Download Comprehensive Evaluation of Optimal Environmental Policies about

Comprehensive Evaluation of Optimal Environmental Policies about
Nitrogen cycle for Sustainable Development in China: Case Study of
SongYuan City.
Li’ang AN, Yoshiro HIGANO
Master program in Environmental Sciences, Tsukuba University
Abstract:
Nitrogen is precursor of environmental problem, which contributes to smog, acid rain
and global warming. Anthropogenic input can result in nitrogen saturation, which
broken material circulation and can damage the development of sustainable society. In
this study, we analyze the conditions of nitrogen material circulation, simulate the
interrelation between the excessive emission of nitrogen and socio-economic structure
by the mathematical model in the study area, and observe if the nitrogen utilization
can satisfy the requirements of environment and economy, in order to reach a decision
regarding the optimal solution to the comprehensive problem.
We formulate the comprehensive system as a linear optimization model. It is built
based on the principle of nitrogen material balance, Input and Output table and other
macroeconomic indicators to analyze the interrelation between nitrogen material
circulation system and socio-economic system. Use the LINGO software to simulate a
computer modeling of the nitrogen material circulation system and the socioeconomic system. The computer modeling is utilized to give predictions, which can
be employed in the process of decision-making.
Key words:
Nitrogen material balance, Input and Output Simulation, mathematical model
1. Introduction
China is a large agricultural country. With 70% of its 1.5 billion people living in rural
areas, China faces grave challenges from both global economic integration and global
changes in the natural environment. As a developing country with 9.6 × 106 km2 of
land, China must acquire a good understanding of sustainable development; develop
scientific methods for evaluating the sustainable capability of its socio-economic
development, and deal with the issues of imbalance between economy and
environment of socio-economic development in order to devise policies to achieve the
goal of sustainable development across the country.
Fig.1 The material balance model: interdependence of economics and environment
Source: Callen and Thomas “Environmental Economics and Management—Theory, Policy,
and Applications”—Irwin, USA, p. 6. A slight change in the Figure is incorporated. [1]
The relationship between the economy and the environment is generally explained in
the form of a “Material Balance Models” developed by Alen Kneese and R.V. Ayres.
The material balance models Inputs are bestowed with physical property of energy
which is received from the sun. The resulting output from input carries the same level
of energy. Similar to this, there are wastes resulting from consumption activities.
Materials and energy are drawn from the environment, which are used for production
and consumption activities and returned to environment as wastes. So far as this
balance is maintained, there are no environmental issues. The material balance model
of the economy is given in the Figure 1.
Fig.2 Source: Pidwirny, M. (2006). "The Nitrogen Cycle". Fundamentals of Physical Geography,
2nd Edition. Date Viewed. [2]
The nitrogen cycle represents one of the most important nutrient cycles found in
terrestrial ecosystems (Figure 2). Nitrogen is used by living organisms to produce a
number of complex organic molecules like amino acids, proteins, and nucleic acids. The
store of nitrogen found in the atmosphere, where it exists as a gas (mainly N2), plays
an important role for life. This store is about one million times larger than the total
nitrogen contained in living organisms. Other major stores of nitrogen include organic
matter in soil and the oceans. Despite its abundance in the atmosphere, nitrogen is
often the most limiting nutrient for plant growth. This problem occurs because most
plants can only take up nitrogen in two solid forms: ammonium ion (NH4+) and the
ion nitrate (NO3-). Most plants obtain the nitrogen they need as inorganic nitrate from
the soil solution. Ammonium is used less by plants for uptake because in large
concentrations it is extremely toxic. Animals receive the required nitrogen they need
for metabolism, growth, and reproduction by the consumption of living or dead
organic matter containing molecules composed partially of nitrogen.
2. Statement of the problem
The activities of humans have severely altered the nitrogen cycle. Some of the
major processes involved in this alteration include:
The application of nitrogen fertilizers to crops has caused increased rates of
denitrification and leaching of nitrate into groundwater. The additional nitrogen
entering the groundwater system eventually flows into streams, rivers, lakes, and
estuaries. In these systems, the added nitrogen can lead to eutrophication.
Increased deposition of nitrogen from atmospheric sources because of fossil fuel
combustion and forest burning. Both of these processes release a variety of solid
forms of nitrogen through combustion.
Livestock ranching. Livestock release a large amount of ammonia into the
environment from their wastes. This nitrogen enters the soil system and then the
hydrologic system through leaching, groundwater flow, and runoff.
Sewage waste and septic tank leaching.
3. Model Structure
Nitrogen load of production in Songyuan city
(1)
: Total nitrogen of production
: Nitrogen from farming waste
: Nitrogen from industrial waste
: Nitrogen from disposal waste into river
: Nitrogen from Excretion
Flow balance in commodity market
(2)
: Column vector of the total production of each industry (Figure 3)
: Input-output coefficient matrix.
: Total non-governmental consumption
: Total governmental consumption
: Column vector of the total investment of each industry
: Export of each industry
: Import of each industry
Objective function
(3)
(4)
: Total nitrogen of constraint discharge
NOX
Factitious
fixation
fixation
Fertilizer
NH3
NOX
Arable land
Farming
Crops
Compost
Industrial
Fodder
Food
Stockbreeding
Excretion
Composting
Product
Industry
Excretion
Consume
Disposal
Service
Leavings
Leavings
NOX
Leavings
NOX
Fig.3 Nitrogen flow and classification of the production in Songyuan city
4. Result
The expectant result will reduce the nitrogen discharge having maintained GDP.
References
[1] Callen and Thomas “Environmental Economics and Management—Theory,
Policy, and Applications”—Irwin, USA, p. 6. A slight change in the Figure is
incorporated.
[2] Pidwirny, M. (2006). "The Nitrogen Cycle". Fundamentals of Physical Geography,
2nd Edition. Date Viewed.