The challenge of achieving basal energy, iron and zinc provision for home consumption through family farming in the Andes: a comparison of coverage through contemporary production systems and selected agricultural interventions

Background Child undernutrition is persistently high in the central Andes of Peru, and numerous smallholder households fail to meet their basic needs of energy, iron and zinc. Food-based approaches assume household-level nutrition can be improved following agricultural interventions. This study assesses for the first time whether current Andean production systems provide sufficient energy, iron and zinc output to meet household-level requirements and explores the likely effect of commonly promoted food-based approaches. Across four communities, we determined the crop and livestock production output for each household (n = 165) during one growing season. The household-level nutritional demand or input was calculated as a function of household composition and daily requirements of energy, iron and zinc as established by FAO/WHO. We examined five scenarios, current practice or status quo and four food-based interventions: (1) increased potato yield, (2) introduced biofortified potatoes, (3) promotion of guinea pigs and (4) a mixed strategy combining all of the above. Results Under status quo, 86, 62 and 76 % of households obtained sufficient production output to meet energy, iron and zinc requirements, respectively. Considering the three parameters simultaneously, 59 % of households were able to meet their energy, iron and zinc requirements. The total crop production among households provided more than the necessary energy, iron and zinc output to meet the demand of all 165 households. Yet, significant differences between households account for individual deficits or surpluses in household-level output–input balances. Potato (Solanum spp.), barley (Hordeum vulgare) and faba (Vicia faba) production was particularly significant in determining the energy, iron and zinc output. Livestock did not make a substantial contribution. The main difference between households with negative versus positive coverage, in terms of household-level production output from agriculture meeting demand (=input), was available cropping area given household size. None of the explored food-based interventions closed the energy, iron and zinc deficit from production among households with negative coverage. Conclusions The smallholder production systems analyzed are only partially capable of providing sufficient production output to cover household-level energy, iron and zinc demands. Of the four interventions examined, a mixed strategy holds most potential for reducing nutrition gaps. Particularly potato yield increases had a positive effect. The carrying capacity of high-altitude Andean farming systems is strained for households with limited land. Food-based approaches to nutrition under scenarios similar to those reported in this study are advised to balance agricultural interventions with options to enhance off-farm access to food

Traditional soil fertility management ameliorates climate change impacts on traditional Andean crops within smallholder farming systems

Global changes, particularly rising temperatures, threaten food security in smallholder mountain communities by impacting the suitability of cultivation areas for many crops. Land-use intensification, associated with agrochemical use and tillage threaten soil health and overall agroecosystem resilience. In the Andean region, farmers often cultivate crops at multiple elevations. Warming climates have led to a shift in cultivation upslope, but this is not feasible in many areas. Traditional soil fertility management practices together with a focus on traditional (orphan) crops offers promise to cope with rapid climate warming in the region. To understand the impacts of warming and changing nutrient management, we established two side-by-side experiments using the traditional Andean crops Oxalis tuberosa (Oca) and Lupinus mutabilis (Tarwi) at three elevations, each with two fertility treatments (organic and synthetic). Soil and climate data (i.e., temperature and precipitation) were collected throughout the growing season, and crop performance was evaluated through impacts on yield and other growth metrics (e.g., biomass, pest incidence). We used two-way ANOVA to assess the influence of site (elevation) and management type (organic vs. synthetic) on crop performance. Results indicated that warmer climates (i.e., lowest elevation) negatively impact the production and performance of O. tuberosa, but that organic fertilization (sheep manure) can help maintain crop yield and biomass production in warmer conditions relatively to synthetic nutrient inputs. In contrast, L. mutabilis showed accelerated growth in warmer conditions, but grain yield and biomass production were not significantly affected by site and showed no interaction with nutrient management. Our findings highlight that climate warming represents a serious threat to small-scale crop production in the Peruvian Andes and could cause severe declines in the production of locally important crops. Additionally, the continued reliance traditional crops with organic inputs, instead of synthetic fertilizers, may help support agricultural productivity and resilience under climate change

Drivers of growth and establishment of the invasive plant Rumex acetosella within Andean fallow systems

Intensification of crop rotations and associated agricultural practices are reducing the capacity of traditional fallows to restore soil fertility and provide forage in Andean cropping systems. While the implementation of improved fallows offers great promise to enhance forage provision and maintain soil productivity, effects of these practices on the establishment of problematic weeds, including non-native plant species, remain poorly understood. To address this knowledge gap, we studied: i) how biotic and abiotic environmental factors influence the establishment and productivity of weeds in traditional fallows; and ii) to what extent improved fallows can help control weedy vegetation in smallholder rotations of the high Andes. Specifically, in this research, we focused on the invasive plant species Rumex acetosella L., which is a common concern of farmers throughout the central Peruvian Andes. We leveraged a multi-site, participatory research trial established in 2017 across eight communities in the region to understand the main drivers of R. acetosella presence and productivity. We used a total of 82 sites, each with paired treatments of traditional fallow (control with natural revegetation) and improved fallow (seeded with Vicia sativa L. and Avena sativa L.). Prior to treatment establishment we measured soil texture, pH, soil organic matter content as well as exchangeable macro-nutrients. Vegetation data was recorded in each treatment and divided into four categories: 1) A. sativa, 2) V. sativa, 3) R. acetosella, and 4) other weeds, and weighed to determine the relative biomass contribution of each. From these data, we calculated an index for R. acetosella pressure, weed pressure, and forage productivity. Our findings indicate that improved fallows greatly suppress weedy vegetation relative to unmanaged controls, including the invasive R. acetosella. Multivariate analyses suggested that R. acetosella abundance was associated with the presence of other non-planted weeds and predictors of soil fertility. The mean R. acetosella index in improved fallows was significantly lower compared to traditional fallows. We found R. acetosella biomass to be greater at lower productivity sites, i.e., those at higher elevations with cooler climates and sites with less fertile soils. Our findings indicate that if the fallow portion of a rotation is kept productive via adequate soil fertility inputs, the biomass of weeds, including the alien R. acetosella, is dramatically reduced

Resource concentration dilutes a key pest in indigenous potato agriculture

Modern restructuring of agricultural landscapes, due to the expansion of monocultures and the resulting elimination of non-crop habitat, is routinely blamed for rising populations of agricultural insect pests. However, landscape studies demonstrating a positive correlation between pest densities and the spatial extent of crop monocultures are rare. We test this hypothesis with a data set from 140 subsistence farms in the Andes and find the inverse correlation. Infestations by the Andean potato weevil (Premnotrypes spp.), the most important pest in Andean potato agriculture, decrease with increasing amounts of potato in the landscape. A statistical model predicts that aggregating potato fields may outperform the management of Andean potato weevils by IPM and chemical control. We speculate that the strong pest suppression generated by aggregating potato fields may partly explain why indigenous potato farmers cluster their potato fields under a traditional rotation system common in Andean agriculture (i.e., “sectoral fallow”). Our results suggest that some agricultural pests may also respond negatively to the expansion of monocultures, and that manipulating the spatial arrangement of host crops may offer an important tool for some IPM programs

Unearthing unevenness of potato seed networks in the high Andes: a comparison of distinct cultivar groups and farmer types following seasons with and without acute stress

The purpose of the research was to understand the fine-grained dynamics underlying potato seed networks in a center of crop origin and biodiversity, the central Andes of Peru, by differentiating between seasons with and without acute stress (i.e. frost, late blight), cultivar groups, and farmer types. Cultivar groups were classified into (i) bred varieties, (ii) commercial floury landraces, (iii) non-commercial floury landraces (single cultivars), (iv) non-commercial floury landraces (mixed cultivars), and (v) bitter landraces. Farmer types were classified as (i) general farmers, (ii) seed specialists, and (iii) custodian farmers. We documented seed provisions and acquisitions through the application of a semi-structured survey to 336 households in 2014-2015 in two main regions of the Peruvian central Andes: Huancavelica and Pasco-Junin. Farmers self-determined the most recent seasons with and without acute stress, specified the cause of the stress (i.e. frost, hail, late blight, drought), and described seed transactions for each season. The survey consisted of ten sections: (i) socioeconomic data; (ii) cropping season; iii) cultivar-level procurement; iv) seed volumes; v) specific seed sources and sinks; vi) social relationship to providers and clients; vii) seed transaction types; viii) place (s) of seed transaction; ix) seed destination/origin; x) quality guarantee of seed (including certification). For each respondent, every single transaction of seed acquisition and provision was recorded as a separate entry. Results confirm that seed networks are uneven and distinct for cultivar groups and farmer types. The study details the adaptations the system makes in the aftermath of acute stress and assesses the implications of its dynamics for conservation. Seed networks did re-organize following seasons with acute seed stress. A notable shift involved a contraction of seed networks within sub-regional clusters. Following stress, the directionality of seed provision versus acquisition inverts. We conclude that the self-regulatory capacity of farmer seed networks represents a strong safety net through which smallholders can respond to crop failure and seed stress

Unearthing unevenness of potato seed networks in the high Andes: a comparison of distinct cultivar groups and farmer types following seasons with and without acute stress

The purpose of the research was to understand the fine-grained dynamics underlying potato seed networks in a center of crop origin and biodiversity, the central Andes of Peru, by differentiating between seasons with and without acute stress (i.e. frost, late blight), cultivar groups, and farmer types. Cultivar groups were classified into (i) bred varieties, (ii) commercial floury landraces, (iii) non-commercial floury landraces (single cultivars), (iv) non-commercial floury landraces (mixed cultivars), and (v) bitter landraces. Farmer types were classified as (i) general farmers, (ii) seed specialists, and (iii) custodian farmers. We documented seed provisions and acquisitions through the application of a semi-structured survey to 336 households in 2014-2015 in two main regions of the Peruvian central Andes: Huancavelica and Pasco-Junin. Farmers self-determined the most recent seasons with and without acute stress, specified the cause of the stress (i.e. frost, hail, late blight, drought), and described seed transactions for each season. The survey consisted of ten sections: (i) socioeconomic data; (ii) cropping season; iii) cultivar-level procurement; iv) seed volumes; v) specific seed sources and sinks; vi) social relationship to providers and clients; vii) seed transaction types; viii) place (s) of seed transaction; ix) seed destination/origin; x) quality guarantee of seed (including certification). For each respondent, every single transaction of seed acquisition and provision was recorded as a separate entry. Results confirm that seed networks are uneven and distinct for cultivar groups and farmer types. The study details the adaptations the system makes in the aftermath of acute stress and assesses the implications of its dynamics for conservation. Seed networks did re-organize following seasons with acute seed stress. A notable shift involved a contraction of seed networks within sub-regional clusters. Following stress, the directionality of seed provision versus acquisition inverts. We conclude that the self-regulatory capacity of farmer seed networks represents a strong safety net through which smallholders can respond to crop failure and seed stress. (2014-10