Agricultural Subsystem Research Articles

Changing urban phosphorus metabolism: Evidence from Longyan City, China

Rapid worldwide urbanization calls for a better understanding of phosphorus (P) metabolism and the interaction of the physical, ecological and social drivers of P cycling in urban systems. We quantified the P metabolism in Longyan, a city with a major agricultural economy, and analyzed its long-term trends over the rapid urbanization period of 1985–2010. Both input P (from 4811t P to 14,296t P) and output P (from 4565t P to 13,509t P) increased significantly. The agricultural subsystem contributed most to the P metabolism, accounting for 85% of total P input. The share of P input lost to the environment, i.e. discharge to water, accumulation in the soil and landfill, increased from 66% to 72%, while food production efficiency decreased from 48% to 29%. Per capita P input showed linear relationships with the Human Development Index (HDI), S-curve relationship with the urbanization rate, and logistic curve relationship with per capita disposable income. A more meat-based diet shift both in Longyan and surrounding cities greatly affected Longyan's food production structure. Our results demonstrate that P metabolic quantity, configuration, and efficiency in production systems can change drastically in response to changes in consumer and producer behavior as well as in socioeconomic structure. A larger regional scale should be considered in urban P management, when trying to mitigate the increase in P use. The results also imply that sustainable urban P management will require a system-wide, cross-sector and cross-boundary approach.

Development of a life cycle assessment tool for the assessment of food production systems within the energy, water and food nexus

As the demand for services and products continues to increase in light of rapid population growth, the question of energy, water and food (EWF) security is of increasing importance. The systems representing the three resources are intrinsically connected and, as such, there is a need to develop assessment tools that consider their interdependences. Specifically when evaluating the environmental performance of a food production system, it is necessary to understand its life cycle. The objective of this paper is to introduce an integrated energy, water and food life cycle assessment tool that integrates EWF resources in one robust model and at an appropriate resolution. The nexus modelling tool developed is capable of providing an environmental assessment for food production systems utilising a holistic systems approach as described by a series of subsystems that constitute each of the EWF resources. A case study set in Qatar and characterised by an agriculture sub-system, which includes the production and application of fertilisers and the raising of livestock, a water sub-system represented by mechanical and thermal desalination processes and an energy sub-system, which includes fossil fuel in the form of combined cycle natural gas based energy production and solar renewable energy is used to illustrate the model function. For the nexus system analysed it is demonstrated that the food system is the largest contributor to global warming. The GWP can be reduced by up to 30% through the utilisation of solar energy to substitute fossil fuels, which, however, comes with a significant requirement for land investment.

The Evaluation of Groundwater Resources Value of Beijing Based on Emergy Theory

Accurate yet valid evaluation of values of groundwater resources is difficult. However, it is of an urgent need. Based on water resource system, the emergy synthesis of the ecological economics was used to make a systematic study on the assessment of the quantity of groundwater resources. Taking Beijing in 2012 as an example, the values of groundwater for residents life subsystem, the industrial subsystem, and the agricultural subsystem are 7.64, 6.00, and 3.25 billion Yuan, accounting for 45.24, 35.5, and 19.24% of the total value, respectively. The total value of the underground water accounts for 1.51% of the GDP in Beijing for that year. Meanwhile, Contribution Rate of Groundwater Resources (GWCR) in Beijing decreased in the following order: groundwater contribution rate for industry (GWCRI 4.52%), groundwater contribution rate for agriculture (GWCRA 3.24%), and groundwater contribution rate for residential life (GWCRL 0.71%). The conclusions will provide important basis for the government’s scientific decision to improve the level of comprehensive management of water resource.

The Effects of Energy Contributions into Subsidiary Processes on Energetic Efficiency of Biomass Plantation Supplying Biofuel Production System

Abstract A number of technologies of biofuel production from various biomass crops are already in use, and many studies on new ones are carried out. Biomass production, like any other production processes, involves a number of necessary processes that facilitate subsequent production steps. Those subsidiary processes (e.g. tillage or logistic operations) are connected with consumption of energy. It is therefore important to assure that the sum of energy inputs into those technological steps does not exceed the energy output from the system. Obviously, large energy gain is desired. The paper is devoted to the estimation of energy inputs made into the subsidiary processes occurring in the agricultural subsystems in which various topological structures of plantations as well as for various technologies of tillage, and different requirements for transportation are allowed. Mathematical model describing above mentioned dependencies is derived, and appropriate algorithm elaborated for numerical computations, that have been performed for rapeseed plantations. The results demonstrate evident effects of the choices of technology, and organization of work onto efficiency of plantation as measured by EROEI - type indicator.

A Social Approach for the Assessment of Transition Farms: Taking Steps toward Whole-System Organic Certification in Mexico

This paper integrates a methodology for an assessment previous to organic certification of transition farms. The methodology was designed and applied to a farm in the municipality of Villaflores, Chiapas. Research consisted of grouping certification standards from different certification agencies into an integrated methodology for evaluating the farm prior to it being submitted to the certification process. The norms proposed by the International Federation of Organic Agriculture Movements and the Mexican certifier of ecological products were utilized—both of these accredited by the German certification program—as well as the Japanese Ministry of Agriculture's principles of organic agriculture. The methodology was based on a systemic approach and applied using agricultural anthropology. Field research was conducted from January-May 2012, through interviews, field observations and triangulation of information. Results indicated that within the agricultural sub-system of the farm, 77% of indicators meet the norms of organic certification and within the animal subsystem only 74%. This study permits the pre-assessment of farms and the progress quantification toward organic certification. Given the cost of taking on the certification process, this pre-assessment represents an important tool to help small farmers develop their capacity to identify farm components and interactions, keep records on all farm activities and plan organic transitions.

Water transfer as a solution to water shortage: A fix that can Backfire

summary Zayandeh-Rud River Basin is one of the most important basins in central Iran, which has been continually challenged by water stress during the past 60 years. Traditionally, a supply-oriented management scheme has been prescribed as a reliable solution to water shortage problems in the basin, resulting in a number of water transfer projects that have more than doubled the natural flow of the river. The main objective of this study is to evaluate the reliability of inter-basin water transfer to meet the growing water demand in Zayandeh-Rud River Basin. A system dynamics model is developed to capture the interrelationships between different sub-systems of the river basin, namely the hydrologic, socioeconomic, and agricultural sub-systems. Results from simulating a range of possible policy options for resolving water shortage problems indicate that water is essentially the development engine of the system. Therefore, supplying more water to the basin without considering the dynamics of the interrelated problems will eventually lead to increased water demand. It is demonstrated that the Zayandeh-Rud River Basin management system has characteristics of the ‘‘Fixes that Backfire’’ system archetype, in which interbasin water transfer is an inadequate water management policy, causing significant unintended sideeffects. A comprehensive solution to the problem includes several policy options that simultaneously control the dynamics of the system, minimizing the risk of unintended consequences. In particular, policy makers should consider minimizing agricultural water demand through changing crop patterns as an effective policy solution for the basin’s water problems.

Quantifying Phosphorus Flow Pathways Through Socioeconomic Systems at the County Level in China

SummaryPhosphorus (P) is a key factor in aquatic eutrophication, and P contamination has become a common issue worldwide. Many developing countries, including China, have made great efforts in the anti‐P contamination battle. In this article we mainly discuss the P flow in Wuwei, a typical county in China with insufficient wastewater treatment, using the method of static substance flow analysis. We show that characterizing P metabolic pathways and flows at the county level can provide useful information about P pollution. Through complex calculations, we found that Wuwei County released 3,552 metric tons (t) of P into the local aquatic environment in 2008 and that its P load (3.35 kilograms P per capita per year [kg P/cap/yr] or 19.43 kilograms P per hectare per year [kg‐P/ha/yr]) was greater than both the adjoining counties’ and Chaohu City's average levels combined. The agricultural subsystem discharged the largest quantity of P (2,572 t) and had a relatively low production conversion efficiency (32%) and P waste recycling rate (36%). The rural residential and small‐scale livestock breeding systems also accounted for substantial portions of P discharge. Anti‐P contamination efforts should consequently focus on those three subsystems. Based on the results of this case study, we also discuss the feasibility of potential efforts to reduce P contamination.

Pet Sounds: Subsystems, Regimes, Policy Punctuations, and the Neglect of African American Farmers, 1935–2006

Punctuated equilibrium theory (PET) has reoriented the study of public policy and American politics in particular. In this study, we documented how a policy punctuation that appears to take hold at the macro level of the polity in the form of a policy regime has difficulty penetrating subsystem politics. We drew on subsystems theory, PET, and the latest work on policy regimes to document the resistance of the agriculture subsystem to efforts to add a civil rights dimension to agriculture policy between 1935 and 2006. We concluded that the issue evolution of agricultural support programs, and their insulation from civil rights policy, is a prime example of how subsystems use negative feedback to resist change.

1.4.1 Mixed‐Occupancy Vertical Urban Farm Systems

AbstractA mixed‐use vertical farm is a high‐rise structure that is a combination of residences and agricultural subsystems situated near or within urban centers and serving as a localized food production facility. Plants of different varieties are grown year‐round in high density hydroponics/aeroponics modules. Vertical urban farming takes advantage of the ability to control the weather and lighting environments to maximize plants growth, yield, and quality. A systems approach is needed to understand and simplify the complex system considering whole life‐cycle costs, design, construction, operation, and infrastructure integration for environmental management and residences. Overall, the mixed‐use vertical farm is conceived as a high‐tech solution for countries or cities that have shortages in water, extremely limited arable space, and the need for competitively‐priced farm products. Singapore, a nation incorporating many of these factors, is an example of an excellent candidate for such a system.

Nitrogen Flow in the Rural Ecosystem of Mikasa City in Hokkaido, Japan

ABSTRACT This study of Mikasa City in 2001, which analyzed N flow between N production and N load in seven agricultural and settlement subsystems, i.e., paddy, onion, wheat, vegetable, dairy, chicken, and citizen subsystems, aimed to compare N flow in each subsystem, to determine the main sources of the N load, and to evaluate the influence of agricultural production and food consumption on N cycling in a rural area. The results showed that in Mikasa city, 38.5% of the N load came from point sources and the remainder from non-point sources with intensive vegetable farming imparting a serious N load. Because of the internal N cycling in the dairy subsystem, chemical fertilizer application was reduced by 70.2%, and 23.72 Mg manure N was recycled to the field; therefore, the N utilization efficiency was raised from 18.1% to 35.1%. If all the manure N in the chicken subsystem was recycled, chemical fertilizer application would be reduced by 8.1% from the present level, and the point sources of N pollution would be reduced by 20.8%.

Planning for an Optimal Mix of Agricultural and Wildlife Land Use

A linear programming model was formulated to maximize profit of a small farm subject to constraints on the wildlife and agricultural subsystems. The model was developed to allocate the area among crops, fertilizer levels, and rotations, and to determine the average field size and proper spatial variety of crops. Application of the model to a hypothetical small farm showed that it was most efficient to have a large average field size, and, therefore, less area of edge. Wildlife constraints were then met by the type of crops planted and the area left unharvested. The marginal costs associated with fertilizer, crop minimums, and unharvested acreage constraints were high and produced a significant reduction in profit. J. WILDL. MANAGE. 43(2):493-502 Planning for an orderly environmental development will inevitably produce conflict between economic, recreational, and aesthetic uses of the land. Such a conflict is exemplified by the antagonism between agricultural and wildlife land use. Humans derive economic benefit from crops harvested, and aesthetic benefits such as recreation, education, and relaxation from observing or exploiting wildlife. However, an increase in benefits derived from the agricultural subsystem will often cause a decrease in benefits derived from the wildlife subsystem, and vice versa. The major objective of each subsystem may be at odds with that of the other. One purpose of an environmental plan is, therefore, to provide a satisfactory mix of 2 or more subsystems. a mix which will maximize the attainment of goals of 1 subsystem while maintaining an acceptable standard of the other subsystems. One methodology for finding optimal solutions to complex problems is through linear programming (Hillier and Lieberman 1967, Taha 1971). Problems consisting of hundreds of decision variables and constraints may be solved relatively quickly by computer-implemented linear programming (LP) packages (Spivey 1973). However, LP requires that objectives and constraints be expressed as linear functions of the decisions. Thus, interaction between decision variables cannot be explicitly included. Techniques for approximating nonlinear functions with linear models allow the use of LP in many cases (Dantzig 1963), and the efficiency of LP solution algorithms may then be exploited. I employed LP to produce a plan for the optimal mix of an agricultural-wildlife system. This system is exemplified by the especially difficult case of the owner of a small farm wishing to maximize profit while protecting specified wildlife levels. Choices of crop varieties, fertilizer levels, rotations, cropping regimes, and spatial arrangements are made to meet constraints of farm production and still achieve the desired results. The case study system is a hypothetical, yet realistic, situation which exemplifies interaction between agriculture and wildlife. While some generalities may be made from the results of this case study, the utility is more in the approach that is used. I am grateful to R. H. Giles for presenting me with the original idea for this work. J. Wildl. Manage. 43(2):1979 493 This content downloaded from 207.46.13.98 on Fri, 05 Aug 2016 04:03:35 UTC All use subject to http://about.jstor.org/terms 494 PLANNING AGRICULTURAL AND WILDLIFE LAND USE* Powers

The Agricultural and Persistent Pollution Subsystems in World3

The agricultural and persistent pollution sectors of the Club of Rome's World3 model are analyzed to obtain a better understanding of their inner workings, and to show how such understanding may be acquired step by step, using simple methods of systems and control engineering. Only few of the agricultural sector's equations essentially affect standard-run behavior. Food production is mainly determined by industrial output (exogenous to the sector) and arable land, and is virtually independent of population and pollution. Except for the arable land subsector, the agricultural sector is found to act more or less algebraically. If pollution rises considerably above its standard-run values, however, the sector's properties may be quite different. The persistent pollution sector is found to be fairly inactive for standard-run conditions, but, owing to a particular assumption on its absorption, pollution may suddenly rise to high levels under different conditions and therefore have an important impact on food production and population.

5. The agricultural sub-system

The assumptions about the physical limits of the critical variables in the agricultural sub-system of World 3 are pessimistic. By making more optimistic but, on the basis of available information, equally plausible assumptions about them, any physical limits to agricultural production recede beyond the time horizon of the model. The major problems of feeding the less developed world are seen to lie in political rather than in physical limits.