Potential for broadacre cropping in the NT

Summary

This is the final report for the Potential for broadacre cropping in the NT project which sought to identify potential crops, the timing and length of the potential cropping windows, and the impacts of climate and edaphic conditions on yield and quality.

This report provides an overview of the research undertaken and outcomes of field trials across the Northern Territory. Data gather from these trials were used to determine the productivity of broadacre cropping systems by applying Agricultural Production Systems sIMulator (APSIM) – to investigate how a range of crop species will perform in terms of production and risk profile across the trial sites. Validation trials were conducted under rainfed and irrigated planting systems.

Validation trials included an intensive in-crop sampling and monitoring protocol to match simulated output to actual plant growth dynamics, including soil sampling to at least 1.5 m with full soil water characteristics being determined. Above ground plant data collected in-crop included crop management records, full phenological monitoring, and at determined intervals leaf area, biomass, plant population and light interception, and crop yields.

A key recommendation from this project was the need for the CRCNA to fund a follow up project with the local dryland cotton and broadacre grains growers to address ongoing and emerging needs of the NT cotton industry. In 2023, the CRCNA funded an additional project (Addressing the fundamentals of cropping-systems that deliver sustainable growth of agriculture sector in the Northern Territory) to align with this and subsequent recommendations, which include:

Investigate solutions to unreliable cotton establishment via a structured and integrated research, development and engagement program developed in consultation with growers, providing more than solutions to the known causes in other crops (high soil temperatures, rapid soil drying and surface crusting) usually due to insufficient soil cover.

Understand the impact of various crop rotation combinations on productivity of cotton via evaluation of options with growers. This may include pre and post crop management, on-ground plant cover and species impact.

Optimise nutrition in terms of quantity and time of application of major and minor elements and exploring alternative nutrient options.

Investigate biosecurity risks associated with cotton and grain rotation system. This can be achieved by monitoring and managing the biological threats by ensuring locally adapted integrated pest management techniques are available and adopted.

Map and characterise the soil water availability for developing the enhanced cotton growth model. The enhanced cotton growth model can be applied on the most ‘suitable’ soils to assess regional yield and input variability, and identify better regions / locations for sustainable cotton production in the region.

Determine social acceptance and soil and landscape suitability for the NT Aboriginal titled land.

Assess application of an economic decision support tool to aid growers’ decision making regarding the type of crops that are viable to develop economically efficient and ecologically sustainable farming systems.

Review the alignment of a range of potential cropping systems within the Territory’s environment and regulatory frameworks.

This project included a co-investment from the Grains Research and Development Corporation (GRDC) and the Cotton Research and Development Corporation (CRDC), with funding reported here as combined CRCNA funding. The project aimed to collate historical broadacre cropping data, natural resource information and market insights to support the development of viable broadacre cropping systems in the Northern Territory. This was achieved through collaboration among project participants, each contributing unique expertise to develop crop management strategies that help de-risk broadacre agriculture in the Top End. The initial focus was on dryland and irrigated systems growing cotton and peanuts, while maize, sorghum, rice and pulse crops were also investigated as potential break crop options for cotton and peanut producers. A combination of field trials and simulation techniques was used throughout the project. On-farm demonstration plots established on commercial properties served two key purposes: To further test crop simulation models To provide hand-on experience for producers and serve as extension sites for promoting agricultural methods to local producers. As part of the project’s extension plan, producers were introduced to simple methods for establishing precision and robustness in on-farm crop trials. The project team worked closely with collaborating farmers to ensure that demonstration plots met their objectives without impeding commercial farm operations. Additionally, researchers explored the potential of harvesting wet-season flood flows into off-stream storages to support dry-season cropping – presenting a viable irrigation alternative that could enable further agricultural development across the Northern Territory. A natural resource (soil and climate) database was developed to support agronomic decision-making. Researchers identified suitable crops, optimal cropping windows, and the impacts of climate and edaphic conditions on yield and quality. These factors were used to assess the productivity of broadacre cropping systems and the potential of diversifying pastoral leases. For crops that are technically viable based on environmental conditions and available resources, market opportunity analysis is also essential to support successful adoption.