The effect of organic and conventional management on the yield and quality of wheat grown in a long-term field trial

The performance of winter wheat was evaluated under organic (ORG) and conventional (CON) management systems in the Nafferton Factorial Systems Comparison (NFSC) long-term field trial. The present study separates out the crop protection and fertility management components of organic and conventional production systems using two levels each of crop protection (CP) and fertility management (FM). The experimental design provided the four combinations of crop protection and fertility (CON-CP CONFM, CON-CP ORG-FM, ORG-CP CON-FM and ORG-CP ORG-FM) to evaluate their effects on yield, quality (protein content and hectolitre weight) and disease levels during the period 2004–2008. The conventional management system (CON-CP CON-FM) out-yielded the organic management system (ORG-CP ORG-FM) in all years by an average of 3.1 t ha−1, i.e. 7.9 t ha−1 vs. 4.8 t ha−1. Fertility management was the key factor identified limiting both yield and grain protein content in the ORG management system. The CON-FM produced on average a 3% higher protein content than ORG-FM in all years (12.5% vs. 9.7%). However the ORG-CP system produced higher protein levels than CON-CP although it was only in 2008 that this was statistically significant. In contrast to protein content it was ORG-FM which produced a higher hectolitre weight than the CON-FM system (71.6 kg hl−1 vs. 71.0 kg hl−1). The clear and significant differences in yield and protein content between the ORG-FM and CON-FM systems suggest a limited supply of available N in the organic fertility management system which is also supported by the significant interaction effect of the preceding crop on protein content. The pRDA showed that although fertilisation had the greatest effect on yield, quality and disease there was also a considerable effect of crop protection and the environment

The influence of organic and conventional fertilisation and crop protection practices, preceding crop, harvest year and weather conditions on yield and quality of potato (Solanum tuberosum) in a long-term management trial

The effects of organic versus conventional crop management practices (fertilisation, crop protection) and preceding crop on potato tuber yield (total, marketable, tuber size grade distribution) and quality (proportion of diseased, green and damaged tubers, tuber macro-nutrient concentrations) parameters were investigated over six years (2004–2009) as part of a long-term factorial field trial in North East England. Inter-year variability (the effects of weather and preceding crop) was observed to have a profound effect on yields and quality parameters, and this variability was greater in organic fertility systems. Total and marketable yields were significantly reduced by the use of both organic crop protection and fertility management. However, the yield gap between organic and conventional fertilisation regimes was greater and more variable than that between crop protection practices. This appears to be attributable mainly to lower and less predictable nitrogen supply in organically fertilised crops. Increased incidence of late blight in organic crop protection systems only occurred when conventional fertilisation was applied. In organically fertilised crops yield was significantly higher following grass/red clover leys than winter wheat, but there was no pre-crop effect in conventionally fertilised crops. The results highlight that nitrogen supply from organic fertilisers rather than inefficient pest and disease control may be the major limiting factor for yields in organic potato production systems

Increasing grain selenium concentration via genetic and agronomic innovations.

Aims: To evaluate the potential to enhance grain Selenium (Se) concentration in wheat through agronomic innovation practices and exploitation of existing genetic variation. Methods: Grain samples from eld experiments carried out as part of the EU projects Nitrogen Use Eciency (NUE- CROPS), Healthy Minor Cereals (HMC) and Quality Low Input Food (QLIF) were analysed to identify the effects of wheat species/variety, fertiliser type and crop protection regime on grain yield, grain protein and selenium concentrations. Results: Fertiliser type signicantly affected grain Se concentration. In the NUE-CROPS and QLIF trials the use of farm-yard manure (FYM) resulted in signicantly higher grain Se concentration when compared with mineral fertiliser applied at the same N input level. Similarly, in the HMC trial, FYM and cattle slurry resulted in a signicantly higher grain Se concentration compared with biogas digestate and mineral fertiliser. In the QLIF trials, organic crop protection resulted in signicantly higher grain Se concentration when compared with conventional crop protection. The NUE-CROPS and HMC trials detected signicant differences between varieties of both common wheat ( Triticum aestivum) and spelt ( T. spelta). Correlation analyses across the trials identied a negative correlation between yield and grain Se concentration for spelt and positive correlation between plant height and Se concentration for both species. Conclusions: Higher Se concentrations in the taller spelt varieties suggest that there is considerable potential to breed/select for high grain Se by exploiting traits/genetic variation present in older, traditional wheat species (e.g. spelt)

Benzoxazinoids in wheat allelopathy – From discovery to application for sustainable weed management

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGAllelopathic activity of wheat (Triticum aestivum L.) has previously been associated with the production of phenolic acids and flavonoids (PAF), benzoxazinones (BXZs) and phenoxazinones (PXZs). The biosynthesis of BXZs is closely regulated during cereal growth, with accumulation highest in young tissues with variation associated with genotype and environmental conditions. This review is focused on BXZ metabolites and their impact on germination, seedling growth and physiological, biochemical, transcriptional and proteome traits of surrounding plants and weeds. The major pathways employed by plants for benzoxazinoid detoxification involve hydroxylation and glucosylation and polymerisation of intermediates in these pathways. Allelochemicals from various wheat genotypes have been shown to inhibit the growth of selected weed species, including Bromus japonicus, Chenopodium album, Portulaca oleracea, Avena fatua and Lolium rigidum. Wheat allelopathy is potentially exploited from the standpoint of crop mulches, incorporation of crop residues, tissue disruption, intercropping with allelopathic cultivars and application of aqueous wheat extracts. BXZs have been shown to suppress the growth and development of certain agricultural pests, including insects, fungal pathogens, and weeds. Many native plants, fungi and insect herbivores inherently possess varying tolerance levels towards BXZs. However, other BXZ- susceptible species are adversely impacted by elevated BXZ levels in crop plants. Thus, considerations for the selection and breeding of wheat genotypes possessing enhanced defensive ability via elevated BXZ contents are discussed. Here, these objectives are reconsidered with a focus on co-evolutionary aspects and their potential impacts on biodiversity in the agroecosystems under study. For future breeding efforts to be successful, it is important to take such potential adverse environmental impacts into account, in combination with an increased focus on enhancing beneficial allelopathic effects within agricultural systems

Plant genetic resources and their use in organic agriculture

Organic agriculture and plant genetic resources are closely related topics, as organic farming relies on the conservation and use of diverse and adapted varieties of crops. Plant genetic resources are the raw materials that can help improve the productivity and quality of organic agriculture, as well as enhance its resilience to environmental stresses and pests. Organic agriculture also contributes to the in-situ conservation of plant genetic resources by maintaining and selecting local varieties that have a high degree of genetic variability. An important goal of the ECOBREED project is to identify genetic and phenotypic variations for morphological, abiotic/biotic tolerances/resistance and nutritional quality traits that can be used in organic breeding. The first step to achieve this goal was to make the inventory of available genotypes of four crops: wheat, potato, soybean, and buckwheat. For this purpose, we have examined genetic resources of four crops stored in gene banks, used in previous European and national research projects, and available through plant breeding programmes and seed companies. We have also used agronomic data on available and used varieties in organic farming, varieties characterized by good disease resistance and quality. Selected 200 wheat genotypes originate from 12 different European countries, 197 potato accessions were identified from several databases, the list contains 242 soybean accessions that originated all around the world and of buckwheat were identified through international databases. Much of the material represents cultivars that were released in the last two decades and are included in either the European list or national lists

Improving Crop Health, Performance, and Quality in Organic Spring Wheat Production: The Need to Understand Interactions between Pedoclimatic Conditions, Variety, and Fertilization

Organic wheat production systems have lower yields compared with intensive conventional production and often do not achieve the grain protein content and quality thresholds set by millers and bakers. In contrast, organic production methods were reported to result in higher concentrations of nutritionally desirable micronutrients and lower concentrations of the toxic metal Cd in wheat grain and wholegrain flour. However, although N-availability and variety characteristics are known to affect both gain yields and bread-making quality, the exact reasons for the yield gap and differences in grain processing and nutritional quality between organic and conventional spring wheat production in the UK are poorly understood. The overall aim of this study was therefore to determine to what extent changes in variety choice and fertilization regimes may reduce the yield gap and improve processing quality without affecting nutritional quality in organic spring wheat production. To achieve this aim, we compared crop health, yield, grain processing, and nutritional quality parameters in spring wheat produced using (i) six contrasting spring wheat varieties grown with a standard fertilization regime and (ii) one variety widely used by organic farmers (Paragon) with nine different fertilization regimes in (iii) three UK sites/farms with contrasting pedoclimatic conditions. Significant differences in foliar disease severity, grain yield, and quality parameters were detected between six contrasting spring wheat varieties when grown under organic management regimes. Specifically, the varieties Paragon and Tybalt were identified as the best-performing varieties with respect to foliar disease resistance and grain yield under organic farming conditions and also produced high processing and nutritional quality across the three UK sites. However, the highest grain yields were obtained by Paragon at the Gilchester site and Tybalt at the Sheepdrove and Courtyard sites, while the highest protein contents were produced by Tybalt at the Gilchester site and Paragon at the Sheepdrove and Courtyard sites, which suggests that there is a need for site-specific wheat variety selection in the UK organic sector. Although organic fertilizer input type and level also affected wheat performance, differences between fertilization regimes were smaller than those observed between the five contrasting varieties, which suggests that improvements in spring wheat breeding/selection have a greater potential for increasing crop yield and quality in the organic sector compared with changes to fertilization practices. Overall, results suggest it is feasible to breed/select spring wheat varieties that combine high protein, vitamin E, and micronutrients with low toxic metal (Cd, Pb) concentrations when produced under organic farming conditions. These findings also support the hypothesis that differences in variety choice by organic and conventional farmers have contributed to the differences in nutritional quality between organic and conventional wheat products reported in previous studies

Disruption, not displacement: Environmental variability and temporary migration in Bangladesh

Mass migration is one of the most concerning potential outcomes of global climate change. Recent research into environmentally induced migration suggests that relationship is much more complicated than originally posited by the ‘environmental refugee’ hypothesis. Climate change is likely to increase migration in some cases and reduce it in others, and these movements will more often be temporary and short term than permanent and long term. However, few large-sample studies have examined the evolution of temporary migration under changing environmental conditions. To address this gap, we measure the extent to which temperature, precipitation, and flooding can predict temporary migration in Matlab, Bangladesh. Our analysis incorporates high-frequency demographic surveillance data, a discrete time event history approach, and a range of sociodemographic and contextual controls. This approach reveals that migration declines immediately after flooding but quickly returns to normal. In contrast, optimal precipitation and high temperatures have sustained positive effects on temporary migration that persist over one to two year periods. Building on previous studies of long-term migration, these results challenge the common assumption that flooding, precipitation extremes and high temperatures will consistently increase temporary migration. Instead, our results are consistent with a livelihoods interpretation of environmental migration in which households draw on a range of strategies to cope with environmental variability

Changes in growth and gene expression induced by sulphur deficiency in garlic

Sulfur deficiency in garlic Allium sativum L. caused a reduction in growth together with chlorosis and necrosis of leaves. Large differences in shoot sulfur and sulphate concentrations between deficient and high sulfur treatments were only observed after 54 days growth. Using the mRNA differential display technique, a novel cDNA was isolated from shoots grown in sulfur depleted nutrient solution for 24 days. This novel cDNA was constitutively expressed in the shoots during further growth in sulfur depleted solution, but it was undetectable following 30 days recovery with sulfur supplementation. The cDNA sequence demonstrated a high degree of identity with a coat protein gene of a garlic latent carlavirus. The results suggest a possible relationship between low plant sulfur status and the induction of a latent carlavirus in garlic