Two pathways, same system: Surface drip and SDI share economic drivers, barriers, and feedback loops — but SDI fully eliminates weed pressure, making tillage reduction far easier and unlocking a stronger soil health / carbon income pathway.  |  Academic: core dynamics only  ·  Program Design: adds leverage intervention points
Academic
Program Design
Focus:
+ same direction opposite direction multi-year delay Click R / B circles to highlight loop · click background to reset
Focus:
+ same direction opposite direction multi-year delay Bold red arrow = full weed elimination (SDI only) Click R / B circles to highlight loop · click background to reset
Focus:
+ same direction opposite direction multi-year delay Gold dashed = leverage point Click R / B to highlight loops
Focus:
+ same direction opposite direction multi-year delay Bold red = full weed elimination Gold dashed = leverage point Click R / B to highlight loops
Legend
Nodes
External / exogenous pressure
System variable
Adoption (focal node)
Leverage point (program design only)
Edges
+ same direction
 opposite direction
Strong effect (SDI only)
Leverage intervention
 Causal delay (3–5 yrs)
Feedback loops — click to highlight
R1 Income virtuous cycle · invest_cap → adoption → yield → farm_income
R2 Peer demonstration · adoption → peer demo → enrollment → adoption
R3 Carbon income · enrollment → carbon income → farm income → invest_cap
B1 Water use relief · adoption → water efficiency → scarcity → adoption
R4 Fertilizer trap · perceived risk → fert use → income → perceived risk
R5 Hardpan trap · tillage → hardpan → tillage (reinforcing vicious cycle)
Key differences: Surface Drip vs SDI
DimensionSurface DripSDI
Weed pressureReduced (surface emitters → some dry zones)Fully eliminated (subsurface → dry inter-row throughout)
Tillage reductionPartial — residual weed pressure motivates some tillageFull — no weed pressure → tillage unnecessary from weed perspective
SOC / soil healthModerate; 3–5 yr delayStrong — less disturbance → faster SOC accumulation; 3–5 yr delay
Carbon credit potentialLower (incomplete tillage reduction)Higher (full tillage reduction + SOC pathway)
Equipment costLower — standard drip + pressurizationHigher — SDI premium on top of pressurization
R5 Hardpan loopPartially broken (some tillage continues)Fully broken — no weed pressure → no repeat deep tillage
Program first-year riskLower cost = lower risk thresholdHigher cost = yield guarantee and subsidy more critical
Leverage points — program design version
R2 · Peer demonstration
Pioneer & Innovative Farmer Prioritization
Enrolling innovative farmers first maximises R2. Each pioneer reduces traditional attachment and becomes a recruiter. Konya EAs and Adana 5 confirmed the neighbour-watching dynamic.
Investment barrier
Subsidy Coverage Expansion
50–70% grant threshold cited by EA4, Int4, Mardin 3 & 4. Expands public finance support → lowers net equipment cost. Critical for SDI especially.
R3 · Carbon income
Carbon Income Activation
Pilot payments make R3 real and reduce carbon market uncertainty. SDI's stronger SOC pathway generates more credits. Int2 most interested; EA1 already motivated.
Perceived risk · R4
Yield Guarantee + Loss Compensation
EA5, Int3, Adana 3 & 4 require yield protection. Reduces perceived risk directly — breaking the R4 fertilizer trap and enabling longer contract commitments.
Infrastructure · B1
Closed Canal Infrastructure
Removes pressurisation cost for both drip and SDI. Adana 5 waited years for the canal. Urfa's SDI plans blocked by open-canal rotation rule.
Trust infrastructure
Cooperative / Önder Çiftçi Intermediation
Bridges gov–private distance. EA1 wants gov-run programme; Adana 3 had bad company experience. Pooling also reduces per-farm risk for smaller holdings.
Behavioural barrier
Training & Awareness
"Babadan kalma" habit and inflated risk perception are separate from financial risk. Field agronomist visits and farmer-to-farmer learning address both.
Program design
Context-adapted Contract Design
Flexible, crop-specific protocols reduce perceived risk of long-term commitment. Blanket CA recommendations rejected by beet/groundnut farmers. Periodic subsoiling allowance critical.