Applicability of conservation agriculture for climate change adaptation in Rwanda’s situation

Improving food security and environmental conservation should be the main targets of innovative farming systems. Conservation agriculture (CA), based on minimum tillage, crop residue retention and crop rotations has been proposed against poor agricultural productivity and soil degradation. This paper discusses the applicability and potential benefits of CA in Rwanda under the unfolding climate change scenario. The potential and benefits from CA may vary with rainfall regime. In high rainfall areas (For example North and West of Rwanda), the soils are susceptible to soil erosion and face fertility decline while in low rainfall areas (For example East of Rwanda) crops fail due to sub-optimal water use efficiency. Furthermore, low organic carbon content lower fertilisers response and government targets of increasing production through Crop Intensification Program, is limited. It has been shown that CA can: Reduce soil loss from 35.5 to 14.5 t/ha/year, have 50-70% greater infiltration and increase 42% of organic carbon. Long term analysis using Agricultural Production System Simulator showed that CA can increase yield from 3.6 to 4.4t/ha in areas having >770 mm. Based on the evidence from regional research, CA has a good potential for climate change adaptation in both high and low rainfall areas of Rwanda. However, decreased yield observed in high rainfall areas, increased labour requirements when herbicides are not used and lack of mulch due to priority given to feeding of livestock constrained CA adoption. We conclude that there is a need for critical assessment under which ecological and socio economic conditions CA is suited for smallholder farming in Rwanda

Implications of tillage practices, management of soil surface and fertilizer application on sustainable dryland agriculture: a case study of Eastern Rwanda

Open Access Journal; Published online: 03 August 2017Conservation agriculture (CA) is becoming popular in sub-Saharan Africa as potential solution to soil degradation. However, most findings are based on large scale, mechanized agricultural production systems which are not easy to apply within the smallholder farmer’s context. This study assessed the implications of tillage practices, management of soil surface and fertilizer application on sustainable dryland agriculture of Eastern Rwanda. The experimental design was Split Plot with 4 replications. The main plots were conventional tillage (CT) and no tillage (NT) and sub-plots were: Control, sole residues application (RR); residues application with inorganic fertilizers (RR+IF) and inorganic fertilizers (IF) applied alone. Inorganic fertilizers application increased bean grain and biomass yield by 103%. In no tillage inorganic fertilizers had higher maize grain and biomass yields whereas residues application had 68% higher maize grain and biomass yield in conventional tillage. The significant increase in organic carbon was observed in residues applied with inorganic fertilizers. There was a significant N decrease in all treatments however control and residues had the highest N pool compared to other treatments. Sole residues application and residues applied with inorganic fertilizers treatment increased significantly Available P. The use of inorganic fertilizers in conservation agriculture systems should be promoted as the engine toward successful of CA practices for Bugesera district conditions. These results provide a basis for conducting trade-off analyses to support the development of CA crop management and international development strategies based on available scientific evidence

The Role of Agricultural Projects in Building Sustainable and Resilient Maize Value Chain in Burkina Faso

Poor seed quality and climate change significantly affect the maize value chain in Burkina Faso. To address the challenges, a catalytic project titled “Strengthening resilient seed systems in the maize value chain in Burkina Faso—from research to markets” was initiated to enhance the development of a resilient maize value chain. This study aims to assess the role of the project in developing a sustainable and resilient maize value chain. In this study, we used a mixed approach in design and implementation: qualitative research using key informants’ interviews, secondary data such as baseline survey reports, and lessons learned during the seed value chain greening intervention implemented in the Hauts-Bassins and Cascades regions of Burkina Faso. We analyzed qualitative data following the Gioia method. Kabako, a drought-tolerant hybrid seed variety, doubled crop yields in demonstration plots compared to smallholder farms and regional and national averages. Extension officers and village-based advisors (VBAs) were trained on improved seeds, composting, strip cropping, intercropping, crop rotation, and water management technologies and afterward trained smallholders. The VBAs trained smallholders on proper postharvest management practices and processing. The off-takers acted as the market. However, smallholders also sold their maize products in the informal open markets. The aggregator system was the missing link in Burkina Faso’s maize value chain. There was limited involvement of women in the project. Results obtained from this study are valuable for policymakers and value chain actors in preparing policies and filling missing gaps for exploiting the potential of the maize value chain

Smallholder cropping systems contribute limited greenhouse gas fluxes in upper Eastern Kenya

The contribution of smallholder farming systems to the National greenhouse gas (GHG) budget is missing in most developing countries, including Kenya. Data on the contribution of smallholder cropping systems to the GHG balance is essential for realising Sustainable Development Goal 13 on climate action, i.e., on nationally determined contributions (NDCs) and in compliance with the Paris Agreement. Do smallholder farming systems act as nature-based solutions for greenhouse gas emissions reduction? This study evaluated GHG emissions from cropping systems under on-farm smallholder farming conditions. We had five cropping systems on two smallholder farms: sole maize, maize-bean intercrop, coffee, banana, and agroforestry. Gas samples were collected using three static chambers per cropping system. The gas samples were analysed using gas chromatography (GC) fitted with a 63Ni-electron capture detector (ECD) for N2O and flame ionisation detector (FID) for CH4 and CO2 using N as carrier gas. Cumulative annual fluxes of (CH4, N2O, and CO2) varied significantly in farms one and two across the cropping systems. The cumulative soil GHG fluxes ranged from -1.34kg CH4single bondC ha−1 yr−1 under agroforestry to -0.77kg CH4single bondC ha−1 yr−1 under banana for CH4, 0.30kg N2Osingle bondN ha−1 yr−1 to 1.23kg N2Osingle bondN ha−1 yr−1 for N2O and 5949kg CO2single bondC ha−1 yr−1 to 12,954kg CO2single bondC ha−1 yr−1 for CO2. The maize grain yields ranged from 0 to 3.38 Mg ha−1. The N2O yields scaled emissions ranged from 0.10 to 0.26g kg−1 maize and 0.68 to 1.30g kg−1 beans. Smallholder farmers in Upper Eastern Kenya contribute a limited amount of soil GHG emissions and thus could act as a nature-based solution for lowering agricultural emissions

Soil nutrients and crop yield response to conservation-effective management practices in the sub-humid highlands agro-ecologies of Kenya

Crop productivity in most smallholder farming systems in Sub-Saharan Africa experience low use of soil amendment resources, low and erratic rainfall, frequent dry spells, and droughts. Rain-fed agriculture has a high crop yield potential if rainfall and soil nutrient input resources are utilized effectively. Thus, in 2011, we set up an on-farm experiment in Meru South (sub-humid) and Mbeere South (marginal sub-humid) sub-counties in upper Eastern Kenya to assess conservation-effective management (CEM) practices effects on maize (Zea Mays L.) yields response and soil nutrients. The CEM practices were; tied ridging (TR), mulching (MC), and minimum tillage (MT), with conventional tillage (CT) as a control. There were frequent dry spells and droughts during the experimental period. The experiment ran for four seasons, from the long rains season of 2011 (LR11), short rains seasons of 2011 (SR11), long rains season of 2012 (LR12), short rains 2012 (SR12), and long rains season of 2013 (LR13). In Meru South, TR and MT treatments had significantly higher phosphorus content (100% and 66%, respectively) than the control. Also, in the same site, Cu and Zn were high in MT than in CT treatments. In the Mbeere South site, the aboveground biomass yield was significantly higher in TR treatment (by 71%) than CT during SR11, while in LR12 season, it significantly increased by 72% and 46% under MC and TR treatments, respectively, than the control. The TR treatment had significantly higher aboveground biomass than the control (84% and 115%) in the SR12 and LR13 seasons. In Meru South, MC treatment had significantly higher aboveground biomass, which was significantly higher, by 39%, during the SR11 season and 46% in TR treatment in SR12 season than the control. This study highlighted tied ridging as the best-fit practice for enhancing maize crop aboveground biomass production in rain-fed farming systems of marginal lands and sub-humid regions receiving unreliable rainfall. Further, we recommend longer-term experimentation to explore CEM effects on soil nutrients

Tied-ridging and soil inputs enhance small-scale maize productivity and profitability under erratic rainfall conditions in central Kenya

Deficits in soil moisture and low soil fertility are the major constraints to smallholder farming systems in the SSA (sub-Saharan Africa) region. This study evaluated the effects of tied ridging and selected soil fertility inputs on; soil water content at different depths, maize yields, and economic returns. The treatments were: Tithonia diversifolia + inorganic fertilizer, manure + inorganic fertilizer, inorganic fertilizer, and control with or without tied ridging as the soil water conservation factor. Data were subjected to analysis of variance, and the means were separated using LSD at p ≤ 0.05. Treatments with Tithonia diversifolia or manure combined with inorganic fertilizer with or without tied ridging consistently affected soil water content positively. The effect of tied ridging on soil water content was greater during the short rain season compared to the long rains. In addition, there was evidence that tied ridging and organic soil inputs resulted in greater soil moisture conservation during the critical silking and tasselling maize phenological stages during the short rain season. Treatments had significant effects on grain and stover yields during the long rain 2016 season (p < 0.0001 and p = 0.0477, respectively) and the short rain 2016 season (p < 0.0001 and p = 0.0035, respectively). The highest (4.87 Mg ha−1) maize grain yield was recorded in Tithonia diversifolia plus inorganic fertilizer under tied ridging in the long rain 2016 season, while manure + inorganic fertilizer without tied ridging gave the highest yields (1.27 Mg ha−1) in the short rain 2016 season. The highest net benefits of US$1229.90 ha−1 and US$ 171.57 ha−1 were recorded under Tithonia diversifolia plus inorganic fertilizer with tied ridging during the long and short rain seasons, respectively. Overall, the best-performing treatments in yields and profitability were those that combined organic and inorganic fertilizers, regardless of the presence or absence of tied ridging. Climate-smart agricultural strategies combining tied ridges and organic inputs should be an integral component of farmer management if losses related to soil fertility and water stress are to be minimized under erratic rainfall regimes in the semiarid farming systems of the SSA region

Rainfall variability, drought characterization, and efficacy of rainfall data reconstruction: case of eastern Kenya

This study examined the extent of seasonal rainfall variability, drought occurrence, and the efficacy of interpolation techniques in eastern Kenya. Analyses of rainfall variability utilized rainfall anomaly index, coefficients of variance, and probability analyses. Spline, Kriging, and inverse distance weighting interpolation techniques were assessed using daily rainfall data and digital elevation model using ArcGIS. Validation of these interpolation methods was evaluated by comparing the modelled/generated rainfall values and the observed daily rainfall data using root mean square errors and mean absolute errors statistics. Results showed 90% chance of below cropping threshold rainfall (500 mm) exceeding 258.1 mm during short rains in Embu for one year return period. Rainfall variability was found to be high in seasonal amounts (CV = 0.56, 0.47, and 0.59) and in number of rainy days (CV = 0.88, 0.49, and 0.53) in Machang’a, Kiritiri, and Kindaruma, respectively. Monthly rainfall variability was found to be equally high during April and November (CV = 0.48, 0.49, and 0.76) with high probabilities (0.67) of droughts exceeding 15 days in Machang’a and Kindaruma. Dry-spell probabilities within growing months were high, (91%, 93%, 81%, and 60%) in Kiambere, Kindaruma, Machang’a, and Embu, respectively. Kriging interpolation method emerged as the most appropriate geostatistical interpolation technique suitable for spatial rainfall maps generation for the study region