WaterSubject

We compare the net present costs of two approaches for managing irrigation-induced deep percolation under border-check irrigated pasture: (1) conversion from border-check irrigation to sprinkler irrigation to minimise deep percolation and (2) installation of a subsurface drainage system to extract excess deep percolation under the existing border-check system. Results for a dairy farm in northern Victoria, Australia, show that conversion to sprinkler irrigation is the more cost-effective approach. The net present cost of the second approach varies across an irrigation landscape, depending ... Read More

On-demand pressurized irrigation systems are designed to deliver water with the flow rate and pressure required by the farm irrigation systems, sprinkling or micro-irrigation, and respecting the time, duration and frequency decided by the farmers. Due to the variation in farm demand along the season and the day, a large spatial and temporal variability of flow regimes occurs in these systems, which may affect the performance of the farm systems and the yields of the irrigated crops. Therefore, there is a need ... Read More

Soil column studies were conducted with two soils to assess the effects of irrigation with wastewater on soil and groundwater quality. Upon the application of wastewater, exchange occurred between solution sodium (Na+) and exchangeable cations (Ca2+, Mg2+, K+), whereby these cations were released into solution. The average exchangeable sodium percentage (ESP) of the soils increased during leaching from 9 to 21 and 28.8 to 29.7 after applying 5.0 and 3.5 l (about 7 and 6 pore volumes) of wastewater to the soils ... Read More

Irrigated agriculture in (semi-)arid regions may exert serious pressures on groundwater resources and jeopardise further agricultural and socio-economical developments. For assessing these pressures, we present in this paper results from a groundwater quality survey performed in 2005 within the irrigated agricultural Triffa plain in north-east Morocco. The study focuses on the physico-chemical and bacteriological quality of the groundwater body within the plain and exploits the correlation and spatial dependency of the quality parameters. It is demonstrated that the water quality in this ... Read More

The actual irrigation water demand in a district in Sicily (Italy) was assessed by the spatially distributed agro-hydrological model SIMODIS (SImulation and Management of On-Demand Irrigation Systems). For each element with homogeneous crop and soil conditions, in which the considered area can be divided, the model numerically solves the one-dimensional water flow equation with vegetation parameters derived from Earth Observation data. In SIMODIS, the irrigation scheduling is set by means of two parameters: the threshold value of soil water pressure head in ... Read More

The actual irrigation water demand in a district in Sicily (Italy) was assessed by the spatially distributed agro-hydrological model SIMODIS (SImulation and Management of On-Demand Irrigation Systems). For each element with homogeneous crop and soil conditions, in which the considered area can be divided, the model numerically solves the one-dimensional water flow equation with vegetation parameters derived from Earth Observation data. In SIMODIS, the irrigation scheduling is set by means of two parameters: the threshold value of soil water pressure head in ... Read More

A greenhouse experiment was conducted at Japan International Research Center for Agriculture Science (JIRCAS), Okinawa Subtropical Station, Ishigaki, Japan with three multiple water application and two single water applications to study the effects of them on tomato yield, soil water content and water use efficiency. Multiple water application is a technique use to add the required amount of water during irrigation in multiple equal parts a day instead of one complete set (single water application) during the irrigation event. The multiple water ... Read More

Nitrate resulting from nitrogen fertilisers used in Agriculture is a widespread contaminant of shallow groundwater and causes adverse effects on human, animal and ecosystem health. In order to evaluate the full extent of groundwater nitrate contamination, and how it might evolve in time, it is essential to understand controls on aquifer assimilative capacity. This level of understanding will also help to better target policies and incentives aimed at controlling the amount of nitrate entering downstream water systems. The potential for nitrate attenuation in ... Read More

Borkhar district is located in an arid to semi-arid region in Iran and regularly faces widespread drought. Given current water scarcity, the limited available water should be used as efficient and productive as possible. To explore on-farm strategies which result in higher economic gains and water productivity (WP), a physically based agrohydrological model, Soil Water Atmosphere Plant (SWAP), was calibrated and validated using intensive measured data at eight selected farmer fields (wheat, fodder maize, sunflower and sugar beet) in the Borkhar district, ... Read More

Second-order rate constants of the direct ozone reactions (kO3,M) and the indirect OH radical reactions (kOH,M) for nine chemicals on the US EPA's Drinking Water Contaminant Candidate List (CCL) were studied during the ozonation and ozone/hydrogen peroxide advanced oxidation process (O3/H2O2 AOP) using batch reactors. Except for the thiocarbamate herbicides (molinate and EPTC), all other CCL chemicals (linuron, diuron, prometon, RDX, 2,4-dinitrotoluene, 2,6-dinitrotoluene and nitrobenzene) show low reactivity toward ozone. The general magnitude of ozone reactivity of the CCL chemicals can be ... Read More