“Fallow Band System,” a land management practice for controlling desertification and improving crop production in the Sahel, West Africa. 1. Effectiveness in desertification control and soil fertility improvement

Figures & data

Figure 1. Outline of the “Fallow Band System”. A, B, and C refer to the steps explained in the main text.

Figure 2. Experimental settings in 2007 and 2008.

Table 1. Data of wind erosion events in 2008

Date	U max (m s^−1)	Wind direction	Duration (hour:minute)	WPBag (kJ m^−2)
22-January	8.4	E	3:54	92
27-January	8.3	E	4:04	80
30-January	8.5	E	3:09	106
14-February	8.7	ESE	3:48	147
18-February	9.4	E	5:16	215
26-March	8.8	NE	4:49	133
10-May	11.9	SE	2:11	322
18-May	10.5	SSE	2:36	460
20-May	16.8	ESE	0:58	1045
25-May	13.8	SE	0:58	372
30-May	10.3	SE	0:34	110
7-June	15.4	NE	0:25	554
9-June	11.9	SE	0:54	170
14-June	9.2	ENE	0:56	39
19-June	11.4	NE	0:17	156
29-June	13.9	E	1:17	792
4-July	14.9	ENE	1:46	549
11-July	12.6	E	1:10	312
31-July	9.5	SSE	0:40	70
3-September	11.2	E	0:16	325
Wind direction: E, east; ESE, east-southeast; NE, northeast; SE, southeast; SSE, south-southeast; ENE, east-northeast. U max, maximum wind velocity; WPBag, summation of wind power based on Bagnold expression.

Figure 3. Cumulative loss of (a) soil particles and (b) coarse organic matter (COM) from the cultivated band and fallow band. Arrows represent the sowing date (on June 19, 2008). Pearl millet was harvested at the middle of October.

Figure 4. Trapping efficiency of the fallow band for incoming (a) soil particles and (b) coarse organic matter (COM). Arrows represent the sowing date (on June 19, 2008). Pearl millet was harvested at the middle of October.

Figure 5. Cumulative amount of trapped (a) soil particles and (b) coarse organic matter (COM) in a hectare of fallow band. Arrows represent the sowing date (on June 19, 2008). Pearl millet was harvested at the middle of October.

Figure 6. Change in surface elevation of the fallow band. The zero in the vertical axis is the average elevation value measured before wind erosion.

Figure 7. Weight loss of coarse organic matter (COM) in litter bags during cropping season at depths of 0.02, 0.05, and 0.10 m. Error bars indicate standard error. Mean values with different letters are significantly different at the P < 0.05 significance level.

Figure 8. Total carbon dioxide (CO₂) emission during the cropping season in the cultivated band and former fallow band. Error bars indicate standard error. Mean values with different letters are significantly different at the P < 0.05 significance level.

Figure 9. Bulk density of trapped materials in the former fallow band and that of the topsoil at a depth of 0 to 0.05 m in the cultivated band. Error bars indicate standard error. Mean values with different letters are significantly different at the P < 0.05 significance level.

Figure 10. Particle size distribution of trapped soil particles in the former fallow band and topsoil at a depth of 0 to 0.05 m in the cultivated band. Error bars indicate standard error.

Figure 11. Field hydraulic conductivity in the former fallow band and in the cultivated band. Error bars indicate standard error. Mean values with different letters are significantly different at the P < 0.05 significance level.

Figure 12. Volumetric water content during the early cropping season in surface soil at a depth of 0 to 0.3 m in the former fallow band and the cultivated band. Rainfall data were collected at the meteorological station at the Internal Crops Research Institute for the Semi-Arid Tropics West and Central Africa (IWCA) located approximately 1 km from experimental plots. Pearl millet was sowed on June 19, 2008.