416
T. Hishinuma et al.
protective conservation-type agriculture. The quantity of artificial fertilizers and crop
protection chemicals applied to agricultural fields in these systems were 91 kg N/ha
and 56 kg/ha, respectively, reductions of 60–70% from the amount of these inputs
used in 1992 (Ministry of Agriculture Forestry and Fisheries 2018).
On the other hand, applying organic fertilizers or composted livestock manure to
agricultural fields could lead to excess levels of nutrients in the soil, because the use
of low-nutrient compost requires the application of much larger volumes, compared
with the high-nutrient artificial fertilizers (Mishima and Kimura 2004). In addition,
the input of organic fertilizer to rice paddies, instead of artificial fertilizers, increases
methane emissions (Masuda and Tomioka 2013). Furthermore, the environmental
impact associated with the agricultural system should take into account not only direct
emissions from agriculture, such as greenhouse gas and acidification gas emissions,
and nitrogen and phosphorus leaching from the soil, but also indirect emissions, such
as from the manufacture of such inputs.
The life-cycle assessment (LCA) technique is a useful measure to reveal the
environmental impact of component elements of agricultural production systems.
Because the production of artificial fertilizers and crop protection chemicals
consumes large amounts of fossil fuel, low-input agriculture can be effective at
mitigating eutrophication and reducing global warming potential, such as with
conservation paddy rice farming systems (Kurosawa et al. 2007).
In this current study, we evaluated the environmental impact of paddy rice
farming systems, comparing conservation-type systems applying organic fertilizers
or composted animal manure relative to the use of artificial inputs in a conventional
system, using scenario analysis with process-based LCA.
27.2 Materials and Methods
27.2.1 Framework of Evaluation
In this study, LCA and farmgate balances (FGB) approaches were used to quantify
the environmental impacts from different paddy rice farming systems, in terms of gas
emissions and the potential of T-N and T-P leaching into water bodies (Fig. 27.1). The
process model of the paddy rice farming system was set as the same, to compare the
environmental impacts between the environmental conservation-type system and the
conventional type system with respect to the differences in inputs, ignoring the differences in working processes and machinery usage. The collected data and amounts of
inputs and rice yield from each scenario were applied to the process model and were
assessed in terms of environmental impacts, using LCA and FGB. The LCA technique
is a method by which environmental aspects and the potential impacts of a production system (considered as a process chain) can be analyzed throughout a product’s
life-cycle (ISO 2006). In this study, environmental impacts from the different rice
paddy farming systems were compared by scenario analysis using the LCA method,
T. Hishinuma et al.
protective conservation-type agriculture. The quantity of artificial fertilizers and crop
protection chemicals applied to agricultural fields in these systems were 91 kg N/ha
and 56 kg/ha, respectively, reductions of 60–70% from the amount of these inputs
used in 1992 (Ministry of Agriculture Forestry and Fisheries 2018).
On the other hand, applying organic fertilizers or composted livestock manure to
agricultural fields could lead to excess levels of nutrients in the soil, because the use
of low-nutrient compost requires the application of much larger volumes, compared
with the high-nutrient artificial fertilizers (Mishima and Kimura 2004). In addition,
the input of organic fertilizer to rice paddies, instead of artificial fertilizers, increases
methane emissions (Masuda and Tomioka 2013). Furthermore, the environmental
impact associated with the agricultural system should take into account not only direct
emissions from agriculture, such as greenhouse gas and acidification gas emissions,
and nitrogen and phosphorus leaching from the soil, but also indirect emissions, such
as from the manufacture of such inputs.
The life-cycle assessment (LCA) technique is a useful measure to reveal the
environmental impact of component elements of agricultural production systems.
Because the production of artificial fertilizers and crop protection chemicals
consumes large amounts of fossil fuel, low-input agriculture can be effective at
mitigating eutrophication and reducing global warming potential, such as with
conservation paddy rice farming systems (Kurosawa et al. 2007).
In this current study, we evaluated the environmental impact of paddy rice
farming systems, comparing conservation-type systems applying organic fertilizers
or composted animal manure relative to the use of artificial inputs in a conventional
system, using scenario analysis with process-based LCA.
27.2 Materials and Methods
27.2.1 Framework of Evaluation
In this study, LCA and farmgate balances (FGB) approaches were used to quantify
the environmental impacts from different paddy rice farming systems, in terms of gas
emissions and the potential of T-N and T-P leaching into water bodies (Fig. 27.1). The
process model of the paddy rice farming system was set as the same, to compare the
environmental impacts between the environmental conservation-type system and the
conventional type system with respect to the differences in inputs, ignoring the differences in working processes and machinery usage. The collected data and amounts of
inputs and rice yield from each scenario were applied to the process model and were
assessed in terms of environmental impacts, using LCA and FGB. The LCA technique
is a method by which environmental aspects and the potential impacts of a production system (considered as a process chain) can be analyzed throughout a product’s
life-cycle (ISO 2006). In this study, environmental impacts from the different rice
paddy farming systems were compared by scenario analysis using the LCA method,