Mark Hunt’s Weather Assessment
15th April – 20th April 2010
Well the 'thermal to tee-shirt forecast' seems to have been reasonably accurate, but if the weather systems pan out as they look at present, it's going to be more thermals than tee shirts for next week. Currently we are in the grip of a high pressure which is funnelling cool(ish) air off the continent on a North-East wind and, the closer you are to the East of the country, the chillier that wind is as it scoops clouds in off the North Sea. The wind strength will back off as we head towards the weekend so the chance of frosts will increase and it wouldn't surprise me if we get one or two over the weekend.
Before we leave this, wasn't the end of last week a cracker, a lovely warm wind, the sun shining and everyone seemed to be smiling!
No sign of rain at present for this week or next, other than some North Sea mizzle. As we move into next week, we look to be repeating a similar pattern except this time the high pressure will bring in cooler / colder air from the continent by the end of next week. Again, the further you are west, the less effect this will have, so for once the lads in the west of Ireland will get the best mix of fine days, but still cool nights. Now this might change yet as it's a complicated mix of weather systems at present, but that's how it looks to me.
Agronomically speaking, the combination of dry cold isn't a great one, but there are a few management tips that can make this less painful, particularly after The Masters. Though that said, did anyone else see the aeration lines on the close up camera shots, it looked like Graden Lines to me?
Managing Dry Cold
1. Nutrition
Soil temperatures, although currently pretty good at around 10°C (higher at midday), may take a bit of a tumble if we get night frosts so, the best way of keeping the plant ticking over and stopping greens losing their colour is to bypass the cold soil and apply a foliar treatment. Nitrogen forms to use depend on how much growth you want to produce, but a mix of sulphate of ammonia and potassium nitrate will work well and, provided day temperatures stay the right side of double figures, urea will begin to kick in as well, especially on higher heights of cut areas. On greens, I'd look to be applying 5-6kg N per hectare in total per application. Water volumes should be 400L maximum per hectare and light rates of iron, inputting 1-1.5kg per hectare Fe will work well. (That's around 20 litres per hectare of a 6%Fe product) Little and often is the key here, rather than a lot and infrequent.
2. Irrigation and Wetting Agent Usage
During these conditions, the surface 1-2" (2.5-5.0cm) will dry out quite readily, especially if it's breezy, so maintaining light irrigation is the key to provide uniform moisture distribution through the rootzone profile. Many people are reluctant to irrigate when it's cold, but sometimes the lack of moisture becomes the growth-limiting factor rather than the lack of soil temperature. Irrigating in the morning (as opposed to the night) will knock temperatures down for a couple of hours maximum before they rise again. It goes without saying that it pays to have a wetting agent on before periods like this, but if you are applying one at present, make sure there's enough water applied through the irrigation system to move the wetting agent through the profile. If only a small amount of water is applied with the wetter, it will concentrate everything in the surface, including the wetter. Modern soil surfactant technology is pretty good, but it's only as good as the irrigation management that accompanies it.
Sometimes, it's just the high spots on greens that dry out, so a bit of hand watering during the warmer parts of the day will maintain moisture levels and do little to impact on the soil temperature.
3. Cutting Height
Poa doesn't like dry-cold, but Bent does, so conditions like these tend to exaggerate the difference between the two grass species. Basically the Bentgrass is growing and the Poa isn't, so at higher heights of cut, the difference between the two growth habits is very obvious and the surface is bumpy, whereas at tighter heights of cut, it isn't. My unfortunate analogy relates to those of us who (like me) are folically challenged (thin on top), if you have a tight haircut, it doesn't look as bad, but if you do a Status Quo job, it looks awful. (No feedback required please)
The next time I post, I'll have done a degrees-days calculation, so we can see how it's looking for the next pleasant phase of the Spring - Poa Seedhead development.
Mark Hunt
Technical Director
Headland Amenity Ltd
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