COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Cover crops (functionnal mixtures) in OGH
Hélène VEDIE
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Soil Fertility Management in GH Greenhouse : intensive system, 2 crops/year
- Problems of soil structure (intensive traffic, inter-rows…)
- Increased Soil Organic Matter (SOM) mineralization (soil tillage,
climate, solarization…)
- High nutrient demand
- Weed species selection (chickweed, purslane, amaranth…)
- Sanitary problems with poor crop diversification Solanaceae – Cucurbitaceae – Asteraceae
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Why growing cover crops in OGH ?
One solution to some of the problems in greenhouses : crop rotation, soil structure, SOM improvement (low ressources of animal manure or
compost), crop nutrition, weed management, sanitary problems…
- Both can be viewed as a type of crop rotation (diff. families)
- Many similar functions – many similar species - Main difference : a cover crop will protect the soil between 2
crops, & possibly during the crops (living/dead mulch)
a green manure is a « soil building crop » to produce OM for incorporation into the soil between 2 crops
Cover crops and green manures
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
1. GENERAL BENEFITS OF COVER CROPS
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Cover crop… to enhance Crop rotation
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Soil structure improvement During cover crop cultivation
Surface protection
Roots work
They improve soil porosity
They maintain soil aggregates
They produce exsudates
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Soil structure improvement After cover crop incorporation
Earthworms stimulation : +++ porosity
Microbial biomass activity : +++ soil aggregates, stability
Soil structure stability
Weeks Months Years
Green manure
Straw
Compost
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
SOM and nutrition improvement - By bringing +/- large amounts of organic matter, will have +/-
effects on SOM (with indirect effects on soil structure) and biological activity
a question of amounts a question of quality (C/N) - C/N < 25 : mineralization – N release C/N > 25 : immobilization – +++ SOM - Strategy ? : terminate the GM early to increase N availability… but overall biomass and OM production are reduced
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
SOM and nutrition improvement
C/N around 12 (from 10 for pea to 18 for italian RG + vetch)
0123456789
Dry biomass (t/ha)- autumn 2013 - 3,5 months
Fabaceae Poaceae + fabaceae
Faba bean + lentil
Rye + pea
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
SOM and nutrition improvement
C/N around 35 (from 28 for millet to 57 for sorghum)
0
2
4
6
8
10
12
14
16
18
20
Millet (+pois) Sorgho Lablab Moha (+trèfle) Sarrasin (+vesce) Niébé
Dry biomass (t/ha)- summer 2013 - 53 days
Poaceae
Fabaceae
Fabaceae Polygonaceae
(+fab)
Temp. : 25,4 °C
Vigna sinensis
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
SOM and nutrition improvement
0,0
2,0
4,0
6,0
8,0
10,0
12,0
Dry biomass (t/ha)- summer 2014 - 48 days
Polygonaceae + Fabaceae Poaceae + Fabaceae
Temp. : 23,9 °C
Buckwheat + brassica juncea + Vigna sinensis
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
SOM and nutrition improvement Cover crops trap +/- important amounts of soil nutrients
100 -200 N / 30 P2O5 / 150-300 K2O Differences with families/species ; soil contents…
and will release these nutrients in a more readily available form
Cover crops can explore different ressources Dif. Plant rooting patterns extraction in different soil layers
ex.: root density/ symbiotic association with mycorrhizae for immobile P
Root activity effect on nutrient availability: insoluble nutrients are released by
the action of organic acids, chelates…produced by the roots
- mustard, buckwheat / P
- brassica sp. / K et S
Legumes capacity to fix N2 from the atmosphere (nodules)
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
SOM and nutrition improvement Nutrients release will depend on the mineralization rate of
the cover…. : - Soil temperature - Soil humidity - Faster decomposition if the cover is chooped and turned under - P and K have a very good availability
- C:N ratio for N availability
Sometimes contradictory results on a green manure effect on subsequent crop nutrition… but globally positive effects on the long term
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
SOM and nutrition improvement 2t/ha Dry Biomass
N mineralized
(% N org)
Soil temperature and humidity !!!
Modelisation according Justes et al., 2008
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Weed control weed growing is limited by :
- Direct competition (light, water, nutrients…)
- Allelopathy : biochemicals produced by plants (buckwheat, rye)
fast growing cover crops have general suppressive effect Buckwheat, Italian ryegrass, Brassica sp., sorghum sp., millet, …
… some have more specific effects (Pousset, 2000)
-Rye against couch grass (Elytrigia repens L.) -Rapeseed against brassica weeds
-High nitrogen consummers (brassica sp.) against nitrophilous weed species (chickweed [stellaria media], nettel [Urtica sp.]
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Suppressive effects on pathogens
Many beneficial effects of cover crops on plants pathogens have been attributed to their direct and indirect effects on the physical and chemical properties of the soil as well as to promoting the activities of beneficial microorganisms (Abawi, 2000)
Soil-inhabiting organisms can affect plants pathogenic organisms by competition (nutrients, space, water…) and direct predation or parasitism
Toxic compounds produced during growth (root exudates) or during decomposition can inhibit some soil-borne pathogens
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Suppressive effects on pathogens Some examples to control root-knot nematodes (Meloidogyne sp.)
Crotalaria retusa Crotalaria grantiana
Crotalaria sp. (Fabaceae)
Non-host plants
Ovicidal effect of root exudates
Nematostatic effect of plant extracts
Tagetes sp. (Asteraceae)
Nematicidal effect of root exudates
Trap plants : no reproduction
Tagetes patula
Tagetes minuta
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Suppressive effects on pathogens Toxic compounds released by some plants (biofumigation)
Brassica sp. contain GLS (brassica juncea, forage radish…)
Sorghum sp. contain dhurrin (sorghum-
sudangrass hybrids)
Alliaceae sp. contain thiosulfinates (allium,
onion…)
Breakdown in the soil
isothiocyanates Hydrogen cyanide
Dimethyl Disulfide (DMDS)
Many litterature with results on soil-borne diseases (verticillium, sclerotinia, fusarium..)and nematodes Not always very clear effects in the fields…
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Suppressive effects on pathogens Some risks too !!!
Family/specie Risks
Brassica sp. Hosts for various fungi: clubroot
(plasmodiophora brassicae) sclerotinia (autumn),
rhizoctonia (summer) and many pests: flea
beetle (delia radicum) diamondback moth
(plutella xylostella) cabbage worms (pieridaea sp.),
slugs, …)
Phacelia Host for Y potato virus and pests
(aphids, white flies, thrips)
Trèfle, vesce Slerotinia, slugs…
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
A good cover crop …
Will allow soil fertility (physical, chemical, biological properties) enhancement, weed suppression, and, to some extent, will have some suppressive effects on pathogens….
First… : a good cover
crop has to grow under greenhouse !
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
2. CULTIVATING COVER CROPS UNDER GREENHOUSE
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
When growing cover crops in OGH ?
Cash crop
Inter cropping
Cover crop
Solarization
Autumn Winter Spring Summer Greenhouse occupation
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
How to choose ?
CHOICE
Cultivation conditions (crop
rotation, sanitary problems…)
Inter cropping Period
Seeds (availability,
price)
Inter cropping duration
Main goal of the cover crop ?
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Growing cover crops in summer Poaceae
SORGHUM/SUDANGRASS -50 kg/ha or less -Cycle : short to long (cuttings)
PEARL MILLET (Pennisetum glaucum)
-30 kg/ha or less -Cycle : short to long (cuttings)
Panicum germanicum -30 kg/ha or less -Cycle : up to 50 d -Less weed suppression
Fast growth – high biomass - Weed suppression – High temperatures
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Growing cover crops in summer Brassicaceae
FODDER RADISH (Raphanus sativus)
-20 kg/ha -Cycle : short (30 d)
TURNIP RAPE (Brassica rapa oleifera)
-10/15 kg/ha -Cycle : medium (40 d)
MUSTARDS (Sinapis alba, brassica juncea)
-10/15 kg/ha -Cycle : short (30-40 d)
Fast growth – high biomass - Weed suppression – Diseases (rhizoctonia) and pests (flea beetle,
diamondback moth) risks
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Growing cover crops in summer Polygonaceae
BUCKWHEAT (Fagopyrum esculentum)
-40/60 kg/ha -Cycle : short (30-40 d)
Fast growth – Soil structure - Weed suppression – high T°C CMV risk
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Growing cover crops in summer Fabaceae
FIELD PEA (Pisum sativum arvense)
-150-200 kg/ha -Cycle : 40-50 d
COWPEA (Vigna sinensis)
-80 kg/ha -Cycle : 40-50 d
Tonga bean, hyacinth bean
(Dolichos lablab, Lablab purpureus)
-80 kg/ha -Cycle : 40-50 d)
Fast growth – High temperature – N2 fixation Medium weed suppression : to be mixed with other plants (stake)
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Growing cover crops in autumn/spring
Basically, most of the cover crops used in open field can be used in the mild seasons under greenhouse : the references are numerous, and adapted to all the geographical areas
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Poaceae: Italian ryegrass, rye,
oat, barley, wheat…
Brassicaceae: mustards,
radish, turnip…
Fabaceae: common vetch,
hairy vetch, field pea, crimson clover (t.i), beersem clover (t.a), lentil, horse bean…
Growing cover crops in autumn/spring
! Sclerotinia, slugs risk
! Sclerotinia, slugs risk
! Sclerotinia on rye in 2013
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
3. CULTIVATING COVER CROPS FUNCTIONNAL MIXTURES ?
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
COVER CROPS MIXTURES : WHY ?
The potential to fulfill all the cover crops benefits may be increased by using mixed rather than single species cover crops. Mixtures may also increase cover crop survival (soil, weather, pests conditions…)
Research on mixed species cover crops is in its infancy : many of the potential benefits are hypothesized rather than known.
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
COVER CROPS MIXTURES : HOW ?
Susan Tallman, USDA, W Sare
To reduce nitrogen imputs To add soil carbon and promote aggregation
To minimize compaction and move nutrients upwards
To provide ground cover to reduce weed establishment and evaporation
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
COVER CROPS MIXTURES : HOW ? Interest to mix species from different functionnal groups : - Improve overall performance due to their seedling
vigor, rooting behavior and environmental tolerances - Complementary development ex : erect cereal as a
stake for viney legumes (vetch, pea, cowpea…) - Complementary N content (C/N ratio) to manage N
release - Interest to mix erect plants for biomass with smaller,
shade tolerant, to compete with weeds
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
COVER CROPS MIXTURES : HOW ? And difficulties : - Good seed rates to allow each specie to grow
Brassica have to be sown with very low rates in the mixes - Seeds with different sizes require different depth of planting : difficult in
1 pass - The more species in the seed mix, the potentially more expensive…
17 species ?
More research is needed
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
4. GREEN MANURE versus COVER CROP ?
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
The cover crop can be used as a “dead mulch”
Some conditions : - Sufficient biomass (10 t/ha ?) - Growth stage of the CC / species choice to avoid regrowth (no herbicides !!!)
- Specific machinery
Many questions : - Subsequent crop nutrition ? - Pests and diseases development on decaying CC ?
As for the green manure, it will be implemented between 2 crops
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
The cover crop can be used as a “dead mulch”
Some publications
Much more research is needed, no references under greenhouse
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
A cover crop can be used as a “living mulch”
Cover crop sown before plantation : - Very high competition with the cash crop - Even with legumes CC (clover)
Undersowing : - Popularised by Iain Tolhurst and Eliot
Coleman - First results show no competition with
the crop ? - Not suitable for too dense foliage crops
(leafy winter vegetable) or sensitive to root competition (onion, radish…)
- One solution to implement a cover crop in greenhouses with longer cash crops ?
The cover crop is implemented during the cash crop
Cover crop between the cash crop raws
COST Action FA 1105: Training School - 15-19 Sept 2014 - CIHEAM – IAMB
Soil fertility, Suppressiveness & Water management for organic agriculture: constraints and opportunities for greenhouse horticultural production
COST FA 1105: Biogreenhouse Towards a sustainable and productive EU organic greenhouse horticulture
Thank you for your attention
Cover crops in OGH