101 Questions answered
Best Crops for Dispersive Soils: Triticale, Select Oats, and Tailored Choices
This is a tough one to answer as dispersive soils can come with a range of other issues (high pH, boron toxicity and salinity to name a few) that also impact crop growth. The best first step is to test the soil to work out what the main issues are and use these as a guide to choosing crop varieties. For example, if high salinity is also an issue, salt tolerant crops are the way to go.
If dispersion leads to regular waterlogging, choose crops more tolerant of this. Grain legumes have varying tolerance to waterlogging from faba bean > yellow lupin > grass pea > narrow-leafed lupin > chickpea > lentil > field pea.
The overall winner is probably Triticale, which is best adapted to alkaline and waterlogged soils, and also tolerates sodic soils and soils high in boron.
Some oat varieties also fare well in saline-sodic soils. SAGIT trials from 2017 to 2020 tested oats in the lab and then the field, concluding that oats that yield well on saline-sodic soil (salinity ~7 dS/m, ESP 60% from 0–20 cm) include:
- Bannister, Bilby, Mitika, Williams, Echidna and Kowari for grain yield. They out-yielded Mace bread wheat and Aurora durum wheat, and had a similar yield to Compass barley.
- The most tolerant hay oats were Kangaroo, Wintaroo and Mulgara.
Pasture oats, e.g. Bond, Wizard, and overseas oat varieties did not tolerate the saline-sodic soil. Crop varieties are regularly released so check first.
Based on the southern region Lentil grow notes, tolerance to sodicity in the root zone is: faba bean> field pea > canola > lucerne, chickpea, lentil, lupins. From research in WA, lentils and chickpeas don’t like ESP values of 10% or higher.
Safflower seems to be less tolerant to sodicity than canola and wheat (https://sagit.com.au/project/evaluating-super-high-oleic-acid-safflower-in-sodic-and-saline-soils-s-ua921/)
