Emergy evaluation of three cropping systems in southwestern Australia

Abstract

Wind erosion and rising water tables are serious threats to the ecological sustainability of annual plant-based farming systems on deep, infertile sandplain soils in southwestern Australia, In this study, an annual cropping system was compared with two novel perennial plant-based systems designed to address these threats in terms of their use of renewable indigenous resource, their use of non-renewable indigenous resources, their purchased inputs of energy and materials, and profitability. The farming systems were an annual lupin/wheat (Lupinus angustifolius L.lTriticum aestivum L.) crop rotation, a plantation of the fodder tree tagasaste (Chamaecytisus proliferus L.) and an alley cropping system in which the lupin/wheat rotation was grown between spaced rows of tagasaste trees. Flows of energy and materials between the environment and the economy were identified for each farming system and the natural and human activity involved in generating inputs as goods or services then valued in terms of the equivalent amount of solar energy required for their production using the emergy method of Odum [Ecological and General Systems: An Introduction to Systems Ecology. University Press of Colorado, revised edition of Systems Ecology, 1983, Wiley, New York, 644 pp.; Environmental Accounting: Emergy and Environmental Decision Making. Wiley, New York, 370 pp.]. The results showed that the two largest energy flows in the conventional lupin/wheat cropping system were wind erosion and purchased inputs of phosphate. The renewable component of production was 15% of total flows in the lupin/wheat system, 30% in the alley cropping system and 53% in the tagasaste plantation. The annual net income from the plantation system was nearly four times higher, and from alley cropping 45% higher, than from the lupin/wheat rotation. This analysis suggested that once the two agroforestry systems were fully established, the tagasaste plantation was the most efficient at transforming natural resources into goods and services and the most profitable, while the lupin/wheat system was the least energy efficient and the least profitable.

Emergy-Based Adjustment of the Agricultural Structure in a Low-Carbon Economy in Manas County of China

“…The theories and methods of Emergy have been widely applied to different systems to better understand the issues that are related to resource management and to evaluate alternative solutions in regards to policy questions [16][17][18][19]. Emergy analysis has been used to analyze different agricultural systems to compare and contrast resource use, productivity, environmental impact and sustainability in different countries [20][21][22][23][24][25]. Currently, there are few studies that have applied an emergy evaluation to agricultural structure adjustment with other mathematical methods.…”

Environmental Assessment of Integrated Food and Cooking Fuel Production for a Village in Ghana

“…For the PP, HH Biogas, and Village Biogas options soil organic carbon loss is set to 395 kg/ha/year (before recycling), based on [27,28]. Biogas production is modeled with residue-to-product ratios from [29], and biogas potentials from [29,30].…”

Soil organic carbon as an indicator of environmental quality at the national scale: Inventory monitoring methods and policy relevance

“…Conservation of nutrients and soil would make agricultural operations more sustainable and efficient, as well as potentially more profitable. In a case study for southwestern Australia, Lefroy and Rydberg (2003) analyzed the energetic costs for different practices, and found that agroforestry was more sustainable and profitable than other cropping systems due to reduced erosion and its benefit for the agricultural operation. In addition, SOC could be used as an indicator of water quality to the extent that increasing soil organic matter is associated with reduced losses of nutrients to groundwater and overland flow, which is transferred into streams and aquifers.…”