Key Messages:

• Understanding of growers in N (Nitrogen) decision-making process: This project aims to investigate producers’ nitrogen (N) challenges, seeking to explore conventional practices and critically examine decisions linked to annual planning, N applications, and budgeting that potentially exacerbate perceived risks.
• Nitrogen (N) decisions: The nitrogen (N) decisions theme will utilise a comprehensive system approach to aid growers in evaluating N decision strategies involving both fertiliser application and legume utilisation (crop rotation).

Project Summary:

The Nitrogen Banking Project is a part of RiskWi$e, a National Risk Management Initiative. It is a 5-year initiative by GRDC and CSIRO that will run from 2023 to 2028. It seeks to understand and improve the risk-reward outcomes for Australian Grain Growers by supporting grower on-farm decision-making. This project will study various nitrogen (N) management strategies.

Facey Group will compare how different nitrogen application approaches affect the grain yield and profitability of crop sequences that are relevant to our region. Each treatment will receive N fertiliser to achieve the maximum potential yield based on factors like initial soil water and nitrogen levels, timing of the planting season, and rainfall received so far. Scenarios will be simulated for a typical to above-average growing season finish.

We plan to evaluate these N management strategies over several cropping seasons to understand their long-term impacts. The goal is to determine which strategies lead to higher yields, better grain quality, and improved profitability (measured by gross margin and risk) for farmers. This project wants to help WA farmers optimise their nitrogen decisions by investigating if nitrogen applications can help crops in the future, not just the current growing season even in dry conditions and sandy WA soils.

Project Background:

Crop nitrogen (N) requirements are difficult to predict because they involve significant uncertainty. Nitrogen is a large input cost so deciding how much nitrogen to apply is challenging for wheat and canola farmers. The return on investment from applied nitrogen depends on environmental factors such as when and how much it rains, how much nitrogen is already in the soil, and how much nitrogen may be lost.

Studies show that, after water availability, insufficient nitrogen is the main yield-limiting factor for wheat. In Western Australia, the large crop and lower applications of nitrogen due to high prices have led to a high proportion of Australian Standard White (ASW) wheat being produced. The low proportion of protein produced in wheat crops under these conditions suggests that available nitrogen limits the protein percentage in the grain. Research has also indicated that the problem is worse in years when there’s an average amount of rain or more. These are usually years when farmers can make increased profits due to high rainfall, so missing out on that earning opportunity can have a big impact.

This project will aim to support Western Australian farmers in different ways they can predict nitrogen requirements. Existing methods of planning how much nitrogen to use, only look at one year and don’t take into consideration how nitrogen might help future crops. This makes farmers use less nitrogen than they might need or benefit from in the future. In the eastern states of Australia, new ways of managing nitrogen have helped wheat and other crops grow better in some kinds of soil.  Researchers aren’t sure these ideas will work in WA due to the sandy soils. Growers in WA are already careful with nitrogen applications due to the risk of leaching or volatilisation in sandy soils, and because the soil has limited soil moisture retention.