Evaluating alternative fertilisers and their impact on yield and quality of spelt and rye under different management systems

PhD ThesisSpelt (Triticum spelta) and rye (Secale cereale) are low-input cereals attracting growing interest as sustainable and nutritionally beneficial alternatives to modern wheat (Triticum aestivum). The effects of fertiliser type, fertiliser rate and variety choice on spelt and rye crop yield and quality were assessed in single-site field trials in the 2014-15 and 2015-16 seasons. The multi-factorial trials at Nafferton Farm in Northumberland evaluated four varieties (including both landraces and modern varieties) each of spelt and rye grown with four fertiliser N input types (farm yard manure compost, cattle slurry, mineral N and biogas digestate) at two rates of N (50 and 100 kg/ha). Farmer Participatory trials took place across 10 farms (4 conventional and 6 organic) in Northeast England during the 2016-17 and 2017-18 seasons. The same four varieties of spelt and rye were evaluated under individual farm management systems and two fertiliser input types (biogas digestate and ‘typical’ farm inputs). Data collection was supported by the creation of an online database and web platform for data recording and subsequent statistical analysis. In the Nafferton field trials, biogas digestate was the highest yielding fertiliser treatment for spelt (3.64 t/ha) while digestate (5.27t/ha) and mineral N (5.21 t/ha) were the highest yielding N treatments for rye. Yields were significantly higher for both crops in 2015 (spelt: 3.60t/ha; rye: 5.74t/ha) compared to 2016 (spelt: 2.86 t/ha; rye: 3.74t/ha) due to higher solar radiation from April to July. The highest yielding varieties were the spelt landrace Oberkulmer Rotkorn (3.74 t/ha) and the modern rye variety Elias (5.59 t/ha). Rye was not susceptible to foliar disease but yellow rust was present in the spelt and was significantly higher in the spelt x wheat cross Filderstolz. Grain quality parameters (Hagberg Falling Number, specific weight and protein content) varied significantly by variety and year. In the Farmer Participatory trial, conventional farms (spelt: 3.15t/ha; rye: 3.68t/ha) produced higher yields than organic farms (spelt: 2.18t/ha; rye: 2.23t/ha). Biogas digestate inputs produced higher yields (spelt: 2.68t/ha; rye: 3.70t/ha) than typical farm inputs on both organic and conventional farms. Oberkulmer Rotkorn (2.72t/ha) and Elias (3.76t/ha) were the highest yielding spelt and rye varieties in the multi-site trial. Across both the factorial field trial and Farmer-Participatory trial, the same spelt (Oberkulmer Rotkorn) and rye (Elias) varieties produced the highest yields while biogas digestate produced higher yields than all other fertiliser inputs except mineral N

Nutritional benefits from fatty acids in organic and grass-fed beef

Livestock production is under increasing scrutiny as a component of the food supply chain with a large impact on green-house gas emissions. Amidst growing calls to reduce industrial ruminant production, there is room to consider differences in meat quality and nutritional benefits of or-ganic and/or pasture-based management systems. Access to forage, whether fresh or conserved, is a key influencing factor for meat fatty acid profile, and there is increasing evidence that pasture access is particularly beneficial for meat’s nutritional quality. These composition differences ul-timately impact nutrient supply to consumers of conventional, organic and grass-fed meat. For this review, predicted fatty acid supply from three consumption scenarios were modelled: i. average UK population National Diet and Nutrition Survey (NDNS) (<128 g/week) red meat consumption, ii. red meat consumption suggested by the UK National Health Service (NHS) (<490 g/week) and iii. red meat consumption suggested by the Eat Lancet Report (<98 g/week). The results indicate average consumers would receive more of the beneficial fatty acids for human health (especially the essential omega-3, alpha-linolenic acid) from pasture-fed beef; produced either organically or conventionally

Milk Fatty Acids: The Impact of Grazing Diverse Pasture and the Potential to Predict Rumen-Derived Methane

The sustainability of dairying has been questioned, yet cattle exploit non-food resources (especially forages) and provide key nutrients for consumers’ health. This study, using different forage types, considered milk’s nutritional quality, focusing on fatty acid profiles alongside methane emissions—investigating whether methane can be predicted from milk fatty acids (FAs). Compared with grass/clover/maize silage, cows grazing grass/clover pasture produced milk 70% higher in beneficial omega-3 FAs, which increased by an additional 15% when grazing more diverse pasture. Milk from grazing also had less omega-6 FAs (compared with silage diets), and their ratio with omega-3 FAs fell from 2.5:1 on silage to 1.2:1 when grazing grass/clover and 1.1:1 on diverse pasture. Measured methane emissions (at 8.7 g/kg energy-corrected milk) were lower than published values, and existing models for estimating methane from lactating cows were poor predictors for this dataset. The multiple regression of methane against milk FAs in this study provided predictions with an R2 of 0.56 for daily emissions and 0.65 relative to milk output. Grazing quality and a diverse pasture with productive cows were potentially beneficial to milk nutritional quality, and our results reinforce the theory that milk fat composition could be an accessible tool for methane prediction; however, they also suggest that more work is needed for alternative production systems

Milk Fatty Acids : The Impact of Grazing Diverse Pasture and the Potential to Predict Rumen-Derived Methane

The sustainability of dairying has been questioned, yet cattle exploit non-food resources (especially forages) and provide key nutrients for consumers’ health. This study, using different forage types, considered milk’s nutritional quality, focusing on fatty acid profiles alongside methane emissions—investigating whether methane can be predicted from milk fatty acids (FAs). Compared with grass/clover/maize silage, cows grazing grass/clover pasture produced milk 70% higher in beneficial omega-3 FAs, which increased by an additional 15% when grazing more diverse pasture. Milk from grazing also had less omega-6 FAs (compared with silage diets), and their ratio with omega-3 FAs fell from 2.5:1 on silage to 1.2:1 when grazing grass/clover and 1.1:1 on diverse pasture. Measured methane emissions (at 8.7 g/kg energy-corrected milk) were lower than published values, and existing models for estimating methane from lactating cows were poor predictors for this dataset. The multiple regression of methane against milk FAs in this study provided predictions with an R2 of 0.56 for daily emissions and 0.65 relative to milk output. Grazing quality and a diverse pasture with productive cows were potentially beneficial to milk nutritional quality, and our results reinforce the theory that milk fat composition could be an accessible tool for methane prediction; however, they also suggest that more work is needed for alternative production systems

Evaluating the effect of agronomic management practices on the performance of differing spelt (Triticum spelta) cultivars in contrasting environments

Spelt (Triticum spelta) is an ancient wheat which is attracting renewed interest with an increasing demand for wholegrains and ancient cereals in the diet. This study evaluates the yield and quality performance of four contrasting European spelt varieties (both landraces and modern cultivars) grown with different fertiliser types (cattle slurry, farm yard manure, and biogas digestate in comparison with mineral N) and rates (50 and 100 kg N ha−1) in contrasting environments, i.e. the UK and CZ in the 2014−15 and 2015−16 seasons. Grain yield was similar in both seasons but was greater in CZ than the UK (4.9 vs 3.2 t ha−1) which was also supported by a much greater harvest index (HI) of 40.4 vs 31.3 % and all yield components measured. The yield differences were largely related to differences in climate and disease levels, i.e. leaf blotch (S. tritici) and yellow rust (Puccinia striiformis), which were much greater in the UK. Clear varietal differences were evident between the two sites especially in susceptibility to yellow rust. Leaf chlorophyll data showed that the uptake efficiency of the biogas digestate was similar to that of mineral N resulting in greater grain yield when averaged across sites and seasons. Significantly lower levels of yellow rust were observed under the biogas digestate treatment in the UK relative to the other fertiliser types. Clear genotype (G) x environment (E) interactions show the benefits of selecting spelt varieties suited to particular environments. Although yields of spelt are lower than common wheat, the crop benefits from lower inputs of fertiliser and the use of biogas digestate where available can provide a clear opportunity for organic and reduced input growers. The ability of the crop to produce a high grain protein content from low levels of fertiliser input shows the clear potential of spelt production systems whereby wheat in the UK struggles to achieve13 % protein from much greater rates of N fertiliser

Evaluating the effect of nitrogen fertilizer rate and source on the performance of open-pollinated rye (Secale cereale L.) cultivars in contrasting European environments

Rye (Secale cereale L.) is a minor cereal with potential to support sustainable farming practices. This study evaluated the performance of four old and modern European open-pollinated winter rye cultivars grown with different nitrogen (N) sources (cattle slurry, farmyard manure, biogas digestate, mineral N) at two rates of N 50 and 100 kg ha−1 in the United Kingdom and Estonia, in the 2014–2015 and 2015–2016 growing seasons. Grain yield in Estonia was higher than the United Kingdom (6.2 vs. 4.8 t ha−1), which was attributed to a higher ear density (409.4 vs. 249.7 ears m−2) and grain number per ear (50.2 vs. 43.2), although 1,000-grain weight was higher in the United Kingdom. There were clear differences between sites in the response to N source with significant N source × year interactions. Biogas digestate and mineral N produced higher grain yield than farmyard manure and cattle slurry in the United Kingdom, whereas in Estonia cattle slurry had a lower grain yield than the other N sources. Foliar diseases were absent in Estonia and in the United Kingdom, and N source only affected powdery mildew and leaf blotch on Leaf 2. The response of grain quality to N source and variety was consistent across both sites. The modern variety Elias had the highest Hagberg falling number and specific weight but the lowest protein content, whereas the variety Schlägler had the highest protein content but lowest specific weight. The benefits of selecting cultivars for specific environments are shown by the interactions between genotype and environment

Diet, but not food type, significantly affects micronutrient and toxic metal profiles in urine and/or plasma; a randomized, controlled intervention trial

Background: Observational studies have linked Mediterranean Diets (MedDiets) and organic food consumption with positive health outcomes, which may be explained by higher mineral micronutrient and phenolic intake and lower dietary exposure to toxic compounds. Objectives: We aimed to determine the effects of diet and food type (organic compared with conventional) on urinary excretion (UE) and/or plasma concentrations of mineral micronutrients, phenolics, and toxic metals. Methods: Healthy adult participants were randomly allocated to a conventional (n = 14) or an intervention (n = 13) group. During a 2-wk period, the intervention group consumed a MedDiet made entirely from organic foods, whereas the conventional group consumed a MedDiet made from conventional foods. Before and after the intervention period, both groups consumed their habitual Western diets made from conventional foods. The primary outcome was UE and/or plasma concentrations of selected mineral micronutrients, toxic metals, and phenolic markers. In addition, we monitored diets using food diaries. The participants were aware of study group assignment, but the study assessors were not. Results: Changing from a Western Diet to a MedDiet for 2 wk resulted in significant increases in UE of total phenolics and salicylic acid (by 46% and 45%, respectively), the mineral micronutrients Co, I, and Mn (by 211%, 70%, and 102%, respectively), and the toxic metal Ni (by 42%), and plasma Se concentrations (by 14%). However, no significant effects of food type (organic compared with conventional) were detected. Redundancy analysis identified vegetables, coffee, wine, and fruit as positive drivers for UE of phenolic markers and mineral micronutrients, and fish consumption as a positive driver for UE of Cd and Pb. Conclusions: Although small effects of food type cannot be ruled out, our study suggests that only changing to a MedDiet with higher fruit and vegetable, and lower meat, consumption results in a large increase in phenolic and mineral micronutrient intakes. This trial was registered at clinicaltrials.gov as NCT03254537

Diet, but not food type, significantly affects micronutrient and toxic metal profiles in urine and/or plasma; a randomized, controlled intervention trial

ABSTRACT Background Observational studies have linked Mediterranean Diets (MedDiets) and organic food consumption with positive health outcomes, which may be explained by higher mineral micronutrient and phenolic intake and lower dietary exposure to toxic compounds. Objectives We aimed to determine the effects of diet and food type (organic compared with conventional) on urinary excretion (UE) and/or plasma concentrations of mineral micronutrients, phenolics, and toxic metals. Methods Healthy adult participants were randomly allocated to a conventional (n = 14) or an intervention (n = 13) group. During a 2-wk period, the intervention group consumed a MedDiet made entirely from organic foods, whereas the conventional group consumed a MedDiet made from conventional foods. Before and after the intervention period, both groups consumed their habitual Western diets made from conventional foods. The primary outcome was UE and/or plasma concentrations of selected mineral micronutrients, toxic metals, and phenolic markers. In addition, we monitored diets using food diaries. The participants were aware of study group assignment, but the study assessors were not. Results Changing from a Western Diet to a MedDiet for 2 wk resulted in significant increases in UE of total phenolics and salicylic acid (by 46% and 45%, respectively), the mineral micronutrients Co, I, and Mn (by 211%, 70%, and 102%, respectively), and the toxic metal Ni (by 42%), and plasma Se concentrations (by 14%). However, no significant effects of food type (organic compared with conventional) were detected. Redundancy analysis identified vegetables, coffee, wine, and fruit as positive drivers for UE of phenolic markers and mineral micronutrients, and fish consumption as a positive driver for UE of Cd and Pb. Conclusions Although small effects of food type cannot be ruled out, our study suggests that only changing to a MedDiet with higher fruit and vegetable, and lower meat, consumption results in a large increase in phenolic and mineral micronutrient intakes. This trial was registered at clinicaltrials.gov as NCT03254537

Diet and food type affect urinary pesticide residue excretion profiles in healthy individuals: results of a randomized controlled dietary intervention trial

Background Observational studies have linked pesticide exposure to various diseases, whereas organic food consumption has been associated with positive health outcomes. Organic farming standards prohibit the use of most pesticides, and organic food consumption may therefore reduce pesticide exposure. Objectives To determine the effects of diet (Western compared with Mediterranean) and food type (conventional compared with organic) and sex on urinary pesticide residue excretion (UPRE), as well as associations between specific diet components and UPRE. Methods In this 2-wk, randomized dietary intervention trial, healthy adults were randomly allocated to an intervention (n = 13) or conventional (n = 14) group. Whereas participants in the intervention group consumed a Mediterranean diet (MedDiet) made entirely from organic foods, the conventional group consumed a MedDiet made entirely from conventional foods. Both groups consumed habitual Western diets made from conventional foods before and after the 2-wk intervention period. The primary outcome was UPRE. In addition, we assessed diet composition and pesticide residue profiles in foods eaten. Participants were aware of group assignment, but the study assessors were not. Results During the intervention period, total UPRE was 91% lower with organic (mean 17 μg/d; 95% CI: 15, 19) than with conventional (mean 180 μg/d; 95% CI: 153, 208) food consumption (P < 0.0001). In the conventional group, switching from the habitual Western diet to the MedDiet increased insecticide excretion from 7 to 25 μg/d (P < 0.0001), organophosphate excretion from 5 to 19 μg/d (P < 0.0001), and pyrethroid residue excretion from 2.0 to 4.5 μg/d (P < 0.0001). Small but significant effects of sex were detected for chlormequat, herbicide, and total pesticide residue excretion. Conclusions Changing from a habitual Western diet to a MedDiet was associated with increased insecticide, organophosphate, and pyrethroid exposure, whereas organic food consumption reduced exposure to all groups of synthetic chemical pesticides. This may explain the positive health outcomes linked to organic food consumption in observational studies. This trial was registered at www.clinicaltrials.gov as NCT03254537

Integrated soil and crop management in organic agriculture: A logical framework to ensure food quality and human health?

The environmental and biodiversity benefits of organic farming are widely recognized, but there is still controversy about the effects of organic production methods on the nutritional composition of food and human health. In the first part of this article therefore, we critically review the evidence that organic farming methods improve the nutritional quality of food crops. Moreover, we summarize our current understanding of how quality gains are linked to the implementation of the “innovations” introduced into conventional crop production during the intensification or “green revolution” of agriculture over the last 100 years. In the second part of the article, we critically review the evidence for the range of health benefits related to organic food consumption. Specifically, we describe and discuss the results from: (i) dietary intervention studies which have found that organic food consumption substantially reduces pesticide exposure in humans and affects feed intake, growth, hormone balances and immune system responsiveness in animal models; (ii) human cohort/epidemiological studies which have reported significant positive associations between organic food consumption and the lower incidence of a range of diseases including obesity, metabolic syndrome, cancer, hypospadias, pre-eclampsia, eczema and middle ear infections in infants; (iii) interactions and trade-offs between diet (e.g., whole-grain, fruit and vegetables and reduced red-meat consumption) and food types (organic versus conventional) concerning public health and future food security. The article also identifies knowledge gaps and highlights the need for (i) long-term, factorial field experiments to understand the relative effects of agronomic and pedoclimatic drivers on crop quality and safety, and (ii) clinical trials and additional human cohort studies to confirm the positive health outcomes linked to organic food consumption. The main conclusions from our review are that there is growing evidence that (i) agricultural intensification has resulted in a reduction in the nutritional quality of food and the sustainability of food production, and (ii) organic farming practices not only improve food quality and human health, but also food security. This is particularly true where current nutritional guidelines (increasing whole-grain, fruit and vegetable products, while reducing red-meat consumption) are implemented