Information
Level 2 Detail of experimental conditions (what might be found in a journal paper or project brief in Hydstra)
Description of study
What?
A farm system modelling study analysed the impact of current management practices on water and nitrogen loss below the root zone and identified viable alternative management practices for reducing these losses.
When and Where?
The study is based on seven farms in the Panatana catchment that represent the typical range of soil, crop and management practices evident in the region.
How?
Interviews were conducted with each farmer to collect key management details relating to crop sequence (Figure 1), cultivar selection, crop establishment (e.g. sowing date, seeding rate), nutrient management, irrigation management, tillage practices and residue management.
Farmers were also asked to provide estimates for crop yield to enable comparison with simulated values. Rotations for the seven farms are comprised of up to five annual crops including a range of vegetable crops (i.e. potato, broccoli, fresh pea, green bean), poppy and wheat. All rotations have a pasture phase of between 2-6 years in duration and fodder ryegrass is commonly grown in-between summer crops to reduce drainage and to provide valuable winter feed for stock (Figure 1).
Nitrogen fertiliser was applied at sowing and as a top-dressing later in the season. Irrigation water was used on all farms. Each farm had a focus on minimising tillage and retaining crop residues in order to maintain soil health and nutritional status.
One soil on each farm was fully described and characterised to a depth of ~120cm and these results were used to parameterise model configurations for each farm. Each simulation used long-term daily temperature, radiation and rainfall data for the Devonport Airport (41.7°S, 147.1°E), sourced from the SILO database. For each farm, a series of separate model runs offset by one year (the number of runs determined by the number of crop elements in the rotation) were conducted such that each element of the crop rotation was simulated in every year of the 25-year period from 1980 to 2005.
Soil, management and climate data/information collected from each case farm was used to calibrate and parameterise the farming system model, Agricultural Production Systems Simulator. Model output from the baseline (current management) runs was used to analyse system water and nitrogen balances and, more specifically, the extent of water and nitrogen ‘leakage’ from these systems and the mechanism and source of loss. The final step was to identify and analyse a number of practical, alternative management options that have the potential to reduce nutrient and water loss while maintaining productivity.
Project administration
Site identifier code: N/A
Principal investigator: Lisson S & Cotching B
Principal data manager: N/A
Principal organizations: CSIRO Sustainable Ecosystems, Tasmanian Institute of Agricultural Research
Data custodian: CSIRO Sustainable Ecosystems
Key co-operators: N/A
Data access policy: Research has been published but base data is not archived
Planned pathway for data: completed study, no evidence of formal database records.
Data warehousing: for ongoing studies -na
Planned data upload frequency: for ongoing studies -na
Key references and sources of this data synthesis
These data summaries have been extracted from:
- Lisson S & Cotching B. (2010) Strategies to reduce nitrate leaching losses from intensive crop production in northern Tasmania. 15th Australian Agronomy Conference. Australian Society of Agronomy.
Keywords:
Nitrate leaching, drainage, nitrogen, farm system modelling