Australian Mungbean Association

Australian-grown mungbeans have quality written all over them!

Solving the leaf chlorosis mystery

7 March 2017

by Paul McIntosh, Pulse Australia

 

Well it has been a rugged summer for most crops and many mungbean crops have certainly been struggling in the heatwave conditions. For the most part, many of us have been amazed at how tough little mungbean plants have been in the extreme hot and dry conditions.

One question that keeps arising is inter-veinal chlorosis, where plants have distinct yellowing between standout greenish veins. In the last few years there has been plenty of discussion amongst agronomic advisors, nutritional experts, crop experts and farmers over the cause of this discolouration and, in some cases, leaf crinkling.

Questions have been asked as to whether it is related to a particular variety or is it a nutritional toxicity or deficiency, an imbalance of elements within the plants or is it something completely different. All of these possibilities could explain the physical symptoms observed in the field but there has not been a definitive answer.

The evidence through weight of many observations and combined with both soil and tissue tests is certainly leading us to the conclusion that the problem is manganese deficiency. Although unconvinced for a long time myself and wondering how an element that is usually in abundance in our soils can be the deficient element in the plants I have come to accept it as the most probably cause of the yellowing and associated leaf crinkling seen across some mungbean paddocks.

Plant nutrition experts explain that high nitrate levels within the plant can induce manganese deficiency in plants. This highlights the importance of correct inoculation procedures and effective nodulation, or the practice of having large amounts of nitrogen available in your soil.

Mungbeans, like other legume crops, often grow out of this induced deficiency state as their root systems develop and soil moisture levels improve.

If you have other experiences to share, please call me on 0429 566 198 or send an email to paul@pulseaus.com.au  If you have used a foliar manganese spray in your mungbean crop, even as a shotgun method, I’d be very interested to know how it went on your crop.

 

Further information:

Mungbean nutrition

www.mungbean.org.au