Foulkes M.J.,University of Nottingham |
Slafer G.A.,University of Lleida |
Davies W.J.,Lancaster University |
Berry P.M.,ADAS High Mowthorpe |
And 6 more authors.
Journal of Experimental Botany | Year: 2011
A substantial increase in grain yield potential is required, along with better use of water and fertilizer, to ensure food security and environmental protection in future decades. For improvements in photosynthetic capacity to result in additional wheat yield, extra assimilates must be partitioned to developing spikes and grains and/or potential grain weight increased to accommodate the extra assimilates. At the same time, improvement in dry matter partitioning to spikes should ensure that it does not increase stem or root lodging. It is therefore crucial that improvements in structural and reproductive aspects of growth accompany increases in photosynthesis to enhance the net agronomic benefits of genetic modifications. In this article, six complementary approaches are proposed, namely: (i) optimizing developmental pattern to maximize spike fertility and grain number, (ii) optimizing spike growth to maximize grain number and dry matter harvest index, (iii) improving spike fertility through desensitizing floret abortion to environmental cues, (iv) improving potential grain size and grain filling, and (v) improving lodging resistance. Since many of the traits tackled in these approaches interact strongly, an integrative modelling approach is also proposed, to (vi) identify any trade-offs between key traits, hence to define target ideotypes in quantitative terms. The potential for genetic dissection of key traits via quantitative trait loci analysis is discussed for the efficient deployment of existing variation in breeding programmes. These proposals should maximize returns in food production from investments in increased crop biomass by increasing spike fertility, grain number per unit area and harvest index whilst optimizing the trade-offs with potential grain weight and lodging resistance. © 2010 The Author(s).
Thorman R.E.,ADAS Boxworth |
Fernanda-Aller M.,ADAS Wolverhampton |
Jackson D.R.,ADAS Wolverhampton
Atmospheric Environment | Year: 2014
We carried out four replicated field experiments to measure the impacts of immediate incorporation of solid manures on emissions of ammonia (NH3) and nitrous oxide (N2O). Four manures: cattle farmyard manure (FYM); pig FYM; layer manure and broiler manure were applied to the soil surface or immediately incorporated by mouldboard plough, disc or tine. Two of the experiments were carried out on a clay soil and two on a sandy soil to find out whether soil type interacted with incorporation technique to influence emissions of NH3 or N2O. Ammonia emissions were measured for 1 or 2 weeks while N2O emissions were measured for 60 days in one experiment and for a complete year in the other three experiments.Immediate incorporation by plough reduced NH3 emissions by c. 90% and by c. 60% by disc and tine (P<0.001). There was no effect of soil type on NH3 abatement efficiency by plough or tine but the disc was less effective on the coarse sandy soil.Cross-site analysis indicated no effect of incorporation by disc or tine on emissions of N2O-N after 60 days but incorporation by plough increased direct emissions of N2O-N compared with surface application of manure (P<0.001). Direct emissions of N2O-N, at c. 0.67% of total N applied, were substantially greater at the coarse-textured site than at the heavy clay site (0.04% of total N applied; P<0.001). The impact of incorporation on total annual direct emissions of N2O-N differed in the three experiments where emissions were measured for a full year. There was no effect of incorporation on N2O-N emissions in the first experiment on the clay soil, and in the second experiment at this site incorporation by plough or disc, but not tine, reduced direct emissions of N2O (P=0.006). However on the sandy soil direct emissions of N2O-N were increased when manures were incorporated by plough (P=0.002) but not when incorporated by disc or tine.These results confirm that immediate incorporation of solid manures by plough is the most effective means of reducing NH3 emissions following the application of solid manures. The results also indicate that immediate incorporation of solid manures to reduce NH3 emissions does not necessarily increase emissions of N2O. However, the impacts of immediate incorporation on emissions of N2O may be related to soil type with a greater possibility of emission increases on coarse sandy soils. © 2013 Elsevier Ltd.
Berry P.M.,ADAS High Mowthorpe |
Kindred D.R.,ADAS Boxworth |
Olesen J.E.,University of Aarhus |
Jorgensen L.N.,University of Aarhus |
Paveley N.D.,ADAS High Mowthorpe
Plant Pathology | Year: 2010
A method for calculating the effect of disease control on greenhouse gas (GHG) emissions associated with wheat production, reported previously, was developed further to account for effects of disease control on the amount of fertilizer nitrogen (N) which should be applied and on changes in land use. Data from nine randomized and replicated field experiments from the UK and Denmark showed that the economic optimum N input to winter wheat was greater if diseases were controlled by fungicides, than for untreated wheat. The GHGs associated with this additional N largely negated the benefit to emissions per tonne of grain resulting from disease control. However, the mean grain yield obtained without fungicide treatment was 6·71 t ha-1, compared to 8·88 t ha-1 with fungicide treatment, if N input was optimal for each situation. In the absence of disease control by fungicides, and assuming that the optimum N rate was used, an additional 481 kha of wheat would be required to maintain UK wheat production at the current level. If the additional land area came from converting temperate grassland to arable production, the GHG emissions caused by ploughing grassland would cause emissions to rise from 503 to 713 kg CO2e per tonne of grain produced. This would result in an additional 3·15 Mt CO2e per year to produce the typical UK annual production of 15 Mt. This analysis reinforces the importance of winning the 'arms race' against pathogen evolution towards fungicide insensitivity and virulence. © 2010 The Authors. Journal compilation © 2010 BSPP.
Grimmer M.K.,ADAS Boxworth |
van den Bosch F.,Rothamsted Research |
Powers S.J.,Rothamsted Research |
Paveley N.D.,ADAS High Mowthorpe
Pest Management Science | Year: 2014
BACKGROUND: In the European Union, assessments of resistance risk are required by the regulatory authorities for each fungicide product and are used to guide the extent of anti-resistance strategies. This paper reports an evaluation of a widely used 'risk matrix', to determine its predictive value. Sixty-seven unique cases of fungicide resistance in Europe were identified for testing the risk assessment scheme, where each case was the first occurrence of resistance in a pathogen species against a fungicide group. RESULTS: In most cases, high-, moderate- and low-risk categories for fungicide, pathogen and agronomic systems were each associated with significant differences in the number of years from fungicide introduction to the first detection of resistance (FDR time). The combined risk, calculated by multiplying the individual risk factors using the risk matrix, had useful predictive power (72.8% of FDR time variance accounted for VAF) for all fungicides, but only limited predictive power (25.8% VAF) for single-site acting fungicides (the predominant type). CONCLUSION: The resistance risk matrix has significant, but limited, predictive value. New fungicide modes of action, or pathogens that have become newly prevalent, cannot be assigned to risk categories until new methods of resistance risk assessment are developed. © 2013 Society of Chemical Industry.
Messelink G.J.,Wageningen UR Greenhouse Horticulture |
Bennison J.,ADAS Boxworth |
Alomar O.,IRTA - Institute of Agricultural-Alimentary Research and Technology |
Ingegno B.L.,University of Turin |
And 5 more authors.
BioControl | Year: 2014
Biological pest control in greenhouse crops is usually based on periodical releases of mass-produced natural enemies, and this method has been successfully applied for decades. However, in some cases there are shortcomings in pest control efficacy, which often can be attributed to the poor establishment of natural enemies. Their establishment and population numbers can be enhanced by providing additional resources, such as alternative food, prey, hosts, oviposition sites or shelters. Furthermore, natural enemy efficacy can be enhanced by using volatiles, adapting the greenhouse climate, avoiding pesticide side-effects and minimizing disrupting food web complexities. The special case of high value crops in a protected greenhouse environment offers tremendous opportunities to design and manage the system in ways that increase crop resilience to pest infestations. While we have outlined opportunities and tools to develop such systems, this review also identifies knowledge gaps, where additional research is needed to optimize these tools. © 2014 The Author(s).
Chadwick D.,Rothamsted Research |
Sommer S.,University of Southern Denmark |
Thorman R.,ADAS Boxworth |
Fangueiro D.,University of Lisbon |
And 3 more authors.
Animal Feed Science and Technology | Year: 2011
Slurry, farmyard manure and poultry manure are an inevitable consequence of livestock products generated from housed animals. These manures are recycled back to land for plants to use the nutrients they contain. However, since they contain inorganic N, microbially available sources of C and water, they provide the essential substrates required for the microbial production of N2O and CH4. These greenhouse gases can be produced and emitted at each stage of the 'manure management continuum', being the livestock building, manure stores, manure treatment and manure spreading to land. The contribution that manure management makes to total national agricultural emissions of N2O and CH4 vary, but can exceed 50% in countries reporting to the UNFCCC in 2009. On farm management decisions interact with environmental controls such as temperature and water availability of key microbial processes (i.e., nitrification, denitrification, methanogenesis, CH4 oxidation), affecting the magnitude of emissions from each stage of the manure management continuum. We review the current understanding of how manure management influences direct and indirect N2O emissions and CH4 emissions, introduce new data comparing direct N2O emissions following spreading of a range of manure types by different methods, and highlight some of the mitigations being considered by researchers and policy makers in developed and developing countries. This article is part of the special issue entitled: Greenhouse Gases in Animal Agriculture - Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors; K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson. © 2011 Elsevier B.V.
Wang J.,Rothamsted Research |
Cardenas L.M.,Rothamsted Research |
Misselbrook T.H.,Rothamsted Research |
Cuttle S.,Rothamsted Research |
And 2 more authors.
Environmental Pollution | Year: 2012
Grazed grassland systems are an important component of the global carbon cycle and also influence global climate change through their emissions of nitrous oxide and methane. However, there are huge uncertainties and challenges in the development and parameterisation of process-based models for grazed grassland systems because of the wide diversity of vegetation and impacts of grazing animals. A process-based biogeochemistry model, DeNitrification- DeComposition (DNDC), has been modified to describe N 2O emissions for the UK from regional conditions. This paper reports a new development of UK-DNDC in which the animal grazing practices were modified to track their contributions to the soil nitrogen (N) biogeochemistry. The new version of UK-DNDC was tested against datasets of N 2O fluxes measured at three contrasting field sites. The results showed that the responses of the model to changes in grazing parameters were generally in agreement with observations, showing that N 2O emissions increased as the grazing intensity increased. © 2011 Elsevier Ltd. All rights reserved.
Pask A.J.D.,University of Nottingham |
Sylvester-Bradley R.,ADAS Boxworth |
Jamieson P.D.,New Zealand Institute Of Crop and Food Research |
Foulkes M.J.,University of Nottingham
Field Crops Research | Year: 2012
To reduce crop N requirements without reducing productivity it will be important to identify and quantify the inessential N in crop canopies. Field experiments established in October 2005 and October 2006 at ADAS Terrington, UK, and in June 2006 at Lincoln, New Zealand, tested wide-ranging N levels applied to one variety of feed winter wheat. Amounts of structural, photosynthetic and reserve N (SN, PN and RN, respectively) were defined and measured in components of the crop canopy (leaf lamina, leaf sheath, true stem and ear/chaff and grain) at anthesis and harvest, and the amounts of N remobilised from the PN and RN pools were calculated. At anthesis, RN accumulated for all N treatments in all experiments, and accounted for 44% of above-ground N (AGN) in optimally fertilised crops. This RN was principally located in the true stem, but was observed in all crop components at non-limiting fertiliser N treatments. Post-anthesis, RN appeared to be remobilised in preference to PN, thereby contributing to the maintenance of green area during the grain-filling phase and photo-assimilate production. The efficiency of post-anthesis N remobilisation of true stem RN was low (48%) compared to chaff (56%), leaf sheath (61%) and leaf laminae (76%), and in well fertilised crops significant quantities of '. accumulation' RN remained in true stem at harvest. The accumulation of significant quantities of RN at anthesis, even with deficient N supplies, suggests that it has a functional role during the grain-filling phase of growth. As '. accumulation RN' does not contribute to either the quantity or quality of grain, it reduces N-utilisation efficiency (UTE). Potential to improve UTE exists through increasing RN use during grain-filling and reducing '. accumulation RN' in non-photosynthetic organs. © 2011 Elsevier B.V..
Lutman P.J.W.,Rothamsted Research |
Moss S.R.,Rothamsted Research |
Cook S.,ADAS Boxworth |
Welham S.J.,Rothamsted Research
Weed Research | Year: 2013
This study reviews 52 field experiments, mostly from the UK, studying the effects of cultivation techniques, sowing date, crop density and cultivar choice on Alopecurus myosuroides infestations in cereal crops. Where possible, a statistical meta-analysis has been used to calculate average responses to the various cultural practices and to estimate their variability. In 25 experiments, mouldboard ploughing prior to sowing winter cereals reduced A. myosuroides populations by an average of 69%, compared with non-inversion tillage. Delaying drilling from September to the end of October decreased weed plant densities by approximately 50%. Sowing wheat in spring achieved an 88% reduction in A. myosuroides plant densities compared with autumn sowing. Increasing winter wheat crop density above 100 plants m-2 had no effect on weed plant numbers, but reduced the number of heads m-2 by 15% for every additional increase in 100 crop plants, up to the highest density tested (350 wheat plants m-2). Choosing more competitive cultivars could decrease A. myosuroides heads m-2 by 22%. With all cultural practices, outcomes were highly variable and effects inconsistent. Farmers are more likely to adopt cultural measures and so reduce their reliance on herbicides, if there were better predictions of likely outcomes at the individual field level. © 2013 European Weed Research Society.
Sylvester-Bradley R.,ADAS Boxworth |
Riffkin P.,Australian Department of Primary Industries and Fisheries |
O'Leary G.,Australian Department of Primary Industries and Fisheries
Field Crops Research | Year: 2012
With the ultimate aim of developing a Crop Design Tool that will specify resource-efficient ideotypes for any environment, modelling procedures are proposed and tested here whereby wheat phenology can be optimised according to risks of abiotic damage (frost, heat and drought) to seedling establishment and grain set. Then crop growth can be estimated from availability of water and solar radiation, and optimum DM partitioning to grain can be specified by allocating a minimum of support dry matter (DM) to stems (to resist lodging), leaves (to optimise photosynthesis), and flowers (to bear grains).Ideotypes for reference regions (with mature wheat breeding programmes) of the Mallee and Wimmera in Victoria, the Canturbury plains in New Zealand and Norfolk in the UK gave estimated grain yields of 1.9, 3.0, 7.2 and 6.2tha-1 DM respectively, similar to those shown by current cultivars, but with earlier flowering and harvest dates, with heavier stems, and high redistribution of stem DM to grain. Ideotypes for five sites in the Australian High Rainfall Zone showed high grain yield potentials, ranging from 4.5tha-1 DM at Kojonup to 7.8tha-1 DM at Hamilton, allowing for yield loss due to abiotic stress. These were characterised by early stem extension and flowering dates but also by long crop construction periods (from the start of stem extension to anthesis) of 800-1100°Cd and increased harvest indices compared to cultivars currently adopted from other regions. The challenges in testing these ideotypes will be in finding germplasm that demonstrates unusual phenology with short stature, and growing these to maximise light interception in spring. The main uncertainties in the estimation procedures arose from poor quality wind data, a poorly quantified association between stem material density and stem strength, and lack of data on maximum capacity to store redistributable stem DM. Sensitivity analysis showed grain yields of ideotypes to depend on maximum wind gusts during grain production as well as on plant-available water. The most effective single means of increasing potential grain yields was predicted clearly to be through increasing the conversion of radiation to DM. © 2011 Elsevier B.V.