30 Sep 2024. Paul McIntosh, Pulse Australia and WeedSmart.
Another large week of learning there was for me at the UniSQ in Toowoomba.
Once again these microscopic eel like organisms called nematodes, do so much unseen damage to your crops root system ability to extract nutrition and moisture from the soil.
Symptoms in wheat can be stunting, yellowing of bottom leaves, poor tillering and lack of biomass and lots of wilting when the season runs a bit dry. All very subjective methods of above ground indicators. I know myself that you can explain these symptoms away due to being a bit dry, very cold weather blast lack of Nitrogen or Phosphorous in the root zone or even just a “doughy” (read: poor) variety of wheat.
Of course it is not just wheat affected, if these nematodes with names like Pratylenchus Thornei ( Pt) or Pratylenchus Neglectus (Pn) are present in damaging numbers in your soil. Other crops like barley, chickpeas, soybeans, grain sorghum and faba beans can all suffer from the yield depressing fate of either of these nematode species. Of course, variety choice can play a part in this yield reducing impact of nematodes as well. So not only species, but variety as well.
Thankfully enough testing has been done over the years by Professor John Thompson and his team, originally at DAF Qld and then passed onto UniSQ, that we gain more knowledge each year on these damaging pests. Crops that have low impact levels from Pt or Pn are humble plants like millet, maize, sunflowers, cotton plus older out of fashion crops like canary and linseed
Needless to say you don’t want to have your cropping choices determined by these pesky below-ground easily-spread-around critters. So you can test your soil to determine pre-plant what your level of risk might be - but do we take advantage of this service?
Rob Long an old agronomy mate from Moree, realised many years ago (or it could be decades, sorry Rob), that utilising a South Australian Research Institute test process called Predicta B was a way of measuring the nematode levels in your soil. Sounds very good and practical doesn’t it, until the amazing fact presented by Rob last week was that only 1500 Predicta B tests are done in Australia each year. Compare that to around 300,000 soil tests for nutrition are done each year. Now Predicta B does more than test for nematodes, it can also test for crown rot plus 11 other soil issues like Phytophthora root rot.
It was quite staggering when Rob also did an approximate analysis on lost grain production from these below-ground issues we all may have.
With yield impacts of around 20% each year by nematodes and another potential 30% by crown rot, how much yield are we loosing in our grain growing areas?
So Crown Analytical Services in Moree can certainly deliver this soil analysis test to predict the impacts on your following crops by nematodes and other soil diseases and your local agro can even take the simple soil test required.
Get with it folks and look to unseen issues in your soil, that can be tested for by a humble soil test in your paddock.
Wheat crop on Darling Downs in 2020 looking unthrifty.