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

Abstract

Striga hermonthica is a major constraint to smallholder subsistence agriculture production in the sub-Saharan African region. Low soil fertility and overall environmental degradation has contributed to the build-up of the parasitic weed infestation. Improved cropping systems have to be introduced to address the interrelated problems of S. hermonthica and soil fertility decline. Thus, the effects of improved fallow with leguminous shrub Sesbania sesban on maize yields and levels of S. hermonthica infestation on farm land in the bimodal highlands of western Kenya were investigated. The experimental treatments were arranged in a phased entry, and randomized complete block scheme were six months Sesbania fallow, 18 months Sesbania fallow, six months natural fallow consisting of regrowth of natural vegetation without cultivation, 18 months natural fallow, continuous maize cropping without fertilizer application, and continuous maize cropping with P and N fertilization.Results show that Sesbania fallows significantly (p<0.05) increase maize yield relative to continuous unfertilized maize. S. hermonthica plant populations decrease in continuous maize between the first season (mean = 428 000 ± 63 000 ha -1 ) and second season (mean=51 000 ± 15 000 ha -1 ), presumably in response to good weed management. S. hermonthica seed populations in the soil decrease throughout the duration of the experiment in the continuous maize treatments. Short-duration Sesbania fallows can provide modest yield improvements relative to continuous unfertilized maize, but short-duration weedy fallows are ineffective.Continuous maize cultivation with good weed control may provide more effective S. hermonthica control than fallowing.

Why Promote Improved Fallows as a Climate-Smart Agroforestry Technology in Sub-Saharan Africa?

“…and cripple its growth and development by improving soil inorganic N [29]. Similarly, field experiments in Kenya confirmed 34% reduction in Striga hermonthisa seeds in soils under improved fallows compared with maize monocultured fields, recording 11% increase during the same cropping period [41]. The thick mulch layer of tree fallows reportedly suppressed perennial grasses such as Imperata cylindrical and the general weed biomass of arable lands in Nigeria and Zambia [42].…”

The rooted pedon in a dynamic multifunctional landscape: Soil science at the World Agroforestry Centre

“…While not ultimately leading to widespread success, the research done on hedgerow intercropping and improved fallows helped identifying underlying principles on the technical, social and economic side (Shepherd et al, 1997;Swinkels et al, 1997;Shepherd and Soule, 1998;Ndufa et al, 1999;Sjögren et al, 2010). The search for locally appropriate agroforestry solutions continued.…”

<i>Aeschynomene histrix</i> (Joint Vetch) fallow and nitrogen fertilizer effects on <i>Striga hermonthica</i> infestation and maize (<i>Zea mays</i>) productivity in southern Guinea Savanna of Nigeria

“…Benth.) is a major biotic constraint threatening the production of several cereal crops, in small-holder farmlands in sub-Sahara Africa (Sjogren et al, 2010;Jamil et al, 2012). The weed is a root hemiparasite claimed to be affecting an estimated 45 million ha of arable farmlands in Africa (Olupot et al, 2003).…”

“…It is known to attach itself to the roots of the host crop, such as maize, sorghum, millet, rice, finger millet, pearl millet, wheat and sugar cane, thereby reducing their productivity. Striga infestation and poor soil fertility are among factors that cause severe yield losses in maize production (Sjogren et al, 2010;Kamara et al, 2012;Uzoh et al, 2015). This implies that maize farmlands are faced with a complex of biotic and abiotic problems (Kamara et al, 2012).…”

“…This implies that maize farmlands are faced with a complex of biotic and abiotic problems (Kamara et al, 2012). For instance, in Africa, an estimated 75,000 ha of smallholder farmlands under maize cultivation are under Striga infestation, which is on the increase both in severity and spread due to the continuous depletion of the soil fertility (Sjogren et al, 2010). In Nigeria, over 85% of maize and sorghum farmlands are infested with Striga (Kamara et al, 2012), causing severe yield losses to complete crop failure, and in most cases, farmers are made to abandon such infested land (Kolo and Adamu, 2006;Kamara et al, 2012).…”