Title:Influence of soil hydraulic variability on soil moisture simulations and irrigation scheduling in a maize field
Abstract: Hydrological models play a crucial role for their ability to simulate
water movement from soil surface to groundwater and to predict onset of stress
conditions within agricultural fields. However, optimal use of mathematical
models requires intensive, time consuming and expensive collection of soil
related parameters. Typically soils to be characterized exhibit large variations
in space and time as well during the cropping cycle, due to biological processes
and agricultural management practices: tillage, irrigation, fertilization and harvest.
This paper investigates the variability of soil hydraulic properties over a cropping
cycle between April and September 2015, within a surface irrigated maize field (6 ha)
located in northern Italy. To this aim, undisturbed and disturbed soil samples were
collected from different locations within the study area and at different depths,
during three measuring campaigns, at the beginning, in the middle of the cropping
season and after the harvest. For each soil sample, several parameters were monitored:
organic matter and bulk density together with soil hydraulic parameters.
Soil parameters of Soil water retention curve parameters were measured following
the evaporation method, while the saturated hydraulic conductivity was determined
in the laboratory using the well-known falling head method. Results show that soil
properties, mainly the saturated hydraulic conductivity, are subjected to
significant variations. The variability of these parameters was taken into
consideration when simulating soil moisture using FEST-WB model.
An improvement in soil water content simulations was observed as compared
to field measurements with implications on prediction of water stress
conditions that is fundamental for irrigation scheduling