Resources Technology and Environment in Agricultural Development

IIASA's Food and Agriculture Program is undertaking research on a complex set of issues grouped under the title: "Limits and Consequences of Food Production Technologies". The fundamental question addressed in this research is "what long-term technical development paths are feasible and likely for increasing food production, based on the present availability of resources (including energy), the long-run feedback on the environment, and the short-run pressures reflected in current agricultural policies". The objective of the research on this set of issues is to construct a model, or family of models, which will increase understanding of the resources-technology-environment (R-T-E) system in agricultural production, thus providing guidance to policies to make the system more serviceable in meeting rising world demands for food. As indicated in the quoted statement, the focus is on the behavior of the R-T-E system over the long-term. It is not necessary for our purposes to define the long-term precisely, but we think of it as a period of 2 to 3 decades. The aim of this paper is to provide an intellectual background that will be useful to the modeling effort. To this end the paper seeks to identify the principal elements in the R-T-E system, to describe the relationships among these elements, and to analyze the forces which move and modify the system through time. Throughout the analysis major emphasis is given to the role of relative prices of agricultural resources as signals to farmers of relative resource scarcity. This reflects the author's orientation and training, but it means that the analysis is not directly applicable to centrally planned economies. Farmers in those economies will feel many of the same sorts of resource pressures as farmers in market economies -- for example, the increasing cost of energy -- but the indication of those pressures and the modes of response to them are different. This limitation of the analysis should be kept in mind

The Impact of Concentrate Price on the Utilization of Grazed and Conserved Grass

A linear programming model was designed and constructed to facilitate the identification of optimal beef production systems under varying technical and policy scenarios. The model operates at a systems level and most activities that could occur in Irish spring-calving, suckler beef production systems are included. In this paper, the components of the model are described together with a simple application of the model involving changing concentrate prices

A bio-economic model for cost analysis of alternative management strategies in beef finishing systems.

peer-reviewedGlobal population growth together with rising incomes is increasing the demand for meat-based products. This increases the need to optimize livestock production structures, whilst ensuring viable returns for the farmers. On a global scale, beef producers need tools to assist them to produce more high-quality products whilst maintaining economic efficiency. The Grange Scottish Beef Model (GSBM) was customized to simulate beef finishing enterprises using data from Scottish beef finishing studies, as well as agricultural input and output price datasets. Here we describe the model and its use to determine the cost-effectiveness of alternative current management practices (e.g. forage- and cereal-based finishing) and slaughter ages (i.e. short, medium or long finishing duration). To better understand drivers of profitability in beef finishing systems, several scenarios comparing finishing duration, gender, genetic selection of stock for growth rate or feed efficiency, as well as financial support were tested. There are opportunities for profitable and sustainable beef production in Scotland, for both cereal and forage based systems, particularly when aiming for a younger age profile at slaughtering. By careful choice of finishing systems matched to animal potential, as well as future selection of high performing and feed efficient cattle, beef finishers will be able to enhance performance and increase financial returns

A Multicriteria Assessment of Forage or Concentrate-Based Finishing Diets for Temperate Pasture-Based Suckler Beef Production Systems

This study evaluated the effect of contrasting ‘finishing’ diets on animal performance, meat nutritional value, land use, food-feed competition, farm economics and greenhouse gas (GHG) emissions in temperate pasture-based suckler weanling-to-steer beef systems. Post-weaning, eight-month-old, spring-born, late-maturing breed steers (333 kg) were assigned to one of three systems: (1) Grass silage + 1.2 kg concentrate DM (148 days), followed by pasture (123 days) and finished on ad libitum concentrates (120 days) - slaughter age, 21 months (GRAIN); (2) as per (1) but pasture (196 days) and finished on grass silage ad libitum + 3.5 kg concentrate DM (124 days) - slaughter age, 24 months (SIL+GRAIN); and (3) grass silage-only (148 days), pasture (196 days), silage-only (140 days) and finished on pasture (97 days) - slaughter age, 28 months (FORAGE). The mean target carcass weight was 390 kg for each system. Data generated was used to parameterise a farm-level beef systems model. Measured concentrate DM intake was 1187, 606 and 0 kg/head, and average daily gain was 0.83, 0.72 and 0.62 kg for GRAIN, SIL+GRAIN and FORAGE, respectively. Direct (pasture) land use was lowest for GRAIN. FORAGE was more profitable and was the only net producer of human edible protein and energy/ha. GRAIN produced the lowest GHG emissions per animal and meat essential amino acid concentration. FORAGE was more favourable for GHG emissions per kg of net (produced vs. consumed) production of human edible protein. Muscle amino acid and saturated fatty acid concentrations did not differ between the production systems, but FORAGE had the highest muscle concentration of omega-3 poly-unsaturated fatty acids. Differences in muscle mineral concentration were small. In conclusion, there are inverse relationships between food-feed competition, land-use, economics and GHG emissions per unit of product among different systems

Performance, profitability and greenhouse gas emissions of alternative finishing strategies for Holstein-Friesian bulls and steers

peer-reviewedModifying finishing strategies within established production systems has the potential to increase beef output and farm profit while reducing greenhouse gas (GHG) emissions. Thus, the objectives of this study were to investigate the effects of finishing duration on animal performance of Holstein-Friesian (HF) bulls and steers and evaluate the profitability and GHG emissions of these finishing strategies. A total of 90 HF calves were assigned to a complete randomised block design; three bull and three steer finishing strategies. Calves were rotationally grazed in a paddock system for the first season at pasture, housed and offered grass silage ad libitum plus 1.5 kg DM of concentrate per head daily for the first winter and returned to pasture for a second season. Bulls were slaughtered at 19 months of age and either finished indoors on concentrates ad libitum for 100 days (19AL), finished at pasture supplemented with 5 kg DM of concentrate per head daily for 100 (19SP) or 150 days (19LP). Steers were slaughtered at 21 months of age and finished at pasture, supplemented with 5 kg DM of concentrate per head daily for 60 (21SP) and 110 days (21LP) or slaughtered at 24 months of age and finished indoors over the second winter on grass silage ad libitum plus 5 kg DM of concentrate per head daily (24MO). The Grange Dairy Beef Systems Model and the Beef Systems Greenhouse Gas Emissions Model were used to evaluate profitability and GHG emissions, respectively. Average daily gain during the finishing period (P<0.001), live weight at slaughter (P<0.01), carcass weight (P<0.05) and fat score (P<0.001) were greater for 19AL than 19SP and 19LP, respectively. Similarly, concentrate dry matter intake was greater for 19AL than 19SP; 19LP was intermediate (P<0.001). Live weight at slaughter (P<0.001), carcass weight (P<0.001), conformation score (P<0.05) and fat score (P<0.001) were greater for 24MO than 21SP and 21LP, respectively. During the finishing period concentrate dry matter intake was greater for 21LP than 21SP with 24MO intermediate; 542, 283 and 436 kg DM, respectively. Although pasture-based finishing strategies had lower gross output values, concentrate feed costs were also reduced thus net margin was greater than indoor finishing strategies. Reducing concentrate input increased GHG emissions for bulls and steers slaughtered at the same age, respectively. Although prolonging the finishing duration reduced GHG emissions for bull and steer production systems, finishing bulls and steers over a longer period at pasture did not enhance animal performance and profit

Beef production from feedstuffs conserved using new technologies to reduce negative environmental impacts

End of project reportMost (ca. 86%) Irish farms make some silage. Besides directly providing feed for livestock, the provision of grass silage within integrated grassland systems makes an important positive contribution to effective grazing management and improved forage utilisation by grazing animals, and to effective feed budgeting by farmers. It can also contribute to maintaining the content of desirable species in pastures, and to livestock not succumbing to parasites at sensitive times of the year. Furthermore, the optimal recycling of nutrients collected from housed livestock can often be best achieved by spreading the manures on the land used for producing the conserved feed. On most Irish farms, grass silage will remain the main conserved forage for feeding to livestock during winter for the foreseeable future. However, on some farms high yields of whole-crop (i.e. grain + straw) cereals such as wheat, barley and triticale, and of forage maize, will be an alternative option provided that losses during harvesting, storage and feedout are minimised and that input costs are restrained. These alternative forages have the potential to reliably support high levels of animal performance while avoiding the production of effluent. Their production and use however will need to advantageously integrate into ruminant production systems. A range of technologies can be employed for crop production and conservation, and for beef production, and the optimal options need to be identified. Beef cattle being finished indoors are offered concentrate feedstuffs at rates that range from modest inputs through to ad libitum access. Such concentrates frequently contain high levels of cereals such as barley or wheat. These cereals are generally between 14% to 18% moisture content and tend to be rolled shortly before being included in coarse rations or are more finely processed prior to pelleting. Farmers thinking of using ‘high-moisture grain’ techniques for preserving and processing cereal grains destined for feeding to beef cattle need to know how the yield, conservation efficiency and feeding value of such grains compares with grains conserved using more conventional techniques. European Union policy strongly encourages a sustainable and multifunctional agriculture. Therefore, in addition to providing European consumers with quality food produced within approved systems, agriculture must also contribute positively to the conservation of natural resources and the upkeep of the rural landscape. Plastics are widely used in agriculture and their post-use fate on farms must not harm the environment - they must be managed to support the enduring sustainability of farming systems. There is an absence of information on the efficacy of some new options for covering and sealing silage with plastic sheeting and tyres, and an absence of an inventory of the use, re-use and post-use fate of plastic film on farms. Irish cattle farmers operate a large number of beef production systems, half of which use dairy bred calves. In the current, continuously changing production and market conditions, new beef systems must be considered. A computer package is required that will allow the rapid, repeatable simulation and assessment of alternate beef production systems using appropriate, standardised procedures. There is thus a need to construct, evaluate and utilise computer models of components of beef production systems and to develop mathematical relationships to link system components into a network that would support their integration into an optimal system model. This will provide a framework to integrate physical and financial on-farm conditions with models for estimating feed supply and animal growth patterns. Cash flow and profit/loss results will be developed. This will help identify optimal systems, indicate the cause of failure of imperfect systems and identify areas where applied research data are currently lacking, or more basic research is required

Evaluating socio-economic and environmental sustainability of the sheep farming activity in Greece: a whole-farm mathematical programming approach

Ruminant livestock farming is an important agricultural activity, mainly located in less favoured areas. Furthermore, ruminants have been identi fi ed as a signi fi cant source of GHG emissions. In this study, a whole-farm optimization model is used to assess the socio-economic and environmental performance of the dairy sheep farming activity in Greece. The analysis is undertaken in two sheep farms that represent the extensive and the semi-intensive farming systems. Gross margin and labour are regarded as socio-economic indicators and GHG emissions as environmental indicators. The issue of the marginal abatement cost is also addressed. The results indicate that the semi-intensive system yields a higher gross margin/ewe (179 €) than the extensive system (117 €) and requires less labour. The extensive system causes higher emissions/kg of milk than the semi-intensive system (5.45 and 2.99 kg of CO2 equivalents, respectively). In both production systems, abatement is achieved primarily via reduction of the fl ock size and switch to cash crops. However, the marginal abatement cost is much higher in the case of the semi-intensive farms, due to their high productivity

Making Classical Ground State Spin Computing Fault-Tolerant

We examine a model of classical deterministic computing in which the ground state of the classical system is a spatial history of the computation. This model is relevant to quantum dot cellular automata as well as to recent universal adiabatic quantum computing constructions. In its most primitive form, systems constructed in this model cannot compute in an error free manner when working at non-zero temperature. However, by exploiting a mapping between the partition function for this model and probabilistic classical circuits we are able to show that it is possible to make this model effectively error free. We achieve this by using techniques in fault-tolerant classical computing and the result is that the system can compute effectively error free if the temperature is below a critical temperature. We further link this model to computational complexity and show that a certain problem concerning finite temperature classical spin systems is complete for the complexity class Merlin-Arthur. This provides an interesting connection between the physical behavior of certain many-body spin systems and computational complexity.Comment: 24 pages, 1 figur