Multifunctional Agroecosystems Research Articles

Análise multivariada como ferramenta na seleção de agroecossistemas sustentáveis de cultivo de meloeiro no Semiárido

ABSTRACT Soil management systems, including tillage and green manuring, are important for the control of nematodes and for the sustainable production. The objective was to select, through multivariate analysis, sustainable agroecosystems for yellow melon cultivated under irrigated conditions in the Brazilian semi-arid region. The long-term experiment is set up in Argissolo Vermelho- Amarelo (Ultisol) with six multifunctional agroecosystems, composed of the combination of three mixtures of cover crops (1 - 75% legumes + 25% grasses and oilseeds; 2 - 25% legumes + 75% grasses and oilseeds and 3 - spontaneous vegetation) and two types of soil management (no tillage-NT and tillage-T). The purpose was to evaluate the nutritional status of plants, soil fertility, nematode population in roots and soil, and the yield. Data were analyzed with multivariate techniques, allowing the grouping of the agroecosystems based on their similarities and complexity of functions. The incorporation of plant residues to the soil reduces nematode population, but their maintenance on the surface allows the improvement of fertility and yield, even under larger nematode populations. The agroecosystems that associate the nonincorporation of residues from cover crops with larger species diversity in composition constitute the most complex model, allowing different environmental functionalities. Thus, it is recommended not to incorporate the plant residues, planting the melon seedlings directly in the straw. However, considering that the results obtained with the non-incorporation of spontaneous vegetation were similar to those obtained with the incorporation of commercial cover crops, it is concluded that this practice is also viable and adapted to the semi-arid conditions.

Synergism between production and soil health through crop diversification, organic amendments and crop protection in wheat‐based systems

Abstract One of the critical challenges in agriculture is enhancing yield without compromising its foundation, a healthy environment and, particularly, soils. Hence, there is an urgent need to identify management practices that simultaneously support soil health and production and help achieve environmentally sound production systems. To investigate how management influences production and soil health under realistic agronomic conditions, we conducted an on‐farm study involving 60 wheat fields managed conventionally, under no‐till or organically. We assessed 68 variables defining management, production and soil health properties. We examined how management systems and individual practices describing crop diversification, fertiliser inputs, agrochemical use and soil disturbance influenced production—quantity and quality—and soil health focusing on aspects ranging from soil organic matter over soil structure to microbial abundance and diversity. Our on‐farm comparison showed marked differences between soil health and production in the current system: organic management resulted in the best overall soil health (+47%) but the most significant yield gap (−34%) compared to conventional management. No‐till systems were generally intermediate, exhibiting a smaller yield gap (−17%) and only a marginally improved level of soil health (+5%) compared to conventional management. Yet, the overlap between management systems in production and soil health properties was considerably large. Our results further highlight the importance of soil health for productivity by revealing positive associations between crop yield and soil health properties, particularly under conventional management, whereas factors such as weed pressure were more dominant in organic systems. None of the three systems showed advantages in supporting production‐soil health‐based multifunctionality. In contrast, a cross‐system analysis suggests that multifunctional agroecosystems could be achieved through a combination of crop diversification and organic amendments with effective crop protection. Synthesis and applications: Our on‐farm study implies that current trade‐offs in managing production and soil health could be overcome through more balanced systems incorporating conventional and alternative approaches. Such multifunctionality supporting systems could unlock synergies between vital ecosystem services and help achieve productive yet environmentally sound agriculture supported by healthy soils.

Weed community dynamics under repeated fertilization with different nutrient sources over 5 years

Soil fertility management through the application of synthetic fertilizer or livestock manures is crucial to maintaining the productivity and profitability of cropping systems. Little, however, is known about the response of weed communities to different livestock manure nutrient sources. As weed communities with increased diversity are considered part of more sustainable agroecosystems, it is necessary to find management practices that result in diverse weed communities of acceptable densities without negative impacts on crop productivity. Here, we monitored the effect of five nutrient sources, with similar goals for nitrogen (N) management, including synthetic fertilizer, liquid pig manure, two types of solid pig manure, and solid dairy manure on the weed community in a five-year (2008-2012) study. The abundance, species richness, Simpson’s diversity, Simpson’s evenness, and species turnover in weed communities were assessed over time. Crop biomass, mid-season plant-accessible soil nitrate-N, and pre-season soil phosphorus were determined. The application of liquid pig manure or synthetic fertilizer enhanced crop biomass likely through increased crop accessibility to N. The continued use of these sources of nutrients over time, contributed to low density, low species richness, and low diversity weed communities, particularly through the decline of broadleaf weed species. Liquid pig manure and synthetic fertilizer treatments were lower in weed density and diversity than solid manures. Solid manure treatments were associated with increased weed densities and reduced crop biomass; however, these nutrient source treatments resulted in more diverse weed communities. Regardless of the nutrient treatments, we observed drastic declines in weed community abundance, species richness, and diversity in drier years. Our study suggests that a management practice that increases the accessibility of N to the crop, possibly through a mixture of solid manures and synthetic fertilizers or liquid pig manure, may be ideal for promoting a profitable cropping system with decreased densities and improved diversity in weed communities. Technological advances that provide more precise placement of solid manures to increase the accessibility of N to the crop, may further contribute to achieving such profitable and multifunctional agroecosystems.

Integrating effects of neighbor interactions for pollination and abiotic resources on coffee yield in a multi‐strata agroforest

AbstractAnimal‐pollinated plants interact with neighbors for both abiotic resources and pollination, with consequences for reproduction and yield. Yet few studies have compared the relative magnitude of these effects, particularly in agroecosystems. In vertically stratified communities, such as agroforests, neighbor effects may be stratum‐dependent. Understanding the net effects of neighbors on crop yield is important for managing multifunctional agroecosystems to simultaneously support production and biodiversity. This study evaluated the effects of neighboring plants on pollen deposition, fertilization, and yield in Coffea arabica in a shaded organic coffee farm with high non‐crop plant abundance and diversity in Chiapas, Mexico. We assessed the impact of (1) floral resources at three vertical strata (herbs, coffee bushes, and canopy trees) on stigma pollen load (a measure of interaction for pollination), and (2) floral density and canopy cover (proxies for competition for abiotic resources) on yield (final fruit set and per‐fruit weight), using structural equation modeling to evaluate the relative effect of each interaction type. Coffee competed for pollination with neighbors (conspecifics and heterospecifics) across strata. Pollen load influenced final fruit set, but the effect of neighbor competition for pollination was weaker than effects mediated by interactions for abiotic resources. Effects of interactions for abiotic resources were heterogeneous across strata, with negligible effects of herb‐layer or coffee flower density but net positive effects of canopy trees on final fruit set. Overall effects of neighbors on coffee yield were weak, suggesting that coffee agroecosystems can be managed to maintain high plant density and diversity without sacrificing yield.Abstract in Spanish is available with online material.

Selection of green manures to provide ecosystem services in a semi-arid environment

Green manure is a soil management technique which provides several benefits to agroecosystems, improving the chemical, physical and biological quality of the soil, allowing them to provide different ecosystem services. Thus, the purpose of this work was to select green manures to compose multifunctional agroecosystems that provide ecosystem services in a semi-arid environment through the addition of biomass, C and N, and nutrient cycling. Thus, 29 treatments were evaluated in two cultivation cycles, using 14 species of legumes, oilseeds and grasses, distributed in single and intercropped crops. The green manures were cut at 70 days after sowing, and samples of the shoot and root parts were collected, with the production of fresh and dry biomass and the N, P, K, Ca, Mg and S levels being evaluated. C and biomass from rhizodeposition were also estimated. From these data, the accumulation of nutrients in the shoot and root biomass was calculated. Data were compared using descriptive and multivariate statistics. There is a positive relationship between the growing number of species used in consortium and the greater production of shoot and root biomass, favoring the increase in the capacity of the agroecosystem to provide provision and regulation services, with the latter being associated with climate change mitigation measures, highlighting the importance of biodiversity.

The Political Ecology of Hedgerows and Their Relationship to Agroecology and Food Sovereignty in the UK

Hedgerows can make an important contribution to agroecological transitions and to an overall contribution to multifunctional agro-ecosystems with multiple benefits for biodiversity, climate change mitigation, soil health, human health, well-being, and livelihoods. Where such agroecological transition assumes the form of political agroecology, this can underpin transformation of the farming system towards food sovereignty. Current mismanagement of hedgerows is constraining the optimum delivery of ecosystem services by these important features of the British landscape. This mismanagement is, moreover, an integral part of a (capitalist) productivist degradation of the countryside that is contributing to the delivery of ecosystem disservices and is, therefore, antithetical to the adoption of agroecological production practises. Being contrary to the requirements of political agroecology, it is similarly antithetical to the requirements of food sovereignty. In response, this paper outlines what appears to be required, in policy and political terms, for the adoption of an agroecological and food sovereignty framework enabling the sustainable management of hedgerows and maximising their potential for ecosystem services delivery.

Grazed temporary grass‐clover leys in crop rotations can have a positive impact on soil quality under both conventional and organic agricultural systems

AbstractSoil quality (SQ) is the ability of soil to provide ecosystem functions and services. Implementation of a certain agricultural system can affect SQ and therefore play an essential role in achieving sustainable agriculture. The aim of this study was to explore how agricultural systems (conventional vs. organic), grazing regime (non‐grazed vs. grazed) and the different proportions of temporary grass‐clover leys in crop rotations (ley time proportion, LTP) affect SQ within a mixed (cropping and pasture/dairy system) commercial farming enterprise in the UK. Seven SQ indicators were evaluated, including chemical (pH; available phosphorus (P); potassium (K)), physical (bulk density, BD; aggregate stability, AS) and biological (total carbon (C); microbial biomass carbon, MBC) sectors. All SQ indicators were measured at three depth intervals (0–0.15, 0.15–0.30, 0.30–0.60 m), except for AS and MBC, which were only considered for the topsoil (0–0.15 m). The findings reflected existing knowledge on the advantages of organic vs. conventional systems for SQ indicators, with the former showing higher MBC and similar K, BD, AS and C in the 0–0.30‐m compared to the latter. Lower topsoil available P in organic systems can be related to the lack of measurements in all P pools. When grazing was included: (a) both agricultural systems showed higher topsoil available P, C and MBC; and (b) there was a higher topsoil K in organic systems, whereas it positively affected topsoil BD and C (0.15–0.30 m) in conventional systems. Increasing LTP to 30–40% of the full crop rotation increased topsoil AS and C (0–0.30 m) in a linear fashion. Subsoil conditions (>0.30 m) favoured K, BD and C in conventional systems, but these results should be considered carefully. It was concluded that both organic and conventional systems delivered similar levels of SQ and that reviving mixed farming systems may be a key factor for delivering multifunctional agroecosystems that maintain SQ and optimize ecosystem services.Highlights Single‐farm comparison of top‐ and subsoil quality in organic and non‐organic systems. The organic system increased microbial biomass carbon but decreased topsoil available phosphorus. Grazing increased topsoil available phosphorus, carbon concentration and microbial biomass carbon. Temporary leys in rotations increased topsoil aggregate stability and carbon concentration. Mixed farming is a key factor for delivering multifunctional agroecosystems.

Optimizing multifunctional agroecosystems in irrigated dryland agriculture to restore soil carbon – Experiments and modelling

Irrigated dryland agroecosystems could become more sustainable if crop and soil management enhanced soil organic carbon (SOC). We hypothesized that combining high inputs from cover crops with no-tillage will increase long-term SOC stocks. Caatinga shrublands had been cleared in 1972 for arable crops and palm plantations before implementing field experiments on Mango and Melon systems (established in 2009 and 2012, respectively). Each of the two experiments were managed with no-till (NT) or conventional till (CT), and three types of cover cropping, either a plant mixture of 75% (PM1) or 25% (PM2) legumes, or spontaneous vegetation (SV). The RothC model was used with a daily timestep to simulate the soil moisture dynamics and C turnover for this dry climate. Carbon inputs were between 2.62 and 5.82 Mg C ha−1 year−1 and increased the depleted SOC stocks by 0.08 to 0.56 Mg C ha−1 year−1. Scenarios of continuous biomass inputs of ca. 5 Mg C ha−1 year−1 for 60 years are likely to increase SOC stocks in the mango NT beyond the original Caatinga SOC by between 19.2 and 20.5 Mg C ha−1. Under CT similar inputs would increase SOC stocks only marginally above depletion (2.75 to 2.47 Mg C ha−1). Under melon, annual carbon inputs are slightly greater (up to 5.5 Mg C ha−1 year−1) and SOC stocks would increase on average by another 8% to 22.3 to 20.6 Mg C ha−1 under NT and by 8 Mg C ha−1 under CT. These long-term simulations show that combining NT with high quality cover crops (PM1, PM2) would exceed SOC stocks of the initial Caatinga within 20 and 25 years under irrigated melon and mango cultivation, respectively. These results present a solution to reverse prior loss of SOC by replacing CT dryland agriculture with irrigated NT plus high input cover crops agroecosystems.

Exploring social preferences for ecosystem services of multifunctional agriculture across policy scenarios

Multifunctional agroecosystems are the result of complex adaptive interactions between humans and nature where trade-offs between food production and other ecosystem services are key. Our objective is to explore the social preferences for ecosystem services, and the associated willingness to pay, in three multifunctional agroecosystem in Europe (Mediterranean, Atlantic, Alpine) under alternative agrienvironmental policy scenarios. We use the same methodology (a choice experiment including equivalent attributes and levels) to rank and estimate the economic value of provisioning, regulating, supporting and cultural ecosystem services. We define the scenarios (current situation, abandonment and enhanced management) in biophysical terms to elucidate changing relations between social perception and level of delivery of ecosystem services. We derive some lessons. i) Value of ES: biodiversity and regulating ecosystem services always produce welfare gains; people, however, perceive trade-offs between delivery of agricultural landscapes and quality food products. Nevertheless, preferences are heterogeneous and vary across regions, scenarios and ES. ii) Policymaking: society’s willingness to pay for the delivery of ecosystem service exceeds largely the current level of public support. Moreover, further abandonment and intensification of agriculture is clearly rejected by the public. iii) Methodological: monetary valuation is context dependent and extrapolation of economic values can be misleading.

Increasing the proportion and quality of land under agri-environment schemes promotes birds and butterflies at the landscape scale

The intensification of agricultural practices that Western nations have experienced after World War II has led to an alarming decline in farmland biodiversity. With the aim of stopping and even reversing this decline, agri-environment schemes (AES) have been implemented in many European countries since the 1990s. In Switzerland, farmers are required to manage at least 7% of their land in the form of biodiversity promotion areas (BPA), which are extensively managed, wildlife-friendly farmland habitats such as hay meadows and traditional orchards. We investigated how the occurrence and characteristics of these BPA influence birds and butterflies in the Swiss lowlands. Butterfly species richness and abundance increased by 22% and 60%, respectively, when the proportion of BPA in the landscape increased from 5% to 15%. Likewise, bird species richness increased, but to a lesser extent, with the proportion of BPA in the landscape. For birds, the proportion of BPA characterized by a high ecological quality played a role in promoting both priority-farmland and red-listed species. For both taxonomic groups, the amount and quality of BPA habitats contributed more to species richness than their spatial configuration, connectivity included. This study shows that AES measures implemented at the field scale have positive effects on mobile species that are noticeable at the landscape scale, and that the fraction of AES in the cultivated landscape matters more than their spatial configuration, which has strong implications for designing multi-functional agro-ecosystems.

Effects of Xanthomonas wilt and other banana diseases on ecosystem services in banana-based agroecosystems

Banana plantations are multifunctional agroecosystems that besides their main provisioning service also deliver a range of supporting, regulatory and cultural services that are largely unvalorized. Banana is perennial in nature with plantations as old as 50 years reported in the African Great Lakes region. Banana is cultivated in a wide range of agroecologies (from sea level to 2400 m a.s.l.) and cropping systems, where it contributes to various ecosystem services (ES). These include regulating soil erosion, water cycles and quality, and nutrient recycling. However, the outbreak of Xanthomonas wilt of banana (XW) along with some of its management practices, such as uprooting mats/entire fields, is devastating banana production and rendering landscapes bare and prone to degradation. Yet this process is also leading to diversification of agroecosystems in over 70% of farms in the African Great Lakes region with unknown but potentially positive consequences for resilience and adaptation, as well as for local diets. The sustainability of these alternative land-uses is variable. This study reviews the different services offered by banana plantations and the impacts, positive or negative, that XW-driven diversification may have on these services. It suggests the need to consider explicitly the consequences of pests and diseases for the full range of ES provided by the crop and an ES-broad framework for estimation of losses, and planning resources and strategies for disease management. The study also suggests strategies, such as incorporation of shade- and drought-tolerant cover crops, hedges and agroforestry trees, to augment the supply of key ES within XW-affected agroecosystems/landscapes.

A revised trait‐based framework for agroecosystems including decision rules

Abstract Designing agroecological cropping systems, which have enhanced biodiversity and that improve agroecosystem services, is recognized as the most likely method of improving the environmental sustainability of agriculture. However, tools and methods for designing such systems are lacking. To help to fill this gap, we propose a revised trait‐based response/effect framework as applied to agroecosystems, which takes into account farmers’ decision rules. The framework consists of a “Biophysical module”, which describes the biophysical functioning of the agroecosystem on a response/effect traits basis and a “Decision module”, which encompasses the farmer's choices that follow decision rules, to account for the high degree of human control of filters and community structure operating in cultivated systems. The introduction of the Decision module and its interactions with the Biophysical module opens new research priorities related to trade‐offs between services, to species choice and to the relationships between the community composition, functional structure and the functions. Synthesis and applications. We proposed a revised trait‐based response/effect framework as applied to agroecosystems, which incorporates farmers’ decisions. This framework has great potential to address questions related to the strategic choices associated with multispecies cropping system design, from plant (species choices) to community (optimization of community composition) scales. It also contributes to improving the rationale to manage multifunctional agroecosystems, which extend beyond yield alone, by enabling the exploration of trade‐offs between ecosystem services.

SOCIOCULTURAL AND ENVIRONMENTAL BENEFITS FROM FAMILY ORCHARDS IN THE CENTRAL HIGHLANDS OF MEXICO

Cette étude vise à analyser les percep- tions des agro-écosystèmes sur le plan socioculturel et environnemental parmi les propriétaires de vergers familiaux situés dans la zone de transition écolo- gique de l’État de Mexico. La méthodo- logie comporte trois étapes : 1) carac- térisation géographique des localités et des agro-écosystèmes ; 2) analyse des bénéfices sociaux des vergers ; 3) potentiel des vergers et problèmes ren- contrés. L’enquête s’est déroulée sur douze localités situées dans trois munici- palités de l’État de Mexico, à l’aide d’en- tretiens semi-structurés complétés par des observations directes sur le terrain. Les vergers familiaux sont une source de nombreux bénéfices sociaux, environne- mentaux, écologiques et culturels : ils contribuent au bien-être des familles par la production de fruits, de condiments et de plantes utilisées dans diverses céré- monies, récoltées pour l’autoconsomma- tion, la vente ou le troc. Ces vergers sont également une source de bois de feu, de bois de construction, de piquets et d’ornements. Ils sont ainsi à considérer comme des agro-écosystèmes de grande importance et dont le fonctionnement repose sur des relations complexes entre l’ensemble de leurs composantes. Les bénéfices socioculturels et environne- mentaux de ces agro-écosystèmes pro- ductifs aux fonctions multiples peuvent être un atout considérable pour la réus- site de stratégies de cohésion sociale et de sécurité alimentaire en milieu rural, tout en contribuant à la préservation des ressources naturelles de la région.

Soil conditioning affects interactions between native and invasive exotic perennials of semi‐natural grasslands

Summary Semi‐natural perennial grasslands are of increasing importance as components of multifunctional agroecosystems, combining biomass production with provision of other ecosystem services. Soil legacies from previous land use or exotic species can hinder their establishment, but might be overcome through a multi‐stage successional strategy, whereby certain species are used to facilitate native grassland species establishment. We tested this strategy via a feedback experiment examining soil‐conditioning effects on interference interactions between native and exotic species. Soils in a former maize–soybean production field in Minnesota, USA, were conditioned for 3 years with native or invasive exotic perennials or a maize–soybean crop rotation. Nitrogen (N) fertilization was an additional treatment in field plots. In a greenhouse, native and invasive exotic perennial grassland seedlings were grown on these soils, in monoculture and in native–exotic species pairs, with and without N fertilization. The impact of soil conditioning and field and greenhouse N fertilization on interactions between native and exotic seedlings in mixture was determined. Neighbouring plants suppressed biomass production in all native and exotic species. The maize–soybean rotation left a soil legacy that enhanced suppression of native species when grown with exotic species, while exotic species suffered no such disadvantage. The strong and specific disadvantage to native species of maize–soybean soils decreased with greenhouse N fertilization, but remained significant, while field N addition did not alter this effect. Synthesis and applications. We found that the negative soil legacy of the maize–soybean rotation for native plant performance in interaction with exotics was greatly diminished in soils conditioned by native or exotic perennial species, irrespective of nitrogen addition. This highlights the potential value of perennial species in conversion from row‐crop agriculture to grasslands, because all perennial species alleviated the enhanced suppression of natives observed on maize–soybean soils. We did not find strong evidence that these perennial species were capable of specifically facilitating native species over exotics, but a broader range of species should be evaluated.

Sustainable use of genetic resources: the characterization of an Italian local grapevine variety (‚Grechetto rosso') and its own landscape

Biodiversity and landscape are two tightly liked environmental traits, so that the loss in traditional agricultural landscapes imply the erosion of precious local germplasm. The on-farm conservation of local cultivars assure the preservation of optimized environment-genotype interactions, unique multifunctional agro-ecosystems and landscapes. Therefore, the safeguard of endangered genetic resources has to consider genotyping, phenotyping, but also the characterization of the related landscapes. The objective of this study was to provide the characterization of a local Italian grapevine, i.e. 'Grechetto rosso' through an integrated approach based on conventional ampelographic and molecular determinations and on the characterization of the landscape in the innate environment. 'Grechetto rosso' has affinity with 'Sangiovese', of which keeps the main ampelographic characters. Nonetheless, its diversity is prevalently expressed in berry characters, like the occasional presence of a not uniformly pigmented pulp, week epicuticular waxes and a red-coloured skin. This berry characters appeared to be related to the micro-environmental variables, i.e. the occurrence of cold-temperate nights during the ripening period and a rather temperate climate of the innate area. The 'Grechetto rosso' wine-grape-growing area is characterized by high naturality, and the 47 % of the 'Grechetto rosso' vineyards are still mixed with olive groves (traditional arrangement), while the remaining surface is represented by either specialized (46 %) or neglect (residual/relict) (7 %) vineyards. 'Grechetto Rosso' vineyards are distributed even in steep and extremely steep slope areas. The resulting description represents an example of useful information for promoting a sustainable use of grapevine genetic resources based on the in situ conservation on farm.

Assessing the ecosystem services supplied by freshwater flows in Mediterranean agroecosystems

a b s t r a c t Water performs essential ecological functions in agroecosystems and supplies an array of hydrologic ecosystem services (HES). The nature and quantity of HES is intimately linked with the management of the territory, and the capacity of the different land uses to partition rainfall into green (evapotran- spiration) and blue (runoff) freshwater flows. This paper presents an innovative method to empirically assess the underlying relationship between the use and management of Mediterranean agroecosystems, their spatial pattern of green and blue freshwater flow generation and the provision of HES. We test this approach in Sierra Norte de Sevilla, a characteristic Spanish agro-forestry system. To assess the hydrological functioning we used the spatially explicit hydrologic model BalanceMED. HES' identifi- cation and societal valuation was done through an expert panel. The hydrologic performance and the social values ascribed to the different services were combined to identify key provisioning areas or HES hotspots. Our results show that multifunctional agroecosystems, where agrarian and forestry activi- ties co-exist, optimize the partition and use of freshwater flows and supply the largest bundles of HES at a wide range of spatial scales. The often low profitability of these extensive activities is prompting either the intensification or the abandonment of many Mediterranean agro ecosystems. We discuss the trade-offs in HES associated with these land use trends, and we illustrate the potential options available for implementing payments for ecosystem services (PES) schemes to pursue win-win management solutions.

Farmer typology, future scenarios and the implications for ecosystem service provision: a case study from south-eastern Spain

Farming communities are increasingly expected to manage their agricultural activities in ways that ensure sustainable flows of a wide range of ecosystem services for society. The land use and management choices that farmers make are dependent upon their socio-economic characteristics and background, and in turn have important implications for the landscape and associated ecosystem services. Thus, a better understanding about the linkages between the characteristics of farmers, farm management and land use is important for managing multifunctional agro-ecosystems. In this paper, we first develop a typology of farmers for Torrealvilla catchment in Murcia, Spain, according to the characteristics of their households and farm management (e.g. the farmer’s age, household income, water access, land tenure and farm labour). This analysis distinguishes six types of farmers. Secondly, we analyse the link between farmer typology and the farmers’ responses to a number of scenarios. The scenarios describe different likely changes to agriculture in the catchment in terms of environmental constraints (irrigation water availability and rainfall pattern) and environmental policy regulation (water taxation and subsidies). This exercise enables us to explore the range of future land use changes that are likely to occur in the study area. The results indicate that: rain-fed agriculture is expected to experience gradual but extensive abandonment; vegetable/fruit farming and pig/animal rearing are likely to stagnate or even decline; and growing of grapes is likely to expand. Thirdly, we qualitatively evaluate how future land use changes are likely to affect key ecosystem services in the study area including future agricultural production and associated local income generation, erosion control, maintenance of the groundwater table and various cultural services associated with a heterogeneous agro-ecosystem. Particular changes such as expansion of grape production will increase food production and local income at the cost of further depletion of the aquifer and increased risk of salinisation. The outcomes of the study highlight that, to be effective, the design of agri-environmental schemes and other government interventions (e.g. specific compulsory regulations on farming practices and associated water use) should carefully take into account the characteristics of the farmers within the area of interest, their land uses and the possible diversity of responses to policy and environmental drivers. Opportunities exist for future studies quantifying the extent of the impacts of ecosystem service provision through formal models combining farmers’ land use decision-making and spatially explicit modelling of landscape processes.

A protocol for the conceptualisation of an agro-ecosystem to guide data acquisition and analysis and expert knowledge integration

Innovative agricultural systems need to combine the production of goods with the provision of environmental services. When agronomists analyse or design multifunctional agro-ecosystems, they thus need to include knowledge of an increasing range of scientific disciplines (plant biology, soil science, ecology, etc.) while continuing to use their systemic approach as a cornerstone. Increasing amounts of knowledge of different types (concepts and data) will thus have to be included in systemic approaches that are developed in the agronomic domain. Knowledge integration and sharing are frequently hampered by the lack of detail in the assumptions made in each discipline. We hypothesise that a standardised description of the conceptual model underlying data collection and the analysis of agro ecosystems would improve transparency and knowledge integration.Here we propose a protocol to formalise the conceptual modelling of an agro-ecosystem (CMA) related to a specific agronomic issue. The CMA protocol is implemented in four iterative steps: (i) structural analysis, (ii) functional analysis, (iii) dynamic analysis, and (iv) consistency check. The final product is a conceptual model of an agro-ecosystem whose key elements are a structured knowledge base and associated graphical representations. The protocol was drawn up based on three case studies concerning three different biophysical objects (coffee agroforest, cotton, grapevine) with different problems to be addressed. They are given here as an illustration of how to apply the CMA protocol, and to show how it can be used as a tool to build a systemic representation of a complex agro-ecosystem, as a tool for agronomic diagnosis and yield gap analysis, or as a tool to elicit a range of expert knowledge to design new field experiments.The CMA protocol proved to be efficient in guiding the process of conceptualisation up to the point at which the variables that need to be measured in the field are identified and interlinked. It enabled elicitation and integration of knowledge from different biophysical disciplines and different types of expertise during the conceptualisation process. It also enabled identification of knowledge gaps, and the design and analysis of experiments to tackle complex problems. The CMA yielded by the protocol could be used again, thanks to its transparency and modularity. Further work is underway to improve the CMA representation and its uses in numerical model specification and in participatory methods for the design of cropping systems.

Symbiotic nitrogen fixation and the delivery of multiple ecosystem services: a global change perspective.

Abstract A key challenge facing humanity in the coming decades will be ensuring food supply to a growing human population without compromising the sustainability of many agro-ecosystems worldwide. Although agricultural soils remain firmly at the foundation of human life-support systems, human domination of terrestrial ecosystems over the last century has greatly affected their long-term sustainability as well as reducing soil biological diversity. This has mainly occurred through widespread land-use changes and through the chronic deposition of biologically available nutrients, such as nitrogen (N) and phosphorous (P). Here I argue that a better understanding of the ecological role of symbiotic N-fixers could help in developing more sustainable multifunctional agro-ecosystems. N-fixers are beneficial for the delivery of multiple ecosystem services such as greater primary productivity (i.e. increased crop yields), increased soil carbon (C) and N sequestration, and higher soil biological diversity. Understanding the ecological mechanisms responsible for the provision of these ecosystem services may also be critical for reducing the global-warming potential of many agricultural practices worldwide.

Managing water in agriculture for food production and other ecosystem services

Agricultural systems as well as other ecosystems generate ecosystem services, i.e., societal benefits from ecological processes. These services include, for example, nutrient reduction that leads to water quality improvements in some wetlands and climatic regulation through recycling of precipitation in rain forests. While agriculture has increased ‘provisioning’ ecosystem services, such as food, fiber and timber production, it has, through time, substantially impacted other ecosystem services. Here we review the trade-offs among ecosystem services that have been generated by agriculture-induced changes to water quality and quantity in downstream aquatic systems, wetlands and terrestrial systems. We highlight emerging issues that need urgent attention in research and policy making. We identify three main strategies by which agricultural water management can deal with these large trade-offs: (a) improving water management practices on agricultural lands, (b) better linkage with management of downstream aquatic ecosystems, and (c) paying more attention to how water can be managed to create multifunctional agro-ecosystems. This can only be done if ecological landscape processes are better understood, and the values of ecosystem services other than food production are also recognized.