Webinar: Making reseeding work for you

Join Ben Wixey and William Fleming for a discussion on reseeding and how to determine what type of reseeding is right for your farming system.

The webinar will explore some of the reasons you should consider reseeding: factors that cause deterioration of leys; spring vs autumn reseeding; establishment methods; overseeding vs full reseed and management of your new leys. This will be an ideal opportunity for you to ask questions of our grassland experts and get their guidance on how a successful reseeding plan can improve your production from grass.

Webinar Q & A

What is the best way of reseeding permanent grassland that has got tired without ploughing or spraying off?

Very difficult, need seed to soil contact and every advantage for the new seedlings. Therefore, graze to floor and harrow hard to open up the old sward, correct any pH problem well in advance. If you can see enough soil to allow seeds to reach soil and be pressed in by the roller then use tetraploid seeds and roll tight. The only other option is to try and destroy the permanent pasture mechanically to allow new seeds to have contact with soil.  

We have a red clover ley (AberClaret) coming into its fourth season. When do we need to reseed, can we avoid ploughing and do we need to move away from red clover to avoid disease? Our land is on the heavy side.

Unfortunately, you shouldn’t use red clover again on that field for six to seven years due to Sclerotinia and stem eelworm. Both are naturally present in all soils and numbers multiply with the red clover plants as a host. If you don’t drill red clover for six to seven years, those populations in the soil naturally die back down. After this next season, I would suggest assessing the red clover content to make a decision on keeping the ley down for another 12 months or whether it is time for a change. Burn off the existing ley and follow the advice given in the webinar for direct drilling.               

What is Germinal doing with the latest research to help farmers reduce N inputs and drought tolerance?

The obvious answer here is Aber High Sugar Grass (Aber HSG). It doesn't take any less nitrogen to grow the crop, but it has been proven to increase the usage of dietary nitrogen in the rumen whilst also reducing the amount of ammonia and methane released. We have a very strong legume breeding programme and using the correct white clover in grazing situations and red clovers in cutting situations (and possibly for strong liveweight gain with lambs and youngstock) is the answer. We also have our embedded research and breeding team working at Aberystwyth University looking at novel legumes that hopefully will provide high volumes of forage while fixing and releasing more N to the companion cropping. We have already brought to the market a hybrid white clover, AberLasting, that is a cross with Trifolium Ambiguum and Trifolium Repens so the forage clover is producing rhizomes as well as stolons. This is helping production in drought situations all around the world. We also have a stoloniferous red clover very close to the market. This red clover type will produce higher yields of protein and be able to cope in a grazing environment. The grass breeding actively looks at nitrogen response in relation to yield and quality and much work is going on with rooting depth to aid nutrient uptake. There is also a programme and varieties coming to the market soon that have improved phosphate use efficiency, so you can grow the same amount of forage for less phosphate use. On the drought tolerance front, we have our first perennial ryegrass Festulolium cross up for recommendation onto the recommended list at the end of this month. We believe this grass, the first of its type, will bring some drought tolerance to a perennial grass sward. We have it in trials across the UK on-farm and at our Germinal Research Station in Melksham and will release results shortly.

Views on mixed-species swards?

A massive subject. It makes great sense to increase the sward diversity to provide protein, energy and minerals but you need to understand your objectives of the livestock and soil types and the overall farm plan of how it fits into rotation. These are detailed discussions and any of the team would be glad to have these conversations with you or anybody else who is thinking about multi-species leys. Mixed swards have big potential when used in the correct situation, but they are not right for every scenario.

With understocking, is regular topping a good solution?

Resetting the grass after grazing is vital if the outgoing stock has not left a uniform residual cover at about 1500kg dm/ha or 5cm. Most toppers won’t get down to 5cm so a good mower is the best tool to use. Remember to clean up quickly with dry stock any grass left on the sward surface to avoid damage to the sward.                                                

Can aerating fields cause the pH to go back as it’s increasing root structure? We also applied plenty of calcium lime over the years off soil tests.

We think it is very unlikely that aeration would result in pH drop. It is far more likely that something else is going on with the soil, possibly a calcium-magnesium ratio balance. We would strongly recommend a broad-spectrum soil analysis to see what is happening with the micronutrients and their ratios to each other.                                               

Going back to the first question regarding red clover. Can you sow white clover after a red clover ley?

Yes, the diseases that affect white clover are different and, therefore, no issue with following red clover swards with a white clover sward.

How late in the spring can you sow Clover into an Autumn sown grass ley after spraying out broadleaf weeds in the spring?

Clover grows at soil temperatures of 8°C. Therefore, in the spring, we need soil temperatures up to at least this level, but before grass growth takes off. Either we must manage that grass growth, so the clover seedling has a chance of establishing, or we introduce the clover after a silage cut or tight grazing in the summer months.

Are leather jackets an issue in spring reseeds?

The leather jacket larvae that have overwintered under the soil, having been laid in the old sward by the crane fly in August and September, can cause significant damage to spring-sown grass leys. The best advice, if in a high-risk situation, i.e grass following long term grass is to insert a break crop ideally brassica as the crane fly prefers to lay her eggs into grass swards or cereals.

Are there any specific varieties that you would recommend for sowing after maize in late September/early October?

If you are trying to establish a long-term ley then I would recommend drilling before late September. If, however, you are trying to establish a short-term ley and keep the ground covered for winter then Italian ryegrass, hybrid ryegrass and even some westerwolds would do the job. Interestingly we have a new winter active Triticale in development which can be sown after maize, grows through the winter and can be harvested for silage in late March/early April before another maize crop.

Do you recommend sowing a brassica crop as a break between the old established grass to a new ley? Any suggestions for the control of Frit Fly and Wireworm in new leys?

Our recommendation of using a brassica crop as a break crop would also help with reducing populations of Frit Fly and Wireworm. Unfortunately, there is no chemical spray that controls these pests anymore. We have heard anecdotally that power harrowing and rolling with a heavy roller reduces their mobility, but we haven’t seen any scientific work on this practice.                                               

Are there any BASIS or NRoSO points available for attending this webinar?

Unfortunately not – we will try for a retrospective allocation and let you know. The next webinar on March 2nd may have BASIS and NRoSO points                                    

We reseed in the spring; what options do we have to prevent and limit the threat from leatherjackets now that Dursban is banned? Brassicas and break crops are not an option

We only have anecdotal evidence that spraying the grass ley off as early as you can travel reduces the food source for the leather jackets and therefore, their burden on the following new ley.                                              

Power harrow or disc for making a fine seedbed?

The tool is not the important part, it is choosing whatever equipment is suitable and available to create a FINE FIRM SEEDBED. Remember, we are looking for maximum contact between seed and soil.

What drilling depth would you overseed? Quite often the grass seed goes in too deep which ends in failure

Very true in all drilling circumstances. As a rule of thumb seeds shouldn’t be drilled deeper than one and a half times the size of the seed. Therefore, we recommend clover seed and other such small seed species like plantain are placed on the surface.

There seem to be fewer and fewer sprays for grassland weeds and none for safe for clover. Thoughts?

This is complicated and the options are limited. We must advise you to talk to a qualified agronomist, but we believe there is optimism with new products coming to the market and we are carrying out work at the Germinal Research Station in partnership with some of these chemical manufacturers.

We have direct drilled a field of grass in early September, establishment so far is patchy. Is there a chance it could recover by spring?

Unfortunately, it is unlikely any grass seed will germinate now, it is more likely to have been eaten or rotten away over the winter.

After ploughing, how would you prepare the seedbed and with what machinery?

We are looking for a fine firm seedbed therefore we need a small aggregate size and the important operation once we have this is rolling tight to create the most contact between seed and soil. I am afraid there is no standard machinery policy, it is whatever works for your soil type and the conditions on the day.

Is spring reseeding riskier in terms of weed burden and germination compared to late August?

We think there is very little difference between autumn and spring weed burdens. However, the chemistry works better in warmer conditions and therefore weed populations would be easier to control after a spring reseed.

What advantages would there be to growing a forage brassica crop to use as a break crop rather than direct grass to grass?

Brassica crops are not hosts for the parent pests to lay their eggs. Therefore, creating a cleaner seedbed with less risk of pest problems. You also get two chances at weed control and a high protein break crop that can provide valuable forage at a period when you might be short of livestock feed.

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