Land Suitability of the Fitzroy, Darwin and Mitchell Catchments. A technical report to the Australian Government from the CSIRO Northern Australia Water Resource Assessment, part of the National Water Infrastructure Development Fund: Water Resource Assessments

[摘要] The Northern Australia Water Resource Assessment (NAWRA) seeks to support decision making for sustainable regional development, by clarifying the scale and nature of the opportunities for agriculture and other users of water resources in three study areas in northern Australia: the Fitzroy in WA; the Wildman, Adelaide, Mary and Finniss in the NT (the Darwin catchments); and the Mitchell in Qld. Together these represent 197,000 km2, predominantly used for extensive livestock grazing.A fundamental input to the assessment of water resource development, principally for agricultural purposes, is an understanding of the soil and landscape resources available. Specifically, an understanding of the suitability of soils for a wide range of crops, planting seasons and irrigation management is vital. This document reports on the work of the NAWRA Land Suitability Activity which produced a set of maps and data for 126 crop x season x irrigation type combinations for all three areas at a spatial resolution of 90m. It also produced land suitability maps and data for aquaculture. A companion report Thomas et al (2018) details the Digital Soil Mapping (DSM) process and outputs which underlie the final crop and aquaculture suitability presented here. A set of 41 crops was considered, including cereals, forages, horticultural, industrial, oilseed, pulses and trees. This list was developed in consultation with the NAWRA Agricultural Viability Activity and was extended through consideration of planting season and irrigation type, including rainfed, based on known or potential viability for northern Australia. A single land suitability framework was compiled that was common to the three Assessment areas and was compatible with existing jurisdictional frameworks. Similarly, a suitability framework was developed for aquaculture.A set of environmental covariates was used in the DSM process to randomly select initial field sites, and subsequently validation sites, in order to collect new data. A total of 736 sites were sampled in the field and combined with a dataset of almost 60,000 existing sites collected north of north of latitude 20º S. From this a range of soil and landscape attributes were modelled and used to produce a set of 17 limitations which were used in the land suitability framework. Soil and landscape variables/factors were determined in the field, through chemical and physical laboratory analyses (386 samples) and through Mid-Infrared Spectroscopy (2,500 samples). The final products are spatially explicit maps and datasets at 90m resolution which comply with the five class conventions of the Food and Agriculture Organisation; ranging from “suitable” to “unsuitable”. The final suitability for each pixel is defined as the most limiting (i.e. highest scoring) limitation. A quantitatively estimated reliability for each prediction is included. Broadly speaking, depending on crop x season x irrigation type there is about 3 million ha of Class 3 or better soil in the Fitzroy catchment, about 500,00 ha in the Darwin catchments and about 1 million ha in the Mitchell catchment.The work presented here represents substantial improvement on the existing information on the suitability of the three areas for the crops and aquaculture species considered, particularly in the Fitzroy and the Mitchell catchments

[发布日期] 2018-07-10 [发布机构] CSIRO

[学科分类] 地球科学(综合)