richard dick- shrub resource islands in the sahel.ppt
TRANSCRIPT
Delivery of Hydrologic and Microbial Services by Shrub Rhizospheres to Increase Crop
Productivity and Stability in the Sahel Global Forum for Innovations in Agriculture,
Abu Dhabi, 9-10 March, 2015
Richard P. Dick, Director ([email protected])
Soil Microbial Ecology Laboratory Ohio State University, Columbus Ohio, USA
Overgrazing Cropping intensification and disturbance
Landscape Exploitation
Increasing rural and urban populations Scavenging for fuel resources
Challenges of Semi-arid Agroecosystems in the Sahel
Subsistence Faming
Low primary productivity Efficiency of water and nutrients
Sahalian Agroecosystems: Carbon - A Major Agronomic Constraint
Loss of soil organic matter inputs: Decreases nutrient/water efficiency and optimal yields (Badiane et al., 2001; Sanchez et al., 1997) Even with fertilizer applications yields continue to go down over the long-term (Sanchez et al., 1997; Merckx et al., 2001).
1. Unique Research Opportunity • Shrub-crop rhizosphere interactions/ecology
• Possible because of minimally mechanized agriculture in the Sahel
• Food security • Rural poverty • Buffering capacity for global climate change • Desert encroachment
2. Potential Applications for Africa
3. Implications for semi-arid regions worldwide
Dr. Mateugue Diack, Univ of Gaston Berger, Decomposition Dr. Ibrahima Diedhiou, Univ. of Thies, Senegal, Plant ecology Dr. Modou Sene, CNRA/ISRA, Senegal, Hydrology Dr. Richard Dick, Ohio State University, Soil biology Dr. Mamadou Khouma, UNDP (formerly ISRA), GIS and plant nutrition
Dr. Samba Ndiaye, Univ. Thies, (formerly ISRA), Agroforestry Dr. Jay Noller, Oregon State University C and biomass – landscape level Dr. Maria Dragila, Oregon State University, Hydrology Dr. Aminata Badiane, USAID (formerly ISRA), Soil biochemistry Ms. Astou Sene, ISRA, Socio-economics
Phase I – Collaborators USAID ($US 250,000)
US National Science Foundation Project (1.2 $US million)
1999-2008
Dr. Samba N. Samba Agroforestry
Ms. A. Sene Rural Sociology
Dr. Aminata Badiane Soil Biochemistry
Dr. Modou Sene Soil Physics
Dr. Mamadou Sene Agronomy/GIS
Research Coordinator
Dr. Ibrahima Diedhiou Post doc - Plant ecology
Sire Diedhiou, Senegal Soil microbiology
Ekwe Dossa, Togo Soil chemistry Nutrient cycling
Abel Lufafa Uganda
Landscape carbon dynamics
Fred Kizito, Uganda Hydrology/soil physics
PhD Students
Dr. Richard Dick, Ohio State University, Soil Biology Dr. Ibrahima Diedhiou, Univ. of Thies, Senegal, Plant Ecology Dr. Brian Mcspadden Gardener, Ohio State University, Plant Pathology Dr. Hassna Founoune-Mboup, Institut Senegalais de Recherches Agricole, Plant Science Dr. Teamrat Ghezzehei, University of California, Merced, Hydrology, Soil & Env. Physics
Dr. Lydie Lardy, IRD Dakar, Molecular Biology Dr. Yacine Ndour, Institut de Recherche pour le Development, Soil Microbiology Dr. Paul Schreiner, USDA-ARS, Mycorrhizal Fungi Dr. Komi Assigbetse, IRD Dakar, Molecular Biology
Phase II – Collaborators US National Science Foundation Project
(2.6 $US million)
2011-2016
Phase II – Collaborators
Richard Dick Soil microbiology
Ibrahima Diedhiou Plant ecology
Brian Mcspadden Gardener Microbial diversity
Teamrat Ghezzehei Soil Physics hydrology
Paul Schreiner Mycorrhizal fungi
Yacine Ndour Soil microbiology
Komi Assigbetse Molecular microbiology
Lydie Lardy Nitrogen cycling
Hassna Founoune-Mboup Mycorrhizal fungi
Students
Nathaniel Bogie, PhD Rhizpsphere hydrology
Matthew Bright, PhD Mycorrhizal fungi
Chelsea DeLay, MS Diazotrophs and nitrogen cycling
Spencer Debenport, PhD Beneficial microorganisms
Esther Lattin, MS Enzymes and
microbial communities
Roger Bayala, Post doc Fieid research coordinator
hydrology
3 m 3 m
Dominant Native Shrubs in Farmers’ Fields
1m
" Northern region, typically sandy " Mean annual rainfall 300 mm " Mean annual temperature 30 oC
" Southern region, higher clay content " Mean annual rainfall 750 mm " Mean annual temperature 32oC
Guiera senegalensis Piliostigma reticulatum
G. Senegalensis 3 Mg dry stem+leaves ha-1
P. reticulatum 3 Mg dry stem+leaves ha-1
Shrub Biomass Study Factorial Treatments: Biomass Rate - 1.5 or 3 Mg ha-1
Fertilizer - 0, 0.5, 1.0 or 1.5 X Recommended Rate
Effect of Shrub Residue (absence of shrub plant) and rate of fertilizer in on Crop Yields in Senegal.
‡Values within columns followed by the same superscript letter are not significantly different at P <0.05
Residue Treatment Rate ha-1 2004 Peanut
2005 Millet
2006 Peanut 2007 Millet
--------------------------------------------kg ha-1---------------------------------------
Control No residue 816a 537a 712b 1197c
G. senegalensis Biomass
1.5 Mg 766a 664a 912b 1296c
G. senegalensis Biomass
3.0 Mg 857a 755a 1116a 1609a
P. Reticulatum Biomass
1.5 Mg 615a 583a 908b 1385b
P. Reticulatum Biomass
3.0 Mg 691a 588a 1116a 1479b
NS NS P<0.05 P<0.05
Ekwe Dossa N and P Cycling PhD Candidate
Shrub X Fertilizer Rate (Bambey ~500 mm)
Factorial: 1) + and - Shrub
2) 0, 0.5, or 1.0 Rec. Fret. Rate
Plus Shrub Litter Incorporation
Guiera senegalensis
Minus Shrub
†Rate Shrub No shrub Shrub Increase
Shrub No shrub Shrub Increase
------------ kg ha--1------------- % ---------- kg ha-1 ----------- % 2004 season (Arachis hypogaea) 2005 season (Pennissetum glaucum) 0 190a† 78b 143 218a 11a 1818
0.5 135a 103a 32 359a 148b 142 1.0 153a 116a 36 422a 278b 52 1.5 203a 91b 123 605a 503a 20
Mean 170a 97b 400a 260b 2006 season (Arachis hypogaea) 2007 season (Pennissetum glaucum)
0 384a 273b 41
197a 6b 3183 0.5 542a 449b 21 403a 85b 374
1.0 556a 579a -4 378a 200b 89 1.5 708a 532b 33
622a 174b 257
Mean 547a 458b
400a 116b
Effect of shrub (G. senegalensis) and rate of fertilizer on Crop Yields in the Peanut Basin, Senegal.
‡Values within columns followed by the same superscript letter are not significantly different at P <0.05
†Fertilizer rate is 0, 0.5, 1.0 or 1.5 the recommended NPK rates appropriate for each crop.
(Dossa et al. Agronomy J. 2012)
G. Senegalensis and P. reticulatum are found in farmers’ fields between < 200 to ~ 1200 mm from Senegal to Niger and Chad
Dramatic Yield Response to Shrub Intercrops:
Why?
Improved Water Relations
Improved Nutrient Status Beneficial Microorganisms
Increased Soil Organic Matter and Nutrient Availability
(Dossa et al., 2008; 2009)
• Root turnover • Litter inputs from aboveground biomass
Shrub Roots go very deep
• Roots grow to 10 meters or more • Perform hydraulic lift – movement of water through
roots from wet subsoil to surface soil at night when PS stops (Kizito et al., 2012)
Shrub impact on water balance
" Hydraulic lift under dry
conditions " Ground water recharge with
excess precipitation " No competition of shrubs with
crops for water
WATER TABLE
ET P
ΔSW
Gin
DP
Crop
Shrub
?
Kizito et al. 2006; 2012
Shrub Rhizosphere Promotes Beneficial Microorganisms Harbor bacteria and fungi for crop roots that:
- increase nutrient availability - provide plant growth promoting hormones - increase N fixation by free living microbes
Promote mycorrhizal fungi-infecting shrubs/crops: - common hyphal connections of shrub to crop roots - improves water relations of crops - promote P and other nutrients for crops
0 1 2 3 40
20
40
60
80
100
Wet season
Distance from Center of Shrub (R=canopy radius)Center R/2 1 R 2 RM
icrob
ial B
iom
ass C
(µg g
-1)
Dry season
Rhizosphere soil
Non-rhizospheresoil
Dry season
Wet season
Soil Microbial Biomass C (incubation-fumigation) (0-20 cm depth) in the Wet and Dry Season of P. reticulatum (n=3).
Microbial Diversity with PLFA Analysis
Variance explained (PCA): 64% Correlation with Axis 1
! Fungi, 18:2ω6c (0.89) ! Actinomycetes, 10Me 18:0 (0.86) ! 15:0 3OH (0.85) ! Rhizosphere effect (p<0.001) ! Seasonal effect (p<0.02)
PLFA
Axis 1
Axi
s 2
Rainy season Dry season Rhizosphere Bulk Non-rhizosphere P. reticulatum : red color G. senegalensis: black color
(18
%)
(46 %)
Non-rhizosphere soil
Bulk soil Rainy season
Bulk soil Dry season
Rhizosphere
Rainy season Dry season Rhizosphere Bulk Non-rhizosphere P. reticulatum : red color G. senegalensis: black color
Mescosm for studying hydraulic redistribution relative to microbial and crop responses in rhizo- vs. mycorrhizo-spheres.
G. senegalensis Millet
Perforated 35 m stainless steel sheet coated with PTFE
tap root chamber
water container 15 m air gap
mycorrhizae fungi
75 cm
Root chamber
Millet under water stress in mesocosm: Effect of Mycorrhizal hyphae
Intact microcosm Turned microcosm Hyphae connections No hyphal connection
Paradigm shift Biogeochemical processes can proceed in
the dry season of arid regions. Hydraulic lift maintains microbial communities and activities – Therefore, driving processes that can improve crop yields – notably nutrient release for crop uptake
Overall Conclusions Shrubs can act as “mother” plant for crops
Shrub Rhizospheres: ü Increase microbial diversity/activity ü Harbor beneficial microorganisms ü Are performing hydraulic lift ü Increase nutrient availability and decomposition rates
Crop Productivity P Shrub residues do not inhibit yield & can increase yield P Shrubs do not compete for water with crops P Shrubs assist crops through drought periods P Non-thermal systems with shrub present increase crop
yields dramatically with G. senegalensis P Shrubs decrease time to maturityb
Publications Diack, M., M. Sene, A. N. Badiane, M. Diatta, and R. P. Dick. 2000. Decomposition of a native shrub (Piliostigma
reticulatum) litter in soils of Semiarid Senegal. J. of Arid Soil Research and Rehabilitation 14(3):205-218. Iyamuremye, F., V. Gewin, R.P. Dick, M.Diack, M.Sene, A.N. Badiane, and M. Diatta. 2000. Carbon, nitrogen,
and phosphorus mineralization of agroforestry plant residues in soils of Senegal. J. of Arid Soil Research and Rehabilitation 14:359-371.
Badiane, A.N., A. Faye, C.F. Yamoah, and R.P. Dick. 2002. Compost and mineral fertilizers for millet production by farmers in semi-arid Senegal. Biol. Ag. Hort. 19:219-230.
Lufafa, A., I. Diédhiou, S. Ndiaye, M. Séné, M. Khouma, F. Kizito, R.P. Dick, and J.S. Noller. 2008. Carbon stocks and patterns in native shrub communities of Sénégal’s Peanut Basin. Geoderma 146: 75-82
Kizito, F., M. Dragila, M. Sène, A. Lufafa, I. Diedhiou, E Dossa, R.P Dick, M Khouma, A. Badiane, and S. Ndiaye. 2006. Seasonal soil water variation and root dynamics among two semi-arid shrubs coexisting with Pearl millet in Senegal, West Africa. J. of Arid Environments 67:436.
Lufafa, A., Wright, D., Bolte, J., Diédhiou, I., Khouma, M., Kizito, F., Dick, R.P., Noller, J.S., 2008. Regional carbon stocks and dynamics in native woody shrub communities of Senegal’s Peanut Basin. Agriculture, Ecosystems and Environment 128:1–11.
Kizito, F., M. Senè, M. I. Dragila, A. Lufafa, I. Diedhiou, E. Dossa, R. Cuenca, J. Selker, R. P. Dick. 2007. Soil water balance of annual crop-native shrub systems in Senegal’s Peanut Basin. Ag. Water Management 90:137 – 148.
Dossa, E.L. M. Khouma, I. Diedhiou, M. Sene, F. Kizito, A.N. Badiane, S.A.N. Samba, and R.P. Dick. 2009. Carbon, nitrogen and phosphorus mineralization potential of semiarid Sahelian soils amended with native shrub residues Geoderma 148:251–260
Dossa .E. L., J. Baham, M. Khouma, M. Sene, F. Kizito, R.P. Dick. 2009. Phosphorus Sorption and Desorption in Semiarid Soils of Senegal Amended with Native Shrub Residues Soil Science 173:669-682.
Publications (continued) Lufafa, A.; Diedhiou, I.; Ndiaye, N.A.S.; Sene, M.; Kizito, F.; Dick, R.P.; Noller, J.S.
Allometric relationships and peak-season community biomass stocks of native shrubs in Senegal's Peanut Basin. Journal of Arid Environments73:260-266.
Diedhiou, S., A.N. Badiane, I. Diedhiou, M. Khoum, A.N.S Samba, M. Sène and R.P. Dick. 2009. Succession of Soil Microbial Communities during Decomposition of Native Shrub Litter of Semi-Arid Senegal. Pedobiologia 52:273—286.
Dossa , E.L.,S. Diedhiou & J. E. Compton, K. B. Assigbetse & R. P. Dick. 2010. Spatial patterns of P fractions and chemical properties in soils of two native shrub communities in Senegal. Plant Soil 327:185–198
Kizito, F., M. I. Dragila, M. Senè, R. J. Brooks, F. C. Meinzer, I. Diedhiou, M. Diouf,, A. Lufafa, R.P. Dick, J. Selker, R. H Cuenca. 2012. Hydraulic Redistribution by Two Semi-arid Shrub Species: Implications for Sahelian Agro-ecosystems. J. Aird Environments. 83:69-77.
Dossa, E.L. M. Khouma, I. Diedhiou, M. Sene, F. Kizito, A.N. Badiane, S.A.N. Samba, and R.P. Dick. 20012. Crop Productivity and Nutrient Dynamics in a Shrub (Guiera senegalensis) -Based Farming System of the Sahel. Aronomy J. 104:1255–1264.
Diedhiou1, S., E.L. Dossa, A.N. Badiane, K.B. Assigbetsee, I. Diedhiou, N.A.S. Ndiaye5, M. Khouma, M. Sène and R.P. Dick. 2012. Microbiology and Macrofaunal Activity in Soil beneath Shrub Canopies during Residue Decomposition in Agroecosystems of the Sahel. Soil Science Society of America J. Soil Science Soc. Am. J. 77:501-511
Dossa, E.L. I. Diedhiou, M. Khouma,, M. Sene, A.N. Badiane, S.A.Ndiaye, K.B. Assigbetse, S. Sall, A. Lufafa, F. Kizito, S. Diedhiou, and R.P. Dick, and J. Saxena 2012. Crop productivity and Nutrient Dynamics in a Shrub (Piliostigma reticulatum) -Based Farming System of The Sahel. Agron. J. 105:1237-1246.
WEST AFRICAN SHRUB INTER-CROPPING INITIATIVE:
ALearning and Observatory Network Focused on Subsistence Farm Families
Guiding principles
Gender neutral Locally defined criteria of success
Integrate ‘expert’ and ‘non-expert’ knowledge
World Agroforestry Centre, Nairobi, Kenya Ohio State University
Technology Development
Participating Countries: Burkina Faso, Mali, Niger, Senegal
Approach On-farm demonstration and technology development A. Test and demonstrate: Optimized shrub-crop system – high shrub density/no burning
vs. Traditional management – low shrub density/coppicing& residue burning
B. Monitoring: C sequestration, soil quality, crop water stress levels and yield, and socio-economic impacts of shrub-based farming systems C. Farmer-researcher data analysis and interpretation
Expected Results: Technology Adaptation and Transfer
Successful shrub-based farming options in the Sahel documented, and findings made available to stakeholders (FBO, NGO, government agencies, ) for decision making.
Farmer-centered decision-support tools will be developed using focus sessions, workshops, and field surveys.
Expected Products 1. Roadmap for scaling and fundamentals for full
technology transfer campaigns
2. Optimized Shrub-Crop Manuals for agricultural professionals and policy makers - local language and French for both literate and illiterate end users
3. Smart Phone apps and technology transfer platforms – including real time crop management information transfer
Expected Products (continued)
4. Website Model for farmers and ag professionals with downloadable and printable extension instruments - local language and French
5. Carbon Credit Calculator - App for smart phones that uses easily measurable above ground measurements to verify C sequestration rates at the farmer level
Richard Dick
School of Environment an Natural Resources
Ohio State University [email protected]
Thank You Questions?
Reestablishment Technology
1. Grow seedling in spring season P. reticulatum by seed; G. senegalensis by layering mother plant
2. Transplant seedling into farmers fields during wet season
3. Allow seedlings to grow without further irrigation over dry season.
Stem from mother plant
New seedling growth
Dr. Ibrahima Diedhiou
Cooperating Farmer
Shrub Reproduction
Piliostigma reticulatum Interplanting for Mango Seedling
Establishment Plant mango on established P. reticulatum
Hydraulic lift “irrigation” High mango seedling survival – likely because of
water and improved soil quality