Cover crop establishment
The group is learning to understand parameters for getting good establishment in hop soil situations, and were able to achieve better establishment in the second year of growing cover crops. One of the growers has sown cover crops on about 6 acres - roughly 10% of the farm, and has already seen benefits such as less erosion, better trafficability, and now the cover crops have been terminated the mulch is adding to soil fertility. Whilst impacts on yield aren't easy to measure, given other variables such as weather, this triallist has deemed the cover crops a great success and has decided to sow them over the whole farm this summer, with the exception of a few small areas they don't want to disturb the soil due to wilt.
Some new growers have joined the group and are doing their first year of cover crops.
Soil parameters will not be measured this year, as it is expected to take several years for the cover crops to make a significant impact, but will be measured at the end of the project and compared with the baseline data taken at the beginning of the field lab.
Milestone: Establishment of cover crops Year 2
Second year cover crops drilled
Two triallists have got their cover crops in early (one before harvesting the hops) so they feel that there should be a better establishment than last year. The triallist who drilled before harvest hopes that as the seed is already in the ground waiting to emerge, as soon as the hops are harvested there will be light and more warmth than usual for them to establish much better. The triallists will be recording their observations and taking photos of emergence in order to reflect on these alongside the soil health analysis.
A new triallist has also joined the group after seeing the first year of methods rolled out.
After discussions with the researcher last November, the triallists won't be taking yield data as they don't feel this will be able to tell them clearly if the cover crops have had a beneficial effect. There are too many other confounding factors upon yield, such as rainfall, temperature and mildew.
The group's plan is take soil health measurements again in November 2019, by which time they hope that there are some significant improvements to compare against November 2017 results. They will be meeting later in autumn to verify these plans with the researcher.
Milestone: Second year cover crops drilled
The hop harvest is normally around the August bank holiday but the coordinator thinks that this will probably be a few days earlier this year due to the dry weather.
The farmers have discussed about potentially drilling in a few of the cover crops before harvest. This wasn’t thought of as a possibility due to the ground being so dry but over the weekend they have had 20 ml of rain in Kent so potentially now possible. Despite this, the farmers plan to drill the majority of the cover crops after hop harvest.
Triallist coordinator Rob Saunders gave a presentation about the scope of the trial, including photos from one of the more 'light touch' triallists (growing cover crops but not taking measurements), which shows that their growth is very encouraging.
Some of the triallists also took part in a panel session at the Innovative Farmers Network Day in May, to explain that in comparison to other research grants this had been much easier to access, and the support from researchers has been positive.
Milestone: Progress meeting
Initial lessons from the first year
From the first year of cover cropping the group has realised a few initial lessons that can be built upon in subsequent years. These include upping the seed rate and creating a better seed bed for good cover crop establishment. The drilling of the cover crop needs to done quicker i.e. earlier in the season, so that there is less time between harvest and drilling. Next Autumn they will also look to cover a wider area with the cover crops at each farm.
Milestone: First year reflections
Cover crop termination
Termination of the cover crops will be undertaken during late February, early March using the method of choice for each farmer, (the majority will be glyphosate this year with the hope in subsequent years the group will use other approaches such as Crimper roller).
Milestone: Cover crop termination
Baseline data collection
The two Kent trial sites have undertaken their baseline data collection. The data recorded included a visual assessment of the soil, pH profiles, earthworm counts and SOM measurements. In December the two Hereford trial sites will undertake baseline data collection. These initial sets of data will be available online in the new year.
Milestone: Baseline data collection
Confirmation of soil measurements
The group decided that the following soil parameters will be measured:
• Earthworm counts
• Water infiltration rate
• Visual evaluation of soil structure
• OM content
• Soil Mineral Nitrogen content
• Solvita test (CO2 release as an indicator of biological activity) - if practical
Milestone: Methods discussed & finalised
The proposed method is to measure relevant soil parameters – water infiltration rate, earthworm population, OM content & soil mineral nitrogen content, to establish a baseline, then areas of cover crops in alleyways, carry out follow-up evaluations to identify effects in the spring, and share best practice.
Cover Crop Options
A number of parameters must be met by any candidate cover crops:
• Suitable for late summer/autumn sowing
• Easy to establish, tolerant of ‘poor’ seedbeds
• Fast growing
• Easy to kill, or manage in such a way that it does not, in itself, become a problematic weed.
• Ideally, exerts allelopathy, thereby reducing the germination of other weeds.
• Mixed stands may be more successful and resistant to pest and disease than single species.
In gardens where wilt-susceptible varieties are grown, the cover crop must not become a reservoir or nursery for wilt. Further research and consultation are needed, but this may restrict the options to monocots.
• Rye: excellent leaching prevention, useful OM useful soil structure improvement.
• Black Oat: excellent leaching prevention, excellent OM, excellent soil structure improvement
• Rye/Black Oat mix
In less wilt susceptible varieties, the list of candidate plants is potentially less restricted.
Candidate plants as above, plus:
• Buckwheat: excellent OM, not frost hardy so ‘self-destructs’, said to promote P availability.
• Rye/Vetch/Phacelia mix: useful leaching reduction, excellent OM, useful soil structure improvement.
• Black Oat/Vetch mix
• Rye/Vetch mix
• Rye/Mustard mix
Crop Destruction Options:
• Leave to degrade
• Spray off in spring
• Spray off and roll flat / roll flat and spray off (a ‘bracken roller’ with serrations to promote bruising and breakdown) may be advantageous). This approach is preferred as it potentially promotes/preserves allelopathy (inhibition of weed germination).
• Spray off and cultivate (least preferred as promotes breakdown of OM and creates a new weed seedbed).
Milestone: Methods discussed & finalised
Drilling of the cover crops
The cover crops have been sown after harvest in alternative rows to help avoid any soil cooling effects of the cover crop in Spring which may affect soil health.
After drilling the farmers have concluded future cover crops need higher seed rates and the two Kent sites have expressed their desire to sown their cover crops just before hop harvest (August) next year.
Milestone: Crops drilled
There will be three tiers to this farming group and field lab:
• Primary Hosts: 4 ‘full evaluation’ sites where changes to all relevant soil parameters will be measured during the course of the field lab.
• Additional Hosts: ‘light touch’, ‘observation’ sites where growers will establish and manage various mixes according to their own requirements, sharing their experiences but not taking detailed data beyond what is practical for them.
• Observers: the remainder of the group will follow the trials and learn from the outcomes at regular meetings.
Milestone: Methods discussed & finalised
Initial meeting consultation
Discussion with Hop specialists regarding which cover crops to use within the trials.
The specialists expressed that, depending on the cover crops used, there could be a risk of increasing verticillium wilt in the following Hop crops. Following consultation the trial farmers have chosen to use a cereal monoculutre cover crop this year, including forage rye, triticale and oats.
Milestone: Initial idea formation