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Why are legume crops rare in Europe even though they grow well there? This opinion paper brings together concepts from crop physiology, classical economics and sociotechnical theory to address this question. It argues for increased focus on research and innovation on crop performance. The starting point is that trade policy no longer explains the marginalisation of legumes. A more recent premise that mutually supporting social, technical and agricultural factors have combined over time to establish and maintain the current cropping systems is also incomplete. However, these propositions have led to significant investment in research on niche value chains in the hope that these will combine within transition pathways to break through system incumbency that "locks out" legumes. It is argued here that this approach is incomplete for crops because the scaling up and agglomeration of niche processing and marketing activities does not improve the fundamental crop resource capture and conversion processes in the field upon which farm productivity depends. Reconsideration of some economic and crop physiological basics is required. Farmers aim to make rational decisions and to focus on what they do best. The principles behind international trade described in the 19th century and the fundamental biophysical crop‐level processes that were elucidated in the 1960s together explain the cropping choices many European farmers make. We need more focus on raising the on‐farm performance and competitiveness of the legume crops themselves and the farming systems in which they are grown. Efficient, productive legume crops are important also if we are to avoid a trade‐off between environmental gains in Europe and disbenefits elsewhere because of effects on global trade. [ABSTRACT FROM AUTHOR]

Climate change brings increasing attention to winter sowing of traditionally spring sown crops. Crop stand height, soil coverage, grain yield and yield components of six winter pea varieties and one spring pea variety were compared in eastern Austrian growing conditions in 2014 and 2015. Crop stands of winter pea were taller up to the end of May before they declined and crop stands of spring pea were taller from early June on. Winter pea covered the soil at least partly over winter and showed faster soil coverage in spring. At the end of May, just some weeks before harvest, spring pea attained equal soil coverage. Grain yield of winter pea was almost double that of spring pea due to higher pod density whereas spring pea produced more grains pod−1 than four out of six winter pea varieties and a higher thousand grain weight than all winter pea varieties. Consequently, grain density was higher for winter pea while the single pod yield was higher for spring pea. Growing winter peas in Central Europe might be a good strategy for increasing grain legume productivity and thereby European feed protein production. [ABSTRACT FROM AUTHOR]

The sustainability of an organic crop rotation frequently depends on the residual effects of legume pre-crops. However, the contribution of legumes varies considerably depending on their species as well as local soil and climatic conditions. This research aims to compare the pre-crop effects of traditional grain and forage legumes with those of soybean (Glycine max (L.) Merr.), which is not widespread in Europe latitude 55° due to climatic constrains, on the productivity of subsequent cereals. A three-year (2016-2018) crop rotation was investigated using four pre-crops: spring barley, spring barley intercropped with red clover, pea and soybean. The effect of pre-crops on grain yield and quality and chemical composition of subsequently grown spring wheat was explored. Nitrogen (N) content in grain and straw, mineral nitrogen (Nmin) content in the soil were measured, the carbon to nitrogen (C:N) ratio and net N balance were calculated. The rotation was repeated twice and the results showed that pea and soybean did not produce sufficient biomass and amount of fixed N to maintain a stable positive residual effect in both rotation replications. Under favourable conditions, pea derived 66.1 kg ha-1 N and soybean - 64.7 kg ha-1 N from the atmosphere, while red clover intercropped with spring barley produced 65.4-82.7 kg ha-1 N yearly. Most of the total N (Ntot) accumulated by pea and soybean plants, 69% and 80%, respectively, was removed with grain yield, while comparable percentages of N (59-68%) were left by the residues of red clover and spring barley mixture. As a result, the greatest effect on subsequently grown spring wheat was exerted by the mixture of spring barley and red clover (yield increase 354-1414 kg ha-1). Comparing grain legumes, only efficiently nodulated soybean produced a positive +20.6 kg ha-1 net N balance and increased the yield of spring wheat by 920 kg ha-1. Pea resulted in the negative net N balance and increased the yield of spring wheat by 534 kg ha-1. Mineral nitrogen in the soil increased under all legume pre-crops only in the second year of the crop rotation. [ABSTRACT FROM AUTHOR]

• Pea accumulated around 2.7 kg S Mg−1 seed yield and barley 3.1 kg S Mg−1 seed yield. • SHI of pea (0.63) has not been influenced by the cropping system (sole or intercrop). • Gypsum, kieserite, epsom salt showed effects on S concentration in pea, not on yield. • Pea in pure stands recovered significantly more S, than total pea-barley intercrop. • S accumulation of pea and barley is adapted to its S demand for adequate growth. With the aim of gaining a better understanding of the Sulphur (S) supply of pea (Pisum sativum L.) in pure stands and in mixed stands with barley (Hordeum vulgare L.), field trials were conducted at several sites in central Europe. The fertilizers gypsum, kieserite, elemental S (40 kg S ha−1) and the foliar fertilizer epsom salt (8.4 kg S ha−1) have been tested on long-term (>10 years) organically cultivated arable land in the years 2012 to 2014. The objectives of this study were to evaluate pea's capacity to acquire sulphur as a sole crop and as intercrop with barley. The present investigations suggest that S supply via the pedosphere and the atmosphere was obviously high enough for adequate S concentrations in the pea plants and therefore compensated the barleys competition for plant available S in the mixed stands. The study showed that pea and barley adjusted its S accumulation to its yield formation. Although the fertilization with gypsum and kieserite significantly increased S concentrations and narrowed the N:S ratios in pea, the yield did not rise significantly. An average N:S ratio in pea leaves at flowering of 15.6 and a corresponding S concentration of 0.29% in DM seemed to be adequate to cover the S requirement of pea. The sulphur harvest index (SHI) averaged 0.63 and has not been influenced by the cropping system (sole or mixed crop). The fertilizers gypsum, kieserite and epsom salt showed effects on S concentration in the pea plant, elemental S did not. The apparent recovery efficiency of S of gypsum, kieserite, epsom salt and elemental S was low with 5.7%, 4.5%, 8.2% and 0.1%. In summary, S fertilization does not currently appear to be necessary for pea seed yield level up to 4.1 Mg ha-1 under the tested environmental conditions. [ABSTRACT FROM AUTHOR]

Intercropping is a cropping practice with the potential to increase the sustainability of the agricultural systems. Field pea has been largely studied in intercrop with wheat and barley in Northern and Central Europe whereas much less research has been carried out in semiarid environments of Southern Europe. A two-year field experiment was conducted in Southern Italy with the aim to assess yields and yield components and N use of field pea and four different cereals – wheat, barley, oat and triticale – grown in additive and replacement intercrop. The cereal was the dominant partner in intercrop, strongly outcompeting pea. Cereal height and biomass yield and intercrop density affected yield component parameters of pea causing a severe reduction of number of pods per plant and death of pea plants. Pea yields were generally lower in intercrop than in sole crop. Consequently, nitrogen accumulation in intercrop and Land Equivalent Ratio (LER) N yields-based values resulted negatively affected. LER values were highest in barley-pea intercrops for both grain and straw nitrogen yields. Cereal grain and straw N content increased in intercrop compared to the sole crop while pea grain N content was reduced. The results of this study indicate that cereal-pea intercropping can be a way of improving the grain and straw quality of the intercropped cereal and reducing N inputs into agricultural systems compared with the sole cropping. The choice of the companion cereal and the intercrop density should, however, be carefully evaluated in drought-prone environments like those of Southern Europe. [ABSTRACT FROM AUTHOR]

Pea was a part of the everyday diet of the European hunter-gatherers at the end of the last Ice Age. The major criteria to determine the domestication in pea are non-dehiscent pods, larger seed size and smooth seed testa. Pea seeds were found among the earliest findings of cultivated crops at the site of Tell El-Kerkh, Syria, from 10th millennium BP. Along with cereals and lentil, pea has definitely become associated with the start of the 'agricultural revolution' in the Old World. Pea entered Europe in its southeast regions and progressed into its interior via Danube. Its distribution was rapid, since the available evidence reveals its presence in remote places at similar periods. The linguistic evidence supports the fact that pea had been present in nearly all regions of Europe. Most of European peoples have their own words denoting pea, meaning that it preceded the diversification of their own proto-languages. [ABSTRACT FROM AUTHOR]

Abstract: Cereal–legume intercrops are gaining increasing interest in Europe. Modelling, by taking into account the complexity of species interactions, can be a very useful tool to study such systems and to test new strategies in various soil and climatic conditions. The present work describes the adaptation of an intercrop model for pea–barley intercrops through the extrapolation of the STICS sole crop model and its parameterisation from experimental data recorded on sole crops. Several improvements have been added to the existing crop model to allow an inversion of dominance in height between species during the crop cycle and a trophic link between crop growth rate and the potential for N2 fixation. A 2-year dataset on pea and barley sole crops grown under non-limiting water conditions and with full crop protection was first used for calibration. The intercrop model was subsequently tested on experimental datasets of pea–barley intercrops grown under the same conditions as the sole crops. The intercrop experiments used to test the intercrop model differed in soil type, soil N supply and plant densities of each species. The development of the intercrop model through the extrapolation of the sole crop model and its parameterisation from experimental data recorded in sole crops allowed an accurate simulation of the interactions for nitrogen between intercropped species. The simulated crop growth, N accumulation and N2 fixation in intercrops were in agreement with the observations from the experimental dataset. Moreover the behaviour of the model was consistent with the general knowledge about those intercropping systems. However the simulation of competition for light needs to be improved, especially the simulation of height growth. A thorough validation on many data sets, independent of those used for parameterisation, is still required. This model needs to be tested under a wider range of situations and for other limiting factors than nitrogen occurring in low-input farming systems. [Copyright &y& Elsevier]

Didymella pinodella is the major pathogen of the pea root rot complex in Europe. This wide host range pathogen often asymptomatically colonizes its hosts, making the control strategies challenging. We developed a real-time PCR assay for the detection and quantification of D. pinodella based on the TEF-1 alpha gene sequence alignments. The assay was tested for specificity on a 54-isolate panel representing 35 fungal species and further validated in symptomatic and asymptomatic pea and wheat roots from greenhouse tests. The assay was highly consistent across separate qPCR reactions and had a quantification/detection limit of 3.1 pg of target DNA per reaction in plant tissue. Cross-reactions were observed with DNA extracts of five Didymella species. The risk of cross contamination, however, is low as the non-targets have not been associated with pea previously and they were amplified with at least 1000-fold lower sensitivity. Greenhouse inoculation tests revealed a high correlation between the pathogen DNA quantities in pea roots and pea root rot severity and biomass reduction. The assay also detected D. pinodella in asymptomatic wheat roots, which, despite the absence of visible root rot symptoms, caused wheat biomass reduction. This study provides new insights into the complex life style of D. pinodella and can assist in better understanding the pathogen survival and spread in the environment. [ABSTRACT FROM AUTHOR]

Industrialised agriculture is heavily reliant upon synthetic nitrogen fertilisers and imported protein feeds, posing environmental and food security challenges. Increasing the cultivation of leguminous crops that biologically fix nitrogen and provide high protein feed and food could help to address these challenges. We report on the innovative use of an important leguminous crop, pea (Pisum sativum L.), as a source of starch for alcohol (gin) production, yielding protein-rich animal feed as a co-product. We undertook life cycle assessment (LCA) to compare the environmental footprint of 1 L of packaged gin produced from either 1.43 kg of wheat grain or 2.42 kg of peas via fermentation and distillation into neutral spirit. Allocated environmental footprints for pea-gin were smaller than for wheat-gin across 12 of 14 environmental impact categories considered. Global warming, resource depletion, human toxicity, acidification and terrestrial eutrophication footprints were, respectively, 12%, 15%, 15%, 48% and 68% smaller, but direct land occupation was 112% greater, for pea-gin versus wheat-gin. Expansion of LCA boundaries indicated that co-products arising from the production of 1 L of wheat- or pea-gin could substitute up to 0.33 or 0.66 kg soybean animal feed, respectively, mitigating considerable greenhouse gas emissions associated with land clearing, cultivation, processing and transport of such feed. For pea-gin, this mitigation effect exceeds emissions from gin production and packaging, so that each L of bottled pea gin avoids 2.2 kg CO 2 eq. There is great potential to scale the use of legume starches in production of alcoholic beverages and biofuels, reducing dependence on Latin American soybean associated with deforestation and offering considerable global mitigation potential in terms of climate change and nutrient leakage - estimated at circa 439 Tg CO 2 eq. and 8.45 Tg N eq. annually., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)