Message Board - Natural Turf: Yellow and green grass: What's the cause?
13 Mar 2009 by philipfish
Hi all,
Two weeks ago I re-seeded several parts of my tennis court which were a bit bare. The repairs were covered with thin agricultural fleece. Today I removed the fleece. The old grass under the fleece was a vivid, healthy green (no sign of any germination yet), while the rest of the court (a ryegrass mix) was showing the first phase of yellowing. I fed the whole court with half a bag of 6-3-18 three weeks ago.
Here's the question; why has the grass under the fleece remained green, while the rest of the court turned yellow? I realise that the fleece has "warmed" the soil below and kept the mild frosts off, but why has the grass not yellowed like the rest of the court? If the recenet rains have washed the nutrients out of the rest of rest of the court surely the same thing should have happened under the fleece!
Any ideas?
Phil
13 Mar 2009 by glenkeeran
Hi Phil
My best guess is that the germination sheet raises the temperature of the soil beneath by 2oc. My best guess "without seeing anything" is that the grass outside the sheet is still dormant while the grass under it is starting to grow.
Brian
everything happens for a reason
13 Mar 2009 by Barry Pace
And maybe other things lurking within the soil have been stimulated into action by the nice jacket???
Oh sorry we cant go there ROFL.......
Plastic.... it's The End I tell you... THE END!!!!
13 Mar 2009 by philipfish
Brian
Your right about the grass under the sheet starting to grow as its now considerably longer than the grass not under the sheet. But I would expect if it grows more quickly it would need to draw more nutrients and would yellow quicker than the surrounding grass?
Phil
13 Mar 2009 by glenkeeran
Hi Philip
would you consider covering the entire court??
Brian
everything happens for a reason
13 Mar 2009 by philipfish
Brian
It would be a good idea to give everything a kick start at the begining of the season. Unfortunately, I have only a limited amount.
Phil
14 Mar 2009 by glenkeeran
Hi Philip
The reason i asked is that germination are quit inexpensive over here and maybe your budget might of streached that far???
Brian
everything happens for a reason
14 Mar 2009 by Aladdin
I doubt you have need to be concerned, Mr. Fish.
I, too, was a little concerned at the yellowing of the ryegrass on my football pitch. Advice from various quarters plus research indicates that there's little to worry about. It seems that ryegrass does yellow in the cooler months, especially where it's been particularly wet.
I imagine the greener grass has been fooled into thinking it's further into Spring than it actually is.
Yellow grass 1
Yellow grass 2
Ignore the childishness!!
From the posh end of the room!!
14 Mar 2009 by philipfish
Aladdin
I am not worried about the yellow grass - I've allways been told its because rye is hungry and all the nutrients have been washed out. But why is the grass under the fleece not yellow? There was no more nutrient under the fleece! Yet, it grows better die to the warming effcets of the fleece, but why does it not yellow?
Phil
14 Mar 2009 by Aladdin
An interesting question, Mr. Fish, and one that I cannot answer.
One can only wonder if the composition of the fleece has anything to do with it. Or is there something in your soil that has been activated by the warmth?
Where's Mr. Asquith when you need him?
From the posh end of the room!!
14 Mar 2009 by Poa7
This yellowing of the grass that can be seen during the winter months, more so during the later months, is known as chilling stress.
Typically you will see yellow (necrotic) spots or strips on the leaves. You can put it down to loss of chlorophyll and a reduction in photosythetic activity by the plant. There are physiological processes that occur in the plant during winter that cause this to occur.
We could go into excactly what, but it wouldn't really answer the question.
The absence of this yellowing under the covered portion of the area that philipfish noted, will more likely than not be due to the raised temperature under the canopy.
I once asked my old Head Geenkeeper this very question, his answer to me was "Well, if you'd been out all winter, you wouldn't be looking to good either!"
I had to find the answer out myself - lol
14 Mar 2009 by Barry Pace
I say again that maybe the things in the soil that are needed to make the transition of nutrients from the soil to the plant were stimulated by the fleece cover and couple degree warmth...................
Plastic.... it's The End I tell you... THE END!!!!
15 Mar 2009 by Eddy21 Last edited 15 Mar 2009
Hi Philip,
It would be interesting to know the exact difference in soil temperature on both the uncovered area and the covered areas of the court, and what type of material are the covers you are using?
Id also be interested to know a little more about your soil type and also what form of N you applied 3 weeks ago. Have you experienced high amounts of rainfall recently?
Philip, have thought about an application of Iron (Fe) as this may replenish Chlorophyll levels if the turf appears a little chlorotic like you say?
Have you carried any form of aeration recently on the uncovered and unseeded parts?, as getting some air into the profile may stimulate our aerobic friends and make that transition that Barry has talked about in the previous post a little easier to occur.
Im only asking these questions as it may enable the readers to make some links and create a better picture of your circumstances and maybe offer you some more solutions.
Bonne courage
DE
Learning is there for every man
15 Mar 2009 by philipfish
Eddy 21
I sarrel rolled the area i repaired before seeding.
The fleece is standard 20g agricultural fleece.
We have had 28 mm of rain in the last 14 days, with 16.5 mm falling on one day, 4.8mm on two days and one day with 1.4mm.
The fertilzer I used three weeks ago was 12.5kg of Vitax Autumn (standars relaease) 6-3-18.
I apllied iron and a small amount of liquid N yesterday.
I have had yellowing throught the year whenever the N levels fall. The grass allways recovers quickly after applying N. N does not appear to stay long in my soil, presumably due the leaching during heavy rain.
My soil is GOSTD Surrey Loam with about 18% clay content.
Phil
15 Mar 2009 by Eddy21 Last edited 15 Mar 2009
Hi Philip,
Cheers for your reply.
It maybe worth putting down a base feed with more slow release properties to keep the N levels up towards the start of the season over a longer period of time. You can then top up accordingly with straights as and when needed after this. This way you might not get these dips as much as there should be enough residual N in the profile to keep you ticking over.
Its sounds as though you are doing a good job.Dont hold back with the cultural practises, especially the aeration, it is all so important.
Bonne courage
DE
Learning is there for every man
15 Mar 2009 by philipfish
Eddy21
Thanks for the tip regarding slow release. I have always used the straights as I have expected them to produce more instant result. I shall try some slow release.
Phil
15 Mar 2009 by Philmort
Seems as though the grass likes aeration (sarrel) plus warm coat (fleece)
Proud to serve grassroots cricket
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