Lupin yields are holding firm with the application of lime, according to three-year trials in WA that covered a wide range of soils and rainfall.
The trial results clarify earlier reports that showed yield losses averaging 30 per cent at a liming application rate of 2 t/ha under Gungurru lupins at Holt Rock with acid soil conditions.
However, more recent data showed a Merrit lupin yield average of 0.65 t/ha, with liming, consistent with district averages in a sub-par year.
Agriculture WA researcher Chris Gazey said the trials show lupins are unlikely to show yield losses with liming as long as the nutrition levels are adequate. Trial plots were also kept free of weeds and disease to reduce stress. The long-term trials were supported by growers through the GRDC.
Wheat gets a head start
Overall the effects of lime on lupin yields appear to be neutral over time. However wheat has shown yield increases of 50 per cent in some areas.
In a 1996 trial south-east of Merredin, wheat with a tonne of lime applied per hectare showed a yield increase of almost half a tonne per hectare - up from 2.21 t/ha with no lime.
Mr Gazey said farmers should consider applying lime during the wheat phase of their rotation to capitalise on a potential 'nitrogen flush'.
"Growers are encouraged to check soil pH and plant nutrient status regularly, especially after liming."
The long-term payoff is the impact of lime on reducing soil acidity. Agriculture WA has estimated there are about 4.7 million hectares of acid soils in WA which cost growers more than $70 million in lost production each year.
Subprogram 3.4.3 Contact: Mr Chris Gazey 08 9368 3633