Monthly Archives: July 2015

July 14th

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Hi All,

bearSo this is my last blog for a few weeks just prior to setting out for Alaska. I’m looking forward to experiencing a true wilderness with no phone network and no WIFI. That said, it is going to be slightly strange not having use of a smartphone for information, pulling up weather forecasts and the like, kind of like turning the clocks back.  I remarked to a friend recently that I wasn’t worried about bears because I’m a reasonable runner and I just need to out-run my colleagues rather than the bear itself but this nice photo dropped into my Inbox recently so I’m not so sure now…..:) My mum suggested that I take extra toothpaste because apparently Bears like toothpaste so when approached I simply splodge a couple of dollops of Colgate’s finest and make my escape. I think it’s more likely they’ll use it to clean their teeth afterwards :)

All things being well I hope to be back in blog land on August 3rd.

General Weather Situation

So after a dreary and drizzly Monday, how is the rest of the week looking ?

For Tuesday we have a band of rain moving across Ireland, currently it’s affecting an area from Kerry up to east Leinster but during the course of the morning it’ll move eastwards to clear the west of Ireland and affect the east coast. There’s also some rain across South Wales (there you are Debbie) and touching the south west. Further east and north we have a hazy, dull start with cloud cover and a gentle westerly breeze and in places the cloud will be thick enough to give some light rain / heavy drizzle. Through the morning this rain will push across Ireland and into South Wales and the north west of England, but it will be light and drizzly by the time it reaches here. Through the afternoon the rain will move eastwards to the north east of England, but further south there’s a chance of the cloud breaking to leave a lovely evening for me to do my last minute packing !! Temperatures are likely to be high teens and low twenties if you happen to see the sun for any length of time, so nice and pleasant.

Onto Wednesday and overnight we have a band of rain pushing into the south west and Wales and this rain will move across England in the early hours. It’ll be light in intensity maybe 1-2mm but welcome for most I’m sure. By the morning rush hour that rain is likely to affect most of the U.K up to Newcastle, with intermittent lighter rain / drizzle over Munster and Leinster and a separate band of rain affecting north east Scotland. Through the morning this rain will clear Ireland, Scotland and the south of England leaving a band stretching across the north Midlands up to the north east of England. By late afternoon / early evening this will be confined to the latter. Temperatures will be similar to Tuesday, perhaps a degree or two higher in the south of England with those longer sun hours. Winds will again be light and from the west.

For Thursday we have a new band of rain, potentially heavy, pushing into south west Munster and looking likely to affect the west coast of Munster and Connacht through the morning, afternoon and into the evening. Further east over Ireland you should miss this. For the U.K it looks like a pretty dry picture for Thursday with cloud cover slowly breaking through the morning in places to give spells of hazy sunshine. Later in the day we have a threat of rain pushing into the south coast of England, with a chance of some heavier rain later over the south east of England, principally Kent. Warmer temperatures are likely with the low twenties forecast accompanied by a reversal in the wind direction, blowing off the continent from the east, but light in nature all the same. Now with temperatures rising and an easterly airflow there’s a risk of some thunderstorms breaking out on Thursday night into Friday morning along the east coast I think.

As we move into Friday that rain over the south east looks to intensify in nature and shift northwards into Essex, Suffolk and Norfolk, though this may well change as it’s continental rain and so fickle in its nature. That heavy band of rain affecting the west of Ireland may be slow to clear and as it does so on Friday morning it moves eastwards across the country. By morning rush hour that rain is into the north west of England and The Borders pushing up into Scotland on Friday morning. Through Friday morning and afternoon the rain slowly pushes north over Ireland so a bit of a soggy one there and for Scotland too. For the south of England and The Midlands that early cloud cover and possible light rain will give way to longer spells of hazy sunshine and pleasant temperatures up into the low twenties again. Further north and west where you have rain it’ll be cooler, more like mid to high teens and a return to a moderate / blustery westerly wind.

So how is the forthcoming weekend looking ?

Well Saturday looks a pretty nice day for most, lots of sunshine around and with that we will have some pleasant temperatures but since we still have a low pressure close, they’ll only be high teens, low twenties maybe in the Costa Del SOE. Later on Saturday you’ll see some rain crossing Ireland and moving into the north west of England, south west of Scotland. Sunday looks a repeat of Saturday for many, dry on the whole except for a new band of rain that’s projected to push into Connacht and Donegal during the early morning on Sunday and this will move east into western Scotland by the afternoon / evening. So all in all not bad, nothing too hot temperature-wise and light to moderate winds from the west forecast for the south of England, but nearer that low pressure in the north and Scotland the isobars will be packed so potentially windier and cooler for you over the weekend.

Weather Outlook

With low pressure influencing this week we have a change on the way pretty much kicking in from the start of the week as high pressure is set to build. So next week looks like being drier and warmer, potentially hot as we approach mid-week in the south of England especially. Before you get too worried though remember that we still have a jet stream with southerly tendencies and this means that it is only a matter of time before a new Atlantic low pressure whisks over to nudge the high out of the way. Sure enough this is currently projected for the end of next week, Thursday onwards as a low pressure pushes in to bring wind and rain to the north and west, but this one may just sit low enough to bring rain to the south of England as well and a cooler northerly airflow over the weekend possibly. The combination of heat building during the week and moist air pushing in from the west suggest to me that it may be a thundery end to the week, next week with a high likelihood of electrical storms as the air masses meet.

Agronomic Notes

Pathogen Activity

With moisture coming in last week and over the weekend following a dry spell of weather we have a surge of pathogen activity specifically Fairy Ring and Waitea Patch, but also some Microdochium pressure.

Waitea

Just to re-visit the subject briefly. If you’re seeing rings of fungal activity that suggest they may be Superficial Fairy Ring or possible Waitea, there’s a number of steps you can take to ascertain which species of pathogen you are dealing with. I say species because Superficial Fairy Ring is a Basidiomycetes sp. and Waitea is a Rhizoctonia sp., so very different in their activity, but similar in terms of symptom expression.

The first thing to do is to take a small corer and take a profile in the ring itself. Lay the profile horizontally and take a small syringe / dropper and place drops of water from the bottom of the profile upwards, say every 5mm or so. Watch the behaviour of the drops. If they soak into the profile you know the rootzone is not hydrophobic, however if they bead up you can see that hydrophobicity is present and get an understanding of how deep this is in the profile. Typically Superficial Fairy Ring (SFR) is present in the surface organic matter, 10-20mm deep and so often when you do the droplet test you notice the drops behave as shown below.

HydrophobicFairyRingCore

So if you’ve taken a sample from a ring and notice surface hydrophobicity that suggests fungal activity, but it is not a definitive because organic matter itself can be naturally hydrophobic. So next you need to look for any signs of fungal activity and in the above photograph you can see white, cottony mycelium amongst the organic matter. If you have a Veho scope handy you can pick this out much easier at x100 / x200 magnification.

The picture below shows Basidiomycete mycelium coating a sand particles and the root system of a Poa plant.

Fairy Ring mycelium covering roots and sand particles

Next take a good smell, this is actually best done when you first remove the core and try and detect the familiar mushroom odour associated with Fairy Ring activity.

Lastly if you incubate the sample in a plastic bag, you know pop it in the airing cupboard for the Mrs to find at a later date because you’ve forgotten you put it there :) you will sometimes see with Waitea, fungal mycelium growth in the turf surface as opposed to the rootzone.

So to summarise, you have 4 definite features that can help to differentiate between SFR (lazy because I keep typing Superficial wrong :))

  1. Presence of hydrophobicity (SFR)
  2. Presence of mycelium often cottony white (SFR if in rootzone)
  3. Mushroom odour from surface of core (SFR)
  4. Surface mycelium growth ( Waitea-only)

It matters with these two which one you actually have because the management is quite different.

Waitea tends to like moisture so if you’re seeing the rings on an area of turf that sits wetter, maybe in the shade or possibly an area that gets routinely over-watered from the irrigation system, then this may point the finger Waitea’s way. Drying out the rootzone is a good way of reducing the appearance of Waitea Patch without having to resort to a fungicidal treatment.

With SFR, the opposite is true of course because the activity of the fungus can make the rootzone naturally hydrophobic and so hand watering with a wetting agent tablet (to neutralise the hydrophobicity) is a good idea. You can also check to see if the tablet is actually doing its job by testing the area the next day or so and seeing if the area is still water-repellent or not. If it is, hand the tablets back to the rep and ask for your money back :) (ha ha)

if you chose to go the fungicidal root then Azoxystrobin is usually effective against both pathogens, but of course you should be mixing with a wetting agent if you know you’re dealing with SFR. (Provided of course they are tank-mix compatible)

Other Pathogens

After last years high level of Anthracnose activity, some of you may be nervously looking at the grass sward to detect any early signs. I have noted some indication of basal yellowing of the grass plant lately however on examination there is no indication of any Acervuli – spore-producing structures on the healthy tissue. I have found some on dead and decaying plant tissue but this is normal as it is a saprophyte. I put some of this basal yellowing down to Spiral nematode activity rather than Anthracnose incidentally.

Taking on board that we first had temperatures high enough for spore germination of Anthracnose at the end of June, it is likely that the fungus has only recently started growing. We know that Anthracnose grows very slowly on the plant and according to the disease oracle – Kate Entwistle (No ‘h’ you know :)), it is also quite sensitive to damage during the early stages of development. It needs good levels of soil moisture and humidity so maybe this last week and the early part of next week will help it on its way.

I repeat that I’m only talking about the fungal mycelium stage of development and this is one you’d only see if you have a high-powered microscope and know what you’re looking for. The actual turf symptoms (Leaf-yellowing, basal rot, Acervuli on foliage and the crown of the plant) come later, roughly 4-5 weeks after the initial germination of the spore I think, but this timescale will depend on the environmental conditions. If they are not conducive to Anthracnose mycelium development, the disease symptoms may not actually appear at all.

That’s why it is important to apply a preventative fungicide (if you chose to go down this route) long before actual turf symptom expression.

It is also vitally important to maintain good levels of plant health during the next 6 weeks because a weak plant makes an ideal calling card for this and other plant pathogens. So if you’re chasing a super-low N figure I hope you have your ‘i’s dotted and your ‘t’s crossed and more importantly, know why you’re doing it in the first place.

Maintaining adequate nutrition is key to Anthracnose management, ‘little, but often’ is an extremely apt saying when it comes to this disease. Research conducted in the U.S has consistently shown that good levels of nutrition (sufficient and regularly-applied rather than excessive) are equally as effective as applying a fungicide when it comes to Anthracnose management. If you want a refresher course have a look at this very informative pdf on Anthracnose  here

Ok that’s it for this week, bit of a short one I know but needs must.

Catch you on the flip side.

Mark Hunt

 

 

 

July 6th

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Hi All,

What a weather week we had last week with a new record high temperature at Heathrow for July at 36.7°C, pipping the previous record recorded at Wisley of 36.5°C, recorded in 2006. I measured 35.5°C here in The Midlands and decided to test my stamina by going for a 4 mile lunchtime run at the hottest point of the day, I don’t think I’ll do that again :( We also measured some extremely high E.T (Evapo-transpiration) levels during that heat, more on that later.

The heat of mid week was followed by some of the most active thunder and lightning storms ever recorded with hail the size of golf balls, torrential rain and over 13,000 lightning strikes recorded from Friday evening through to Saturday morning. As predicted the storms came off the continent as they had done earlier in the week. The lightning archive on Netweather Extra shows the path of the storms in the merged graphic below ;

Lightning030715

Sadly I didn’t manage to get a water sample from these storms, but it’s a fair bet that it was loaded with N and you’ll already be noticing the result on your turf areas. It always amazes me how you can irrigate an area during dry spells but the moment we get rain and particularly rain from thunderstorms, they green up. I measured 13.4mm fell here in Market Harborough over a short period.

So what kind of a weather week do we have in store for us this week ?

Well a very different week you may be pleased to hear, as an Atlantic low pressure system will bring cooler and wetter weather to the west and north, whereas the south east of England may just sit in a high pressure bubble. Either way it’ll be pleasantly cooler at least for the early part of the week.

So Monday sees the first of those rain fronts already into the south west of Ireland and pushing across during the day to give some pretty heavy rain across Leinster and south east Munster. The rain will move diagonally (/) north east across to skirt Wales by early afternoon and then push into The Lakes and south west / central Scotland by the evening, so a wet end to the day there. South of a line roughly along the M62, it’ll be a different with hazy cloud and sunshine making it a pleasant day, dry and warm. Winds will be moderate and from the south west, courtesy of that low pressure and it’ll be high teens under that rain in the north and west, but low twenties south of that rain.

Come Tuesday and that rain pushes into Wales and the south west / north west of England overnight and then moves east across the U.K during the day. Ireland and Scotland will continue their wet theme through Tuesday with frequent rain showers and a cooler south west wind. There’s always the chance of missing westerly rain if you’re located in central or eastern England and this could well be the case for Tuesday with a likelihood of that rain fizzling out  during Tuesday afternoon. Cooler temperatures for Tuesday, mid to high teens the order of the day and still with that south west wind in situ.

Wednesday continues the unsettled theme for the week albeit with less rain around in general. So we start Wednesday with rain still affecting Ireland, Wales, the west coastline of the U.K and Scotland. Through the morning that rain fizzles out over Ireland in general but will still affect Leinster, Wales, the west coast of England and Scotland. During the morning that rain could shift eastwards to affect the north of England and during the afternoon potentially the east coast pushing down into The Wash area. Behind it it’ll leave a drier picture, brighter in the south where that hazy sunshine will give way to clearer spells of sun. Temperatures will range from mid-high teens under that rain to low twenties in the Costa Del Sol of England. Potentially a little cooler across The Midlands as that wind moves round during the day, through westerly to slightly north-westerly.

For Thursday we have a much drier picture across all of the U.K and Ireland. Later in the morning we will see a rain front tickle the coast of south west Munster, The Dingle Peninsular and that rain will push across Ireland during Thursday. Some of that rain may just reach south west Scotland by late Thursday night, but away from this localised area of rain, it’ll be a lovely sunny summers day, dry and warm with temperature in the low twenties for all and hazy sunshine giving way to brighter spells later in the afternoon.

Closing out the week we have that rain pushing into Scotland, North Wales and northern England overnight, clearing Ireland as it does so. Further south and east, another lovely day with hazy sunshine breaking up to give a warm / hot day, with temperatures pushing right up to the low / mid-twenties again across Central England. Winds will be lighter and from the south, that’s what will cause the heat to start to build again in the south of England. Where you have the rain it’ll be cooler, maybe only mid-teens across Scotland as you pick up a cooler easterly airflow.

The weekend could continue the ‘mixed bag’ sort of weather because the low pressure system is projected to push across the U.K during Saturday and Sunday. That suggests the unsettled, cooler theme will continue for the west and north with rain likely on Saturday. Further south it’s a tricky one to call because it really depends just how far south the influence of that low pressure extends. In the far south east we could see the effects of continental weather again with heat funneling up from the south and giving hot temperatures for Saturday at least, maybe mid to high twenties. It wouldn’t surprise me if we get some more thunderstorms on Saturday night as that hot air meets the cooler, moist air, though none are currently forecast. That heat should dip away on Sunday to a more pleasant low twenties sort of feel for England and potentially drier as well for the north and west.

Weather Outlook

Looking ahead we don’t have a clearly-defined, settled, weather pattern because we have a low-lying jet stream and another Atlantic low pressure system waiting in the wings. So next week looks like starting off settled and dry with warm temperatures in the south and south-east.  Further north and west will become affected by this new Atlantic low pressure system later on Tuesday and that’ll push down to affect all areas of the U.K and Ireland from mid-week onwards so potentially some rain around for the driest areas at the close of the week. To summarise, warm, dry and settled in the south for the early part of the week with unsettled weather pushing into the west and north from Tuesday onwards and pushing south to affect all areas by the close of the week.

Agronomic Notes

Lots to talk about today after last weeks weather :)

Firstly – Evapotranspiration

Last week as we know saw unprecedented high temperatures and they were accompanied by some pretty blustery winds and these really ‘broke the mould’ as far as I’m concerned in terms of recorded E.T levels.

Looking at the data from The Oxfordshire for last Wednesday we see that the total moisture loss recorded over the 24 hour period was 10.72mm !, now that’s the highest I’ve known recorded. The weather station was check / calibrated earlier this year so I have no reason to doubt the figure but I’m interested in what other sites recorded, did you also see extremely high E.T figures last Wednesday, if so how high ?

Here’s how the day played out in terms of temperature, wind strength and E.T…

24hrET010715

What made Wednesday, July 1st such a brutal day from a moisture loss perspective was a double peak in E.T, with the normal increase in E.T up to 2 p.m, but this was then followed by a second peak as the air temperature increased further from 3 p.m through to 6 p.m and that was unusual.

So we lost 10.72mm from the turf over a 24 hour period.

The perceived wisdom is that in order for a cool season grass species like Perennial Ryegrass or Poa annua to survive you’ll need to replace a minimum of 40% of that moisture loss by rainfall and / or irrigation. So that means for Wednesday alone you’d have needed to apply 4.3mm of water. If you wanted to apply enough moisture to maintain growth, that figure would have to increase to 60% of E.T and 6.4mm. It is however is a very subjective area and there are a lot more variables involved than just how much water you are able to apply that will determine whether the grass plant will survive or not.

Consider the picture below….

PoaRyeDrought

Here we have a Poa annua plant (with a new seedhead visible) that has managed to survive last week’s high temperatures and maintain leaf colour. Next to and around it, is a modern Perennial Ryegrass mix, bred for drought tolerance and fineness of leaf and you can see it hasn’t performed as well. So why is this the case, how come Poa has the upper hand when everything you read says it should be one of the first grass plants to check out when the E.T  leveryegrasscrownl is high and moisture scarce ? It’s a difficult question to answer and one I can’t immediatley get to the bottom of, but I suspect that the Poa annua plant has the deeper root system in this case. That said, you would think that the Ryegrass would be the deeper-rooted plant and so more likely to maintain moisture status in the plant itself, but this doesn’t seem to be the case.

The other question in my mind is whether the bleached ryegrass will actually survive and regenerate with moisture ?

Taking out an individual plant and stripping back the leaves to reveal the crown shows that it is still intact and that a new leaf is already being formed.  (see image above)Veho200

This image incidentally was taken with a simple Veho Discovery x200 microscope that connects to your P.C / Tablet through a U.S.B port and is an invaluable tool (I find) when you have this kind of turf-related issue.

So provided there is sufficient moisture, nutrient and an intact root system (all three are linked of course) to sustain this new growth, it should regenerate. Of course the Poa plant sitting next to it will have set its seed by then so I’d expect to see an increase in Poa annua on this area of turf after heat stress.

Makes you kind of wonder then if you still believe the theory that stressing your turf out will favour grass species other than Poa annua doesn’t it ?

Talking of other plant species that’ll show an increase in population density during a drought we can expect to see more moss and algae on thin areas of the sward where grass cover has been lost.  This is because moss can survive dessication better than grass during high temperatures / low moisture. The algae is normally a result of grass density loss and colonisation of decaying plant material.

Before I leave drought and drought survival, one of the key factors that will help achieve plant survival during periods of weather like this is your root system and that comes down to another set of variables, not least organic matter content, compaction, etc.

In other words all the things we do when we aerate to try and control organic matter, relieve compaction and increase the air-filled porosity of the soil we are maintaining (to encourage better rooting). All this work comes home to roost when we go through periods of weather like this. So if after last week you’re looking at a pretty healthy sward with minimal grass loss and good coverage, use that to reinforce with your management why it’s so important to do what you do aeration-wise at other times of year.

Looking back at June….

GDDmonthlycomparisonandcumulativeJantoDec2010to2015image

June was a so-so month from a growth perspective as the GDD information above shows and although we had reasonable temperatures through the second part of the month, it wasn’t temperature that was growth-limiting in June, it was rainfall.

The chart below shows growth potential and rainfall for a site in York (Cheers Adrian) and you can clearly see the up and down nature of growth (normally it’s more consistent once we reach the end of May) and the large gaps between periods of rainfall. (particularly after the middle of the month)

GPRinfallJuneYork

Nutrition, aeration and disease activity going forward…

With a more unsettled picture for the weather this week and potentially next, we can use the lower temperatures, lower E.T and higher potential for rainfall (except the south / south east) to gently bring the grass plant back on track. This should be done with a light / moderate amount of nutrition to increase the grass plant’s nutrient status and in conjunction with biostimulant use to maintain plant health, the two go hand in hand at this time of year. If your grass is stressed then drop your PGR rate or cut it out altogether until you have achieved recovery. Light aeration (Solid tining, Sarel rolling, etc) will help to stimulate new root development and vent the soil. I’d be careful with verticutting or scarifying if the plant is under stress and follow up aeration with topdressing if practically feasible.

Disease-wise, the high temperatures and rainfall will undoubtedly trigger off lots of Fairy Ring activity, along with Waitea Patch (they look similar sometimes) and these will require management in the usual ways. Speaking of disease I’d be using this week to get my preventative fungicide down for Anthracnose if you haven’t already done so. With last week’s high temperatures I think we’d have seen Anthracnose spore germination in the soil. It doesn’t necessarily follow that you’ll see Anthracnose this year but fore-armed is fore-warned. This is really a priority on turf areas that suffered high levels of Anthracnose activity in the summer / autumn of 2014.

Ok that’s all for now, enjoy the cooler temperatures and particularly the cooler nights, it should mean getting some shuteye is easier for one and all :)

All the best.

Mark Hunt