Micro-dosing as a pathway to Africa’s Green Revolution: evidence from broad-scale on-farm trials

Abstract

Next to drought, poor soil fertility is the single biggest cause of hunger in Africa. ICRISATZimbabwe has been working for the past 10 years to encourage small-scale farmers to increase inorganic fertiliser use as the first step towards Africa's own Green Revolution. The program of work is founded on promoting small quantities of inorganic nitrogen (N) fertiliser (micro-dosing) in drought-prone cropping regions. Results from initial on-farm trials showed that smallholder farmers could increase their yields by 30-100% through application of micro doses, as little as 10 kg Nitrogen ha -1 . The question remained whether these results could be replicated across much larger numbers of farmers. Wide scale testing of the micro-dosing (17 kg Nitrogen ha -1 ) concept was initiated in 2003/2004, across multiple locations in southern Zimbabwe through relief and recovery programs. Each year more than 160,000 low resourced households received at least 25 kg of nitrogen fertiliser and a simple flyer in the vernacular explaining how to apply the fertiliser to a cereal crop. This distribution was accompanied by a series of simple paired plot demonstration with or without fertiliser, hosted by farmers selected by the community, where trainings were carried out and detailed labour and crop records were kept. Over a 3 year period more than 2,000 paired-plot trials were established and quality data collected from more than 1,200. In addition, experimentation to derive N response curves of maize (Zea mays L.), sorghum (Sorghum bicolor (L.) Moench) and pearl millet (Pennisetum glaucum (L.) R.Br.) in these environments under farmer management was conducted. The results consistently showed that micro-dosing (17 kg Nitrogen ha -1 ) with nitrogen fertiliser can increase grain yields by 30-50% across a broad spectrum of soil, farmer management and seasonal climate conditions. In order for a household to make a profit, farmers needed to obtain between 4 and 7 kg of grain for every kg of N applied depending on season. In fact farmers commonly obtained 15-45 kg of grain per kg of N input. The result provides strong evidence that lack of N, rather than lack of rainfall, is the primary constraint to cereal crop yields and that

An evaluation of the use of participatory processes in wide-scale dissemination of research in micro dosing and conservation agriculture in Zimbabwe

“…It is the work conducted by ICRISAT and partners that led to the participatory development (Ncube et al, 2007) and subsequent wide-scale promotion of micro-dosing (MD) (Twomlow et al, 2008b) as well as the adaptive work on conservation agriculture (CA) (Mazvimavi and Twomlow, 2009;Twomlow et al, 2008c). CA is a technique that requires the application of basic principles such as minimum soil disturbance, soil cover through mulching, crop rotation and integrated management.…”

“…The PETs differed from the traditional demonstration plots which are planned and managed by extension staff and only required farmers to simply observe and learn (Rusike et al, 2006). Initial results, based on 1,200 farmer-managed paired plots (Twomlow et al, 2008b) and subsequent survey work (Rohrbach et al, 2005) showed that MD (17 kg nitrogen ha −1 ) increased grain yields by 30-50% across a broad spectrum of soil, farmer management and seasonal climate conditions. The broad-scale testing encouraged DFID to launch a protracted relief program (PRP) for Zimbabwe <http://www.prpzim.info/> in 2004.…”

“…The process must be farmer-centred, fully involving the intended beneficiaries from the early stages of problem identification through to technology development and adaptation (Pretty and Hine, 2001;Rusike et al, 2006;Ncube et al, 2007;Twomlow et al, 2008b).…”

Millet response to microdose fertilization in south–western Niger: Effect of antecedent fertility management and environmental factors

“…Compared to broadcast fertilizer applications, P use efficiency is greatly increased with microdosing. Because various trials demonstrated strong positive effects on yields and high returns on investments (Pender et al, 2008), the microdose technique has been referred to as the second of a 4-step agricultural intensification pathway for Sub-Saharan Africa (Aune and Bationo, 2008;Twomlow et al, 2008), and has been promoted accordingly.…”

Affordable Nutrient Solutions for Improved Food Security as Evidenced by Crop Trials

“…To improve nutrient input, smallholder farmers need actionable strategies such as micro-dosing: applications of small quantities of fertilizers. Field studies have shown that micro-dosing presents an attainable strategy for smallholder farmers in line with their financial means that can result in significant yield gains [14]. Importantly, previous higher fertilizer rate recommendations have ignored the sizeable but unlikely investment that would be required by poor and risk adverse smallholders.…”