management practices affecting microbial populations. Enzymes may thus be a
vehicle of both increase and reduction of nitrogen availability and therefore
impact on nitrogen-footprint in a positive or negative way.
Keywords
Enzymes Á Footprint Á Nitrogen Á Soil
1 Introduction
This chapter looks at the role that soil enzymes may play in determining Nitrogen
(N) Footprints. Climate change and increased global demand for food and energy are
consequences of an exponential growth in the world population. The need to produce more food requires greater agricultural production which will necessarily mean
higher nutrient availability requirements. Future global food demand can be met by
continuing the on-going agricultural intensification and the reliance on inorganic
fertilizers or alternatively through an Input–Output optimization at the farm level to
increase N use efficiency (NUE). Different production paradigms have different
implications in terms of N management (and N pollution) for a nutrient that indispensable for food production [1]. Furthermore, there are other pathways of N
management between where N is used in food production and eventually appears
“on the table” (e.g. transportation, energy production, wastewater treatment) [2].
While meeting food demand by intensifying agriculture and using more fertilizers, N
pollution will also continue to increase unless action is taken to reduce losses to the
environment. Although nitrogen is indispensable for food production, N losses lead
to a series of negative impacts on human and environmental health. The N-footprint
concept was created in 2011 as a tool to allow individuals and institutions to
understand how their personal behaviour influences N losses to the environment.
The quantification of the N lost as a result of food and energy consumption, as a
N-footprint, allows us to take action with the objective of reducing N-footprints at
different levels, with the ultimate goal of reducing the global amount of reactive N
released by human activities. The calculation of N-footprint depends upon the calculation of crop- and country-specific virtual nitrogen factors (VNF) defined as the
units of reactive N released to the environment per unit of reactive N consumed in
the process [3]. VNFs are specific for each crop and region and the ‘Applied N’ is
only a part of the chain of N losses considered (see example in Fig. 1). Increasing
nitrogen use efficiency (NUE) in soils to reduce Applied N losses is a major challenge. For example, estimated N losses from agricultural soils to the environment for
the EU28, through gaseous emissions, leaching and runoff, are approximately 50%
or greater of the N inputs to agricultural soils (including atmospheric deposition) [4].
The remaining 50% being recovered by crops (field losses associated with imported
crops are not considered). Increasing our understanding of the role of enzymes and
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C. M. d. S. Cordovil et al.
vehicle of both increase and reduction of nitrogen availability and therefore
impact on nitrogen-footprint in a positive or negative way.
Keywords
Enzymes Á Footprint Á Nitrogen Á Soil
1 Introduction
This chapter looks at the role that soil enzymes may play in determining Nitrogen
(N) Footprints. Climate change and increased global demand for food and energy are
consequences of an exponential growth in the world population. The need to produce more food requires greater agricultural production which will necessarily mean
higher nutrient availability requirements. Future global food demand can be met by
continuing the on-going agricultural intensification and the reliance on inorganic
fertilizers or alternatively through an Input–Output optimization at the farm level to
increase N use efficiency (NUE). Different production paradigms have different
implications in terms of N management (and N pollution) for a nutrient that indispensable for food production [1]. Furthermore, there are other pathways of N
management between where N is used in food production and eventually appears
“on the table” (e.g. transportation, energy production, wastewater treatment) [2].
While meeting food demand by intensifying agriculture and using more fertilizers, N
pollution will also continue to increase unless action is taken to reduce losses to the
environment. Although nitrogen is indispensable for food production, N losses lead
to a series of negative impacts on human and environmental health. The N-footprint
concept was created in 2011 as a tool to allow individuals and institutions to
understand how their personal behaviour influences N losses to the environment.
The quantification of the N lost as a result of food and energy consumption, as a
N-footprint, allows us to take action with the objective of reducing N-footprints at
different levels, with the ultimate goal of reducing the global amount of reactive N
released by human activities. The calculation of N-footprint depends upon the calculation of crop- and country-specific virtual nitrogen factors (VNF) defined as the
units of reactive N released to the environment per unit of reactive N consumed in
the process [3]. VNFs are specific for each crop and region and the ‘Applied N’ is
only a part of the chain of N losses considered (see example in Fig. 1). Increasing
nitrogen use efficiency (NUE) in soils to reduce Applied N losses is a major challenge. For example, estimated N losses from agricultural soils to the environment for
the EU28, through gaseous emissions, leaching and runoff, are approximately 50%
or greater of the N inputs to agricultural soils (including atmospheric deposition) [4].
The remaining 50% being recovered by crops (field losses associated with imported
crops are not considered). Increasing our understanding of the role of enzymes and
134
C. M. d. S. Cordovil et al.