A conducive biophysical environment is necessary for smallholder farmers to achieve optimal yields, which are required for secured food and improved livelihoods. Such an environment includes available arable land, fertile soils, adequate water supply, favorable climatic conditions, flora and fauna.
Land availability is a basic requirement to be successful in farming (Deville et al., 2002). High population growth rates and certain socio-cultural factors have, however, been limiting land access in most of the developing world. For example, several studies have indicated gender bias in access to land for agriculture (Neumayer, 2014; AGRA, 2013). In many African and Asian countries, men are the predominant agricultural land owners (Deininger et al., 2015), while women can only work on their husband’s land.
Favorable climatic conditions are important biophysical factors for successful farming. Rainfed agriculture is dominant in smallholder agricultural systems. This means that farmers are dependent on the weather for the right quantity of water (rain) and sunshine (temperature), which are important prerequisites for crop growth. In recent years, a shift in the onset of rains, unpredictable rainfall patterns, increased in-season droughts and floods and reduction in annual rainfall totals (Lacombe et al., 2012; Laux et al., 2008) have negatively affected smallholder farmers in some of the world’s poorest regions. For example, in-season droughts can have grave consequences for food security due to lack of facilities for supplemental irrigation (Oweis and Hachum, 2009). Similarly, recent floods have destroyed food crops and other properties, further impoverishing the already poor farmers (Asare-Kyei et al., 2015).
Farm soils must be fertile and have the requisite nutrients for crop development to attain high yields. Successful farming requires regular application of nutrients (fertilizer) to the soil as its nutrients get depleted. But the low economic status of smallholder farmers presents a challenge to the purchase and regular application of fertilizer (AGRA, 2013). Vlek et al. (2008) classified 65% of the land area in sub-Saharan Africa as degraded. This, coupled with a reduction in fallow periods and continuous cultivation, has resulted in poor soils and low yields for smallholder farmers mostly in that region (Bationo et al., 2007; Enyong et al., 1999). Farmers who practice integrated crop-livestock systems, however, are able to apply manure on their plots, although this is usually insufficient to provide the nutrients that are required for optimal yields (Bationo and Mokwunye, 1991).
In addition to low nutrient application, soil erosion and pollution constitute other sources of biophysical vulnerability to smallholder farmers. The increased use of marginal lands (due to pressure on available lands) for agriculture results in the washing away of top soil and depletion of residual nutrients. Recurrent bush fires also degrade the arable land and reduce yield potential (Eriksen, 2007). Further, uncontrolled use of pesticides, especially on cotton and irrigated fields, have been found as an important source of soil and pollution (Ouédraogo et al., 2009; Toé et al., 2000; Williamson et al., 2008).
In recent years, poor land access and infertile soils have induced human migration within some regions in developing countries. In West Africa for instance, there is increased migration of farmers and nomads from the drought-affected Sahelian agro-ecological zone to the more humid Sudanian savanna areas in search of productive lands for farming and livestock raising (Ouedraogo et al., 2010; Paré et al., 2008). This puts a further strain on the land, and is resulting in further soil degradation.