The Hot, Dry Season StrategyApril 15, 2016 | Category: Agronomy |
There are some reasonably credible weather predictions that 2016 may be warmer and drier than usual.
Is it reasonable to consider some strategies that could capitalize on opportunities or mitigate the losses that extreme weather might bring our way? I think so. However, you will need to assess my suggestions as to whether they are sound practices with little downside, or practices that might have some negative impacts on your operation if the weather forecast does not turn out to be accurate.
- Get Longer Season Hybrids. Capitalize on the additional yield potential that could come your way by adding some longer season hybrids to your portfolio. This suggestion makes most sense to those producers who are normally conservative in their hybrid CHU selections.
- Switch-up Planting Order. Normally producers plant their longest hybrids first and as the planting season progresses, switch to their shorter CHU hybrids. This can result in many fields pollinating in roughly the same window. In the case of a hot, dry summer prediction, it might be less risky to spread pollination out as much as possible. This could be accomplished by planting some shorter CHU hybrids early and move some of your longer season hybrids to somewhat later in the planting window.
- Mixing Hybrids. In stressful weather conditions, pollen supply can sometimes precede receptive silks and make pollination less successful. One way to try and manage around this would be to add a hybrid to the planter that silks 3-5 days later than the dominant hybrid in the field. For example, 75% of the field is to be planted with a 2850 CHU hybrid and we mix in 25% of the seed of a 2950 CHU hybrid with similar traits and plant height. The aim here is to ensure adequate pollen supply for the vast majority of the field, even if hot, dry conditions disturb the natural pollination synchrony.
- Conserve Soil Moisture – Reduce Spring Tillage. Keep spring tillage to the minimum required to produce a good seedbed. Spring secondary tillage should be level, shallow and fast. Avoid the temptation to do too much tillage, as it will dry the soil and reduce aggregate stability; you will need all the soil structure and porosity possible to ensure maximum rainfall infiltration.
- Conserve Soil Moisture – Kill Cover Crops Early. The presence of cover crops can improve soil structure and rainfall infiltration, but don’t allow over wintering cover crops (i.e. winter rye) to grow too long in the spring and deplete soil moisture.
- Maximize Root Exploration for Water. If the growing season does turn out to be hot and dry, you cannot stand to have roots that are trapped in the surface soil layers from compaction that occurs during spring tillage or planting operations. Do not work soils wet. Be careful that down pressure on the planter row units is suitable. Check for sidewall compaction caused by the planter. If the season is going to be long, don’t rush in the spring. It will create poor soil conditions and compromise the crop’s ability to capture all the soil water possible.
- Plant into Moisture. If the season comes in warm and dry early (April – May), be sure to plant corn into moisture. We say this every year, but if rainfall is limiting, you must ensure the crop gets planted into moisture and off to a fast start. As soil moisture profiles move downwards, you need early germinated corn roots chasing that moisture front, not sitting there waiting for a rain to germinate.
- Watch for Fertilizer Burn. Below average rainfall in May often increases the amount of fertilizer burn. Double check dry fertilizer rates (i.e. no more than 70 lbs N and K combined if urea is in the dry blend). Also check that the clearance of your fertilizer openers is correct (i.e. 2” away from row and 2” below the seed). This often requires a run across the yard with the fertilizer running to double check.
- Dry Soils and Frost Damage. Planting seasons dominated by high pressure weather can result in an increased risk of spring frost on clear, cold nights. Hopefully we got this out of our system last year, but a few lessons might be worth remembering. In high residue situations (i.e. corn after grain corn), removing residue out of the row zone with trash whippers did provide some reduction in the frost damage. In the case of dry soils and intense cold exposure (i.e. 8 hours below 0°C), be careful to not overestimate the plants recovery, even if the growing point appears undamaged – watch it closely and be prepared to act.
- Nitrogen Strategies for a Dry Year. A warm, dry spring or summer can have a significant impact on the most profitable N strategy. Often, reduced rainfall and warm temperatures improve mineralization of nitrogen from organic sources and may reduce N losses caused by leaching or denitrification – thus reducing your total N fertilizer demand. 2012 also showed Corn Belt growers that in a dry year, delayed (sidedress timing and beyond) N applications are less likely to make it into the crop to provide any yield boost. In a warm, dry year, I would prefer to have 100 lbs N up front and make some smart decisions around the last 40 lbs; than have 40 lbs up front and hope we have enough rain to get the last 100 lbs into the crop.
Of course while writing this article I get the feeling that the jinx will be surely in place – 2016 will have perfect rainfall! I’ll live with that. If you want to discuss any of the ideas in this article, be sure to drop me a line at firstname.lastname@example.org or contact your local Maizex representative.
Maizex Seeds Agronomy Lead
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