Cosmic ray probe survey data of soil surface neutron counts and associated soil analysis data across grain growing regions in NSW and QLD

Abstract

This dataset includes cosmic ray probe survey data that details soil neutron counts detected using CSIRO's CosmOz Rover. Cosmic ray probes measure the flux of fast neutrons which is inversely proportional to the amount of hydrogen atoms. Water molecules are the dominant source of hydrogen atoms in soil so they can be measured close to the Earth's surface and used to infer soil moisture content. In addition to the neutron count, the survey data also contains barometric pressure (mb), temperature (℃) and relative humidity (%). These measurements are needed to correct the raw neutron count data by removing influences from atmospheric pressure and water content above the soil surface. Surveys were carried out across the grain growing regions in NSW and QLD, particularly Northern NSW, South-Eastern NSW, and South-Eastern QLD, and were completed over a period of 4 years from 2020-2023. Surveys were completed between 1 and 4 times within this 4 year period for each of the farms. The mobile system has 16 capsules that each measure neutron count at 1-minute intervals and log the GPS locations of each measurement. Survey data is in .csv format with 20 surveys completed across 8 farms. Soil sampling campaigns were completed concurrently with the CosmOz surveys and the data is available in this collection. Soil moisture, bulk density, soil organic carbon, and clay content was measured from each sample and was used to calibrate the neutron count from the surveys. 20 cores were taken at each farm to a depth of 30 cm. Sampling sites were defined using a stratified random sampling scheme based on k-means clustering, where strata were defined using farm characteristics. The available soil data for each farm is in .csv format.

The datasets are stored on the USYD-RDS at \\shared.sydney.edu.au\research-data\PRJ-soilwaternowarchive. This data has restricted access, third-parties need to contact the University of Sydney and the GRDC to access the data according to agreed terms and/or with a data supply and licence agreement. Please contact Dr Patrick Filippi (patrick.filippi@sydney.edu.au) to request access to the data.