Are the nutrients in your soil balanced and bioavailable? Could you be wasting money on over-fertilising some of your paddocks? Perhaps your one underperforming paddock just needs a dose of lime? There’s one way to answer all of these: Do a soil test. Soil testing is the easiest way to ensure you’re doing the right thing to improve soil health and crop productivity.
Here are our top five reasons why soil testing could benefit your paddocks.
1. Determine soil pH.
Crops grow best in neutral pHs between 6.0 and 7.0, where they can access nutrients more efficiently. Some areas, like the Mid North, have naturally more acidic soils. However, it’s generally the case that agricultural practices will cause soil acidification over time. In particular, ammonium-based fertilisers can be major contributors to soil acidification, especially in situations where the nitrogen is leached rather than taken up by plants. Low soil pH can restrict plant productivity and reduce nutrient availability. Poor soil pH means poor productivity and thus poor yields. So it’s an important issue to fix. Soil testing can help determine which paddocks might be more acidic and might require an application of lime to help improve pH levels and prevent production losses.
2. Get more efficient fertiliser use.
Everything we grow requires nutrients from the soil. It’s essential to understand what nutrients crops have used up and what needs replacing. After each harvest, Nitrogen (N) and Phosphorous (P) are removed from the soil, so we naturally look to replace them each following season. However, how do you know exactly what was used and whether you’re efficiently replacing nutrients or not? As a start, you can look to charts, (like in our article here), to gauge what might’ve been used up. But they can be prone to errors due to variations in yields. It’s possible you could be over-fertilising some paddocks where P is not needed (what a waste of cash in a year like this!) and under-fertilising in others.
To get a straight answer, get a soil test done. This will tell you precisely what is available in the soil and what fertiliser you’ll need to apply—potentially saving you thousands. At the very least, you can have peace of mind that you’ve spent money wisely and have optimised your fertiliser application.
3. Determine and correct nutrient deficiencies.
Like above, we need to know what nutrients we’re taking out to replace them efficiently. Many soils in our areas are deficient in trace elements. And addressing them is beneficial to crop productivity. Just because you may not have seen trace element deficiencies in recent years does not mean they can’t occur. Our soils are most likely to be deficient in zinc (Zn), copper (Cu), and manganese (Mn), and of these, Zn is probably the most important. Zn deficiency can severely limit annual pasture legume production and reduce cereal grain yields by up to 30 per cent. Cu is also highly important. Overall, plant health and access to sufficient trace elements will increase tolerance to stresses such as drought, frost and disease damage. So you can see why it’s essential to correct trace element nutrient deficiencies as much as nitrogen and phosphorous. Plant testing is a reliable method, but you may also get a good idea at the start of the season by doing soil tests.
4. Find and fix any soil structure issues.
Soil salinity and sodicity can be big issues and significantly reduce crop yields.
Salinity is the presence of soluble salts in the soil. Too many of these in the root zone of crops will reduce plant growth through either osmotic stress (it reduces the plant’s ability to extract soil water) or specific ion toxicities (such as chloride toxicity and imbalances in ions needed for plant function).
Sodicity is the presence of excess sodium and decreases plant growth by slowing root growth. The excess sodium at the cation exchange sites in the clay particles impacts plant growth by creating high soil strength and limiting gas exchange in the rhizosphere. This further limits plants ability to take up water by sealing off the soil pores so that roots and water can’t penetrate.
Both issues can have a massive influence on crop yield as they influence nutrient and water uptake. Fortunately, both issues can also be fixed with an application of gypsum!
(If you want to get technical: Gypsum will help improve soil structure in saline soils so that leaching can effectively remove salts from the root zone, and it also helps reclaim sodic soils where the gypsum supplies calcium and the calcium displaces the excess sodium held on the clay-binding sites).
But determining when soil salinity and sodicity is becoming a problem (apart from when it’s too late) is best done early via a soil test.
5. Our agro’s are pleading to dig up your bad paddocks and make them good again.
Being highly motivated young specimens, Sam and Caleb at Saddleworth and Angus at Kadina want nothing more than to escape the confines of the office and go examine your worst paddocks. It’s tragic really, but they are determined to make your paddocks as productive as possible. And there’s only so much they can do from the desk. They need to know what’s happening in that wormy darkness below the layer of crusted dust and dried stubbles. Their utes are filled with diesel, buckets and bags are packed, and they’re sitting waiting patiently for your phone call.
So, if you’re keen on improving yields this year, or want to make sure you’re not wasting money on the dearest fertiliser we’ve seen in a decade, or if you feel sorry for our lads and want to let them out of their cages, call us now and book in a test.
P.S. Check out this timeline guide from GRDC.