Reviewing the Economics of Southern NSW Farming Systems

Reviewing the economics of brown manure cropping systems in southern NSW, reinforces the findings of previous economic analysis; that these systems can be more profitable, at lower risk than cash crop-only systems. Mixed farming systems, with well managed pasture phases remain a very profitable and sustainable farming system for southern NSW.

The original economic analysis was conducted by Robert Patterson in 2012. Using a 1,600ha model southern NSW farm, it found cropping systems that include brown manured legumes can be as profitable as 100% cash crop systems, at much lower cost, with lower risk. The analysis compared continuous cropping where all crops are harvested, against a system where 25% of the crop area is sown to pulse crops which are terminated in spring. A mixed farming system with cropping plus merino sheep was also analysed. The different systems were analysed for cashflow and profitability.

This work has been updated by Chris Minehan in 2022, to assess the impact of very high input prices for fertiliser and some chemicals. Conclusions were the same as the original work, that the lower cost structure of both the brown manure system and the mixed farming system, made them more profitable, with lower risk, compared to the 100% cash crop system.

Under the Inflated Input Price scenario, all three systems had smaller cash surpluses. The mixed farming and brown manure crop systems had large enough cash surpluses originally, that they remained cash positive, even with higher input costs.

Brown manure crops provide complete weed control, plus large amounts of organic Nitrogen and stored soil water for the following crop. Canola crops following brown manured legumes can be more than 50% higher yielding than canola sown after cereal crops, as shown in the example below. Yield increases of 25% are observed regularly in cereals following a BM vetch and canola phase, due to reduced disease pressure from the double break and carryover Nitrogen.

The table below looks at the differences in relevant costs and returns, relating to canola grown on a property in southern NSW in 2021, following on from both wheat and brown manure vetch in 2020. The relevant yield maps are above.