DESIGNING BIODIVERSE AGROECOSYSTEMS

Transcription

1 DESIGNING BIODIVERSE AGROECOSYSTEMS FOR ENHANCING AGROECOLOGICAL SERVICES Sandrine Petit Colleagues from Unité Mixte de Recherche AGROECOLOGIE, Dijon Stéphane Cordeau, Violaine Deytieux, Martin Lechenet, Philippe Lemanceau, Nicolas Munier-Jolain Françoise Lescourret

2 Designing biodiverse agroecosystems for agroecological services Necessity for a paradigm change - Agronomic and environmental challenges Provide agricultural products in high enough quantity and quality Decrease the use of inputs Preserve the environment (sol/water/air) / Deliver ecosystem services - Bring together Agronomy and Ecology Design cropping systems that respect and valorize the biodiversity, the regulations and interactions among communities (biotic interactions) Adapt the crop to the environment rather the environment to the crop Emergence and promotion of Agroecology

3 Designing biodiverse agroecosystems for agroecological services The research framework in Agroecologie Dijon 300 members of staff, 95 permanent researchers Evaluation of agricultural practices (A) Biodiversity and biotic interactions (B) Spatial and landscape ecology (C) Design of innovative agroecological system (D)

4 Multiperformance of cropping systems Integrated cropping systems are an interesting alternative 48 cropping systems Organic Integrated Conventional N. Munier-Jolain M. Lechenet Pesticide use Productivity(Tons/ha) Financial margin (euros/ha) Energy efficiency Water pollution Labour Fuel consumption Nitrogen input Lechenet et al., 2014

5 Multiperformance of cropping systems The French DEPHY network Launched in Main action of the national action plan ECOPHYTO ECOPHYTO target : reduce pesticide use by 50% before demonstration farms arable crops, vineyards, orchards, vegetables, horticulture, tropical crops 190 network engineers advising, accompanying, data collection Arable crops Vineyards Orchards A large dataset on contrasted cropping systems in contrasted environments Vegetables Horticulture Tropical crops Data mining «Demonstrate that it is possible to reconcile a reduced reliance on pesticide with agricultural profitability» (i) 3 significant questions what crop management strategies (IPM) for reduced reliance on pesticides? (ii) How IPM strategies are adapted to the contrasted farming contexts? (iii) Is low pesticide use antagonistic with economic profitability?

6 Multiperformance of cropping systems The French DEPHY network IFT : Productivity (MJ.ha -1.year -1 ) IFT : Profitability (.ha -1.year -1 ) Slope > 0 Slope = 0 Slope < 0 Lechenet et al., 2017 No antagonism in 94% of sites! No antagonism in 78% of sites

7 Multiperformance of cropping systems Lessons from the French DEPHY network Contrasted management strategies might produce low TFIs Profiles with low TFI always combine several management measures Temporary grasslands Crop diversification : rustic crops, sowing seasons Cultivar diversification Cereal sowing dates Reduced doses Soil tillage Fertilisation level -> Some agronomic management measures are using cultivated biodiversity as a lever but the systems could make more use of biodiversity and its associated biotic interactions

8 There are complex biotic interactions in agroecosystems e.g. Plant-based trophic networks Pocock et al. 2012

9 Networks of interactions are impacted by land management Land abandonment recent long-term

10 Multiple-scale and multiple-level management strategies to enhance beneficial biotic interactions Competition for ressources competitive advantage for cultivated species ressources available for the pest Allelopathy Targeted effects against bioagressors Trophic regulation: parasitism - predation Promoting trophic regulation of bioagressors by favoring natural enemies Management strategies Selection of plant genotypes At the field level: Crop management Plant associations in time and space At the landscape level: Composition and structure Field margins, hedges,

11 Managing plant diversity in space and time In the field In the field margin In the landscape

12 weed biomass (g/m 2 ) Laurent Falchetto, (INRA-Dijon Genotypes Competition for resources Selection of wheat cultivars for their competitive ability towards weeds Cap Horn wheat cultivars Munier-Jolain et al., 2006

13 Competition for resources Field management Cover crops: plants grown between two crop cycles to suppress weeds Weed biomass response to cover crops: a meta-analysis - 56% weed biomass Living mulch Synchronized sowing Relay intercropping data for 476 experimental units reported in 34 published papers ( ) Verret et al

14 Genotypes and Field management Spatial arrangement of varieties within the crop Mixing susceptible and resistant cultivars limits the progression of apple scab F. Lescourret Didelot et al., 2007

15 Number of aphids Competition for resources: decrease resources for the pest Genotypes Chemical effects of companion plants on pests (effect of Rosemary chemotypes) VOC: Volatil Organic Compounds Direct effect on pests (aphids) - Repellent effect - Interference of odors Host plant (Pepper) Companion plant (Rosemary) Ben Issa, 2014 days

16 Proportion of shoots (%) Num. aphids per shoot Competition for resources: decrease resources for the pest Field management (orchards) Tree pruning proportion of growing shoots and short shoots Carrying capacities / aphids (peach tree-green aphid). Rosettes (short shoots) Growing shoots (long shoots) Pruning intensity (%) Julian days Grechi et al

17 Trophic regulation Field management -> Promoting natural enemies and pest control by banker plants Banker plants Vitis riparia and Viburnum tinus decrease pest incidence in rose crops Parolin et al Viburnum tinus 4 leaf dammage Vitis riparia 0

18 Trophic regulation The key role of carabid beetles in regulating the weed seed bank D. Bohan S. Petit

19 CF A. simialta Males CF A. similata Females Trophic regulation Field management -> limit insecticide use to ensure fitness of natural enemies Nutritional status of the weed seed-eating carabid Amara similata Labuyere et al, 2016 TFI insecticides

20 Trophic regulation Field & Landscape management Beetles banks to increase in-field carabid abundance and weed seed predation The cyclic colonisation of crop fields (Wissinger et al., 1997) BEETLE BANK Reproduce, hivernate CROP FIELD Feeding on pests SPRING AUTUMN CROP HARVEST

21 Philadelphus coronarius Corylus avellana Cornus mas Cercis siliquastrum Viburnum lantana Salix capraea Rhamnus alaternus Sambucus nigra Viburnum tinus Ostrya carpinifolia Hedera helix Trophic regulation Landscape management A hedgerow for the ecological control of orchard pests (1) Choose the appropriate plant species (no pest shared + hosting of natural enemies) (2) Create successive resources for natural enemies all year long Simon et al Fraxinus oxyphylla Ulmus resista Winter shelter Early flowers Alternative preys psyllid aphid, Tydeidae psyllid mite aphid psyllid aphid mite aphid Season flowers Late flowers

22 Abundance Nutritional status Trophic regulation Spatial arrangement of crops in the landscape Carabids are more abundant and better-fed in oilseed rape during spring PhD S. Labruyere Abundance Poecilus cupreus (females) *** Nutritional status P. cupreus (females) ** b 3.0 b 0.06 a a a a Cereal Grass margin Oilseed rape 0.04 Labuyere et al, 2016 Cereal Grass margin Oilseed rape Cereal GFM OSR

23 Trophic regulation Landscape management Diversified landscapes increase weed seed predation Petit et al % cover of grassland % cover of semi-natural habitats size of cultivated fields (ha)

24 Trophic regulation Landscape management But not in all field management strategies Petit et al. 2017

25 Key points High diversity of organisms and complexity of interactions Challenges of agroecology: make biodiversity and biotic interactions our allies! - A given action may have multiple consequences including unintended. - Uncertainty about environmental parameters and consequences on biotic evolution. Valuing biodiversity and biotic interactions requires: - an integrative and systematic approach for identifying the appropriate cropping practices, - more knowledge on biodiversity distribution, biotic interactions and how they vary according to environmental and cropping system changes, - development of models to integrate knowledge and to predict effects of cropping systems on agronomic and environmental performance, in order to ultimately develop tools for decision support.

26 Towards the implementation of agroecological systems The INRA Dijon-Epoisses experimental farm - Demonstrate the performance of agroecological cropping systems - Remain a research platform for the UMR Agroecology 120ha within a cereal-growing area S. Cordeau; V. Deytieux

27 The general framework Research themes that are central to the project Gene Plant Plant Population Community Design and evaluation of plant genotypes Enhance beneficial interactions Analysis of Biotic interactions between Plants and micro-organisms Interfaces between fields and seminatural habitats Farm The role of spatial processes for biodiversity and biotic interactions Maximise multi-performance and ecosystem functions Design and evaluation of agroecological systems

28 The general framework The key management levers Enhance plant diversity and plant cover in space and time Substantial amount of SNH to enhance pest natural enemies Grass margins, flower strips, hedgerows Comparison of no-till and tilled systems

29 Implementation of these principles at the farm scale Direct drilling Tillage Hedgerow Grass strips Flower strips

30 Thank you for your attention