Agronomy for Sustainable Development最新文献

Soil health metrics with strong links to ecological function and agricultural productivity are needed to ensure that future management of agricultural systems meets sustainability goals. While ecological metrics and crop yields are often considered separately from one another, our work sought to assess the links between the two in an agricultural context where productivity is a key consideration. Here, we investigated the value of soil health tests in terms of their relevance to agricultural management practices and crop yields at contrasting long term cropping systems experiments. One site was on a sandy loam Leptic Podzol and the other on a sandy clay loam Endostagnic Luvisol. Furthermore, the experiments had different management systems. One contained legume-supported rotations with different grass-clover ley durations and organic amendment usage, while the other compared a range of nutrient input options through fertiliser and organic amendments on the same rotation without ley periods. Metrics included field tests (earthworm counts and visual evaluation of soil structure scores) with laboratory analysis of soil structure, chemistry and biology. This analysis included bulk density, macroporosity, pH, available phosphorus, exchangeable potassium, soil organic matter and potentially mineralizable nitrogen. Using a novel combination of long-term experiments, management systems and distinctive soil types, we demonstrated that as well as providing nutrients, agricultural management which resulted in better soil organic matter, pH, potassium and bulk density was correlated with higher crop yields. The importance of ley duration and potentially mineralizable nitrogen to yield in legume-supported systems showed the impact of agricultural management on soil biology. In systems with applications of synthetic fertiliser, earthworm counts and visual evaluation of soil structure scores were correlated with higher yields. We concluded that agricultural management altered yields not just through direct supply of nutrients to crops, but also through the changes in soil health measured by simple metrics.

The growing demand for sustainable agriculture is raising interest in intercropping for its multiple potential benefits to avoid or limit the use of chemical inputs or increase the production per surface unit. Predicting the existence and magnitude of those benefits remains a challenge given the numerous interactions between interspecific plant-plant relationships, their environment, and the agricultural practices. Soil-crop models are critical in understanding these interactions in dynamics during the whole growing season, but few models are capable of accurately simulating intercropping systems. In this study, we propose a set of simple and generic formalisms (i.e. the structure and mathematical representation necessary for designing a model) for simulating key interactions in bi-specific intercropping systems that can be readily included into existing dynamic crop models. This requires simulating important processes such as development, light interception, plant growth, N and water balance, and yield formation in response to management practices, soil conditions, and climate. These formalisms were integrated into the STICS soil-crop model and evaluated using observed data of intercropping systems of cereal and legumes mixtures, including Faba bean-Wheat, Pea-Barley, Soybean-Sunflower, and Wheat-Pea mixtures. We demonstrate that the proposed formalisms provide a comprehensive simulation of soil-plant interactions in various types of bispecific intercrops. The model was found consistent and generic under a range of spring and winter intercrops (nRMSE = 25% for maximum leaf area index, 23% for shoot biomass at harvest, and 18% for grain yield). This is the first time a complete set of formalisms has been developed and published for simulating bi-specific intercropping systems and integrated into a soil-crop model. With its emphasis on being generic, sufficiently accurate, simple, and easy to parameterize, STICS is well-suited to help researchers designing in silico the agroecological transition by virtually pre-screening sustainable, manageable intercrop systems adapted to local conditions.

Agriculture faces potentially competing societal demands to produce food, fiber and fuel while reducing negative environmental impacts and delivering regulating, supporting and cultural ecosystem services. This necessitates a new generation of long-term agricultural field experiments designed to study the behavior of contrasting cropping systems in terms of multiple outcomes. We document the principles and practices of a new long-term experiment of this type at Rothamsted, established at two contrasting sites in 2017 and 2018, and report initial yield data at the crop and system level. The objective of the Large-Scale Rotation Experiment was to establish gradients of system properties and outcomes to improve our fundamental understanding of UK cropping systems. It is composed of four management factors—phased rotations, cultivation (conventional vs reduced tillage), nutrition (additional organic amendment vs standard mineral fertilization) and crop protection (conventional vs smart crop protection). These factors were combined in a balanced design resulting in 24 emergent cropping systems at each site and can be analyzed at the level of the system or component management factors. We observed interactions between management factors and with the environment on crop yields, justifying the systems level, multi-site approach. Reduced tillage resulted in lower wheat yields but the effect varied with rotation, previous-crop and site. Organic amendments significantly increased spring barley yield by 8% on average though the effect again varied with site. The plowed cropping systems tended to produce higher caloric yield overall than systems under reduced tillage. Additional response variables are being monitored to study synergies and trade-offs with outcomes other than yield at the cropping system level. The experiment has been established as a long-term resource for inter-disciplinary research. By documenting the design process, we aim to facilitate the adoption of similar approaches to system-scale agricultural experimentation to inform the transition to more sustainable cropping systems.

Climate change is increasingly affecting agriculture worldwide, causing yield losses and undermining food security. Behind the international consensus on the urgent need for ambitious policies to adapt agriculture to climate change (AACC) hides a competition between three agricultural models—agroecology, climate-smart agriculture, and conventional agriculture—each carrying distinctive perspective on how agriculture should adapt to climate change. To date, no study has shown which of these three agricultural models is promoted the most by climate change adaptation policies. To shed light on this question, we undertook semi-structured surveys with resource persons, a literature review and a multi-criteria analysis, identifying and characterizing 226 AACC policy initiatives in seven countries or regions in the north (Andalusia, Occitanie, California, Guadeloupe) and the south (Colombia, South Africa, Senegal). Our aim was to identify (1) concrete strategic options mobilized by policy initiatives to adapt agriculture to climate change and (2) agricultural models that are implicitly or explicitly promoted by these policy initiatives. We identified 14 climate change adaptation options that mobilize a set of three complementary levers of action: (i) transforming production systems or enabling access to productive resources, (ii) providing access to knowledge that is useful for AACC, and (iii) coordinating and financing adaptation actions at territorial or sector scale. Agroecology and climate-smart agriculture are the two agricultural models favored in the mix of policy initiatives in all the studied sites. Despite conceptual differences, in real-life situations, these models do not conflict with each other since they are often promoted concomitantly. AACC policy initiatives, although diversified, seem too fragmented and not sufficiently restrictive to bring about rapid and profound change. This paper presents a new classification of AACC adaptation options, and is the first to reveal which agricultural models are promoted by policy initiatives in a wide range of regions.

Perennial crops replacing annual crops are drawing global attention because they harbor potential for sustainable biomass production and climate change mitigation through soil carbon sequestration. At present, it remains unclear how long perennial crops can sequester carbon in the soil and how soil carbon stock dynamics are influenced by climate, soil, and plant properties across the globe. This study presents a meta-analysis synthesizing 51 publications (351 observations at 77 sites) distributed over different pedo-climatic conditions to scrutinize the effect of perennialization on organic carbon accumulation in soil compared with two annual benchmark systems (i.e., monoculture and crop rotation). Results showed that perennial crops significantly increased soil organic carbon stock by 16.6% and 23.1% at 0–30 cm depth compared with monoculture and crop rotation, respectively. Shortly after establishment (< 5 years), perennial crops revealed a negative impact on soil organic carbon stock; however, long duration (> 10 years) of perennialization had a significant positive effect on soil organic carbon stock by 30% and 36.4% at 0–30 cm depth compared with monoculture and crop rotation, respectively. Compared with both annual systems, perennial crops significantly increased soil organic carbon stock regardless of their functional photosynthetic types (C₃, C₄, or C₃-C₄ intermediates) and vegetation type (woody or herbaceous). Among other factors, pH had a significant impact on soil organic carbon; however, the effect of soil textures showed no significant impact, possibly due to a lack of observations from each textural class and mixed pedoclimatic effects. Results also showed that time effect of perennialization revealed a sigmoidal increase of soil organic carbon stock until about 20 years; thereafter, the soil carbon stocks advanced towards a steady-state level. In conclusion, perennial crops increased soil organic carbon stock compared with annual systems; however, the time since conversion from annual to perennial system decisively impacted soil organic carbon stock changes.

Abstract 

Herd health management is a critical issue for the future of dairy systems. The right combination of preventive and curative practices will depend on management system, level of work productivity, and self-sufficiency objectives, and will entail specific skills and work organizations. However, the combination of work dimensions and animal health management has rarely been explored in the literature on a livestock farming system scale. The Grand Ouest region of France spans a diverse array of livestock farming systems that can serve to design herd health management indicators, farming objectives and work arrangements, and explore their linkages. Here we ran semi-structured interviews on 10 dairy farms, analyzed the farmers’ discourses, and built 7 variables and 25 modalities that, for the first time, cover three components, namely herd health, farming objectives and work arrangements, and we tested various associations between these variables. Our interview data confirms that consultants and veterinarians have a key role to play in building a pool of skills adapted to various types of health management system. Data suggests linkages between prevention measures, alternative or conventional curative interventions, and work-related parameters.

Establishing desirable cropping systems with higher fertilizer-use efficiency and lower risk of environmental pollution is a promising approach for more sustainable agriculture development. Intercropping may facilitate phosphorus (P) uptake and reduce P-fertilizer application rates. However, how root-root interactions mediate enhanced P-fertilizer-use efficiency in intercropping under field conditions remains poorly understood. Using a long-term field experiment established in 2009, where there have been three P-fertilizer application rates (0, 40, and 80 kg P ha⁻¹) and nine cropping systems (four intercropping combinations and corresponding monocultures), we calculated aboveground biomass, grain yield, aboveground P content, P-use efficiency indicators, e.g., the apparent recovery efficiency of applied P, and diversity effects. We also investigated the P-related physiological and morphological traits of crop species and linked root traits with agronomic indicators. We found that 12 years of intercropping significantly increased productivity, shoot P content, agronomic efficiency of applied P, and the apparent recovery efficiency of applied P in all combinations compared with the weighted means of corresponding monocultures; intercropping with 40 kg P ha⁻¹ application showed relatively high productivity, P content and P-use efficiency. The P-uptake advantage in intercropping was mainly related to the positive complementarity effect. The companion crop species (i.e. faba bean, oilseed rape, chickpea, and soybean) exhibited greater P-mobilizing capacity than sole maize. Intercropped maize exhibited greater root physiological, e.g., rhizosheath phosphatase activity and carboxylates (proxied by leaf manganese concentration), and morphological traits (e.g., specific root length) than sole maize, partly related to facilitation by efficient P-mobilizing neighbors. The greater P-use efficiency was mainly contributed by morphological traits of maize rather than traits of companion crop species. We highlight that the enhanced P-use efficiency in intercropping systems is partly mediated by belowground facilitation, and desirable intercropping systems have the potential to save P-fertilizer input and improve the sustainability of P management in agroecosystems.

The increasing human population and demand for animal food products raise the issue of impacts of animal systems on food security caused by their use of human-edible feed and/or tillable land. The utility of replacing animal systems with potential food-crop systems needs to be assessed but is associated with many uncertainties. Some metrics analyse the contribution of current animal systems to food security, especially the dimension of food availability. These methods address feed conversion efficiency (i.e. total (‘gross’) or human-edible (‘net’)) or the efficiency of agricultural land use (i.e. total, permanent grassland, and tillable land) but never both simultaneously. The purpose of this study was to develop a new metric—‘net productivity’—to represent the performances of current animal systems more accurately by considering both the use of human-edible feed and agricultural land. Through a protein assessment, we analysed the ability of the existing and the new metrics to assess the performances of 111 dairy farms in Wallonia (Belgium). We found that net productivity was positively correlated with both metrics of feed conversion efficiency and negatively correlated with the three metrics of land use. To analyse the influence of farm characteristics, we grouped the farms into four clusters using k-means clustering based on these metrics of contribution to food security and then performed redundancy analysis to select the most influential farm characteristics aiming to highlight contrasted farm strategies. The highest net productivity was reached by an ‘intensive and net efficient’ farm strategy, which had intensive grass-based management, high milk production per cow, appropriate use of concentrates, and well-managed dairy followers (i.e. replacement heifers and calves). The newly developed metric of net productivity can be useful to quantify the contribution of dairy systems to food security by considering both the use of human-edible protein and agricultural land simultaneously.

The growth of legumes, reduced tillage and addition of crop residues can be regarded as a good alternative in intercropping systems to increase soil organic matter, soil fertility and biodiversity while enhancing crop production and reducing the use of fertilizers. Despite the potential benefits, there is still a research gap about using the combination of cowpea and melon in intercropping to increase productivity and reduce external inputs. Thus, the aims of this study were to: i) assess if crop yield, crop quality and soil physicochemical properties can be improved by intercropping systems between melon (Cucumis melo L.) and cowpea (Vigna unguiculata (L.) Walp.) with reduced tillage and addition of crop residues, compared with a melon monoculture with intensive tillage and removal of crop residues, all grown under organic management; and ii) evaluated if cowpea grown as intercrop with fertilization reduced by 30% in the diversified plots can partially replace the use of fertilizers with no negative effects on total crop production. In this study we compared over three crop cycles monocrops with three different melon-cowpea intercropping patterns: mixed intercropping, row intercropping 1:1 (melon:cowpea) and row intercropping 2:1 (melon:cowpea). Our results, presented in this study, showed that intercropping systems, regardless of the pattern, kept soil organic C levels, while it significantly decreased in melon monoculture. Intercropping also significantly increased soil total N, available P and exchangeable K (0.13%, 62 mg·kg^-1 and 387 mg·kg^-1, respectively), compared to the melon monocrop (0.11%, 25 mg·kg^-1 and 306 mg·kg^-1). Total crop production was significantly higher under diversified systems, with land equivalent ratios > 1. Hence, the introduction of cowpea associated with melon, combined with reduced tillage and the incorporation of crop residues could be considered as a feasible strategy for sustainable agriculture, with environmental gains and economic savings for fertilizers and water.