm at an average density of 1.4 g cm -3 c

18 Cmic-to-Nmic ratio microbial population Older cells more fungi? Cmic-to-Nmic ratio b b a ab b 5.4 NOFERT CONMIN Younger cells more bacteria? BIODYN BIOORG CONFYM Long-term average ( )

19 Correlation soil microbial biomass - yield Winter wheat grain+straw (Mg ha -1 ) Mineral fertilizer and chemical plant protection Organic plots no mineral fertilizers Y=0.35x , r 2 = Microbial biomass (kg Nmic ha -1 ) NOFERT BIODYN1 BIOORG1 BIODYN2 BIOORG2 CONMIN CONFYM1 CONFYM2 Mäder et al., 2001

20 DOK field trial - Density fractions soil organic matter fractions (µg C g -1 soil) and more stable organic matter More microbes - less undecomposed... CONMIN CONFYM BIOORG BIODYN soil microbial biomass (µg Cmic g -1 soil) light fraction intermediate fraction heavy fraction

21 Earthworm biomass DOK trial Biomass (CONFYM=100%) BIOORG BIODYN CONFYM CONMIN Pfiffner et al., 1998 Biol. Agric.Hortic.

22 Erosion DOK-field trial Fotos: Fliessbach Nov Bio-dynamic with composted manure Conventional without manure

23 DOK-trial: Soil structural stability 6 5 Score NOFERT CONMIN BIODYN1 BIOORG1 CONFYM1 Soil erosion after maize BIODYN2 BIOORG2 CONFYM2 Soil erosion after potatoes

24 Meaningful parameters: Correlation aggregate stability biomass Soil aggregate stability (% stable aggregates > 250µm) 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% y=0.24ln(x) r 2 =0.46 NOFERT CONMIN BIODYN BIOORG CONFYM Soil microbial biomass (µg Cmic g -1 soil) Fließbach et al., 2000

25 Correlation metabolic quotient and diversity q CO 2 (mg CO 2 -C g -1 h -1 ) BIODYN BIOORG CONFYM CONMIN Shannon index H' Mäder et al., 2002: Science 296, 1694

26 Total PLFA/PLEL (biomass) and PCA of PLFA patterns Phospholipids (nmol per g soil) PLEL PLFA PC2 (28.68 %) 1.5 K O M D O K M -1.5 D PC1 (37.60 %)

27 Mycorrhiza diversity DOK trial (microscopy) Mycorrhiza diversity (species number) Grassland W 26 V 27 G 26 Arable Rotation O 26 L 18 Monocropping F 13 S 10 R 8 Oehl et al., 2003 AEM, 2816

28 21 years of research in the DOK trial Organic Conventional Winter wheat 4.7 t/ha 5.6 t/ha crop yield Fertilization 122 kg/ha 360 kg/ha NH 4 NO 3 equivalent Energy 340 l/ha 570 l/ha gasoline equivalent Plant protection g/ha 6.0 kg/ha active ingredients Soil Fertility 40 t/ha 24 t/ha soil microbial biomass 700 sheep 400 sheep Mäder, Fliessbach (2003)

29 Conclusions Higher efficiency of production because of lower input in organic as compared to integrated farming systems Ecological performance of organic farming systems was better in most cases as indicated by environmental indicators for agriculture. Organic farming systems in the DOK trial enhance chemical, physical and biological indicators of soil quality Soil fertility and biodiversity in the DOK trial was found to be higher in organic farming systems.

30 FiBL annual crops department Martin Koller Paul Mäder Andreas Fliessbach Anja Vieweger Bettina Billmann Bruno Nietlispach Christine Arncken Alfred Berner Robert Frei Andi Thommen

31 Acknowledgements Swiss Federal Office for Agriculture (BLW) Swiss Agency for the Environment, Forests and Landscape (BUWAL) Swiss National Science Foundation The Field equipe and the Farmer group Lukas Pfiffner, Thomas Alföldi, Matthias Stolze, Urs Niggli (FiBL, Frick) David Dubois, Padrout Fried (FAL, Zürich) Fritz Oehl, Andres Wiemken, (University Basel) Astrid Oberson, Monika Langmeier, Emmanuel Frossard, (ETH Zürich)