In Santa Catarina, southern Brazil, family farmers modified the conventional no-till system by flattening cover crop mixtures on the soil surface as a strategy to reduce soil erosion and lower fluctuations in soil moisture and temperature, improve soil quality, and enhance weed suppression and crop performance. During 2007 and 2008, we conducted three experiments aimed at understanding the processes and mechanisms at play in successful organic conservation tillage systems (OCT), especially the underpinnings of ecological weed suppression, a key advantage of OCT systems over conventional no-till systems. Our results, as well as farmers observations, suggest that cover crops can enhance weed suppression and hence crop productivity through physical interference and allelopathy and also a host of effects on soil quality, fertility, and soil moisture that we did not measure. Results from the three trials indicate that the best cover crop mixture should include a significant proportion of rye, vetch, and fodder radish as these mixtures produce large biomass, and are readily killed by rolling forming a thick mulch sufficient to provide effective weed control in the subsequent vegetable crop.

Due to beneficial characteristics of cassava such as robustness and versatility for multiple uses, it can have a major role in contributing to local food security. The objective of this study was to find out whether and how the cultivation of cassava benefits smallholder farmers in the regions of Dodoma and Morogoro, Tanzania. In addition, the study assessed the main factors that support or threaten food security of smallholder farmer households in the survey region and analysed whether cassava cultivation could counteract them. We applied a mixed methods approach. Quantitative data were provided by a comprehensive household survey of the Trans-SEC project, and qualitative data were collected by conducting semi-structured interviews. To approach the complexity of our chosen food security definition, three approaches for household food security measurement were applied. These covered the components of food availability, food access, and food utilization. Additionally, dependent variables for regression models were constructed and a multivariate analysis was run. The results show that cassava contributes to food security in the households, but achieving food security through cassava cultivation was constrained by several factors, including pests, missing markets, poor processing, social perception and lack of knowledge. Besides these, other factors affecting food security in the study area were found, uncovering some roots of local food insecurity and serving as a basis for further research and action on how to enhance food security.

The low agricultural productivity of key crops and food insecurity continue to be key issues in Sub-Saharan Africa (SSA) and Tanzania. The growing population, depleting resources, and changing climate further amplify these issues. Globally, many agricultural technologies (AgTs) are available as pathways for improved agricultural productivity and food security, however, they have had relatively little success in SSA and Tanzania. This is because the uptake of AgTs is a complex process, which is highly localized, involving multiple actors, stages, and spatial and time dimensions. Smallholder farmers often experience issues of sustainability, constraints for adoption, and scaling-up throughout the uptake process of AgTs, all of which vary by region. This indicates a need for a systematic and simultaneous understanding of sustainability, constraints for adoption, and scaling-up of AgTs to better guide agricultural strategy and policy interventions in SSA and Tanzania. Moreover, in order to understand the local settings better, a consideration of the perceptions of the farmers themselves, who are the primary actors in the uptake process of AgTs, is key. Acknowledging this, the study takes on a case study approach, using the scaling-up assessment (ScalA) method and three focus group discussions with a total of 44 smallholder farmers to systematically and simultaneously assess the sustainability, constraints for adoption, and scaling-up of three AgTs (use of fertilizers, improved seeds, and small-scale irrigation) in Tanzania. The study finds that the farmers perceive all three AgTs to be sustainable for the study region. Adoption rates are perceived to be medium for use of fertilizers, high for improved seeds, and low for small-scale irrigation. The most significant constraints for adoption experienced by the farmers are lack of technical physical inputs, marketing facilities, and know-how. Scaling-up is perceived to be well fulfilled for use of fertilizers and improved seeds, but only partially fulfilled for small-scale irrigation, which is the most limited of the three AgTs. The most significant constraints for scaling-up experienced by farmers are a lack of confidence in the added value of the AgTs beyond project activities, marketing facilities, and technical physical inputs. The overall success potential is high for the use of fertilizers and improved seeds, and the average for small-scale irrigation. The farmers’ perceptions partially indicate why the bundle of AgTs is lacking in the study region and provide a basis for discussing targeted agricultural and policy interventions in Tanzania.