foundation for advanced studies on international development soil fertility, fertilizer, and the...

Foundation for Advanced Studies on International Development

Soil Fertility, Fertilizer, and the Maize Green

Revolution in East Africa

Tomoya Matsumoto and Takashi Yamano(FASID/GRIPS)


Introduction Maize and Fertilizer Use in Kenya and Uganda Data and Descriptive Analysis

Data Dairy Production Systems and Organic Fertilizer

Use Maize Costs, Income, and Profit Estimation Results

Determinants of Fertilizer Use Determinants of Maize Yield

Conclusions

Contents


There is a growing interests in realizing an African Green Revolution.

Kenya and Uganda provide an interesting contrast in maize production: Kenya high inputs, Uganda low inputs.

In this study, we compare maize production in these countries to identify constraints on maize production

Introduction


To describe fertilizer use and maize production, by calculating costs, income, and profit in Kenya and Uganda

To Estimate the determinants of the maize yield, including soil fertility, inorganic and organic fertilizer applications.

Is it profitable to use fertilizer?

Purpose of This Study


Maize in Kenya and Uganda


Nitrogen Consumption in Kenya and Uganda


RePEAT Panel data Kenya: 2004 and 2007, 725 rural households Uganda: 2003 and 2005, 895 households

Soil Sampling at the first survey Kenya about 77 percent Uganda about 67 percent

Data


Survey Areas


All Purchased HYV Maize

Local/ Recycled

Maize HYV

Difference

Number of Plots 3,131

(100%)

1,848

(59.0%)

1,283

(41.0%)

Maize Yield (kg/ha) 1,986 2,172 1,718 454*

Inorganic Fertilizer Use

(kg/ha)

94.7 119.4 59.2 60.2**

Organic Fertilizer Used

(kg/ha)

1,935 2,258 1,471 787**

Carbon Content (%) 2.48 2.59 2.33 0.26**

Table 1. Summary Statistics in Kenya


All Purchased HYV Maize

Local/ Recycled

Maize HYV

Difference

Number of Plots 3,198

(100%)

680

(21.3%)

2,518

(78.7%)

Maize Yield (kg/ha) 1,561 1,719 1,518 202

Inorganic Fertilizer Use

(kg/ha)

2.4 9.1 0.6 8.5**

Organic Fertilizer Used

(kg/ha)

86 142 71 71

Carbon Content (%) 2.35 2.15 2.40 -0.25**

Table 1. Summary Statistics in Uganda


Soil Nutrient Indicator

N: soil nutrient indicator, E: soil condition,C: inorganic fertilizer, O: organic fertilizer

Maize Yield Function

L: plot size, S: seed quantity, A: TFP

),,( pitpitipit OCENN

iptNSL eNSLAY pitpitpitipit

iptiptNiptSiptLiipt nslay


We control for the household fixed effects to eliminate biases created by the correlation between the household fixed effects and independent variables.

We apply the endogenous switching model to control for the maize seed type selection.


Main Hypotheses

Does the soil fertility increase returns from external fertilizer applications?

Is the inorganic fertilizer application optimal?


Maize Yield

Fertilizer Application(DAP)

Maize Price

Fertilizer Price

Uganda Kenya


We do not find that the returns from external fertilizer depend on the soil fertility.

This suggests that the external fertilizer applications would be useful even on poor soils in Uganda and Kenya.

The soil carbon content has a large impact on the maize yield.

The inorganic fertilizer use in Kenya is at about the optimal application rate.

Main Findings


To increase the inorganic fertilizer use. We need to reduce the fertilizer–maize relative price.

Because we find a large positive impact of the carbon content, the results suggest that it is important to improve the soil fertility.

To do so, the organic fertilizer use has to increase. This is a new area for future research.

Policy Implications


In Uganda

Experiments in Jan-Feb 2009, providing a package of HYV seeds, fertilizer, and extension to households in randomly selected villages of RePEAT Samples

Conduct a survey in 2010 to evaluate the impacts

In Kenya

Experiments in 2010 on crop insurance?

Conduct a survey in 2011

What’s next for RePEAT Survey?

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