Integrated Pearl Millet Management in the Sahel: Effects of Legume Rotation and Fallow Management on Productivity and Striga Hermonthica Infestation

Abstract

Increasing population density and food needs in the Sahel are major drivers behind the conversion of land under natural vegetation to arable land. Intensification of agriculture is a necessity for farmers to produce enough food. As manure is scarce and fertilizers expensive, this study looks into the potential role of cowpea (Vigna unguiculata L.) and short duration fallow in maintaining soil fertility and productivity and in reducing the major weed problem Striga hermonthica (Del.) Benth. The research was carried out 'on-farm' in a traditional millet (Pennisetum glaucum (L.) R.Br.) growing area in the Malian Sahel, near Bankass. The four year experiment combined 0, 2, 5, and 7 years of preceding fallow with (i) 4 years of millet, (ii) 1 year of cowpea + 3 years of millet, and (iii) 1 year of cowpea + 3 years of millet/cowpea inter-cropping.

Effects of improved fallow with Sesbania sesban on maize productivity and Striga hermonthica infestation in Western Kenya

“…The relative increase in S. hermonthica following S18 in our study conflicts with the pattern of reduction of S. hermonthica infection in maize following planted fallows, which is believed to occur due to increased mineral N in the topsoil and/or depletion of S. hermonthica seed during the fallow phase (Gacheru and Rao 2005). This observed suppression may in fact have also been the effect of previous years without a host and due to a persistent seed bank found under both laboratory and field conditions (Samake et al 2006). Fertilizer decreased S. hermonthica plant populations which is consistent with other studies that have shown that nitrogen fertilizer decreases S. hermonthica populations (Odhiambo 1998).…”

Cowpea N rhizodeposition and its below-ground transfer to a co-existing and to a subsequent millet crop on a sandy soil of the Sudano-Sahelian eco-zone

“…Generally a cowpea pre-crop will increase the yield of subsequent millet crops compared to continuous millet (Bagayoko et al 1998;Alvey et al 2001 Samake et al 2006) caused most likely by an improved soil N availability (Bagayoko et al 2000;Shahandeh et al 2004;Bado et al 2006) and to an N sparing effect from growing N 2 -fixing legume crops (Giller 2002). Our results demonstrate that the uptake of cowpea derived below-ground N by a subsequent millet crop the following growth season was relatively small with a N uptake of less than 3 kgN ha, equivalent to around 5% of the total N uptake by millet.…”

“…Knowledge of cowpea symbiotic nitrogen fixation and inputs to soil is based solely on measurement of above-ground plant parts (Bado et al 2006;Bagayoko et al 1998). Despite the fact that forage shoot material is mostly removed from the field to feed livestock in the Sudano-Sahelian region Singh et al 2003), improved cereal yields following cowpea monoculture or cowpea/millet mixtures in the rotation have been reported (Alvey et al 2001;Bado et al 2006;Bagayoko et al 1996Bagayoko et al , 1998Fussell and Serafini 1985;Samake et al 2006). It is therefore necessary to measure the N contained in the roots and rhizodeposits of cowpea to better understand the N effects in rotation and in intercrop with cereals .…”

Striga

“…This has provided the smallholder farmers with a diversity of options to control the parasites. Several researchers have extensively documented these potential options to combat Striga which have been classified into the most commonly used terms: cultural and mechanical control options including hand-pulling, crop rotation, trap-cropping, intercropping, appropriate improvement of soil fertility, and planting methods (Berner et al, 1995;Kuchinda et al, 2003;Hess and Williams, 1994;Hess and Dodo, 2004;Samake et al, 2006;Gworgwor, 2007;Khan et al, 2002Khan et al, , 2006Khan et al, , 2008Eltayb et al, 2013;Hooper et al, 2015); chemical control method such as application of chemical herbicides Kanampiu et al, 2007a;Kanampiu et al, 2007b) and biological control approaches using the pathogenic fungus Fusarium oxysporum as a mycoherbicide, or insects (Abbasher et al 1995(Abbasher et al , 1998Kroschel et al 1996;Marley et al, 1999Marley et al, , 2005Hess et al 2002;Elzein and Kroschel, 2004;Yonli et al, 2006;Zahran, 2008;Venne et al, 2009;Zarafi et al, 2015;Watson, 2013). Recently, the potential of the plant growth promoting rhizobacteria (PGPR) of the genus Bacillus (B. subtilis, B. amyloliquefaciens) and Burkholderia (B. phytofirmans) as Striga biocontrol agent has been surveyed by Mounde (2014).…”