『Abstract
A set of indices was developed in order to classify the vulnerability
of agricultural land to water and nitrogen losses (LOS), setting
a basis of the integrated water resources management in agricultural
systems. To calibrate the indices using multiple regression analysis,
the simulation results of Groundwater Loading Effects of Agricultural
Management Systems (GLEAMS) model for combinations of different
soil properties, topography, and climatic conditions of a reference
field crop were used as “observed values.” GLEAMS quantified (1)
the annual losses of the percolated water beneath the root zone,
(2) the annual losses of the surface runoff, (3) the annual losses
of the nitrogen leaching beneath the root zone, and (4) the annual
losses of nitrogen through the surface runoff, which were used
to calibrate the following indices LOSW-P, LOSW-R, LOSN-PN, and
LOSN-RN, respectively. All the simulations to gain the LOS indices
were carried out for the same reference field crop, the same nitrogen
fertilization, and the same irrigation practice, in order to obtain
the intrinsic vulnerability of agricultural land to water and
nitrogen losses. The LOS indices were also combined to derive
nitrogen concentrations in the percolated and in the runoff water.
Finally, the connection of LOS indices with the groundwater was
performed using an additional equation, which determines the minimum
transit time of the percolated water to reach the groundwater
table.
Keywords: LOS indices; GLEAMS model; Leaching; Runoff; Agrochemicals』
1. Introduction
2. Methodology
2.1. GLEAMS V3.0 model description
2.2. Reference field crop characteristics
2.2.1. Topography
2.2.2. Soil physical-hydraulic properties
2.2.3. Soil biochemical properties
2.2.4. Irrigation
2.2.5. Fertilization
2.2.6. Meteorological conditions
2.2.7. Scenarios
2.3. LOS indices
2.4. Ground and surface water pollution from agricultural land
3. Conclusions
Acknowledgments
References