Irrigation-Fertilizer Input Substitution
Observational StudyReview
Smallholder farmers substitute irrigation access for chemical fertilizer intensity, using irrigated land to secure baseline crop production while reducing expenditures on expensive inorganic cash inputs.
Picture this
Imagine a gardener who can either install a regular sprinkler system or buy expensive concentrated plant food. Because the sprinkler system guarantees a steady crop yield, the gardener reduces their purchase of high-cost plant food.
What the evidence says
Irrigated area increases the probability of purchasing fertilizer (first stage coefficient = +0.655, p < 0.01) but significantly decreases the overall quantity/value of chemical fertilizer applied per household (second stage coefficient = -1.268, p < 0.01).
- Who was studied
- N = 2,217 rural smallholder households across 120 Kebeles in Amhara, Ethiopia.
- How
- Heckman two-step consistent estimator analyzing the decision to purchase inorganic fertilizer (first stage) and the log value of fertilizer purchased (second stage).
What to do
Account for access to irrigation when designing input supply targets, as irrigated farms require lower per-hectare chemical fertilizer volume than rain-fed farms.
From the source
"Negative significance is exhibited by the average area irrigated, suggesting that irrigation maybe a substitute for the application of fertilizer..."
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