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Grain crops are an important part of the human diet, accounting for a third of the consumed calories. Throughout human history, annual grain crops with high yields have been obtained through domestication. However, the “annual” characteristic brings associated a series of economic and environmental disadvantages, such as soil erosion or low soil resources use, that can be solved if the agriculture of annual varieties evolves towards perenniality. For this reason, there are numerous research groups dedicated to study and obtain perennial varieties of the most cultivated grain crops. In this review article, we have summarized the most important advances related to the subject, focusing on the domestication and hybridization of the most productive grains globally: wheat, rice, maize, rye and sorghum. We highlight their benefits for sustainable agriculture worldwide due to perennial grains may contribute to reducing erosion, acting avoiding carbon losses, reducing nutrient losses to waters or capturing nutrients deeper in soil when they are scarce, reducing farm costs and thus, increasing the effectiveness of agricultural grain crops. Despite perennial grain crops having disadvantages, they possess outstanding characteristics which make them resilient crops to deal with the imminent climate change. However, maintaining the perenniality trait without reducing genetic biodiversity is a great challenge of current scientific importance that must be deeply considered. Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG Ministerio de Ciencia e Innovación | Ref. FJC2019-039176-I Xunta de Galicia | Ref. ED481D-2021/016

Abstract Agroforestry systems maintain intermediate levels of biodiversity between natural forests and purely agricultural land-uses and may therefore increase connectivity or sustain biodiversity in fragmented forest landscapes. This hypothesis is tested by comparing the species richness and similarity in species composition between forest fragments and agroforestry systems in two landscapes in Guatemala. Connectivity indices were calculated based on the similarity of biodiversity held between forest and agroforestry. Tree and ant species richness was significantly higher for forest than agroforestry land-uses. Conversely, species richness of leaf hoppers (Cicadellidae) was lower in forests compared to agroforests. Chao-Sorensen estimates indicated a high proportion of ant species were shared (0.78–0.99) between different agroforestry land-uses and forest fragments, but lower proportions of tree (0.39–0.55) and leaf hopper species (0.42–0.65). Including the contribution of agroforestry systems in estimates of forest connectivity, based on their biodiversity relative to forest, substantially increased the land area rated with high connectivity (by 100–300%) and forest edge connectivity (by 70–170%), but had negligible impact on land area rated as dense forest. The major forest fragments in the two landscapes were linked by land rated as medium connectivity for forest biodiversity. Thus, agroforestry contributes to the capacity of the landscape to support biodiversity, but only partially increases connectivity between forest fragments in the two landscapes studied. If these benefits are to be sustained, consideration needs to be given to the incentives for land-owners to maintain agroforestry systems.

Abstract Habitat fragmentation, the transformation of interconnected large habitats into several small patches, is generally considered to have a negative influence on biodiversity. Management policies should therefore favour strategies that minimize fragmentation. We studied amphibian diversity and compositional patterns in a complex montane agroforestry matrix of north-eastern Colombia to assess whether small-scale agroforestry is a viable way of reconciling crop production, farming, and biodiversity conservation. A total of five different land-use systems, including natural cloud forest, were compared. We used standardized visual and acoustic transect sampling routines in combination with field-based habitat assessments to establish amphibian assemblage data sets and corresponding habitat templets. Data sets were analysed using classical species richness and diversity statistics in combination with multivariate procedures to address compositional aspects. PER(mutational)MANOVA models were applied to identify environmental and land-use type-specific drivers of shifts in assemblage composition. Results show that agricultural management has a strong influence on amphibian species richness and diversity. With the exception of high intensity cattle pasture, diversity was generally highest in agriculturally used sites particularly in shaded plantations. Species composition differed markedly between different land-use types, indicating that there was not a single best land-use type that supported all species. This highlights the need for a landscape approach to biodiversity conservation in fragmented forests and consequently requires refocusing on conservation in management units as well as in the matrix. In human modified montane forest landscapes small-scale agriculture that generates landscape heterogeneity should therefore be promoted to effectively safeguard biodiversity.

Abstract The viability of coffee farming in East Africa is endangered by multiple factors including climate change, population pressure, low yields, and coffee price volatility. Sustainable intensification (SI) through intercropping and/or agroforestry has been suggested to improve farmers’ livelihoods, facilitate adaptation of coffee production to climate change and contribute to biodiversity conservation. In order to understand how sustainable intensification through an ecosystem-based approach might offer opportunities to respond to changes in temperature and rainfall, we analyzed a variety of existing coffee agro-ecosystems that differ in vegetation structure, shade tree diversity, and socio-economic characteristics on Mt. Elgon, Uganda along an altitudinal gradient (1100–2100 m.a.s.l.). We (i) compared the performance of the agro-ecosystems regarding coffee yield and shade tree diversity, and (ii) analyzed determinants of adoption of each system. Three different coffee agro-ecosystems were identified: open canopy coffee system, coffee-banana intercropping, and coffee-tree systems, based on the vegetation structure of 144 coffee plots. The vegetation structure of the analyzed coffee systems varied along the altitudinal gradient. Banana density increased with increasing altitude, while shade tree density and diversity increased with decreasing altitude. Coffee yield also increased with increasing altitude, but this relationship varied with shade level. Coffee yields benefited from shade trees at low altitudes, while no yield differences among systems were observed at mid and high altitudes. Increasing water availability and reliance on on-farm food crops with increasing altitude were identified as the main determinants of the increasing intercropped banana densities. High temperatures and longer dry season in combination with reduced access to forest products at lower altitudes, appeared to be the main driver for increased adoption of coffee-tree systems. Furthermore, socio-economic status of farmers influenced the type of coffee system adopted; poor farmers preferred high intercropping (either with bananas and/or shade trees) to diversify income and reduce risks related to open systems, while wealthier farmers mainly owned open canopy coffee systems. Climate, farm and household size, and access to forests and markets, play a crucial role in determining what constellation of plot-level provisioning ecosystem services benefit farmers’ livelihoods on Mt. Elgon. Our findings reveal inherent trade-offs in socio-ecological conditions. Minimizing these is required for achieving the multiple objectives of livelihood improvement, sustainable intensification of coffee production, and biodiversity conservation.

Abstract Given that agriculture is one of the activities with highest anthropic intervention on ecosystems, this paper focuses on the importance of aligning food production toward sustainability and the need to rely on evaluation methodologies that guide decision-making and take into account social metabolism. It is concluded that a holistic evaluation of sustainability is necessary, which implies including the social dimension as well as the economic and the ecological one and surpassing the linearity of the current evaluation methodologies.

Reliable information on belowground plant biomass is essential to estimate belowground carbon inputs to soils. Estimations of belowground plant biomass are often based on a fixed allometric relationship of plant biomass between aboveground and belowground parts. However, environmental and management factors may affect this allometric relationship making such estimates uncertain and biased. Therefore, we aimed to explore how root biomass for typical cereal crops, catch crops and weeds could most reliably be estimated. Published and unpublished data on aboveground and root biomass (corrected to 0–25 cm depth) of cereal crops (wheat and barley), catch crops and weeds were collected from studies in Denmark. Leave one out cross validation was used to determine the model that could best estimate root biomass. Root biomass varied with year, farming system (organic versus conventional) and cereal species. Shoot and root biomass of catch crops were higher than for weeds (sampled in late autumn), and farming system significantly affected root biomass of catch crops and weeds. The use of fixed root biomass based on the most influential factors (farming system and species) provided the lowest error of prediction for estimation of root biomass, compared with the use of fixed allometric relations, such as root/shoot ratio. For cereal crops, the average root dry matter in organic farming systems was 218 g m −2 (243 and 193 g m −2 for wheat and barley, respectively), but in conventional systems only 139 g m −2 (142 and 129 g m −2 for wheat and barley, respectively). For catch crops and weeds, the root dry matter in organic farming systems were around 127 and 35 g m −2, and in conventional farming systems 75 and 28 g m −2, respectively. In conclusion, the present analysis indicates that root biomass in cereals, catch crops and weeds can be reliably estimated without considering aboveground biomass, and it may be better estimated using fixed values based on species and farming systems than using fixed allometric ratios.

Recently published green infrastructure, nature-based solutions, and ecosystem disservices (ED) literature have focused primarily on the supply of urban regulating and cultural ecosystem services (ES). Other literature on urban and peri-urban agriculture has mostly studied the role of localized, intensive agricultural practices in providing food to inhabitants. The aim of this review is to raise awareness and stress the knowledge gap on the importance of urban provisioning ES, particularly when implementing an edible green infrastructure (EGI) approach as it can offer improved resilience and quality of life in cities. We compiled and systematically analyzed studies on urban ES and ED related to a number of EGI typologies. Our systematic review of the relevant literature via an EGI framework, identified more than 80 peer-reviewed publications that focused on ES and food production in urban areas. An EGI approach can contribute socially, economically, and environmentally to urban sustainability and food security. However, such benefits must be weighed against ED trade-offs, including: potential health risks caused by human exposure to heavy metals and organic chemical contaminants often present in urban surroundings. We conclude with recommendations and guidelines for incorporating EGI into urban planning and design, and discuss novel areas for future research. edible forest gardens, nature-based solutions, urban agriculture, urban biodiversity, urban food security, urban soil toxicity 53-66 40

Decisions to use crop residues as soil cover for conservation agriculture create trade-offs for farmers who own cattle in crop-livestock systems. Trade-offs among soil C, crop and animal and crop productivity were analysed using the NUANCES-FARMSIM (FArm-scale Resource Management SIMulator) dynamic model. Retention on the soil surface of 0, 25, 50, 75 and 100% of the maize stover yield produced per farm, and the use of the remainder as animal feed was quantified over a 12 year period for four farm types in Murehwa, Zimbabwe. Retaining 100% maize residues in the field led to an annual loss of on average 68 and 93 kg body weight per animal for cattle on farms of the relatively wealthiest farmers (Resource Group, RG1) who had most land and cattle and RG2 respectively), and is therefore unsustainable for livestock production. There was an increase in grain yield of 1.6 t farm-1 and 0.7 t farm-1 for RG1 and RG2 respectively. Farmers without cattle (RG3 and RG4) may have a greater incentive for retaining their crop residues but they have to invest labour to keep the residues during the dry season. However, improved crop productivity for these farmers is limited by lack of access to fertiliser. The current practice of allocating all crop residues to animals results in average gross margin of US$7429 and US$4037 for RG1 and RG2 farmers respectively. Our results showed that from an economic perspective, it is logical that farmers prioritise the sustenance of cattle with crop residues over soil fertility management. We conclude that at current productivity levels, farmers who own cattle have limited scope to allocate crop residues for soil cover as it leads to significant loss in animal production and economic value.