5 things to keep in mind when dry sowing.
Here in SA, we’ve gotten used to dry sowing and what it entails—from how deep to sow our seed to how to best knock out any competition in the crop. Not only is our topsoil lacking moisture from these tough seasons, but the subsoil is suffering badly. Last year’s cereal crop roots extracted all the moisture they could to yield their best, and we’ve hardly had enough rain to replenish it.
There are risks associated with both early and late sowing. Too early, and there may be poor establishment, frost, and weed risks. Too late, and there might be insufficient growth to achieve high yields and the risk of heat stress during grain fill. On top of that, it’s a logistical headache for most growers to try to get every crop sown within the optimal time frame.
So if you are thinking of dry sowing, here are 5 things to keep in mind.
1. Germination of Weeds Alongside Crop
Early sown crops do run the risk of increased competition from weeds. Unfortunately, this does increase our reliance on in-crop selective herbicides and adds to the potential for herbicide resistance. (Another reason why it’s important to keep up an extensive summer spraying program). To reduce the risk, try to implement dry sowing when weed seedbanks are low or only in clean paddocks. Given the dry and relatively weed-free summer we’ve had in the Mid-North, we expect that when the first rains come, there will be a fair amount of weed germination and competition. A pre-emergent herbicide is a vital aspect of dry sowing. Be sure to know what products you’re planning on putting out and how they will perform under various conditions.
2. Should You Be Worried About Frosts During Flowering?
We will not advise you to sow to avoid frost, but it should be something to keep in mind. Studies in WA have shown that dry sowing only had a slight increase in the areas of wheat frosted during flowering compared to late wet sowing – even in high-risk areas. In most cases, the study found that the potential yield advantages from early dry sowing outweighed the damage of increases in area frosted. Across a whole farm situation, growers reported that they found the higher yields from early sowing offset the frost damage in specific areas. The decision to dry sow or not had a negligible impact when looking at whole-farm yields. We recommend choosing appropriate seed varieties for your area and sowing multiple varieties to help mitigate the risk of frost by manipulating flowering dates, as well as implementing other frost mitigation tactics – for example, check out our article on creating Frost Zones here.
3. Check Seed Depth To Avoid Seedling Stress From False Breaks
Light rainfall events do have the potential to start early germination. And if moisture doesn’t keep up, crop conditions can become poor. However, as we have seen in the past few years, wheat seeds remain exceptionally resilient even if no rain has fallen for weeks. An experiment done in WA by Andrew Heinrich has proven the resilience of wheat to survive in dry, hot conditions and still emerge with vigour once rain is received. Once you start sowing, if moisture conditions decline and rain isn’t seen, the risk of a crop not emerging is minimal. The key is to be mindful of sowing depths when it comes to dry sowing. You want to sow seed at the deeper end of the recommended range to reduce the risk of partial germination on light rain.
4. Don’t Get Too Carried Away.
Dry sowing can give you the time to complete large-scale cropping programs without the headache of racing the rain. Early dry sowing also helps mitigate any problems like machinery breakdowns that otherwise make seeding really stressful. The main point here is not to get too carried away. Remember that the crops will only come up when it rains. Whether you’ve finished three weeks before rainfall or just a week before, crops can only germinate after the opening break. Work regular hours, take a decent lunch break and leave the rest to nature. Just try to ensure seed varieties are sown in their ideal sowing window for your area.
5. Good Chance of Improved Yields
Most importantly, early sowing can help boost crop yields and improve crop performance due to a longer growing season. With a longer growing period, plants can put their full strength into maximizing grain fill in spring. Dry sowing means seeds can start to grow in warmer soil conditions and get good early vigour. On the other hand, seeds that are sown after a break are planted into cooler soil temperatures and generally lack vigour by comparison. Having an established crop in spring also reduces the risks of an end-of-season heat stress event, which also helps yield potential. A dry sown crop also make use of every millimeter of rainfall. Whereas crops sown after rainfall will lose soil moisture through the opening of the soil in the seeding pass. Dry sown crops will harvest every millimeter, and knife point press wheel furrows will increase moisture into the bottom of the furrow where the seed is ready to germinate.