Using numerical plant models and phenotypic correlation space to design achievable ideotypes

Numerical plant models can predict the outcome of plant traits modifications resulting from genetic variations, on plant performance, by simulating physiological processes and their interaction with the environment. Optimization methods complement those models to design ideotypes, i.e. ideal values of a set of plant traits resulting in optimal adaptation for given combinations of environment and management, mainly through the maximization of a performance criteria (e.g. yield, light interception). As use of simulation models gains momentum in plant breeding, numerical experiments must be carefully engineered to provide accurate and attainable results, rooting them in biological reality. Here, we propose a multi-objective optimization formulation that includes a metric of performance, returned by the numerical model, and a metric of feasibility, accounting for correlations between traits based on field observations. We applied this approach to two contrasting models: a process-based crop model of sunflower and a functional-structural plant model of apple trees. In both cases, the method successfully characterized key plant traits and identified a continuum of optimal solutions, ranging from the most feasible to the most efficient. The present study thus provides successful proof of concept for this enhanced modeling approach, which identified paths for desirable trait modification, including direction and intensity.Comment: 25 pages, 5 figures, 2017, Plant, Cell and Environmen

Validation of the HEN model for organic laying hens and assessment of nutrition in organic poultry (CTE0202)

Introduction Regulation EC1804/1999 sets out the minimum standards for organic livestock production and UK organic poultry producers have to adhere to for organic poultry. There are several aspects of Regulation EC1804/1999 which are technically and practicably challenging with regards to organic poultry production and most of these relate to feeding organic poultry. The greatest problems relate to the need to feed mainly organic ingredients, there is a future requirement to feed 100% organic ingredients, and the banning of synthetic amino acids in feeds for organic poultry. The issues raised by the introduction of Regulation EC1804/1999 are: 1) how do we match the supply of energy and nutrients to the bird’s needs for health, welfare and performance in a UK organic poultry production system? 2) Do we fully understand the bird’s amino acid needs for metabolic processes and can we meet them when feeding 80% or more organic ingredients? 3) Do UK-grown organic ingredients have lower crude protein and amino acid contents than their non-organic counterparts? If so, this will exacerbate any difficulties in amino acid supply to the birds. 4) What are the implications of Regulation EC1804/1999 in terms of ingredient supply for organic poultry production? These issues were addressed in this project. Firstly by measuring on-farm the hen’s feed metabolisable energy intake responses to temperature in outdoor production systems and examining whether a model (the ADAS HEN model) of inputs (feed metabolisable energy, protein and amino acids) and outputs (egg numbers and weight) could be validated for use in organic egg production systems. If so, this would provide a user-friendly approach for practical decision making at farm level. Secondly, by examining the published literature on recommended nutrient requirements for non-organic poultry and assessing the applicability of the findings to organic poultry. Thirdly, by sampling organically grown crops (wheat, peas and beans) and determining their contents of crude protein and amino acids. Fourthly, by estimating the size of the UK organic poultry flocks and their requirements for organic ingredients. Objectives 1. To validate the HEN model for organic egg production so that the feed energy value relative to protein content may be better matched with feed intake, and energy and nutrient requirements in differing outdoor temperatures. 2. To scope the technical issues relating to the nutrition of organic pullets, laying hens, table birds and breeder flocks. 3. To review the essential amino acid requirements for maintenance, growth, immune system development, behaviour, laying performance, sexual maturity and the risk of prolapse and interpret the relevance of published conventional data to organic poultry production. 4. To examine whether or not there are differences in the contents of crude protein content, lysine, methionine and threonine of organic and non-organic wheat, peas and beans (by analysis). 5. To examine the implications of changes in Regulation EC1804/1999 and Standards (e.g. organic pullet rearing and organic breeder flocks) on the volumes of organic feed ingredients needed for sustained UK organic poultry production (chickens) based on the current sector size. Implication of findings and future work 1. There is an inability to optimise the dietary ratio of metabolisable energy to protein for hens in outdoor production systems, as the hen’s feed metabolisable energy intake responses to low fluctuating outdoor temperatures have not been defined. The implications of this are tempered with respect to organic egg production as the priority when formulating diets is to meet, as far as possible with the limited range of ingredients available, the organic hen’s methionine and lysine requirements, which in practice is resulting in too much crude protein being fed. 2. Feeding excess crude protein will increase the rate of nitrogen excretion from organic poultry, and there will be an increased risk of nitrogen pollution to the air and water environments. 3. Without additional organic methionine-rich protein sources, methionine deficiencies will become more pronounced and more widespread in organic poultry production as the level of permitted non-organic proteinaceous ingredients in the diet fall. This will impact on bird health and welfare. 4. The possibility of lower methionine contents in organically produced wheat, peas and beans will exacerbate problems of methionine supply. 5. There is an urgent need to identify novel sources of organic methionine-rich protein for feeding organic poultry. This is being addressed in Defra-funded project OF0357 ‘Organic egg production – A desk study on sustainable and innovative methods for meeting the hen’s protein requirements’. The project addressed Defra’s policy of supporting the sustainable development of organic poultry production in the UK. The project has provided both Defra and the industry with information about the key scientific and technical problems, and some possible solutions to these problems. Where there are gaps in knowledge it has highlighted future research needs. The move to 100% organic provenance for organic poultry feeds is an important issue for UK consumers

Sowing time, false seedbed, row distance and mechanical weed control in organic winter wheat.

In organic farming, mechanical weed control in winter wheat is often difficult to carry out in the fall, and may damage the crop, and weed harrowing in the spring is not effective against erect, tap-rooted weeds such as Tripleurospermum inodorum, Papaver rhoeas, Brassica napus and others which have been established in the autumn. Some experiments concerning sowing strategy and intensity of mechanical weed control, which included row distance, were conducted. The results underline the importance of choosing weed control strategy, including preventive measures, according to the weed flora in the field. In the experiment with low weed pressure and without erect weeds, there was very little effect of sowing strategy and row distance. In such a case, the winter wheat might as well be sown early, in order to avoid possible yield loss by later sowing, and at normal row distance to enhance the competitiveness of the crop. In the experiments with high weed pressure and erect weeds, the weed control was better with late sowing and large row distance (high intensity control), even though this was not always reflected in the yield. However, the trade-off for lower input to the soil seed bank in organic systems should be enough to balance off the risk of smaller yield

Towards Quantifying The Economic Effects Of Poor And Fluctuating Water Quality On Irrigation Agriculture: A Case Study Of The Lower Vaal And Riet Rivers

Irrigation farmers in the lower reaches of the Vaal and Riet Rivers are experiencing substantial yield reductions in certain crops and more profitable crops have been withdrawn from production, hypothesised, as a result of generally poor but especially fluctuating water quality. In this paper secondary data is used in a linear programming model to test this hypothesis by calculating the potential loss in farm level optimal returns. The model is static with a time frame of two production seasons. Linear crop-water quality production functions (Ayers & Westcot, 1983; adapted from Maas & Hoffmann, 1977) are used to calculate net returns for the eight most common crops grown. Results show optimal enterprise composition under various water quality situations. Leaching is justified financially and there is a strong motivation for a change in the current water pricing system. SALMOD (Salinity and Leaching Model for Optimal irrigation Development) is the Excel Solver model used to derive the preliminary results, but is currently being developed further in GAMS (General Algebraic Modelling System). Useful results have already been obtained on which this paper is based. The ultimate aim for SALMOD is a mathematical model using dynamic optimisation, simulation and risk modelling techniques to aid in whole farm and system level management decisions to ensure sustainable irrigation agriculture under stochastic river water quality conditions.Crop Production/Industries, Resource /Energy Economics and Policy,

Biological Control of Weeds: Theory and Practical Application

Crop Production/Industries,

Desk study – Optimising the synergism between organic poultry production and whole farm rotations, including home grown protein sources

Over the past fifty years, most poultry in the UK have been managed in specialist indoor systems and excluded as a significant enterprise from most other farm types. This meant that there was little information on how to integrate poultry into land-based systems such as organic production. This Defra project OF0163 aimed to assess methods of integrating organic poultry into crop rotations, taking into account the need to meet the birds’ nutritional and physiological requirements for health and performance, the recycling of nutrients between soil, plants and birds and practical limitations of the system. Objectives 1. To review the scientific literature available on home grown protein sources so as to identify their maximum inclusion rates in organic poultry rations (laying hens and table chickens). 2. To measure nitrogen retention and to determine the nutrient content of manure from slow growing meat birds fed non limiting rations versus Label Rouge rations. 3. To measure nitrogen retention and to determine the nutrient content of manure in slow growing meat birds housed at a stable thermoneutral temperature versus a daily ambient temperature cycle during late autumn/winter months. 4. To review the scientific information available so as to determine the optimum position for poultry in whole farm rotations. 5. To provide examples of enterprise costings, including gross margins over variable costs, for mixed farms on a “with poultry” (laying hens and table chickens, separately) and “without poultry” basis. 6. To disseminate information on poultry management techniques as they apply to an organic system of egg production and table chicken production. Results and conclusions are included in a more detailed Executive Summary at the top of the main report

Workshop and desk study to appraise technical difficulties associated with organic pullet rearing

Background To date, Regulation (EC) 1804/1999 and UKROFS Standards allow conventionally reared pullets up to 18 weeks of age to be brought into systems of organic egg production. Pullets must be reared according to the rules laid down in Regulation (EC) 1804/1999 and according to UKROFS Standards for at least six weeks, before the eggs may be sold as organic eggs. The derogation for pullet rearing has been agreed for a transitional period expiring on 31 December 2003. If pullets are to be reared from day old in an organic system in accordance with Regulation (EC) 1804/1999 and UKROFS Standards this may potentially create a number of technical problems, which may disadvantage UK producers considering organic egg production. A series of workshops and a literature review were commissioned by MAFF to provide possible solutions to these technical problems. Objectives 1. To organise a workshop involving key members of the egg sector of the poultry industry, representatives of organic sector bodies and of MAFF to consider technical problems that may occur when rearing pullets organically, and to identify possible solutions. 2. To address some of the perceived technical problems by reviewing the available literature on conventional pullet rearing and assessing the extent to which published results can be applied to organic systems. 3. To reconvene workshop members to discuss findings from the literature review, to identify research priorities and to consider mechanisms for technology transfer. Methodology There were three separate but related stages to the project. Stage one comprised a workshop involving representatives of the egg sector of the poultry industry, of the Soil Association, of ADAS and of MAFF, and attendees were specifically invited to comment on the likely difficulties that might be experienced when attempting to rear pullets in an organic production system. Stage two was a desk study in the form of a literature review. Literature searches of the major international abstracting databases were done using key words related to the technical problems highlighted by workshop one attendees. Stage three was a second workshop where attendees discussed the findings from the literature, identified research priorities and considered mechanisms for technology transfer. Results The outcome of workshop one was that several likely difficulties associated with rearing pullets in an organic production system were identified and these included; 1) the application of light programmes in pullets receiving natural light when the maximum daily light period is 16 hours; 2) nutrition; 3) housing and pasture management, and; 4) food safety risks. Implications of findings, future work and policy relevance The implications of the findings are that with current scientific information there will be technical difficulties associated with rearing pullets in an organic system. The most important technical difficulties are to do with photoperiodism, nutrition, pasture management and rotation, and methods of controlling injurious feather pecking. Also a maximum permissible daylength of 16 hours for rearing organic pullets would mean that producers in Northern European countries may be disadvantaged. The project addressed MAFF’s policy of supporting the development of organic livestock production within the UK. The project has provided information to MAFF and the egg sector of the poultry industry about the key technical problems associated with organic pullet rearing, possible solutions to these problems and, where scientific information is missing, future research needs have been identified