Improving maize productivity in northern Benin through localized placement of amendments and fertilizers

Throughout much of Sub-Saharan Africa, maize production in smallholder farms is characterized by low productivity due to low fertility soils, the scarce availability and use of external inputs and recurrent droughts exacerbated by climate variability. This situation calls for exploring fertilizer and amendment management practices that are efficient and can concurrently improve soil fertility, yields and economic returns. One such technology is the localized application of small quantities of manure and/or mineral fertilizers in the planting holes either at sowing or shortly after planting. Unlike for sorghum and millet, few studies have evaluated the agronomic and economic performances of this technology on maize. Besides, few studies have quantified the risk associated with this technology due to variability in crop management, soil and climatic factors. The general objective of this study was therefore to assess the agronomic and economic potential of localized application of manure and fertilizers in maize-based cropping system in northern Benin, with a long-term goal of developing recommendations. For this purpose, we combined three different approaches: (1) two on-station experiments to assess the agronomic potential and economic profitability of hill-placed manure and mineral fertilizer (or fertilizer microdosing), (2) farmer-field trials to quantify the variability in yield response, economic profitability and risk associated with some of the most promising treatments under real-world conditions and (3) modeling the response of maize across a range of rainfall conditions to further evaluate the sustainability of these practices in northern Bénin. All experiments were carried out in Ina district (Bembèrèkè, northern Benin) from 2012 to 2015. The on-station experiments showed that localized application of manure and fertilizers significantly increased grain and stover yields by 64-132% and 28-131%, respectively, across years. Combining hill-placed manure and fertilizers further increased grain yields by 31-55% on average. The increases in yields under fertilizer microdosing were accompanied by marked increases in nutrient uptake and negative nutrient balances. Nutrient balances were equally or more negative on microdosing fertilized plots than on the unfertilized controls. This was particularly the case for P and K and suggests that microdosing may enhance nutrient mining and should probably not be used for extended periods. The on-farm demonstrations showed a large variability in maize yield responses to fertilizer microdosing which could be partly explained by some measured soil parameters (clay and /or silt, total carbon, exch-Mg, pH) and weed pressure. Overall, absolute yield response tended to decrease with increasing yields in the control plots. Based on the value-cost ratio (VCR) the economic performance of the recommended fertilizer rate was less than that of the microdosing treatments (alone or combined with manure) despite the higher labor cost associated with the latter treatments. Despite the greater variability compared to the control, the risk of no return on investment was nearly nil for microdosing treatments (alone or combined with manure). The long-term scenario analysis using the specifically-parameterized DSSAT model revealed that the application of 2 g of N-P-K15-15-15 fertilizer + 1 g urea per hill (equivalent to 23.8 kg N ha-1) improved both the long-term average and the minimum guaranteed yield without increasing inter-annual variability and the economic risk compared to unfertilized plots. Even though combining microdosing with manure (at least at 1 t ha-1) was economically slightly riskier than microdosing alone, this risk remained low since a VCR of 2 could be achieved in almost 100% of the years. This makes the latter more sustainable and appropriate for smallholder farmers than the current recommendation.(AGRO - Sciences agronomiques et ingénierie biologique) -- UCL, 201

Integrated fertiliser microdosing and organic manure to adapt to climate variability and change in Northern Benin

In Northern Benin, maize is the most important staple food, but its productivity is negatively affected by low inherent soil fertility, soil degradation, and by recurrent droughts exacerbated by climate variability and change. In this study, we combined mineral fertilizer and organic manure to evaluate cropping adaptation options to climate variability in Northern Benin

Fertilizer microdosing enhances maize yields but may exacerbate nutrient mining in maize cropping systems in northern Benin

Fertilizer microdosing is a promising technology to complement traditional fertility management strategies, yet little is known regarding its performance in maize systems in western Africa. This study assessed to what extent the application of fertilizer microdosing to maize in northern Benin may contribute towards improved yields, greater nutrient use efficiency and reduced nutrient mining, in combination or not with various manure management practices. In a 2-year on-station experiment at Ina (northern Benin), four fertilizer options were tested [no fertilizer control, microdosing options 1 (MD1, 23.8 kg N ha−1, 4.1 kg P ha−1 and 7.8 kg K ha−1) and 2(MD2, 33.1 kg N ha−1, 8.2 kg P ha−1 and 15.6 kg K ha−1), broadcast fertilizer at recommended rate (RR, 76 kg N ha−1, 13.1 kg P ha−1, and 24.9 kg K ha−1)] within five manure strata [manure applied through corralling in the same year (Cor-0) as well as one (Cor-1) and two years (Cor-2) before the experiment, transported manure (TM, 3 t ha−1), and no manure (NM)]. On average across all manure strata and years, fertilizer application significantly increased grain yields by 64% for MD1, 81% for MD2 and 93% for RR compared to the unfertilized control. Yields in MD2 were never different from those in RR. Across the manure strata, there was a general tendency for FUEs to decrease from MD1 (8.0–19.0 kg grain kg−1 fertilizer) to RR (4.6-8.0 kg grain kg−1 fertilizer). Maize response to fertilizer microdosing was best in the absence of organic amendments and tended to decrease with increasing fertility. Indeed, the greatest grain yield increases were observed for the NM (+1611 kg ha−1) and Cor-2 (+1468 kg ha−1) strata, followed by TM (+1258 kg ha−1), Cor-1 (+1183 kg ha−1) and Cor-0 (+1126 kg ha−1). Consequently, FUE was also best in NM plots and lowest in recently corralled plots (Cor-0). Fertilizer-induced yield increases resulted principally from larger numbers of grains per cob (+52% on average) and larger 1000-grain weights (+13%). For the NM and TM strata, the partial nutrient balances for the two cropping seasons ranged between −44 and +21, −24 and −9 and −78 and −45 kg ha−1 year−1 respectively for N, P and K depending on the mineral fertilization treatment. The balances ranged between −17 and +54, −77 and −50 and −345 and −228 kg ha−1 over a three-year corralling cycle, respectively for N, P and K. Except for N applied at the recommended rate, partial nutrient balances were equally or more negative on fertilized plots than on the unfertilized controls, indicating that the tested fertilization options may exacerbate nutrient mining. This was particularly the case for P and K and suggests that microdosing should probably not be used for extended periods. Nevertheless, fertilizer microdosing appears better adapted to the realities of smallholder farmers than the RR while still ensuring very significant yield increases. There is a need to evaluate these nutrient management options in farmer’s fields, taking into account climatic, soil and management conditions to better assess and understand the maize response and the magnitude of nutrient mining and to evaluate its economic benefits and risk

Understanding Variability in Maize Yield and Profitability Under Fertiliser Microdosing Technology in Farmer's Fields in Northern Benin

Fertiliser microdosing is currently promoted in semi-arid areas of sub-Saharan Africa as a means to increase crop productivity, profitability and resource use efficiency. However, little is still known regarding the main management and environmental factors that govern yield response to this technique in smallholder farmers’ fields. In this study, the performance of two microdosing options applied alone [(M1, 23.8 kg N ha−1, 4.1 kg P ha−1 and 7.8 kg K ha−1 and M2 (33.1 kg N ha−1, 8.2 kg P ha−1 and 15.6 kg K ha−1)] or combined with hill-placed manure at 3 t ha−1 was evaluated on maize yield at 18 sites in 2014 and 32 sites in 2015. These four treatments were compared to an unfertilised control and broadcast recommended rate (RR, 76 kg N ha−1, 13.1 kg P ha−1, and 24.9 kg K ha−1). We observed a strong positive response for all of the sites to both M1 and M2, which significantly increased maize grain yields by 1143 and 1232 kg ha−1, respectively, compared to the unfertilised control (1069 kg ha−1). Overall, there was no significant difference in yields between microdosing alone and RR in both seasons. Combining microdosing and manure resulted in higher yield responses (by 1911 and 2066 kg ha−1 for M1 and M2, respectively). There was a large variability in yields among farmers, from 512 to 1687 kg ha−1, 976 to 4006 kg ha−1 and 1513 to 4733 kg ha−1 for the control, unmanured and manured fertilised plots, respectively. This variability can be explained by the total rainfall, weed pressure, and the topsoil characteristics (pH, clay content, Exch-K and Mg and organic C). Applying microdosing alone or combined with manure was economically profitable for more than 80 % (VCR=2), while only 58 % achieved a VCR of 2 under the RR treatment. The results indicate that fertiliser microdosing is better adapted to the realities of smallholder farmers than the RR while still ensuring very significant yield increases and economic benefits. However, there is a need to evaluate this technology in a larger zone and number of farms to better predict crop responses and for a widespread adoption

Integrated use of fertilizer microdosing and manure enhances maize yields, nutrient and water use efficiencies in maize cropping systems in northern Benin

In Sub-Saharan Africa, maize productivity is negatively affected by low inherent soil fertility, poor soil fertility management and unpredictable rainfall. In response, fertilizer microdosing has been widely advocated. This paper assesses to what extent the combined application of fertilizer microdosing and manure to maize crop in northern Benin may contribute towards improved yields and nutrient and water use efficiencies

Efficient use of nutrients and water through hill-placed combination of manure and mineral fertilizer in smallhoder maize farming system in northern Benin

Maize, a major staple food in many farming systems in sub-Saharan Africa, is characterized by low productivity due to the scarce availability and use of external inputs and recurrent droughts exacerbated by climate variability. Within the integrated soil fertility management framework, there is thus a need for optimizing the use of fertilizers and manure for the efficient use of limited nutrient resources and rainfall, and to increase crop yield and farmer income

Combining hill-placed manure and mineral fertilizer enhances maize productivity and profitability in northern Benin

Throughout much of Sub-Saharan Africa(SSA), maize production is characterized by low productivity due to the scarce availability and use of external inputs and recurrent droughts exacerbated by climate variability. Within the integrated soil fertility management (ISFM) framework, there is thus a need for optimizing the application of fertilizers and manure to better use the limited nutrient resources and increase crop yield and farmer income. An on-station experiment was conducted in Northern Benin over a 4-year period to evaluate the effect of hill placement of mineral fertilizer and manure on maize yields and soil chemical properties. The treatments consisted in the combination of three rates of manure (0 (NM), 3 (3M) and 6 (6M) Mg ha-1) and three levels of fertilizer (0% (NF), 50% (50F) and 100% (100F) of the rate recommended by extension (76 kg N + 13.1 kg P + 24.9 K ha-1)). On average across the fertilizer rates, hill-placement of manure significantly improved soil organic carbon content, available P and exchangeable K after 4 years by up to 124, 166 and 77%, respectively, compared to the initial values. As a result of the nutrient inputs and improved soil properties, yields increased steadily over time for all manure and fertilizer combinations. Value-cost ratios and benefit–cost ratios were[2 and generally as good or even better for treatments involving 50F compared to NF or 100F. Although applying half the recommended rate of fertilizer without manure as currently done by many farmers appears to make economic sense, this practice is unlikely to be sustainable in the long term. Substituting 50F for 3M or complementing 50F with 3M are two possible strategies that are compatible with the precepts of ISFM and provide returns on investment at least as good as the current practice. However, this will require greater manure production, made possible in part by the increased stover yields, and access to means of transportation to deliver the manure to the fields

On-farm evaluation of fertilizer microdosing technology in smallholder maize farming system of Northern Benin

To address the low inherent soil fertility and in response to the limitations of conventional soil fertility management recommendations, fertilizer microdosing have been developed and widely advocated in recent years in the Sahel. However, little is known regarding the performance of this technology on maize in general and particularly in Benin. For this purpose, 20 farmer demonstrations in 4 villages were set-up across the 2014 growing season in the Ina region, Northern Beni

Microdose fertilization enhances maize yields but exacerbates nutrient mining in maize cropping systems in northern Benin

In Sub-Saharan Africa, maize productivity is negatively affected by low inherent soil fertility, poor soil fertility management and unpredictable rainfall. Recently and in response to the limitations of conventional fertilizer recommendations, microdose fertilization has been widely advocated. However, little is known regarding the effect on yields and nutrient mining for maize systems in western Africa. This paper assesses to what extent the application of microdose fertilization to maize crop in Bénin may contribute towards improved yields and nutrient use efficiency and whether it attenuates or exacerbates nutrient mining

Diversité des pratiques de gestion de la fertilité des sols dans les systèmes de culture à base de maïs au Nord Bénin

Plusieurs pratiques sont utilisées pour la gestion et le maintien durable de la fertilité des sols dans les systèmes de production à base de maïs dans le nord Bénin. Cet article a pour objectif d’identifier les pratiques et de les caractériser. L’étude a été conduite dans les communes de Malanville, Banikoara, et Bembèrèkè