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Knowledge politics in participatory climate change adaptation research on agroecology in Malawi
- Rachel Bezner Kerr, Hanson Nyantakyi-Frimpong, Laifolo Dakishoni, Esther Lupafya, Lizzie Shumba, Isaac Luginaah, Sieglinde S. Snapp
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- Journal:
- Renewable Agriculture and Food Systems / Volume 33 / Issue 3 / June 2018
- Published online by Cambridge University Press:
- 12 April 2018, pp. 238-251
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Climate change is projected to have severe implications for smallholder agriculture in Africa, with increased temperatures, increased drought and flooding occurrence, and increased rainfall variability. Given these projections, there is a need to identify effective strategies to help rural communities adapt to climatic risks. Yet, relatively little research has examined the politics and social dynamics around knowledge and sources of information about climate-change adaptation with smallholder farming communities. This paper uses a political ecology approach to historically situate rural people's experiences with a changing climate. Using the concept of the co-production of knowledge, we examine how Malawian smallholder farmers learn, perceive, share and apply knowledge about a changing climate, and what sources they draw on for agroecological methods in this context. As well, we pay particular attention to agricultural knowledge flows within and between households. We ask two main questions: Whose knowledge counts in relation to climate-change adaptation? What are the political, social and environmental implications of these knowledge dynamics? We draw upon a long-term action research project on climate-change adaptation that involved focus groups, interviews, observations, surveys, and participatory agroecology experiments with 425 farmers. Our findings are consistent with other studies, which found that agricultural knowledge sources were shaped by gender and other social inequalities, with women more reliant on informal networks than men. Farmers initially ranked extension services as important sources of knowledge about farming and climate change. After farmers carried out participatory agroecological research, they ranked their own observation and informal farmer networks as more important sources of knowledge. Contradictory ideas about climate-change adaptation, linked to various positions of power, gaps of knowledge and social inequalities make it challenging for farmers to know how to act despite observing changes in rainfall. Participatory agroecological approaches influenced adaptation strategies used by smallholder farmers in Malawi, but most still maintained the dominant narrative about climate-change causes, which focused on local deforestation by rural communities. Smallholder farmers in Malawi are responsible for <1% of global greenhouse gas emissions, yet our results show that the farmers often blame their own rural communities for changes in deforestation and rainfall patterns. Researchers need to consider differences knowledge and power between scientists and farmers and the contradictory narratives at work in communities to foster long-term change.
Perennial grain on a Midwest Alfisol shows no sign of early soil carbon gain
- Christine D. Sprunger, Steve W. Culman, G. Philip Robertson, Sieglinde S. Snapp
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- Journal:
- Renewable Agriculture and Food Systems / Volume 33 / Issue 4 / August 2018
- Published online by Cambridge University Press:
- 23 March 2017, pp. 360-372
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Perennial grain crops are expected to sequester soil carbon (C) and improve soil health due to their large and extensive root systems. To examine the rate of initial soil C accumulation in a perennial grain crop, we compared soil under perennial intermediate wheatgrass (IWG) with that under annual winter wheat 4 years after the crops were first planted. In addition, we tested the effect of three nitrogen (N) sources on C pools: Low available N (Low N (Organic N); 90 kg N ha−1 poultry litter), moderately available N (Mid N; 90 kg N ha−1 urea) and high available N (High N; 135 kg N ha−1 urea). We measured aboveground C (grain + straw), and coarse and fine root C to a depth of 1 m. Particulate organic matter (POM-C), fractionated by size, was used to indicate labile and more stabilized soil C pools. At harvest, IWG had 1.9 times more straw C and up to 15 times more root C compared with wheat. There were no differences in the size of the large (6 mm–250 µm) or medium (250–53 µm) POM-C fractions between wheat and IWG (P > 0.05) in surface horizons (0–10 cm). Large POM-C under IWG ranged from 3.6 ± 0.3 to 4.0 ± 0.7 g C kg soil−1 across the three N rates, similar to wheat under which large POM-C ranged from 3.6 ± 1.4 to 4.7 ± 0.7 g C kg soil−1. Averaged across N level, medium POM-C was 11.1 ± 0.8 and 11.3 ± 0.7 g C kg soil−1 for IWG and wheat, respectively. Despite IWG's greater above and belowground biomass (to 70 cm), POM-C fractions in IWG and wheat were similar. Post-hoc power analysis revealed that in order to detect differences in the labile C pool at 0–10 cm with an acceptable power (~80%) a 15% difference would be required between wheat and IWG. This demonstrates that on sandy soils with low cation exchange capacity, perennial IWG will need to be in place for longer than 4 years in order to detect an accumulated soil C difference > 15%.
Organic management and legume presence maintained phosphorus bioavailability in a 17-year field crop experiment
- Courtney Gallaher, Sieglinde S. Snapp
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- Journal:
- Renewable Agriculture and Food Systems / Volume 30 / Issue 3 / June 2015
- Published online by Cambridge University Press:
- 31 October 2013, pp. 211-222
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Legumes have been shown to enhance bioavailability of phosphorus (P) from sparingly soluble pools, yet this functional trait remains underutilized in agriculture, and is untested at decadal scales. Management and legume presence effects on temporal soil properties were evaluated in a 17-year field crop experiment using soil samples collected in 1992, 2000 and 2006. Management systems compared included: (1) conventional corn–soybean–wheat rotation (C–S–W), (2) organic (C–S–W+red clover), (3) alfalfa and (4) early successional field. To evaluate the effects of long-term management versus recent management (residues and P fertilizer) on P and bio-availability to soybean, subplots of soybean were established with and without P-fertilizer (30 kg P ha−1), and compared to subplots and main plot with the long-term system. We evaluated soil properties (C, total P, Bray extractable inorganic P, particulate organic matter phosphorus) and soybean P uptake, biomass and yield. Recent fertilizer P inputs had no detectable influence on soil P, and total soil P stayed stable at ~350 mg P kg−1, whereas inorganic P (Pi) declined from an initial value of 54 to an average of 35 mg P kg−1. A P balance was constructed and showed a net loss of −96.7 kg P ha−1 yr−1 for the organic system, yet Bray-Pi and soybean P uptake were maintained under organic production at similar levels to the conventional, fertilized system. Particulate organic matter P was 57, 82 and 128% higher in organic, alfalfa and successional treatments, respectively, compared to conventional. A similar pattern was observed for soil C, soybean yield and bioavailable P, which were 20–50% higher in the organic, alfalfa and successional systems relative to conventional. This study provides evidence that long-term management history influences bioavailability of P.
Opportunities and constraints to legume diversification for sustainable maize production on smallholder farms in Malawi
- Wezi G. Mhango, Sieglinde S. Snapp, George Y.K. Phiri
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- Journal:
- Renewable Agriculture and Food Systems / Volume 28 / Issue 3 / September 2013
- Published online by Cambridge University Press:
- 16 May 2012, pp. 234-244
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Sustainable intensification of smallholder farms in Africa is highly dependent on enhancing biological nitrogen fixation (BNF). Legume diversification of maize-based systems is a core example of sustainable intensification, with the food security of millions of farm families at stake. This study highlights the constraints and opportunities associated with the adoption of legumes by smallholder farmers in southern Africa. A two-part survey of households and farm fields (n=88) was conducted in the Ekwendeni watershed of northern Malawi. Participatory research and education activities have been underway for over a decade in this region, resulting in expanded uptake of a range of legume species as intercrops and in rotation with the staple maize crop. Farmer adoption has occurred to a varying extent for soybean (Glycine max), pigeon pea (Cajanus cajan), velvet bean (Mucuna pruriens) and fish bean (Tephrosia vogelii). Farmers, working with the project valued pigeon pea and other legumes for soil fertility purposes to a greater extent than farmers not working with the project. Legumes were valued for a wide range of purposes beyond soil cover and fertility enhancement, notably for infant nutrition (at least for soybean), insect control, and vegetable and grain production for both market and home consumption. Literature values for BNF in tropical legumes range up to 170 kg N ha−1 for grain and 300 kg N ha−1 for green manure species; however, our field interviews illustrated the extent of constraints imposed by soil properties on smallholder fields in Malawi. The key edaphic constraints observed were very deficient to moderate phosphorus levels (range 4–142, average 33 mg kg−1), and moderately acid soils (range pH 5.1–7.9, average 6.2). The per farm hectarage devoted to legume production relative to maize production was also low (0.15 versus 0.35 ha), a surprising find in an area with demonstrated interest in novel legume species. Further, farmers showed a strong preference for legumes that produced edible grain, regardless of the associated nutrient removal in the harvested grain, and did not sow large areas to legume crops. These farm-level decisions act as constraints to BNF inputs in maize-based smallholder cropping systems. Overall, we found that legume productivity could be enhanced. We documented the value of policies and educational efforts that support farmers gaining access to high-quality seeds, amendments for phosphorus-deficient soils, and promotion of multipurpose legumes that build soils through leafy residues and roots, as well as providing grain for food security and sales.