Suitable Land Areas Research Articles

Regional analysis of the impacts of climate change on cheatgrass invasion shows potential risk and opportunity

AbstractInteractions between climate change and non‐native invasive species may combine to increase invasion risk to native ecosystems. Changing climate creates risk as new terrain becomes climatically suitable for invasion. However, climate change may also create opportunities for ecosystem restoration on invaded lands that become climatically unsuitable for invasive species. Here, I develop a bioclimatic envelope model for cheatgrass (Bromus tectorum), a non‐native invasive grass in the western US, based on its invaded distribution. The bioclimatic envelope model is based on the Mahalanobis distance using the climate variables that best constrain the species' distribution. Of the precipitation and temperature variables measured, the best predictors of cheatgrass are summer, annual, and spring precipitation, followed by winter temperature. I perform a sensitivity analysis on potential cheatgrass distributions using the projections of 10 commonly used atmosphere–ocean general circulation models (AOGCMs) for 2100. The AOGCM projections for precipitation vary considerably, increasing uncertainty in the assessment of invasion risk. Decreased precipitation, particularly in the summer, causes an expansion of suitable land area by up to 45%, elevating invasion risk in parts of Montana, Wyoming, Utah, and Colorado. Conversely, increased precipitation reduces habitat by as much as 70%, decreasing invasion risk. The strong influence of precipitation conditions on this species' distribution suggests that relying on temperature change alone to project future change in plant distributions may be inadequate. A sensitivity analysis provides a framework for identifying key climate variables that may limit invasion, and for assessing invasion risk and restoration opportunities with climate change.

A COMPUTABLE MODEL FOR OPTIMIZING RESIDENTIAL RELOCATION BASED ON QUALITY OF LIFE AND SOCIAL COST IN BUILT-UP AREAS

Population aging and population decline, coupled with a saturation of the Japanese economy and declining fiscal revenue to maintain the existing infrastructure, pose particular problems in suburban areas. A new planning philosophy based on planned-retreat and planned re-concentration is described. To evaluate and identify suitable land areas, a tool for planning decision is provided. In this paper, the previously proposed framework (Kachi et al, 2005) is applied in order to identify the planned retreat and re-concentration areas with the index for social cost effectiveness of Quality of Life (QOL) derived from the given maximization problem. The case study of a rural small-sized city in Japan shows that the clustered urban spatial configuration is appropriate in terms of social cost effectiveness of QOL, although QOL in the suburban areas is higher than that of in the city center.

Miscanthus biomass production for energy in Europe and its potential contribution to decreasing fossil fuel carbon emissions

AbstractField trials throughout Europe over the past 15 years have confirmed the potential for high biomass production from Miscanthus, a giant perennial rhizomatous grass with C4 photosynthesis. However, policies to promote the utilization of biomass crops require yield estimates that can be scaled up to regional, national and continental areas. The only way in which this information can be reliably provided is through the use of productivity models. Here, we describe MISCANMOD, a productivity model, which was used in conjunction with a GIS to plot potential, non‐water‐limited yields across Europe. Modelled rainfed yields were also calculated using a water balance approach based on FAO estimates of plant available water in the soil. The observed yields were consistent with modelled yields at 20 trial sites across Europe. We estimate that if Miscanthus was grown on 10% of suitable land area in the European Union (EU15), 231 TWh yr−1 of electricity could be generated, which is 9% of the gross electricity production in 2000. Using the same scenario, the total carbon mitigation could be 76 Mt C yr−1, which is about 9% of the EU total C emissions for the 1990 Kyoto Protocol baseline levels.

Exploratory study on the land area required for global food supply and the potential global production of bioenergy

The areas of agricultural land on this globe that in the future possibly are available for biomass production for energy use and the potential global production of biomass were calculated. These available land areas increased when the global potential for food production (dependent on agricultural system and available land areas for agriculture) became higher in comparison to the global food requirement (dependent on population growth and mean consumption pattern). This study shows that 55% of the present agricultural land area at the global scale is needed for food production in the future (i.e. year 2050), if a high external input system of agriculture is applied. The remaining 45% can be used for other purposes, such as biomass production. If all potentially suitable land areas would be cultivated, the global potential for biomass production becomes about two times as large. If a low external input system is applied at the global scale for food production, however, no land area is available for biomass production.

Alternative housing systems for pigs: Influences on growth, composition, and pork quality1

Effects of pig birth (first 3-wk period) and rearing environments on growth and muscle quality characteristics of loins were evaluated in three experiments over seasons in west Texas and central Missouri. Housing systems included indoor slatted-floor buildings, indoor deep-bedded buildings, outdoor housing on dirt, and outdoor housing on alfalfa pasture. Experiments were conducted during the growing/finishing phases and pigs were slaughtered at the same age. Loins were collected, vacuum-packaged, and stored for 14 d at 2 degrees C. Pigs born and finished in an outdoor environment during the summer months (Exp. 1) had a greater ADG (0.92 vs 0.82+/-0.06 kg/d, P < 0.05) and had heavier carcass weights (87.9 vs 78.4+/-2.4 kg, P < 0.05) than pigs born and finished in an indoor environment with a slatted-floor finishing building. Carcasses from the outdoor-reared group measured a larger (P < 0.05) loineye area and were fatter (P < 0.01) at the first rib, last rib, and last lumbar vertebra measurements than carcasses from the indoor-reared group. Loin chops from outdoor-reared pigs had darker color scores in the retail display case throughout the 4-d period, measured lower L* values on d 1, and had more discoloration and browning on d 4 than loin chops from the indoor-reared group. During the winter months (Exp. 2), no difference was detected in ADG, carcass measurements, sensory characteristics, or shear force values from indoor-born pigs placed in either an outdoor or indoor finishing environment. Pigs finished on deep bedding (Exp. 3) had heavier carcass weights and more backfat (P < 0.01) than pigs finished on slats, but no differences were detected in sensory panel or shear force results. Overall, carcass measurements, pH, drip loss, sensory panel, and shear force values were similar among the groups finished in different housing systems. Outdoor or deep-bedded systems may increase growth rates of pigs if suitable land area and resources are available, but pork quality of loins will be similar for pigs finished in either conventional or alternative systems.

A Spatial Decision Support System for Livestock Production Planning and Environmental Management

Spatial decision support systems are used to plan production systems and direct the implementation management strategies that are compatible with environmental protection goals. They enable resource managers to select appropriate production technologies that minimize environmental damage, and evaluate alternative management practices. This article describes a spatial decision support system (SDSS) developed to facilitate planning and management of environmentally sound livestock production. The SDSS integrates a geographic information system, spatial and biophysical modeling, and a knowledge-based system into an interactive tool to select suitable watershed land areas for siting livestock production, to select fields for manure application, and to determine the potential impacts of livestock production practices on groundwater quality.

Agronomic modification of resource use and intercrop productivity

Suitable land areas for food production remain fixed or are diminishing, yet farmers and agronomists are faced with the task of increasing production. Raising productivity, through a more effective use of natural (e.g. light) and added (e.g. fertilizer) resources, is possible through intercropping, provided component crop demands for resources are well understood. Management of intercrops to maximize their complementarity and synergism, and to minimize competition between them follows simple natural principles, and its practice is limited only by the imagination of farmers and agronomists. Successful crop mixtures extend the sharing of available resources, over time and space, exploiting variation between component crops in such characteristics as rates of canopy development, final canopy width and height, photosynthetic adaptation of canopies to irradiance conditions and rooting depth. Occasionally, commensalism is effected. Loosely defined as one organism gaining benefits from another without damaging or benefiting it, it is exemplified when one crop modifies the microenvironment to suit another. Prime examples are the benefits of shading during crop, particularly transplanted crop, establishment under hot or dry conditions, the supply of nitrogen and solubilization of phosphorus by legumes for companion crops, and the suppression of weeds through direct competition or allelopathic effects. The onset of competition between intercrops can be delayed by judicious choice of relative planting dates. The differential influence of weather (in particular temperature) on component crop growth and development can be modified through reasoned planting dates, and relative proportions of crop component yields can be targeted. In general, to ensure its high yield the main crop should be planted first. Choice of plant population density and crop geometry, including row orientation, permits a planned sharing of natural resources and manipulation of competitiveness to suit targeted yields. Increases in rectangularity in the crop geometry of the main crop tends to enhance transmission of light to shorter crops for longer periods before canopy closure. Crops harvested for their vegetative yield appear less sensitive to supra-optimum population densities within mixtures than do seed crops. The period over which intercrops compete for resources can be shortened by the supply of external inputs, in as much as they permit greater exploitation of the finite supply of light. Supplementary irrigation has been shown to raise total productivity in various intercrop systems, but little research effort has been turned towards mineral nutrients. Addition of N fertilizer to legume intercrops reduces the relative over-yielding, i.e. compared to mixtures without N fertilizer, but not without overall improvement in total yield. Benefits of residual N on succeeding crops following legume intercrops are also not unsubstantial, and deserve attention when evaluating the merits of intercropping. In order to sustain enhanced productivity from intercrops, it will become increasingly more important to substitute natural resources where feasible for purchased inputs. Since the major focus of intercrop research has been on small-scale resource-poor systems, a serious gap in our knowledge on high input intercrop systems will hinder their rapid spread.

Broiler Litter Application to Land in an Agricultural Watershed: A GIS Approach

This paper studies broiler litter utilization in an agricultural watershed using a Geographical Information System (GIS) and an optimization model. An optimization model is developed which selects broiler litter management practices that maximize total net returns to land and management and estimates economic value of litter as a fertilizer substitute for an agricultural watershed experiencing rapid growth in broiler production. Land application rates are determined based on crop nutrient requirements, fertilizer source, and litter cleanout schedule. Results indicate that litter as a fertilizer is economically favored over commercial fertilizer. Land area required for current litter application does not exceed suitable land application areas after excluding sensitive areas such as streams, roads and sink holes. However, litter from further growth in broiler production will soon reach the maximum capacity of suitable land areas in the watershed. Nutrients in current litter amounts do not exceed crop nutrient requirements, but would equal crop requirements if broiler production is doubled (tripled) and litter application rates are determined on a phosphate (nitrogen or potash) basis. GIS is a powerful analytical tool for analyzing economic and environmental problems. Litter is an inexpensive substitute for commercial fertilizer and its value varies with the nutrient basis used to determine application rates, litter cleanout schedule and litter availability.

An insect introduction to the maritime Antarctic

Although several invertebrates have been introduced by Man into the Antarctic, no holometabolous insects have survived to colonize terrestrial habitats successfully. Data are presented on the survival of populations of a chironomid midge, together with an enchytraeid worm, for 17 years in a maritime Antarctic site at Signy Island, South Orkney Islands. Both species are thought to have been introduced on plant material transplanted from either South Georgia or the Falkland Islands or both in 1967. Population densities average 25718m-2 for the dipteran larvae and 3243 m-2 for the worms. Successful completion of the midge's life cycle was indicated by emergence of brachypterous adults and oviposition (the population is parthenogenetic with only females present). Although both taxa are capable of supercooling to between -13 and -26°C, this capacity may not be sufficient in a severe winter to avoid lethal freezing. Four potential cryoprotectants were found in insect extracts, but in concentrations (< 1 % fresh weight) unlikely to influence cold hardiness. Both invertebrates appear to be pre-adapted for survival in much harsher conditions than they normally experience, by the extension of existing physiological mechanisms. It is concluded that the main limitations to invertebrate colonization of suitable Antarctic land areas by soil-dwelling species are geographical.