It is almost time for harvest - can't believe another season is almost over. I wanted to mention a few things that happened in July and August that didn't make it in their own blog post.

Back in July Napa County UCCE Weed Science Advisor John Roncoroni visited Long Island. His specialty is in weed control and vegetation management for perennial crops, cover crops and aquatic and riparian weed control. We took him to see both trials in this project, the under trellis mowing at LIHREC and the under trellis cover crops at Martha Clara. We also took him out to Bedell where they had planted no mow and red clover. Interestingly he mentioned that in his experience with no mow it isn't a completely no mow situation. It can get up to 16 in high (when it is flowering) so would benefit from a single mowing in the fall. He also felt that even without mowing or incorporation, the clover may add some nitrogen to the soil. Hopefully we will see this is our soil and petiole test results. Last year we mowed the trial at Martha Clara in an attempt to knock back the weeds and allow the cover crop to becom established. This year we will mow and not mow a few replications of each treatment to see the different growth patterns of our cover crops.

John Roncoroni (on the left) and Andy Senesac, Suffolk County Cornell Cooperative Extension weed specialist.

In August we took more data from the two trials. We took petiole samples at veraison to give us a snapshot of the nutritional status of the vines going into harvest. Petioles combined with soil samples will allow us to see if the cover crops are having an impact on the nutrional needs of the plant. It is thought that plants grown under the vine will compete with the vine for nutrients and impact the overall health of the vine. In Martha Clara where vigor is an issue this might not be such a bad thing, but at LIHREC where vigor is not as much of an issue it could be a problem.

                                             Petioles from LIHREC

Also at veraison we took samples of the cover crops, dried and weighed them. This will give us a better idea on their growth over time. The potential problem is that the weeds will start to move in and crowd out the planted covers. Or they don't reseed themselves and start to die out. This gives us an opportunity to better track this.

Clover, before and after sampling. All of the vegetation in the 12 in x 12 in square was harvested. Weeds were removed before I put them in the drying oven. We can use this small sample to extrapolate to the entire plot.

                                                      No mow samples

I haven't talked a lot about the second component of this experiment, looking at herbicide vs allowing native vegetation to grow under the trellis, but keeping it mowed. We are looking at this in our research vineyard at the LIHREC in Riverhead. This is a replicated trial in Merlot. Treatment one is mowing only all season long, treatment two is herbicide only during the season (in this experiment it is post emergent only - glyphosate), treatment three is mowing with one herbicide at the end of June and treatment four is mowing only with one herbicide treatment at the end of July. The idea behind this work is that if a grower didn't want to give up herbicide entirely, is there a key time during the season when an application is more beneficial, in terms of the groundcover's impact on vine growth. This work is in the fifth season and we have seen impacts on vine size. The vines that had herbicide season long have been larger than those with mowing only. The treatments with a single herbicide had more variability from year to year. The interesting thing that came out of this experiment is that a grower may be looking to limit growth in vines. There could be an especially vigorous variety or block where this strategy would be beneficial in managing those vines. In our trial, although the vines with cover are smaller, they are by no means struggling so the impact is not that extreme so far. But we have a few more years of this experiment to flesh this idea out. To see more in depth results of this experiment check them out at our website: http://ccesuffolk.org/grape-research/.

Here are some pictures of the mowing only treatment before and after it is mowed.

Here is a photo of two treatments next to each other - herbicide only vs mowing only.

Been awhile since I posted, but everything is moving along in all of the vineyards. Here are two shots of clusters on June 27th. All varieties are through bloom and almost at bunch closure.

We spent yesterday taking pictures in the vineyards of the newly established ground covers. We also took some data (not replicated) on percent coverage. We wanted to get an estimate of germination of these covers as well as the amount of weeds that established. In an ideal world the covers would outcompete the weeds but since we know that weeds are more competitive (grow quicker, scavenge nutrients better and need less water) they are able to establish. In the fall the weeds will go to seed and then go dormant, this will give the groundcovers a chance to recover. Here is how we estimate coverage: using a square of a known size, we identify total coverage of green cover in that square, percent of that total that is ground cover (whether it is clover or no mow) and the percent that is weeds. We then identify whether the weeds are winter annual broadleaf, summer annual broadleaf, summer annual grass, perennial grass, or perennial broadleaf. From our exeprience with our own trial these different groups of weeds appear at different times of year and the dominant group varies in the different treatments.   

Took some photos at Bedell Cellars the other day. They planted no mow and no mow with red clover under the trellis in an acre of Merlot. Here is a photo of the clover just starting to germinate (still very tiny).

I also stopped at Mattebella Vineyards because their newest planting of no mow is just starting to fill in. They will have their whole vineyard seeded with under trellis cover by the fall of 2012.

Went to Martha Clara yesterday to measure shoots in the trial. Shoot growth is one measurement we take to help us gauge if the ground covers are influencing vine growth. We will measure shoots up until they are hedged which is usually 3 times altogether. While we were there I shot a few photos. After all this rain (2.5inches last week) the clover is enormous. We also have some interlopers (weeds) in the plots so will have to trim them back since they are starting to grow up into the fruiting zone. We had hoped the ground covers would outcompete the weeds but I guess there are always a few escapees. We will have to keep an eye on this.

Weeds in the trial -

Very large clover -

"No mow"

On May 10, 2012, we (the CCE-SC Grape Program) hosted an Adobe Connect meeting ‘Innovative Under Vine Management Strategies.’ For those unfamiliar with this format, it is a way to broadcast presentations to a wide audience for minimal cost. The speaker’s powerpoint presentations are posted to a website. We, as the hosts of the meeting, design and organize the meeting website. Then registrants log onto the website at the designated time. The technology allows the speakers to be heard clearly by all – we had registrants in 21 states and 3 countries. Our speakers and their topics:

Dr. Tony Wolf, Virginia Tech

Intrarow cover crops and other practices to favorably alter vine growth and canopy architecture

The presentation will focus on research and grower experience using intrarow or under-trellis cover crops to (a) reduce soil erosion and to (b) suppress vegetative growth of vigorous grapevines under conditions of excess soil moisture. The discussion will also describe how canopy architecture is favorably altered by such treatments which can have a bearing on fruit composition and wine quality attributes such as color density, but also on pest management.

Dr. Ian Merwin, Cornell University

Vineyard Floor Management and Soil Health

Different systems for managing vineyard soils and ground-cover vegetation influence soil fertility and functionality, soil water retention and release, soil biological activity, vine nutrition, vigor and berry composition, and the natural environment around vineyards and wineries. This presentation will describe some long-term effects of mulches, legume ground-covers, mechanical tillage, and different herbicides on important soil attributes that are often called ‘soil health’. In addition, research on pesticide contamination of soils and surface water around vineyards will be reviewed, and suggestions will be made on ground-cover management systems that promote vine and soil health.

To view a recording of these talks go to http://breeze.cce.cornell.edu/p23i2w5lx87

I visited another vineyard today that is participating in our undertrellis management project, One Woman Wines and Vineyard. Claudia Purita (the one woman) has been mowing her vineyard in its entirety for some time but last year decided to seed new zealand white clover under her vines so she wouldn't need to mow. She planted a half acre of her gruner veltliner and was happy with the outcome so planted the rest (3 acres in total) this spring. I was able to catch up with her today and take a few photos of the freshly seeded rows as well as the clover that was seeded last year.

This photo is of the New Zealand white clover that was seeded in 2011.

This photo is from today and was just seeded this week.

Claudia spent a lot of time preparing the soil prior to planting. The area was hand hoed and rototilled then smoothed out to seed and finally the seed was scratched in. Since Claudia hasn't used herbicide the hoeing was the most time consuming. If a grower is using herbicide hitting the weeds with that first then scratching the seed in will cut the time for bed prep down by a lot. Alternatively if you have a grape hoe (such as a clemens), that might cut down on the time as well. As part of this project we will be evaluating strategies that growers used to plant their cover crops. We will include as many of the costs associated with planting that we can and compare the different methods (including germination success).