4
|
|
(1) |
|
Nitrogen fertilizer |
23.98*** |
|
|
(5.035) |
|
Residual, stage 1 |
-16.33*** |
|
|
(3.916) |
|
Sorghum plot |
622.1*** |
|
|
(236.6) |
|
Sorghum plot x N nutrients/ha |
-5.565* |
|
|
(3.110) |
|
(N nutrients/ha)2 |
0.00795 |
|
|
(0.0439) |
|
Manure |
180.7*** |
|
|
(60.61) |
|
Labor |
3.365*** |
|
|
(0.777) |
|
Herbicides |
-3.601 |
|
|
(15.01) |
|
Equipment |
0.351*** |
|
|
(0.101) |
|
Distance to plot |
-3.118* |
|
|
(1.816) |
|
Soil erosion structure |
115.5 |
|
|
(70.55) |
|
Legume intercrop |
-524.4*** |
|
|
(65.38) |
|
Plain |
-100.5 |
|
|
(119.9) |
|
Slope |
-120.4 |
|
|
(144.2) |
|
Sandy |
-10.72 |
|
|
(76.59) |
|
Silty |
35.67 |
|
|
(80.92) |
|
Clayey |
173.7** |
|
|
(77.86) |
|
Rainfall |
-0.540 |
|
|
(0.979) |
|
Constant |
-18.04 |
|
|
(262.7) |
|
|
|
|
Observations |
1,086 |
|
R-squared |
0.424 |
|
|
(1) |
|
Nitrogen fertilizer |
23.98*** |
|
|
(5.035) |
|
Residual, stage 1 |
-16.33*** |
|
|
(3.916) |
|
Sorghum plot |
622.1*** |
|
|
(236.6) |
|
Sorghum plot x N nutrients/ha |
-5.565* |
|
|
(3.110) |
|
(N nutrients/ha)2 |
0.00795 |
|
|
(0.0439) |
|
Manure |
180.7*** |
|
|
(60.61) |
|
Labor |
3.365*** |
|
|
(0.777) |
|
Herbicides |
-3.601 |
|
|
(15.01) |
|
Equipment |
0.351*** |
|
|
(0.101) |
|
Distance to plot |
-3.118* |
|
|
(1.816) |
|
Soil erosion structure |
115.5 |
|
|
(70.55) |
|
Legume intercrop |
-524.4*** |
|
|
(65.38) |
|
Plain |
-100.5 |
|
|
(119.9) |
|
Slope |
-120.4 |
|
|
(144.2) |
|
Sandy |
-10.72 |
|
|
(76.59) |
|
Silty |
35.67 |
|
|
(80.92) |
|
Clayey |
173.7** |
|
|
(77.86) |
|
Rainfall |
-0.540 |
|
|
(0.979) |
|
Constant |
-18.04 |
|
|
(262.7) |
|
|
|
|
Observations |
1,086 |
|
R-squared |
0.424 |
Source: Authors, based on Sudan Savanna data. Robust standard errors in parentheses. *** p<0.01, ** p<0.05, * p<0.1
Table 5
Millet Yield Response to N Fertilizer Applied, Household Fixed Effects Model
|
Variables |
(1) |
(2) |
(3) |
(4) |
|
Nitrogen Fertilizer |
0.0392 |
-0.00945 |
0.00449 |
-0.00372 |
|
|
(0.0724) |
(0.0685) |
(0.0642) |
(0.0714) |
|
Manure |
|
0.0271** |
0.0222* |
0.0156 |
|
|
|
(0.0122) |
(0.0122) |
(0.0137) |
|
Compost |
|
-0.0774 |
-0.0518 |
-0.0751 |
|
|
|
(0.0754) |
(0.0744) |
(0.0862) |
|
Other Organic Fertilizer |
|
0.0832 |
0.0806 |
0.0803 |
|
|
|
(0.0720) |
(0.0676) |
(0.0657) |
|
Fungicide |
|
-0.668 |
-0.630 |
-1.261 |
|
|
|
(1.004) |
(0.938) |
(0.923) |
|
Herbicide |
|
2.565 |
0.960 |
2.138 |
|
|
|
(10.59) |
(9.893) |
(9.408) |
|
Total Labor |
|
0.470*** |
0.314*** |
0.156*** |
|
|
|
(0.0481) |
(0.0529) |
(0.0602) |
|
Local Seed |
|
|
0.409*** |
0.360*** |
|
|
|
|
(0.0652) |
(0.0698) |
|
Improved Seed |
|
|
0.550*** |
0.350 |
|
|
|
|
(0.208) |
(0.259) |
|
Plot Area |
|
|
|
-0.0310*** |
|
|
|
|
|
(0.00828) |
|
Distance to plot |
|
|
|
0.0334** |
|
|
|
|
|
(0.0150) |
|
Plaine |
|
|
|
0.0543 |
|
|
|
|
|
(0.186) |
|
Plateau |
|
|
|
0.0202 |
|
|
|
|
|
(0.314) |
|
Lowland |
|
|
|
-0.220 |
|
|
|
|
|
(0.383) |
|
Sandy |
|
|
|
-0.00658 |
|
|
|
|
|
(0.411) |
|
Clay |
|
|
|
0.411 |
|
|
|
|
|
(0.448) |
|
Anti-Erosion Structure |
|
|
|
1.789*** |
|
|
|
|
|
(0.369) |
|
Constant |
5.996*** |
4.633*** |
4.267*** |
4.635*** |
|
|
(0.0282) |
(0.139) |
(0.150) |
(0.466) |
|
Observations |
1,376 |
1,182 |
1,018 |
813 |
|
Number of households |
771 |
688 |
585 |
476 |
|
Marginal Effect of N |
10.37 |
-2.34 |
0.99 |
-0.81 |
|
Nutrient Applied |
|
|
|
|
Source: Authors, based on LSMS data. Standard errors in parentheses. *** p<0.01, ** p<0.05, * p<0.1.
Sample sizes drop with missing observations in more complete models, particularly those including seed quantities.
Table 6
Sorghum Yield Response to N Fertilizer Applied, Household Fixed Effects Model
|
Variables |
(1) |
(2) |
(3) |
(4) |
|
Nitrogen Fertilizer |
0.0503 |
0.0663 |
0.0265 |
0.0399 |
|
|
(0.0590) |
(0.0545) |
(0.0582) |
(0.0579) |
|
Manure |
|
0.0356 |
0.0411* |
0.0301 |
|
|
|
(0.0220) |
(0.0245) |
(0.0250) |
|
Compost |
|
-0.184 |
0.432 |
4.949 |
|
|
|
(0.441) |
(1.146) |
(5.166) |
|
Other Organic Fertilizer |
|
-1.010 |
-1.025 |
-0.910 |
|
|
|
(1.889) |
(1.878) |
(1.724) |
|
Fungicide |
|
2.347** |
2.081* |
4.539*** |
|
|
|
(1.168) |
(1.157) |
(1.726) |
|
Herbicide |
|
0.0986 |
0.0539 |
0.0319 |
|
|
|
(0.281) |
(0.310) |
(0.295) |
|
Total Labor |
|
0.496*** |
0.316*** |
0.309*** |
|
|
|
(0.0567) |
(0.0704) |
(0.0761) |
|
Local Seed |
|
|
0.269*** |
0.264*** |
|
|
|
|
(0.0828) |
(0.0864) |
|
Improved Seed |
|
|
0.655*** |
0.444** |
|
|
|
|
(0.202) |
(0.213) |
|
Pesticide |
|
-0.727 |
-3.386 |
-23.47 |
|
|
|
(1.605) |
(5.036) |
(23.03) |
|
Plot Area |
|
|
|
-0.00449 |
|
|
|
|
|
(0.00972) |
|
Distance to plot |
|
|
|
-0.0140 |
|
|
|
|
|
(0.0151) |
|
Plaine |
|
|
|
-0.0652 |
|
|
|
|
|
(0.250) |
|
Plateau |
|
|
|
-0.291 |
|
|
|
|
|
(0.388) |
|
Lowland |
|
|
|
0.0337 |
|
|
|
|
|
(0.310) |
|
Sandy |
|
|
|
-0.325 |
|
|
|
|
|
(0.432) |
|
Clay |
|
|
|
-0.456 |
|
|
|
|
|
(0.401) |
|
Anti-Erosion Structure |
|
|
|
-0.171 |
|
|
|
|
|
(0.441) |
|
Constant |
5.961*** |
4.389*** |
4.351*** |
4.985*** |
|
|
(0.0297) |
(0.175) |
(0.202) |
(0.462) |
|
Observations |
1,170 |
1,001 |
816 |
664 |
|
Number of households |
767 |
666 |
534 |
445 |
|
Marginal Effect of N |
9.56 |
11.70 |
4.73 |
6.44 |
|
Nutrient Applied |
|
|
|
|
Source: Authors, based on LSMS data. Standard errors in parentheses. *** p<0.01, ** p<0.05, * p<0.1.
Sample sizes drop with missing observations in more complete models, particularly those including seed quantities.