Search

The necessity for sustainable agricultural practices has propelled a renewed interest in legumes such as faba bean (Vicia faba L.) as agents to help deliver increased diversity to cropped systems and provide an organic source of nitrogen (N). However, the increased cultivation of faba beans has proven recalcitrant worldwide as a result of low yields. So, it is hoped that increased and more stable yields would improve the commercial success of the crop and so the likelihood of cultivation. Enhancing biological N fixation (BNF) in faba beans holds promise not only to enhance and stabilize yields but also to increase residual N available to subsequent cereal crops grown on the same field. In this review, we cover recent progress in enhancing BNF in faba beans. Specifically, rhizobial inoculation and the optimization of fertilizer input and cropping systems have received the greatest attention in the literature. We also suggest directions for future research on the subject. In the short term, modification of crop management practices such as fertilizer and biochar input may offer the benefits of enhanced BNF. In the long term, natural variation in rhizobial strains and faba bean genotypes can be harnessed. Strategies must be optimized on a local scale to realize the greatest benefits. Future research must measure the most useful parameters and consider the economic cost of strategies alongside the advantages of enhanced BNF. [ABSTRACT FROM AUTHOR]

Legumes are essential to healthy agroecosystems, with a rich phytochemical content that impacts overall human and animal well-being and environmental sustainability. While these phytochemicals can have both positive and negative effects, legumes have traditionally been bred to produce genotypes with lower levels of certain plant phytochemicals, specifically those commonly termed as 'antifeedants' including phenolic compounds, saponins, alkaloids, tannins, and raffinose family oligosaccharides (RFOs). However, when incorporated into a balanced diet, such legume phytochemicals can offer health benefits for both humans and animals. They can positively influence the human gut microbiome by promoting the growth of beneficial bacteria, contributing to gut health, and demonstrating anti-inflammatory and antioxidant properties. Beyond their nutritional value, legume phytochemicals also play a vital role in soil health. The phytochemical containing residues from their shoots and roots usually remain in-field to positively affect soil nutrient status and microbiome diversity, so enhancing soil functions and benefiting performance and yield of following crops. This review explores the role of legume phytochemicals from a 'one health' perspective, examining their on soil- and gut-microbial ecology, bridging the gap between human nutrition and agroecological science. [ABSTRACT FROM AUTHOR]

Ecological intensification (EI) is the enhancement of ecosystem services to complement or substitute for the role of anthropogenic inputs in maintaining or increasing yields. EI has potential to increase farming's environmental sustainability, e.g. reducing environmentally harmful management activities while sustaining yields. EI is based upon ecological processes which in turn are influenced by biodiversity. We review how biodiversity, particularly vascular plant diversity, can regulate ecosystem processes relevant to EI at multiple spatial scales. At an individual plant genotype level, complementarity in functional traits has a direct impact on productivity. At in-field, population level, mixtures of crop types confer resilience to minimize the risk of pest and disease incidence and spread. Scaling up to the field level, a diversity of non-crop plants (i.e. weeds) provides resources necessary for in-field functional processes, both below ground (carbon inputs, decomposition) and above ground (resource continuity for pollinators and natural enemies). At the landscape scale, mosaics of semi-natural and managed vegetation provide buffers against extreme events through flood and drought risk mitigation, climate amelioration and pest population regulation. Overall this emphasizes the importance of heterogeneity across scales in maintaining ecosystem functions in farmland. Major research challenges highlighted by our review include the need: to better integrate plant functional diversity (from traits to habitat scales) into cropping system design; to quantify the (likely interactive) contribution of plant diversity for effective EI relative to other management options; and to optimize through targeted management the system function benefits of biodiversity for resilient, efficient and productive agroecosystems. [ABSTRACT FROM AUTHOR]

Background: Legumes can fix atmospheric nitrogen (N) and facilitate N availability to their companion plants in crop mixtures. However, biological nitrogen fixation (BNF) of legumes in intercrops varies largely with the identity of the legume species. The aim of our study was to understand whether BNF and concentration of plant nutrients by common bean is influenced by the identity of the companion plant species in crop mixtures. In this greenhouse pot study, common beans were cultivated with another legume (chickpea) and a cereal (Sorghum). We compared BNF, crop biomass and nutrient assimilation of all plant species grown in monocultures with plants grown in crop mixtures. Results: We found beans to exhibit low levels of BNF, and to potentially compete with other species for available soil N in crop mixtures. The BNF of chickpeas however, was enhanced when grown in mixtures. Furthermore, biomass, phosphorous and potassium values of chickpea and Sorghum plants were higher in monocultures, compared to in mixtures with beans; suggesting competitive effects of beans on these plants. Concentration of calcium, magnesium and zinc in beans was higher when grown with chickpeas than with Sorghum. Conclusions: It is generally assumed that legumes benefit their companion plant species. Our study highlights the contrary and shows that the specific benefits of cereal-legume mixtures are dependent on the growth rate of the species concerned. We further highlight that the potential of legume-legume mixtures is currently undervalued and may play a strong role in increasing N use efficiency of intercrop-based systems. [ABSTRACT FROM AUTHOR]

This study aims to explore the possibility of a reduced application of inorganic nitrogen (N) fertiliser on the yield, yield qualities, and biological nitrogen fixation (BNF) of the hydroponic common bean (Phaseolus vulgaris L.), without compromising plant performance, by utilizing the inherent ability of this plant to symbiotically fix N2. Until the flowering stage, plants were supplied with a nutrient solution containing N-concentrations of either a, 100%, conventional standard-practice, 13.8 mM; b, 75% of the standard, 10.35 mM; or c, 50% of the standard, 6.9 mM. During the subsequent reproductive stage, inorganic-N treatments b and c were decreased to 25% of the standard, and the standard (100% level) N-application was not altered. The three different inorganic-N supply treatments were combined with two different rhizobia strains, and a control (no-inoculation) treatment, in a two-factorial experiment. The rhizobia strains applied were either the indigenous strain Rhizobium sophoriradicis PVTN21 or the commercially supplied Rhizobium tropici CIAT 899. Results showed that the 50–25% mineral-N application regime led to significant increases in nodulation, BNF, and fresh-pod yield, compared to the other treatment, with a reduced inorganic-N supply. On the other hand, the 75–25% mineral-N regime applied during the vegetative stage restricted nodulation and BNF, thus incurring significant yield losses. Both rhizobia strains stimulated nodulation and BNF. However, the BNF capacity they facilitated was suppressed as the inorganic-N input increased. In addition, strain PVTN21 was superior to CIAT 899—as 50–25% N-treated plants inoculated with the former showed a yield loss of 11%, compared to the 100%-N-treated plants. In conclusion, N-use efficiency optimises BNF, reduces mineral-N-input dependency, and therefore may reduce any consequential negative environmental consequences of mineral-N over-application. [ABSTRACT FROM AUTHOR]

The aim of the current study wat to comparatively assess the impact of different nitrogen (N) fertilization schemes on fresh pod yield and yield quality in either organically or conventionally grown common beans (Phaseolus vulgaris L.). Prior to common bean crop establishment, the experimental field site was cultivated following either organic (a) or conventional (b) farming practices with a winter non-legume crop (Brassica oleracea var. italica) (BR), or (c) with field bean (Vicia faba sp.) destined to serve as a green manure (GM) crop. At the end of the winter cultivation period the broccoli crop residues (BR) and green manure biomass (GM) were incorporated into the soil and the plots that accommodated the treatments (a) and (c) were followed by an organically cultivated common bean crop, while the conventional broccoli crop was followed by a conventionally cropped common bean crop. Additional to the plant residues (BR), sheep manure (SM) at a rate of 40 kg N ha−1 was also applied to the organically treated common beans, while the plots with a conventionally cropped common bean received 75 kg N ha−1. Organic common bean treated with SM + BR produced smaller pods of higher dry matter and bioactive compound content, responses that are correlated with limited soil N availability. No significant variations were observed on yield components and N levels of pods cultivated under organic (SM + GM) and conventional cropping systems. Pod sugar and starch content was not influenced by the different fertilization practices. In conclusion, we have demonstrated that the combined application of SM + GM can be considered as an efficient N-fertilisation strategy for organic crops of common bean, benefiting their nutritional value without compromising yield. [ABSTRACT FROM AUTHOR]

Despite the importance of secondary dormancy for plant life cycle timing and survival, there is insufficient knowledge about the (epigenetic) regulation of this trait at the molecular level. Our aim was to determine the role of (epi)genetic processes in the regulation of secondary seed dormancy using natural genotypes of the widely distributed Capsella bursa-pastoris. Seeds of nine ecotypes were exposed to control conditions or histone deacetylase inhibitors [trichostatin A (TSA), valproic acid] during imbibition to study the effects of hyper-acetylation on secondary seed dormancy induction and germination. Valproic acid increased secondary dormancy and both compounds caused a delay of t50 for germination (radicle emergence) but not of t50 for testa rupture, demonstrating that they reduced speed of germination. Transcriptome analysis of one accession exposed to valproic acid versus water showed mixed regulation of ABA, negative regulation of GAs, BRs and auxins, as well as up-regulation of SNL genes, which might explain the observed delay in germination and increase in secondary dormancy. In addition, two accessions differing in secondary dormancy depth (deep vs non-deep) were studied using RNA-seq to reveal the potential regulatory processes underlying this trait. Phytohormone synthesis or signalling was generally up-regulated for ABA (e.g. NCED6 , NCED2 , ABCG40 , ABI3) and down-regulated for GAs (GA20ox1 , GA20ox2 , bHLH93), ethylene (ACO1 , ERF4-LIKE, ERF105 , ERF109-LIKE), BRs (BIA1 , CYP708A2-LIKE , probable WRKY46 , BAK1 , BEN1 , BES1 , BRI1) and auxin (GH3.3 , GH3.6 , ABCB19 , TGG4 , AUX1 , PIN6 , WAT1). Epigenetic candidates for variation in secondary dormancy depth include SNL genes, histone deacetylases and associated genes (HDA14 , HDA6-LIKE , HDA-LIKE , ING2 , JMJ30), as well as sequences linked to histone acetyltransferases (bZIP11 , ARID1A-LIKE), or to gene silencing through histone methylation (SUVH7 , SUVH9 , CLF). Together, these results show that phytohormones and epigenetic regulation play an important role in controlling differences in secondary dormancy depth between accessions. [ABSTRACT FROM AUTHOR]

Assessing the sustainability of agri-food chains is challenging for several reasons. It should account for the impacts on environmental, social, and economic wellbeing simultaneously, considering both the individual links in the chain and the chain as a whole. The primary aim of this study is to assess the conditions for meeting the sustainability criteria of a legume-based agri-food chain in Slovenia. Therefore, a quantitative sustainability assessment methodology was developed, using a multi-stakeholder approach, which upgraded the traditional SWOT (strengths, weaknesses, opportunities, and threats) analysis. Our approach, called 'Multi-SWOT', aggregates the SWOT table inputs identified by stakeholders into factors, themes and focus areas, according to their importance for the agri-food chain, for each sustainability pillar, and links in the chain. By accounting for the relative number of incentives (beneficial factors) and barriers (constraint factors) we identified those factors that enhance the sustainability of the Slovenian legume-based agri-food chain and the factors jeopardising it. The incorporation of multi-stakeholder perspectives presents an innovative approach that adds value to a standard SWOT analysis. The study serves as a guide to help decision-makers better understand the multidimensionality of sustainability and identify effective activities to support and strengthen the current legume agri-food chain in Slovenia. [ABSTRACT FROM AUTHOR]

To achieve the triple challenge of food security, reversing biodiversity declines plus mitigating and adapting to climate change, there is a drive to embed ecological principles into agricultural, value-chain practices and decisionmaking. By diversifying cropping systems at several scales there is potential to decrease reliance on inputs, provide resilience to abiotic and biotic stress, enhance plant, microbe and animal biodiversity, and mitigate against climate change. In this review we highlight the research performed in Scotland over the past 5 years into the impact of the use of ecological principles in agriculture on sustainability, resilience and provision of ecosystem functions. We demonstrate that diversification of the system can enhance ecosystem functions. Soil and plant management interventions, including nature-based solutions, can also enhance soil quality and utilization of legacy nutrients. Additionally, this is facilitated by greater reliance on soil biological processes and trophic interactions. We highlight the example of intercropping with legumes to deliver sustainability through ecological principles and use legumes as an exemplar of the innovation. We conclude that there are many effective interventions that can be made to deliver resilient, sustainable, and diverse agroecosystems for crop and food production, and these may be applicable in any agroecosystem. [ABSTRACT FROM AUTHOR]

Despite the importance of dormancy and dormancy cycling for plants' fitness and life cycle phenology, a comprehensive characterization of the global and cellular epigenetic patterns across space and time in different seed dormancy states is lacking. Using Capsella bursa-pastoris (L.) Medik. (shepherd's purse) seeds with primary and secondary dormancy, we investigated the dynamics of global genomic DNA methylation and explored the spatio-temporal distribution of 5-methylcytosine (5-mC) and histone H4 acetylated (H4Ac) epigenetic marks. Seeds were imbibed at 30 °C in a light regime to maintain primary dormancy, or in darkness to induce secondary dormancy. An ELISA-based method was used to quantify DNA methylation, in relation to total genomic cytosines. Immunolocalization of 5-mC and H4Ac within whole seeds (i.e., including testa) was assessed with reference to embryo anatomy. Global DNA methylation levels were highest in prolonged (14 days) imbibed primary dormant seeds, with more 5-mC marked nuclei present only in specific parts of the seed (e.g., SAM and cotyledons). In secondary dormant seeds, global methylation levels and 5-mC signal where higher at 3 and 7 days than 1 or 14 days. With respect to acetylation, seeds had fewer H4Ac marked nuclei (e.g., SAM) in deeper dormant states, for both types of dormancy. However, the RAM still showed signal after 14 days of imbibition under dormancy-inducing conditions, suggesting a central role for the radicle/RAM in the response to perceived ambient changes and the adjustment of the seed dormancy state. Thus, we show that seed dormancy involves extensive cellular remodeling of DNA methylation and H4 acetylation. [ABSTRACT FROM AUTHOR]

Compared to sole crops, intercropping—especially of legumes and cereals—has great potential to improve crop yield and resource use efficiency, and can provide many other ecosystem services. However, the beneficial effects of intercrops are often greatly dependent on the end use as well as the specific species and genotypes being co-cultivated. In addition, intercropping imposes added complexity at different levels of the supply chain. While the need for developing crop genotypes for intercropping has long been recognized, most cultivars on the market are optimized for sole cropping and may not necessarily perform well in intercrops. This paper aims to place breeding targets for intercrop-adapted genotypes in a supply chain perspective. Three case studies of legumes and cereals intercropped for human consumption are used to identify desirable intercrop traits for actors across the supply chains, many of which are not targeted by traditional breeding for sole crops, including certain seed attributes, and some of which do not fit traditional breeding schemes, such as breeding for synchronized maturity and species synergies. Incorporating these traits into intercrop breeding could significantly reduce complexity along the supply chain. It is concluded that the widespread adoption and integration of intercrops will only be successful through the inclusion and collaboration of all supply chain actors, the application of breeding approaches that take into account the complexity of intercrop supply chains, and the implementation of diversification strategies in every process from field to fork. [ABSTRACT FROM AUTHOR]

Purpose: (1) To assess the biological N fixation (BNF) potential of varieties of faba bean (Vicia faba L.) cropped with or without compost in an experimental field-scale rotation with no recent history of legumes, (2) to enumerate soil populations of Rhizobium leguminosarum sv. viciae (Rlv), and to genetically characterize the nodulating Rlv strains, (3) compare BNF with other sites in Britain. Methods: BNF was evaluated from 2012 to 2015 using 15 N natural abundance. Treatments were either PK fertilizer or compost. Soil rhizobial populations were determined using qPCR, the symbiotic rhizobia genotyped (16 S rRNA, nodA and nodD genes), and their BNF capacity assessed ex situ. The reliance of legumes on BNF at other British sites was estimated in a single season, and their nodulating symbionts examined. Results: Faba bean obtained most of its N through BNF (>80%) regardless of variety or year. N-accumulation by cvs Babylon and Boxer increased with compost treatment in 2014/2015. Rhizobial populations were c. 105-106Rlv cells g−1 soil regardless of field or treatment. 157 Rlv microsymbionts grouped into two large nodAD clades; one mainly from V. faba, and the other from various legumes. All isolates nodulated, and some performed better than commercial inoculant strains. Conclusions: Faba bean can provide most of its nitrogen through BNF and leave economically valuable residual N for subsequent crops. Recent legume cropping in northern Europe is not essential for effective nodulation: rhizobia may persist in a range of farmland locations. Nevertheless, there is the potential to apply elite rhizobial strains as inoculants in some soils. [ABSTRACT FROM AUTHOR]

Background: Agriculture is facing an unprecedented challenge in having to reduce its environmental footprint whilst ensuring food security to an ever-growing global population. Towards this end, several strategies have been investigated and implemented to help maintain or improve crop yield under reduced water and/or nutrient provision for key commercial commodities such as tomatoes. Despite the high commercial, nutritional, and food-cultural value, there is no synthesis of evidence regarding yield maintenance of tomato (as a model crop) under resource-deficit. This systematic map therefore provides an overview of the evidence that exists on the effectiveness of techniques and management approaches aimed at improving the productivity of field-grown tomatoes under conditions of water-, nitrogen- (N) and/or phosphorus (P)-deficit. Methods: Following the published map protocol, systematic searches of peer reviewed- and grey-literature were conducted using research publication databases, and specialist websites. A total of 14,377 unique articles were identified as potentially relevant to our research question, of which 927 were screened at the full-text level. Of that subset, 291 articles met all the pre-defined eligibility criteria. Basic information and meta-data on the interventions reported were recorded for these articles and a systematic map was compiled with the extracted data. Results: The articles included in the systematic map database were used to identify several significant points including: (1) from the year 2000, the number of articles investigating strategies to improve field-grown tomato yield under conditions of water and/or nutrient deficit follows an upward trend; (2) large evidence bases (> 50%) originated from the United States, India, and Italy; (3) most studies addressed water alone as a resource (49%), with only 18% of studies focussing on N and 4% on P alone. Only 4% of records assessed all three resources simultaneously; (4) most evidence (77%) aims to improve resource use-efficiency via either irrigation, fertilisation, or crop and soil management strategies; and (5) different geographical regions appear to focus on different groups of interventions. Conclusions: This systematic map identifies a range of interventions that have been successfully implemented in fields to improve the yield of commercial tomatoes under conditions of water, N and/or P deficit. However, only half of the relevant literature reported evidence on more than one intervention, which highlights the need for more integrated approaches to assess multiple interventions to adapt to deficits of key-resources simultaneously. In addition, the use of ‘techno-chemical’, ‘breeding and genetic’ and ‘computational’ interventions are only reported in a small number of records (< 8% of the gathered evidence). Hence, these interventions may also be considered as subjects to prioritise in future funding strategies. [ABSTRACT FROM AUTHOR]

The potential to utilize low nitrogen barley for production of distilling quality malt was studied. This presents an opportunity to reduce the environmental impact of nitrogen fertilizer applications. Malting barley (cv. Octavia) was grown without the application of inorganic nitrogen fertilizer, to produce grain with a relatively low nitrogen concentration (1.16%, dry weight basis). Following micro-malting trials, dextrinizing units (58 DU) obtained from low nitrogen malt were much higher than a typical specification of 45 DU for malt with a conventional nitrogen concentration (<1.5%). A higher soluble nitrogen ratio (SNR) or index of modification (IoM) of 49 indicated greater modification of the low nitrogen barley, resulting in higher extract released into the wort. Additionally, much lower levels of β-glucan were found in low nitrogen malt wort (64 mg/L compared with over 100 mg/L in wort of conventional nitrogen malt). Low nitrogen malt also produced higher predicted spirit yields following wort fermentation and wash distillation. These findings indicate that lower nitrogen concentration barley can be processed without negatively impacting malt quality for distilling applications. The implication of these findings to help realize more environmentally sustainable production of barley for malting and use in distilling is discussed. [ABSTRACT FROM AUTHOR]

The success of seed-based conservation and restoration efforts using native plant species is largely determined by ensuring two key life history transitions are accommodated. These are from "seed to germinated seed" and "germinated seed to established seedling." In turn, optimization of these life history transitions is determined by a "genetic × environmental" interaction and later largely characterized by localized climatic (abiotic) conditions. It is these environmental stress factors that can act as natural selection agents for specific plant–trait combinations, or phenotypes. In turn, such adaptation may also limit a species range. To test the relationship between these two early plant life history stage transitions, "seed to germinated seed" and "germinated seed to established seedling," the attributes were characterized for two species of Plantago that occupy contrasting environments and since these species have potential for native seed-based habit restoration and conservation. The species were Plantago coronopus (L.), localized at lower and drier altitudes, and Plantago lanceolata (L.), characterized as occupying higher and wetter altitudinal clines. Seeds were collected from 20 accessions of six natural populations spanning four European countries for both P. lanceolata and P. coronopus. Seed germination (G) and seedling establishment (S) data were determined at six temperatures (T) and six water potentials (Ψ), and the data obtained were analyzed using a generalized linear model (GLM). The results indicate that P. coronopus has adapted physiologically to its high-altitude conditions such that seed germination and seedling establishment may be more readily achieved in this cooler environment where water is less limiting. In contrast, the lower θT of P. lanceolata better facilitates more efficient seed germination and seedling establishment in drier and warmer clines of lower altitude. In addition to establishing a genotypic (species) underpin for seed and seedling trait differences observed, the insights gained may also be exploited to best deploy each species in situ for seed-based conservation and restoration efforts. [ABSTRACT FROM AUTHOR]

Abstract: Globally, annual expenditure on ecological restoration of degraded areas for habitat improvement and biodiversity conservation is approximately $18bn. Seed farming of native plant species is crucial to meet restoration goals, but may be stymied by the disconnection of academic research in seed science and the lack of effective policies that regulate native seed production/supply. To illustrate this problem, we identified 1,122 plant species important for European grasslands of conservation concern and found that only 32% have both fundamental seed germination data available and can be purchased as seed. The “restoration species pool,” or set of species available in practice, acts as a significant biodiversity selection filter for species use in restoration projects. For improvement, we propose: (1) substantial expansion of research and development on native seed quality, viability, and production; (2) open‐source knowledge transfer between sectors; and (3) creation of supportive policy intended to stimulate demand for biodiverse seed. [ABSTRACT FROM AUTHOR]

A comparative analysis was carried out of published methods to assess seed viability using 2,3,5-triphenyltetrazolium chloride (TTC) based assays of seed batches. The tests were carried out on seeds of barley (Hordeum vulgare cv. Optic) as a model. We established that 10% [w/v] trichloroacetic acid (TCA)/methanol is superior to the acetone and methanol-only based methods: allowing the highest recovery of formazan and the lowest background optical density (OD) readings, across seed lots comprising different ratios of viable and dead seeds. Themethod allowed a linear-model to accurately capture the statistically significant relationship between the quantity of formazan that could be extracted using the method we developed and the seed temperature-response, and seed viability as a function of artificially aged seed lots. Other quality control steps are defined to help ensure the assay is robust and these are reported in a Standard Operating Procedure. [ABSTRACT FROM AUTHOR]

The potential of biological nitrogen fixation (BNF) to provide sufficient N for production has encouraged re-appraisal of cropping systems that deploy legumes. It has been argued that legume-derived N can maintain productivity as an alternative to the application of mineral fertilizer, although few studies have systematically evaluated the effect of optimizing the balance between legumes and non N-fixing crops to optimize production. In addition, the shortage, or even absence in some regions, of measurements of BNF in crops and forages severely limits the ability to design and evaluate new legume-based agroecosystems. To provide an indication of the magnitude of BNF in European agriculture, a soil-surface N-balance approach was applied to historical data from 8 experimental cropping systems that compared legume and non-legume crop types (e.g., grains, forages and intercrops) across pedoclimatic regions of Europe. Mean BNF for different legume types ranged from 32 to 115 kg ha-1 annually. Output in terms of total biomass (grain, forage, etc.) was 30% greater in non-legumes, which used N to produce dry matter more efficiently than legumes, whereas output of N was greater from legumes. When examined over the crop sequence, the contribution of BNF to the N-balance increased to reach a maximum when the legume fraction was around 0.5 (legume crops were present in half the years). BNF was lower when the legume fraction increased to 0.6-0.8, not because of any feature of the legume, but because the cropping systems in this range were dominated by mixtures of legume and non-legume forages to which inorganic N as fertilizer was normally applied. Forage (e.g., grass and clover), as opposed to grain crops in this range maintained high outputs of biomass and N. In conclusion, BNF through grain and forage legumes has the potential to generate major benefit in terms of reducing or dispensing with the need for mineral N without loss of total output. [ABSTRACT FROM AUTHOR]

Intercropping is a farming practice involving two or more crop species, or genotypes, growing together and coexisting for a time. On the fringes of modern intensive agriculture, intercropping is important in many subsistence or low-input/resource-limited agricultural systems. By allowing genuine yield gains without increased inputs, or greater stability of yield with decreased inputs, intercropping could be one route to delivering 'sustainable intensification'. We discuss how recent knowledge from agronomy, plant physiology and ecology can be combined with the aim of improving intercropping systems. Recent advances in agronomy and plant physiology include better understanding of the mechanisms of interactions between crop genotypes and species - for example, enhanced resource availability through niche complementarity. Ecological advances include better understanding of the context-dependency of interactions, the mechanisms behind disease and pest avoidance, the links between above- and below-ground systems, and the role of microtopographic variation in coexistence. This improved understanding can guide approaches for improving intercropping systems, including breeding crops for intercropping. Although such advances can help to improve intercropping systems, we suggest that other topics also need addressing. These include better assessment of the wider benefits of intercropping in terms of multiple ecosystem services, collaboration with agricultural engineering, and more effective interdisciplinary research. [ABSTRACT FROM AUTHOR]

Common bean (Phaseolus vulgaris L.) is the most important legume for human consumption worldwide and an important source of vegetable protein, minerals, antioxidants, and bioactive compounds. The N2-fixation capacity of this crop reduces its demand for synthetic N fertilizer application to increase yield and quality. Fertilization, yield, and quality of common bean may be optimised by several other agronomic practices such as irrigation, rhizobia application, sowing density, etc. Taking this into consideration, a systematic review integrated with a bibliometric analysis of several agronomic practices that increase common bean yield and quality was conducted, based on the literature published during 1971–2021. A total of 250 publications were found dealing with breeding (n = 61), sowing density and season (n = 14), irrigation (n = 36), fertilization (n = 27), intercropping (n = 12), soilless culture (n = 5), tillage (n = 7), rhizobia application (n = 36), biostimulant/biofertilizer application (n = 21), disease management (n = 15), pest management (n = 2) and weed management (n = 14). The leading research production sites were Asia and South America, whereas from the Australian continent, only four papers were identified as relevant. The keyword co-occurrence network analyses revealed that the main topics addressed in relation to common bean yield in the scientific literature related to that of "pod", "grain", "growth", "cultivar" and "genotype", followed by "soil", "nitrogen", "inoculation", "rhizobia", "environment", and "irrigation". Limited international collaboration among scientists was found, and most reported research was from Brazil. Moreover, there is a complete lack in interdisciplinary interactions. Breeding for increased yield and selection of genotypes adapted to semi-arid environmental conditions combined with the suitable sowing densities are important agronomic practices affecting productivity of common bean. Application of fertilizers and irrigation practices adjusted to the needs of the plants according to the developmental stage and selection of the appropriate tillage system are also of high importance to increase common bean yield and yield qualities. Reducing N-fertilization via improved N-fixation through rhizobia inoculation and/or biostimulants application appeared as a main consideration to optimise crop performance and sustainable management of this crop. Disease and weed management practices appear neglected areas of research attention, including integrated pest management. [ABSTRACT FROM AUTHOR]

Wild arable plants can be an economic burden but they also support diverse arable food webs and contribute to valuable ecosystem functions. These benefits may have been compromised over recent decades by declining weed diversity. The decline in wild arable plant diversity has been viewed predominantly in terms of species shifts a view that ignores the genetic and functional variation existing within species and the impact on ecological and evolutionary processes which this may have. To examine within-species diversity, ISSR markers were used in parallel with environmental and phenotypic characterisation, to investigate the population structure and diversity of Capsella bursa-pastoris (shepherd's purse) from arable fields in the UK. Analysis of 338 ISSR products for 109 individuals from 51 accessions obtained from the seed banks of 33 arable fields showed that in-field populations of shepherd's purse were genetically differentiated between individuals, and among accessions and fields. In addition, cluster analysis identified three genetically distinct regional-scale populations. Phenotypic variation was present at all scales of genetic differentiation, including the regional scale where populations differed in their key life-history traits: flowering time, fecundity and dormancy. Genetic drift is proposed as a contributor to differentiation among genetically isolated but locally co-occurring accessions. In addition, the genetic and phenotypic variation in shepherd's purse exhibited large scale, spatial trends and showed statistically significant associations with cropping intensity and soil-pH. These results suggest that adaptation as a result of selection by cropping practise and soil-pH has played a role in the ability of shepherd's purse to colonise and persist in arable fields. [ABSTRACT FROM AUTHOR]

Background and Aims The duration of the plant life cycle is an important attribute that determines fitness and coexistence of weeds in arable fields. It depends on the timing of two key life-history traits: time from seed dispersal to germination and time from germination to flowering. These traits are components of the time to reproduction. Dormancy results in reduced and delayed germination, thus increasing time to reproduction. Genotypes in the arable seedbank predominantly have short time to flowering. Synergy between reduced seed dormancy and reduced flowering time would create stronger contrasts between genotypes, offering greater adaptation in-field. Therefore, we studied differences in seed dormancy between in-field flowering time genotypes of shepherd's purse. Methods Genotypes with early, intermediate or late flowering time were grown in a glasshouse to provide seed stock for germination tests. Secondary dormancy was assessed by comparing germination before and after dark-incubation. Dormancy was characterized separately for seed myxospermy heteromorphs, observed in each genotype. Seed carbon and nitrogen content and seed mass were determined as indicators of seed filling and resource partitioning associated with dormancy. Key Results Although no differences were observed in primary dormancy, secondary dormancy was weaker among the seeds of early-flowering genotypes. On average, myxospermous seeds showed stronger secondary dormancy than non-myxospermous seeds in all genotypes. Seed filling was similar between the genotypes, but nitrogen partitioning was higher in early-flowering genotypes and in non-myxospermous seeds. Conclusions In shepherd's purse, early flowering and reduced seed dormancy coincide and appear to be linked. The seed heteromorphism contributes to variation in dormancy. Three functional groups of seed dormancy were identified, varying in dormancy depth and nitrate response. One of these groups (FG-III) was distinct for early-flowering genotypes. The weaker secondary dormancy of early-flowering genotypes confers a selective advantage in arable fields. [ABSTRACT FROM PUBLISHER]

Background and Aims Myxospermy is a term which describes the ability of a seed to produce mucilage upon hydration. The mucilage is mainly comprised of plant cell-wall polysaccharides which are deposited during development of those cells that comprise the seed coat (testa). Myxospermy is more prevalent among those plant species adapted to surviving on arid sandy soils, though its significance in determining the ecological fitness of plants is unclear. In this study, the first mathematical model of myxospermous seed mucilage expansion is presented based on seeds of the model plant species Capsella bursa-pastoris (shepherd's purse). Methods The structures underpinning the expansion process were described using light, electron and time-lapse confocal micrographs. The data and experimental observations were used to create a mathematical model of myxospermous seed mucilage expansion based on diffusion equations. Key Results The mucilage expansion was rapid, taking 5 s, during which the cell mucilage volume increased 75-fold. At the level of the seed, this represented a 6-fold increase in seed volume and a 2·5-fold increase in seed surface area. These increases were shown to be a function of water uptake (16 g water g−1 mucilage dry weight), and relaxation of the polymers which comprised the mucilage. In addition, the osmotic pressure of the seed mucilage, estimated by assessing the mucilage expansion of seeds hydrated in solutions of varying osmotic pressure, was –0·54 MPa (equivalent to 0·11 m or 6·6 g L−1 NaCl). Conclusions The results showed that the mucilage may be characterized as hydrogel and seed-mucilage expansion may be modelled using the diffusion equation described. The potential of myxospermous seeds to affect the ecological services provided by soil is discussed briefly. [ABSTRACT FROM AUTHOR]

Laser photoacoustic spectroscopy continuously quantified the ethylene (C2H4) produced by strawberry flowers and fruits developing in planta. C2H4 was first detected as flower buds opened and exhibited diurnal oscillations (to approximately 200 pl flower−1 h−1) before petal abscission. Exogenous application of silver thiosulphate (STS) to detached flowers inhibited petal abscission and flower senescence. In fruit, C2H4 production was maintained at a ‘low level’ (10–60 pl fruit−1 h−1) until fruit expanded when levels increased in a diurnal pattern (to 200 pl fruit−1 h−1). After expansion, C2H4 production declined to a low level until fruit attained the red-ripe stage for at least 24 h. After this time, C2H4 levels increased linearly (no diurnal fluctuation) to approximately 1 nL fruit−1 h−1. Twenty-four hours after the re-initiation of C2H4 production by red fruit, CO2 levels increased approximately three-fold, indicative of a respiratory climacteric. STS applied to fruits developing in planta and dissected fruit parts ex situ established that C2H4 production is regulated by negative feedback until fruits had expanded. The C2H4 produced by red-ripe fruit was regulated by positive feedback. Anti-1-amino-cyclopropane-1-carboxylic acid oxidase IgG localization identified immunoreactive antigens of 40 and 30 kDa (Mr) within the fruit achenes of expanding and red-ripe fruit. Analysis of dissected fruit showed that seed C2H4 accounts for 50% the C2H4 that is detectable from ripe fruit. [ABSTRACT FROM AUTHOR]

Fruit starch reserves can be an important contributor to the sugar content of some ripe fruit, and despite the relatively high financial premiums (compared to other fruit) commanded by ripe strawberries, neither their starch or sugar biochemistry has been examined in detail. This study assessed the rate of starch biosynthesis and breakdown in developing strawberry and sought to determine the temporal changes in the activities of selected enzymes known to be involved in sucrose-starch interconversions. Scanning electron microscopy revealed that starch levels appeared greatest in immature strawberry (Fragaria×ananassa, cv. Elsanta) at 7 days postanthesis, as evidenced by a decrease in the number of cells containing starch granules as ripening progressed. Levels of key enzymes of starch and sugar metabolism estimated using Western blotting and enzyme activity analysis showed that activities did not correlate with antigen levels. In particular, enzyme activity recovery experiments indicated that losses were due to non-proteinaceous inhibitors, and in particular protein binding: highlighting the potential for misinterpretation of enzyme activity data gathered from ripening (strawberry) fruit tissue extracts. Consequently, in vitro experiments using [U-14C] glucose revealed that incorporation to starch is low (11%) at the earliest developmental stages when starch content is greatest. Starch synthesis rate then declines to non-detectable levels as fruit expand and ripen. These results show that starch accumulates extremely early in the fruit formation process and that starch degradation predominates during fruit growth and development. We estimate that breakdown of transient starch can contribute up to 3% of the sugar accumulated in ripe fruit. [ABSTRACT FROM AUTHOR]

The food- and feed-value systems in the European Union are not protein self-sufficient. Despite the potential of legume-supported production systems to reduce the externalities caused by current cultivation practices (excessive use of N fertilizer) and improve the sustainability of the arable cropping systems and the quality of human diets, sufficient production of high-protein legume grains in Europe has not been achieved due to multiple barriers. Identifying the barriers to the production and consumption of legumes is the first step in realizing new pathways towards more sustainable food systems of which legumes are integral part. In this study, we engage stakeholders and decision-makers in a structured communication process, the Delphi method, to identify policy interventions leveraging barriers that hinder the production and consumption of legumes in the EU. This study is one of a kind and uses a systematic method to reach a common understanding of the policy incoherencies across sectors. Through this method we identify policy interventions that may promote the production of legumes and the creation of legume-based products in the EU. Policies that encourage reduced use of inorganic N fertilizer represent an important step toward a shift in the increased cultivation of legumes. Relatedly, investment in R&D, extension services, and knowledge transfer is necessary to support a smooth transition from the heavy use of synthetic N fertilizer in conventional agriculture. These policy interventions are discussed within current EU and national plant-protein strategies. [ABSTRACT FROM AUTHOR]

This study focuses on four raspberry (Rubus idaeus) genotypes from two different genetic backgrounds: cvs Glen Prosen and Glen Clova, bred at the Scottish Crop Research Institute (SCRI) and genotypes bred at Horticulture Research International (HRI), East Malling (EM), EM 4997 and EM 5007. The ripe fruit of each genotype pair were characterised subjectively by raspberry breeders as relatively firm or soft, respectively. Different stages of fruit development from each genotype were used to quantify fruit firmness, rates of ethylene evolution and ripening rate. Penetrometry data confirmed suspected firmness differences. Firmness correlated with rates of ethylene evolution. Rates of ethylene production also correlated with receptacle size. Storage of green fruits in 20 μl l-1 ethylene reduced fruit firmness, enhanced respiration rate and colour (anthocyanin) development and stimulated the development of cell wall hydrolase activities. However, during natural ripening in the field, fruit respiration rate declined, which indicates a non-climacteric ripening pattern. In drupelets, the activities of polygalacturonase (PG), pectin methylesterase (PME), Cx-cellulase (Cx) and β-galactosidase (β-gal.) increased substantially as ripening progressed. More detailed studies with ripe fruit of cv. Glen Clova indicated major isoforms of PG at pIs 3.3, 8.6 and 10.1; of PME at pIs 7.2, 8.5, 8.7, 8.8; of Cx at pI 2.4; and of β-gal. at pIs 6.3 and 6.7. [ABSTRACT FROM AUTHOR]

The aim of the current study was to contribute to the establishment of sustainable organic crop rotation schemes for common bean under mild-winter climatic conditions. Common bean was cultivated according to organic or conventional farming practices during spring-summer in two successive years with crop and treatment during the preceding winter as either: (a) organic broccoli, (b) conventional broccoli, (c) organic faba bean used as green manure, or (d) fallow. Common bean was either inoculated with Rhizobium tropici CIAT 899 or non-inoculated, while faba bean was inoculated or non-inoculated with Rhizobium laguerreae VFLE1. Inoculating faba bean with rhizobia enhanced dry biomass production and biological N-fixing ability in both experimental years. Furthermore, organic farming did not restrict the yield of broccoli compared to conventional practices during the first year, while the reverse was the case in the second year, due to reduced soil N availability. Furthermore, green manure enhanced the fresh pod yield in the following organic crop of common bean in both years. The lowest yield was recorded in organically grown common bean when the preceding winter crop was organically grown broccoli in both years. Rhizobia inoculation of the common bean during the first year slightly increased atmospheric N fixation by common bean. [ABSTRACT FROM AUTHOR]

The common bean (Phaseolous vulgaris L.) is a grain legume functionally characterized by its capacity for symbiotic of biological nitrogen fixation. As such, it does not demand the application of synthetic nitrogenous fertilizer and can offer environmental benefits as part of holistic cropping systems. While common bean commodities are highly nutritious, commercial cultivation of this crop is declining in already-industrialized countries. However, recent interest of consumers towards diets that benefit environmental and personal health has rekindled commercial interest in legumes, including the common bean. The aim of this protocol is to identify agronomic practices that are capable of increasing the yield and quality of the common bean for use as food. To address this research question, published literature will be screened for inclusion on the basis of defined eligibility criteria to ensure data sources are selected in an objective and consistent manner. Consistency checks will be carried out for the title, abstract and full texts of the literature collated. The output is expected to be a summary of the knowledge available to maximize the productivity and quality of the common bean as food. This anticipated synthesis will be of utility for a wide range of value-chain stakeholders from farmers and consumers, to research scientists and policy makers. [ABSTRACT FROM AUTHOR]

Grain legumes have declined to a low base in many regions of intensified agriculture yet have the potential both to safeguard food security and satisfy rising ethical demands from food consumers. Here, the scope for legume expansion is examined in a long‐established agricultural region in eastern Scotland where grain legumes declined to <0.3% of cropped area in the 1930s and now vary around 1%. Data from the EU's Integrated Administrative and Control System (IACS) were combined with national agricultural survey to resolve uncertainties over possible restrictions to expansion following 20th‐century intensification. The grain legumes, peas and beans for animal and human consumption, were found to occupy six crop‐grass systems covering a wide range of agronomic input and geographical location. The phase of agricultural intensification between 1950 and 1990 had widened rather than restricted the systems in which they occur and could expand. Moreover, the diversity of the crop‐grass systems provides scope for complementary expansion of several products such as beans for aquaculture, pulses for human consumption, and peas for stockfeed without diminishing the areas of the most profitable crops. Among crop systems, N inputs following 20% legume inclusion would fall from the current 178 to 140 kg/ha (78.6%) at the high‐input end of the range and from 92 to 71 kg/ha (77.0%) at the low‐input end. Further reductions to 50%–60% of the existing N input to intensive crop sequences were estimated assuming a residual fixed nitrogen of 50–75 kg/ha and legume inclusion of 33%. Legume expansion would also bring a range of environmental benefits across all crop‐grass systems. While analysis using IACS brought many insights, major limitations to estimating national N‐balances were identified in lack of data on residual N following legumes, in imported animal feed and in the contribution of forage legumes to grassland. [ABSTRACT FROM AUTHOR]

The long-term sustainability of crop production depends on the complex network of interactions and trade-offs between biotic, abiotic and economic components of agroecosystems. An integrated arable management system was designed to maintain yields, whilst enhancing biodiversity and minimising environmental impact. Management interventions included conservation tillage and organic matter incorporation for soil biophysical health, reduced crop protection inputs and integrated pest management strategies for enhanced biodiversity and ecosystem functions, and intercropping, cover cropping and under-sowing to achieve more sustainable nutrient management. This system was compared directly with standard commercial practice in a split-field experimental design over a six-year crop rotation. The effect of the cropping treatment was assessed according to the responses of a suite of indicators, which were used to parameterise a qualitative multi-attribute model. Scenarios were run to test whether the integrated cropping system achieved greater levels of overall sustainability relative to standard commercial practice. Overall sustainability was rated high for both integrated and conventional management of bean, barley and wheat crops. Winter oilseed crops scored medium for both cropping systems and potatoes scored very low under standard management but achieved a medium level of sustainability with integrated management. In general, high scores for environmental sustainability in integrated cropping systems were offset by low scores for economic sustainability relative to standard commercial practice. This case study demonstrates the value of a 'whole cropping systems' approach using qualitative multi-attribute modelling for the assessment of existing cropping systems and for predicting the likely impact of new management interventions on arable sustainability. [ABSTRACT FROM AUTHOR]

Background: There is an urgent need to ensure that food production is maintained in response to either a reduction in use or lack of availability of natural resources. To this end, several strategies have been investigated to determine which agronomic approaches may improve crop yields under conditions of reduced water and/or nutrients provision, with special attention upon nitrogen (N) and phosphorus (P). New technologies and practices have been developed for key commercial crops, such as tomatoes. However, few of these are widely adopted in the field and evidence of their value in this production setting is limited. Methods: This protocol sets out a systematic map methodology that aims to provide a coherent synthesis of the available evidence among the literature on the techniques and management approaches that may ensure the productivity of field-grown tomatoes under conditions of water-, N- and/or P-deficits, either as single or combined stresses. To conduct the literature search, a search strategy was produced to define the scope of the systematic map and to allow reproducibility of the approach. A list of published and unpublished sources of literature were selected and a preliminary trial identified best-fit-for-purpose search-terms and -strings. A literature screening process was set with consistency checks amongst reviewers at the title, abstract and full text screening stages. A series of eligibility criteria were defined to ensure objectivity and consistency in the selection of studies that are best suited to address the research question of the systematic map. In addition, a coding strategy was designed to set the means for meta-data extraction out from the literature for review. A drafted structured questionnaire will serve as the base for collating the meta-data to produce a database where variables will be queried for the evidence synthesis. This work is expected to inform stakeholders, researchers and policy makers regarding the extent and nature of the existing evidence base, and so serve as a basis by-which specific approaches may be highlighted as potential focal-areas in future. [ABSTRACT FROM AUTHOR]

The intensification of arable production since the 1950s has resulted in increases in yield but only at significant cost to the environment, raising serious concerns about long-term consequences for the sustainability of food production systems. While a range of policies and practices have been put in place to mitigate negative effects in terms of pollution, soil degradation and loss of biodiversity, their efficacy has not been properly quantified. Whole-system effects of management change are rarely studied and so trade-offs and conflicts between different components of the agricultural system are poorly understood. A long-term field platform was therefore established in which conventional arable management was compared with a low-input, integrated cropping system designed with the goal to maintain yields whilst enhancing biodiversity and minimizing environmental impact. Over the first rotation, only winter wheat yielded less under integrated management; yield was maintained for the remaining five crops (spring and winter barley, winter oilseed rape, potato and field beans), suggesting a negligible impact on economic returns. Beneficial broad-leaved weeds were significantly more abundant in the integrated management system across all crops whereas grass weeds showed no overall response to treatment. Soil carbon, pH and soil concentrations of the main plant growth-limiting macronutrients were enhanced under the integrated management system. The integrated system was therefore successful in meeting the goals to enhance biodiversity and reduce environmental impact without jeopardizing crop yields. [ABSTRACT FROM AUTHOR]