A presentation by Dr. Julius Okello & Zachary Gitonga of the University of Nairobi

1. 5/27/2010
Introduction
ECONOMIC VALUE OF MANAGING BGBD: THE CASE
OF RHIZOBIUM AND TRICHODERMA SPP • Agriculture remains the engine of growth in
SSA (>30%GDP: 80% employment)
• Opportunities for increasing agric production
in the region eroded by
in the region eroded by
– High population growth
Julius Okello & Zachary Gitonga
– Productive land already in use
University of Nairobi
• Existing land is exhausted from overuse
Introduction contd… Introduction contd...
• Overview Bill and Melinda Gates Foundation committing
– Soil is an important agricultural resource
$198 million to the effort (TSBF,2009)
Abuja heads of state at fertilizer summit
– Soil fertility management a prerequisite for
declaration: increase fertilizer use to 50Kg/Ha by
sustainable agriculture and food security
sustainable agriculture and food security
2015
– FAO: Soil biodiversity (hence soil biological
• Why the big push?
processes) key maintaining soil fertility
– Soil improvement techniques (via use
• Increased attention to soil fertility issues in Africa manure, composting) affected by falling supply of
AGRA launched new soil health program targeting cattle manure
4.1 million farmers – Declining per capita land holding limiting other
techniques (rotation, fallowing, no tillage)
Land and soil degradation Drivers of Land and soil degradation
• Land and soil degradation : decline in land quality • Biophysical causes
further driven by natural processes and human – Soil erosion, salinization, leaching
activity • Social‐economic causes
– Loss of ecosystem goods & services (regulation of – Subsistence agriculture (continuous cultivation: low
y g y pp p
hydrological cycle, support production & CO2 organic input)
sink, Biodiversity loss ) – Low income levels/poverty ‐ results in soil mining
– Continuous cultivation – no fallowing – Land tenure systems & property right regimes (discourages
– Movement to marginal fragile lands investment in conservation efforts)
– Population pressure (farming hillside, marginal (ASAL)
• current land degradation trends could render two‐ areas)
thirds of Africa's croplands effectively non‐productive – Political causes
by 2025 with severe ecological, economic and social • Policy formulation and legislation
consequences (UN 2004) • Land allocation
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Drivers of Land and soil degradation Drivers of Land and soil degradation
• Poverty • Land tenure systems and property rights
– There is a strong link between the prevalence of land
degradation and the incidence of rural poverty, – rural HH with insecure rights are less likely to
– the poorest rural communities in SSA tend to be located in invest in ensuring their future productivity
the ecologically fragile and degraded areas
g y g g – Undefined PR has lead to encroachment of water
Undefined PR has lead to encroachment of water
– Poor people cannot afford to forgo short‐term production shed areas and forests
for the sake of long term sustainability
– low incomes hence low investment in soil improvement
techniques and overdependence on natural resources
• Poor access to advisory support services on sustainable
land mgt practices, alternative land use
Role of BGBD in addressing land and
The other path…
The other path... soil degradation
• This report examines the role micro and • Reduced reliance on organic fertilizers BNF
macrofauna can play in maintaining soil health – Improvement of soil fertility by adding N & P from
and crop yields the biosphere
• It examines the benefits and costs of using
It examines the benefits and costs of using – Increase in soil organic matter due to large
Increase in soil organic matter due to large
beneficial microfauna in agriculture amounts of biomass characteristic of certain
improved varieties;
• Focuses on: – Reduction in soil erosion‐induced nutrient losses
– Rhizobium due to increase in SOM.
– Trichoderma
Beneficial soil micro & macro‐organisms Beneficial Rhozobium
• Several soil‐based micro & macro organism confer benefits
to agriculture • There are diverse species of beneficial Rhizobium
• Micro‐organisms: Trichoderma, Rhizobium, Micorhiza etc in the soils
– Some act as biopesticides and biofertilizer • These arise from two sources:
– For instance Trichoderma spp
– Resident populations existing in soil
Resident populations existing in soil
• Macro‐organisms:
Hymenoptera, Coleaptera, Oligocheata, Orthoptera, Arenae – Populations commercially introduced as inoculants
etc • The MIRCEN project (UoNairobi) isolated several
– examples include nematodes, earthworms, ants species of Rhizobium from Kenya soils
– Improve soil physical condition (structure, aeration)
– “soil engineers” • Examples include R. leguminosarum bv viciae, R.
• These organism are prevalent in Kenyan soils leguminosarum bv phaseoli, R. tropici, etc
• Here, we focus on Rhizobium and Trichoderma
– But emphasize that macro‐organism are equally important
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3. 5/27/2010
Economic value of Rhizobium
CB of Rhizobium on cowpeas: Pakistan
• In Vietnam: Replacing fertilizer N with Rhizobial
Treatment Total variable Gross returns Net returns BCR
cost
inoculants saved farmers money (A$50‐60
Io 6220 8828 2608 1.42 million/yr) in input costs
I1 6308 12220 5912 1.94
I2 6308 12925 6617 2.05
• In Kenya, studies document benefits of Rhizobium
PKS +Io 8501 13249 4748 1.56 – Oti
Otieno et al find that Rhizobium can substitute for N in
t l fi d th t Rhi bi b tit t f N i
PKS+I1 8589 16520 7931 1.92 common beans under wet conditions
PKS+I2 8589 16523 7934 1.92
Source: Sarker et al., 2001
– Woomer et al: yield increase in soy/common beans
Io: No biofertilizer; I1; Biofertilizer type 1, I2: Biofertilizer type2 , PKS =chemical – Onduru et: Rhizobium can augment yields from P
fertilizer
• Use of biofertilizer gives significantly higher net returns than when not used application in dry areas
•Net returns higher when biofertilizer is combined with chemical fertilizer
•BCR highest when biofertilizer is used alone due to low unit cost
Economic benefit of Rhizobium: evidence Economic benefit of Rhizobium: evidence
from Kenya from Kenya
Mean total grain yield (Kgha‐2) of grain legumes under different Rhizobial inoculation response by legumes (Kgha‐1)
nitrogen sources during the long season of 2005 Test crop Site Uninoculated Inoculated % increase
fertilizer Manure Rhizobium Control
Soya beans Homabay 2520 3570 42
Lablab 3.04 2.78 3.06 2.98
Kabete 1021 1613 58
Common bean 2.72 2.63 2.65 2.43
Mtwapa 2333 3850 65
Green gram 1.57 2.58 2.64 1.80
Common beans Kabete 2151 2640 26%
Lima beans 3.05 2.90 2.65 2.56
Mean 2.24 2.14 2.16 2.09
Source: Woomer et al., 1996
Source: Otieno et al., 2009
Rhizobium inoculation improves legume yields and reduce Average pulses yield in Kenya estimated at 286 Kgha‐1 (FAO, 1995)
Bean Inoculation with appropriate rhizobium + agronomic practices can fix
need for inorganic fertilizers (Cheminingw’a 2009) sufficient N hence no need for inorganic fertilizers
Rhizobium inoculant market penetration in Kenya only 0.3%
BC of Rhizobium on cowpeas in Kenya: Onduru
et al 2008 BC of Rhizobium use in cowpeas contd...
Deception Control Rhizobium TSP Rhizobium+TSP
Grain yield (Kgha‐1) 1,100.00 1,175.0 1,387.5 1,700.0 • Benefits outweigh the costs of Rhizobium use
Gross income (KSh/ha) 22,059.50 23,562.3 27,850.6 34,117.3 • BC ratio for Rhizobium alone equals that of TSP
Cost of labour (KSh./ha) 10,760.00 10,800.0 10,840.0 10,800.0
• Combining TSP with Rhizobium gives highest
Rhizobium purchase
purchase 0.00
0 00 117.0
117 0 0.00
0 00 117.0
117 0
[KSh/ha] grain yields hence BC ratio
i i ld h i
TSP purchase [KSh./ha] 0.00 0.00 2,704.0 2,704.0
• Implies good performance when Rhizobium is
Seed purchase [KSh./ha] 1,500.00 1,500 1,500.0 1,500.0 used as a supplement to inorganic fertilizers
Total variable cost [KSh./ha] 12,260.00 12,417.0 15,044.0 15,121.0
Gross margin [KSh./ha] 9,799.50 11,145.3 12,806.6 18,996.3
Benefit cost ratio 1.8 1.9 1.9 2.3
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4. 5/27/2010
Benefits of using Trichoderma Effect of Trichoderma on yields Taita
1.4
1.2
• Is both a biopesticide or biofertilizer
1
Yields [kgs]
• Biopesticide species: Trichoderma koningii and 0.8
Trichoderma harzianum 0.6
Y
• Trichoderma harzianum is abundant in Embu
i h d h i i b d i b 0.4 Wgt grains
Wgt straw
• A plant growth stimulator (biofertilizer): protects 0.2 Wgt litter
plants from destructive fungi 0
– Rhizoctonia solani Pythium, Sclerotia rolfsii
• Controls "damping off"—pre‐germination rot—
hence improves the germination rate Treatment
Trichoderma in Embu CB of Trichoderma
1.6 Wgt bean litter
1.4
Wgt grains • Experimental data suggests that benefits are
1.2
1 significant
0.8
0.6
• These studies however measure only the
0.4 tangible economic benefits
tangible economic benefits
0.2
0 • Intangible benefits (environmental
improvements) largely uncaptured
Why the poor adoption of beneficial
Implications
organisms?
• Odame (1997) lists a number of challenges the • The challenges listed above highlight the need for
MIRCEN project faced viz: strengthening the technology transfer aspects of the
projects create awareness, farmer education etc
– Focus on legumes while ignoring cereals
• Also suggests the need to also target cereals (the main
– Lack of focus on marginal areas
staple food crops in Kenya) and drylands
staple food crops in Kenya) and drylands
– Lack of awareness by farmers (i.e., poor outreach)
• In doing these, the costs of the technology needs to be
– Poor quality control (leading to poor nodulation) kept low to allow greater access by poorer smallholder
• These challenges still dog projects that promote farmers
use of beneficial organisms in Kenya • Commercialization may present efficient way to up the
• Despite commercialization of the Rhizobium production and sales, but may result in higher costs for
small farmers discourage use by such farmers
product (BIOFIX), use by farmers remain low
• Promote technology as GREEN – to horticulture industry
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