Estimating deep drainage and nitrate leaching from the root zone under sugarcane using APSIM-SWIM

Abstract The Burdekin Delta (BD) is located on the dry-tropical coastal strip in North Queensland, Australia. It is one of Australia's premier sugar producing districts with approximately 40,000 ha of land under sugarcane. Because the BD borders the Great Barrier Reef World Heritage Area (GBRWHA), industry, community, regulatory, and environmental organisations are interested in ascertaining the magnitude of deep drainage and nitrate leaching from the root zone and potential implications for the GBRWHA. Direct measurement of deep drainage and nitrate leaching is difficult, and modelling is likely to play an ever-increasing role in guiding experimental work and decision-making. Here, we describe the collection of drainage and nitrate-leaching related data collected over two cropping seasons at a specific field site within the BD and its use in the calibration and application of a drainage and nitrate-leaching model created within the Agricultural Production Systems Simulator (APSIM) modelling framework with constituent crop-growth, soil–water, and nitrogen transformation modules (Sugar, APSIM-SWIM, Soiln2). Model application indicated that the simulated amount of drainage and nitrate leached over a cropping season compared favourably to that derived from inferred drainage and observed soil–water nitrate concentrations. Subsequent investigation of fertilizer management options using the model identified the timing and amount of both irrigation and fertilizer application as key parameters over which management control might be exploited to minimise deep drainage and flux of nitrate to groundwater.

[1]  Peter J. Thorburn,et al.  Nitrate in groundwaters of intensive agricultural areas in coastal Northeastern Australia , 2003 .

[2]  H. Tiessen,et al.  Root dynamics in plant and ratoon crops of sugar cane , 1992, Plant and Soil.

[3]  Ba Keating,et al.  Sugarcane yield and nitrogen uptake in relation to profiles of mineral-nitrogen in the soil , 1995 .

[4]  R. C. Muchow,et al.  Modelling sugarcane production systems I. Development and performance of the sugarcane module , 1999 .

[5]  M. Robertson,et al.  Final report on SRDC Project CLW002 (previously CSS02 & CSS2S) The role of root growth and activity in determining sugarcane productivity , 1999 .

[6]  L. S. Pereira,et al.  Crop evapotranspiration : guidelines for computing crop water requirements , 1998 .

[7]  P. Thorburn,et al.  Modelling nitrogen dynamics in sugarcane systems: Recent advances and applications , 2005 .

[8]  N. Inman-Bamber,et al.  Crop coefficients and water-use estimates for sugarcane based on long-term Bowen ratio energy balance measurements , 2003 .

[9]  P. Ridd,et al.  Submarine Groundwater Discharge from Paleochannels?: 'Wonky Holes' on the Inner Shelf of the Great Barrier Reef, Australia , 2000 .

[10]  Graeme L. Hammer,et al.  APSIM: a novel software system for model development, model testing and simulation in agricultural systems research , 1996 .

[11]  Neil I. Huth,et al.  Simulating infiltration and the water balance in cropping systems with APSIM-SWIM , 2002 .

[12]  G. E. Rayment,et al.  Australian laboratory handbook of soil and water chemical methods. , 1992 .

[13]  Peter J. Thorburn,et al.  Modelling decomposition of sugar cane surface residues with APSIM–Residue , 2001 .

[14]  R. H. Brooks,et al.  Hydraulic properties of porous media , 1963 .

[15]  R. H. Brooks,et al.  Properties of Porous Media Affecting Fluid Flow , 1966 .

[16]  R. Dalal,et al.  APSIM's water and nitrogen modules and simulation of the dynamics of water and nitrogen in fallow systems , 1998 .

[17]  Kenneth K. Barnes,et al.  Soil and Water Conservation Engineering , 1955 .

[18]  Feike J. Leij,et al.  The RETC code for quantifying the hydraulic functions of unsaturated soils , 1992 .

[19]  Senthold Asseng,et al.  An overview of APSIM, a model designed for farming systems simulation , 2003 .

[20]  Keith Beven,et al.  Dispersion parameters for undisturbed partially saturated soil. , 1993 .

[21]  Peter J. Thorburn,et al.  The fate of nitrogen applied to sugarcane by trickle irrigation , 2003, Irrigation Science.