Estimation of infiltration and deep drainage in a furrow-irrigated sodic duplex soil

Abstract

Infiltration and deep drainage fluxes are difficult to measure directly in slowly permeable soils under furrow-irrigated upland crops such as maize (Zea mays L). This paper combines a solute mass balance model and a furrow irrigation advance model to provide an estimate of these fluxes, indirectly from simpler measurements. The models were applied to a newly cleared sodic duplex soil from the Burdekin River Irrigation Area, north Queensland, where no field measures of infiltration and deep drainage were available. The study site was sown to consecutive furrow-irrigated crops after clearing. In applying these models, measures of soil and irrigation water chloride, irrigation water applied, furrow geometry and irrigation advance were required. Estimated infiltration and deep drainage decreased with distance down the furrow from 1044 and 98 mm year-1 at 50 m to 966 and 0 mm year-1 at 260 m. In an area that received an application of gypsum (20 t ha-1) prior to planting the second crop, values ranged from 1617 and 200 mm year-1 at 50 m to 1370 and 70 mm year-1 at 260 m. Infiltration did not satisfy the estimated soil water deficit unless gypsum was applied. Where gypsum was applied, infiltration exceeded the soil water deficit and deep drainage increased. Evapo-transpiration rate and maize yield also increased. If correct, these results have local and regional implications for irrigation design and management.

The Australian Cotton Industry and four decades of deep drainage research: a review

“…For instance, Smith et al (2005) found that deep drainage could be halved using optimised management of furrow irrigation. The data of Dowling et al (1991) from furrow irrigation in the Burdekin are comparable to the data from cotton sites (Fig. 6).…”

“…The new equilibrium under irrigation involved cases of both increased (salinisation) and decreased soil Cl. Dowling et al (1991) used similar methods on a furrowirrigated, sodic duplex soil in the Burdekin, North Queensland, with and without applied gypsum. Deep drainage was highest at the head-ditch end of the field (98 mm/year, without gypsum) and decreased towards the tail-drain (0 mm/year), or 200 and 70 mm/ year with gypsum.…”

“…from neutron moisture meters and capacitance probes) as evidence of no drainage. Figure 8a is an example of such data from a Black Vertosol in the Gwydir valley (Silburn Dowling et al (1991) in northern Australia. and Montgomery 2004).…”

“…) Native vegetation stripsContinuity of sandy beds/aquifers in clayey alluvia Vertical connectivity in multi-aquifer systems Groundwater ,few monitoring bores in shallow aquifers Unsaturated zone capacity and status, time lag Stream incision not surveyed Diffuse groundwater discharge e.g. water use by trees Seasonal deep drainage measured at head, mid and tail positions in furrow-irrigated fields after excluding unusual occurrences (coded B by authors) and the first year of data (adapted fromGunawardena et al 2011) and for a sodic duplex soil in the Burdekin(Dowling et al 1991) using total infiltration instead of rainfall plus irrigation, at 50 m (highest drainage), 125, 200 and 260 m (lowest drainage) along the furrows.…”

Towards effective control of deep drainage under border-check irrigated pasture in the Murray-Darling Basin: a review

“…Likewise, irrigating with water of high sodium content (relative to calcium and magnesium) may lead to sodification and reduced permeability (Ayers 1977). Conversely, the application of gypsum to sodic soils may increase soil permeability (Taylor and Olsson 1987), leading to greater infiltration and D (Dowling et al 1991).…”