3 December 2024. Paul McIntosh, Pulse Australia and WeedSmart.
Had an interesting last week in Nth Qld, presenting at the inaugural GRDC updates in Ayr and Atherton. Part of the presenting team was my olde mate in Stephen Yeates, a principal researcher formerly with CSIRO in the Northern Australia region. Yeatesy really did put up some great research data about growing Mungbeans in the north.
What I took away was that we could even adopt some of the key points that Steve spoke about, for the rest of Queensland and northern NSW.
Both he and our south Qld Mungbean plant physiologist, Dr Kylie Wenham of QAAFI, agree about our Mungbean leaves needing to maximise interception of radiation…..as much radiation or sunlight as they can, as Mungbeanss are fairly low down the list in Radiation Use Efficiency (RUE). Our humble beans certainly require maximum solar radiation interception particularly during grain filling time.
Steve showed some photos of irrigated trial blocks, where one block was much like the solid cropping photo here and the other block was also a beautiful paddock of beans on wider rows with an average row spacing of 75 cms, both with same plant numbers per sq metre.
Admittedly both these large trial areas, were irrigated in that sweet spot of 5 to 10 days before first flowering and 10 days post the first flowering period, however the yield difference was quite spectacular.
With the solid canopy block yielding 2.24 tonne per ha and the still attractive 75 cm row crop at 1.46 tonne per ha, it was chalk and cheese in dollars per ha returns.
He also went on to highlight with his replicated trials, that 97% of irrigation or rainfall moisture events in Mungbean is to cool the leaves.
Kylie also has data on the fact of producing more seeds is a key driver of yield, which is not always obvious to casual observers. Kylie also pointed out in her research at Gatton that seed numbers produced is sensitive to environmental stresses and vapour pressure deficits (VPD). VPD is a more accurate measure to predict plant transpiration and water loss than relative humidity. It basically measures the amount of drying power the air has upon the plant. High VPD creates a thirsty environment and causes the plants to close their stomata to minimise water loss and avoid water tension within the plant. This function usually occurs at the cost of reduced photosynthesis.
They both agreed that water logging from big unavoidable rainfall events or poor irrigation planning on our clean green Mungbean crops, causes root nodules to die back with subsequent nitrogen deficiency issues in the crop.
This not only reduces yields, however also causes delays in crop development and maturity.
So olde and new agronomists learnt plenty in North Queensland this last week, which certainly gives us all more confidence in growing our short and quick does the trick Mungbean crops.
A good solid paddock of Mungbeans in South Queensland.