Zenith Zoysia Seed to Develop a New Oval in the Tropics - Part 4 - Maturing the Grass

It always take some time to develop an oval to the stage where it is getting ready to use.

Plants need to thicken and develop a dense sward above the ground surface while also developing their roots so they can effectively resist all the pressures on the grass that occurs during the playing of ball games or anything else planned for the oval  - it has to mature.

There will need to be regular mowing at about a 7-10 day interval - even more frequent in some cases - to help thicken the sward as lateral growth is encouraged, to fill any thin or bare spots.  Fertiliser is applied - normally at about 4 week intervals [ that is about how long normal agricultural type fertiliser can supply nutrients, particularly nitrogen, although other types [ phosphorus, potassium, trace elements] may be available for longer] for about 12 weeks,

Weed control is vital during this phase, to ensure the favoured grass is encouraged and impediments to growth removed.  Disease management and control may also be an issue in some cases.

In the period from around 45 days through to around 95 days after sowing the Zenith Zoysia area had a second application of fertiliser at about 8 -9 weeks [ 56+ days from sowing] and will be due for another at 12 -14 weeks, except this time it will be a slow release fertiliser, better suited to ongoing turf growth and with an availability period of 12 -16 weeks, thus preventing rapid growth, yet continuing to provide adequate nutrition for the turf for many weeks.

Weed control was instituted with several applications of herbicide.  The earlier applied residual herbicide continued to provide annual grass and some broadleaved weed control, but was boosted with two applications of a product that gives excellent knock down, but not very much residual weed control of broad leaved weeds - Kamba -M, applied at around 70 days after sowing and more recently at approximately 95 days from sowing.  Ideally the latter one would have been sooner, but a 48 hour dry period after application is needed for best results - and it continued to rain every few days!  Makes that a bit tricky.  The second application seems to have been very effective.

However, there have been issues with grass weeds.  While some grass weeds can be controlled with selective herbicides, the real culprit has been Bothriochloa spp plants - a particularly hard to control grass weed, and with few options for herbicide use.  The area did have a lot of these plants initially and were controlled with glyphosate before seed sowing, but the residual seed in the ground has germinated around the same time as the zoysia seed and slowly developed into a problem that requires hand removal.  The dense turf as it develops will eventually prevent most, if not all, future germination from the residual seeds, as well as the seed in the ground dying.  But in the meantime seedlings of it have to go...........  Resorting to hand weeding is almost inevitable in fine turf development, but it is labour and time intensive.  And requires many revisits to the same area to ensure it is all gone, as you can often miss small plants.

By mowing at 7-10 day intervals the weedy grass has time to put up a seed head between mowing periods, allowing easy identification, yet if removed in that 6-10 day time frame it is short enough to prevent any more seed development as full flowering has not started.  A real problem also exists in that the same species is all around the outside of the oval, and could easily re reintroduced to the oval area through mowing, especially if careless mowing of the oval surrounds is carried out.  Not an easy situation to rectify.  Although low levels are present initially, good progress in eliminating the Bothriochloa spp on the oval is progressing okay, but may require a few more weeding / mowing cycles, and ongoing vigilance.

Before mowing - 90 days from sowing

Before mowing - 90 days from sowing

Before mowing - 90 days from sowing

Before mowing at 90 days from sowing

before mowing - 90 days from sowing

After broad leaved weed control 98 days from sowing

Very effective broad leaved weed control at 98 days from sowing

At 98 days - Bothriochloa spp - grass weed in dense Zenith zoysia turf - note emerged seed head 7 days after mowing

Zoysia Seed To Develop a New Sports Oval - Part 2 - Seedlings at Four Weeks from Sowing and Weed Management

While early seedling growth was very good, the dreaded weeds then started to appear!

While herbicides for use on seeded zoysia have been a bit tricky in being able to choose one that had minimum collateral damage to the small zoysia seedling yet was efficacious in removing weedy plants, we decided to use quinclorac [trade name Drive], which will deal with some weedy annual grasses and many broadleaved and leguminous weeds, selectively, without damaging the zoysia seedlings.

Timing is still important...............very important.  It is important to apply Drive in the period of 14 - 28 days after emergence, and in our situation we had major emergence about 8 - 9 days after sowing and we sprayed 25 days after sowing, about 16-17 days after emergence.

Results have been good, with strong control of leguminous and broadleaved weeds, and some weedy seedling grasses.  More work will be needed over the next four weeks to deal with some of the weeds remaining which includes some broadleaved weeds as well as sedges and grasses.

About 4 weeks after sowing we also applied additional fertiliser [ Yara Hydrocomplex ] at a rate equivalent to about 30kg/ha of N.  Included was another approx 10 kg/ha P and 35kg/ha of K and more trace elements and sulfur.

With other species, more fertiliser is used eg couch, but trials have shown there is little additional growth benefit by applying more at this stage to seed sown zoysia, either Zenith or Compadre.  We expect to apply more fertiliser in about another four weeks.

Seedlings are growing well, weeds are mostly dying and the oval is developing steadily.  Yes, there is some uneven seedling distribution, but we did have a very high intensity rainfall event soon after sowing which resulted in washouts, which would have been much worse without the hydroseeding and use of mulch.

Over the past four weeks an early morning irrigation was applied almost every day, along with two very short daytime irrigation periods to boost dampness near the soil surface.  Some might have thought this irrelevant, as there has been quite a reasonable amount of rain - almost daily [ a few days break here and there] but it is essential to keep the surface damp in this initial period, especially as we often had hot sunny days.  Irrigation is now being reduced to three or four times a week, even though we are still receiving an occasional amount of  effective rain. Irrigation will be likely further reduced in coming days, if rain continues.

The next major exercise will be to start light mowing to enhance lateral growth of zoysia and help control any remnant weeds, and to continue with several other herbicide options for ongoing weed management.

weeds dying amid zoysia seedlings after selective herbicide application

close up of zoysia seedlings

overview of oval development at 29 days from sowing- some unevenness, but most areas with high seedling density

close up of dying weeds among zoysia seedlings  - note leaf twisting and colouration

overview of weeds dying at one corner with plenty of zoysia seedlings developing

All photos taken 29 days from sowing.

Uptake in Seed Use for Zoysia Turf Development - Need to Manage Weeds in Established Areas Not Just Mow

Both Compadre and its close cousin Zenith varieties  have seen a significant expansion of usage in domestic turf areas this Australian warm season, with Zenith sometimes being used because of tight seed supply for Compadre, still seen as the preferred variety.

While northern Australia continues with increasing use domestically, there has been some commercial use including where zoysia [ often Compadre as first choice] has been mandated as part of the commercial specifications.

As well, expansion has continued with Compadre especially being now very widely used as sod in commercial developments and areas of sod production have also increased, with Compadre now commonly the specified turf sod of first choice around much of north Australia.

The lateral growth [ rather than increased vertical growth], stolon density and potentially reduced mowing and maintenance plus overall good aesthetic appearance all contribute to this acceptance commercially.

That said, commercial users also need to understand that mowing is now not the absolute only maintenance required.

With many mowing contractors operating across many types of turf, vigilance and control to prevent entry of other turf species is needed [ often by adherence of seed and plant pieces on mowers], and specially to understand  that there are specific herbicide options to consider to keep the zoysia free of other turf species - with prompt maintenance a necessary practice to remove other, now weedy, turf types, to stop their spread.  Use of glyphosate [ Roundup(trademarked)] is not the only nor first option., although use of wick wiping with glyphosate to remove weedy grasses by killing via their seed heads may be an option for some species.......and yes it works well!  There are also very effective solutions for control of sedges in over watered or wetter areas of the turf area.

Mullumbimby sedge - serious sedge weed 

We can offer agronomic services to assist with weed control in zoysia, based on around 35 years of experience with the species in Australia, USA and Asia.

Where a considerable effort has been placed into higher quality turf, then it is important to also devote some effort and money to manage the areas more effectively for long term performance.  Do not ignore the turf weeds!!

Weed Control in Zoysia Turf - Seed Sown or Sod

Weeds in zoysia are mostly fixable.  

We suggest mowing followed by even more mowing as an option, allowing the strong density of zoysia to eventually win out.  There are two classic You Tube videos from the USA showing Compadre  zoysia in two successive years - year one is awful [ and I thought - what a disaster], but in year two it is a magnificent Compadre zoysia lawn.  Mowing and a strong zoysia species - Compadre zoysia - helped fix that problem.

Most broadleaved weeds in Compadre or Zenith seed sown zoysias are controllable with Kamba - M,  a commercially available dicamba / MCPA mix.  Approx price $30 for 1L.  A small quantity will last several years and is NOT residual.  Several repeat sprays may be needed. Use at recommended rates, and small areas can be sprayed with small hand spray bottles.  A few drops of detergent in the mix [ just a few drops!!] may help hold spray on plant leaves.

Or use one of the slow release fertilisers with pendimethalin in the blend as a seedling grass control - while it will not control emerged seedlings it will stop more summer growing grass weeds establishing for up to 10 - 12 weeks.  You must use at the recommended rate, which is on the bag.

You can also wick wipe weeds with glyphosate - BUT you must avoid the zoysia seedlings as they can be easily damaged if herbicide gets onto their leaves.  This can be useful if weeds are taller than the seedlings, as is often the situation.  Multiple applications may be needed. Commercial outlets sell wick wipers or see www.sherwoodmachinery.com.au  who make excellent small units [ any of the 4 smaller rope wick units] and supply by post.

Sedges may also be a problem.  First issue with sedges if they appear usually means overwatering.  Use less applications and make each one longer, if that much water is really needed.  If the soil dries out between waterings, sedges are less of an issue. Or reduce overall watering - the lawn is likely to be okay with less water  Small 25g packs of Sempra are now available through commercial outlets - this is a very specific sedge herbicide [halosulfuron].  Use as directed, and we suggest also continuing to use as a spot spray where needed, after that.  One or two applications usually removes well over 90% of the sedges, but often a few odd plants reappear - so spot spray them as needed.

There are other possible herbicides but some are not available to home owners, and cannot be recommended for use except by commercial operators.

A Ten Point WeedSmart Management Plan

The 10 Point Plan helps you win the battle against crop weeds. Follow the links below for practical tips and tricks to implement these strategies on-farm, and further information on the research to back up these steps.

1. Act now to stop weed seed set

• Research and plan your WeedSmart strategy
• Understand the biology of your weeds
• Be strategic and committed

 read more...

2. Capture weed seeds at harvest

• Consider your options – chaff cart, narrow windrow burning, baling, Harrington Seed Destructor
• Compare the financial cost per hectare
• more difficult on livestock farms but it can be better managed eg move animals carefully from weedy paddocks, allowing time for seeds to exit the gut.

3. Rotate crops and herbicide modes of action

• Protect the existing herbicide resource
• Repeated application of effective herbicides with the same MOA is the single greatest risk factor for herbicide resistance evolution

read more...

4. Test for resistance to establish a clear picture of paddock-by-paddock farm status

• Resistance continues to evolve
• Sample weed seeds prior to harvest for resistance testing

read more...

5. Never cut the rate

• Always use the label rate
• Weeds resistant to multiple herbicides can result from below the rate sprays

read more...

6. Don’t automatically reach for glyphosate

• Diversity, diversity, diversity
• Consider post-emergent herbicides where suitable
• Consider strategic tillage

read more...

7. Carefully manage spray events

• Use best management practice in spray application
• Patch spray area of resistant weeds if appropriate
• No escapes

read more...

8. Plant clean seed into clean paddocks with clean borders

• Plant weed-free crop seed
• The density, diversity and fecundity of weeds is generally greatest along paddock borders and  areas such as roadsides, channel banks and fencelines

read more...

9. Use the double knock technique

• Any combination of weed control that involves two sequential strategies
• A second application to control survivors from the first

read more...

10. Employ crop competitiveness to combat weeds

• Increase your crop’s competitiveness to win the war against weeds
• Row spacing, seeding rate and crop orientation can all be tactics to help crops fight

read more...

This was unashamedly pinched from the Weed Smart web site, part of the Australian GRDC area.

Weeds cost agriculture and horticulture big bucks every year.  Money that is a monster loss to growers.

Be smart  and realise how much weeds cost your property.  It does not matter whether a pastoral property, a small horticultural grower, or a mixed cropping and livestock site........have a weed management plan.

For more information visit - http://www.weedsmart.org.au/10-point-plan/  where there are further links to relevant material.