Table 3.

Production function estimates.

Maize yield on plot	Pooled OLS	Fixed effects
Nitrogen	4.688⁎	8.597⁎⁎
Nitrogen squared	−0.001	−0.004
Nitrogen ∗ phosphorus	0.024	0.021
Seed rate (kg/hectare)	12.849⁎⁎⁎	14.056⁎⁎⁎
Labor (adult equivalency unite)	3.958	171.032
Hired labor	197.446⁎	338.300⁎
Mechanization (1/0)	22.751⁎	64.576+
Irrigation (1/0)	397.193	8.706
Animal traction use (1/0)	183.212	289.753
Chemicals (1/0)	168.271	62.892⁎
Organic fertilizer (1/0)	389.337⁎	268.881+
Commercial seed	270.849	137.064
Commercial seed ∗ nitrogen	−4.300⁎⁎	−1.375
Male (1/0)	686.729⁎⁎⁎	123.725
Age (years)	6.182⁎	8.793
Assets (“000 Naira)	−0.050	0.001
Plot area (hectares)	−675.652⁎⁎⁎	−603.234⁎⁎⁎
Squared plot area (hectare)	71.071⁎⁎⁎	61.075⁎⁎⁎
Topographic wetness index (units)	−56.676⁎	−30.409
No other crop planted	227.909⁎	106.341⁎
One other crop planted	261.100	270.064
Two other crops planted	−20.229	236.743
Plot elevation (meters)	0.556⁎	0.691
Slope (percent)	−13.885	−48.229
Annual precipitation (mm)	0.111	−4.349
Any household member could sell land (1/0)	−54.520	−226.430
Moderate nutrient constraint	435.663⁎⁎⁎
Severe nutrient constraint	−294.136
North east	−348.000
North west	−583.819⁎⁎⁎
2013	−153.039	−49.513
Constant	900.034	522.137
Number of observations	1084	1084
R-squared	0.316	0.751

Source: Authors’ estimations from the LSMS-ISA data.

^⁎Significant at 10 percent.

^⁎⁎Significant at 5 percent.

^⁎⁎⁎Significant at 1 percent.

⁺Significant at 15% or less.