What a difference a month makes! Now all worries of drought have evaporated (excuse the pun). Here at Terravesta Agronomy HQ in northern Cambridgeshire the #TVAgronomist Russell Armstrong has recorded 125mm (5″) of rain for the first 2 weeks of June. Our 10-year average for June is 50mm (2″).
Questions about the emergence of new crops continue to dominate the agronomy hotline (07535 649 111). Now we have adequate moisture, patience is the name of the game. The crops that I’ve looked at this week range between 20-60% emerged. I will be doing final emergence counts in September when we can expect the majority of the rhizomes to have emerged. That being said, experience from previous years has shown that some rhizomes emerge in spring the year following planting; something I’ve seen this week in a second-year crop in Norfolk.
Checking emergence is easy, measure 13.3m along a row and count the number of emerged plants. Divide this number by the number of rhizomes planted per hectare, divided by 100,000 to get the % emergence. Example: 15 plants per 13.3m divided by 0.15 (if you planted 15,000 rhizomes per ha) = 100% emergence. If you planted at 16,000 rhizomes / ha divide by 0.16, 17,000 rhizomes / ha divide by 0.17, 18,000 rhizomes / ha… well you get the idea.
The crop establishment phase in years one and two is all about maximising light interception to build the rhizome to ensure a bigger plant the next year. Weed control in the first year is critical to ensure a good return on investment.
Newly emerging plants are very uncompetitive because of the low planting density and protracted emergence. If weeds are left uncontrolled, they can swamp newly emerged plants, and while it’s unlikely that this will kill the new plants it will hold back their development and result in a smaller crop in the second year. This can delay or reduce the yield of the first harvest.
Post-emergence weed control is restricted to a handful of herbicides mainly from the phenoxy (hormone) and SU (sulfonylurea) groups. Most common arable broad-leaved weeds can be controlled when they are small but as they grow bigger, control can be problematic. The only option for post-emergence grassweed control is Attribut (propoxycarbazone-Sodium) which has several weaknesses including Blackgrass.
If you have concerns about weed control please give the agronomy hotline (07535 649 111) a call.
Research & Development
Terravesta continues to invest in Miscanthus production in the UK and here at agronomy HQ weed control is very high up the list. Over the next few years yours truly #TVAgronomist will be screening herbicides for use in Miscanthus. Herbicides that cut the mustard (or other problematic weeds) will go forward to seek an Off Label Approval (EAMU) for use in Miscanthus.
The agronomy hotline has received a couple of queries about Nitrogen fertiliser use on Miscanthus. The basic message is that research shows that N containing fertilisers or high N muck (chicken/turkey) has no beneficial effects on newly planted or established Miscanthus crops.
However, if you have established Miscanthus crops that are 7+ years old, #TVAgronomist would like to hear from you and is keen to test the phosphate and potash indices of these fields especially where the indices of the soil are known pre-planting of the Miscanthus crop. Call the agronomy hotline (07535 646 111)
If you are planning to plant in spring 2020 then please call the agronomy hotline and speak to Russel Armstrong about land preparation and pre-emergence weed control. Some weeds are much easier to control pre-emergence than post-emergence.
“The day you plant the crop is the day you set your yield”.
If you have any queries about Miscanthus please contact Russell on:
twitter hashtag #TVAgronomist
Agronomy hotline: 07535 649 111