Grassright Summer Bulletin 2008

Weed control and compacted ground and sowing clover to save money.

Now is the time of year to tackle areas of grassland that suffered water-logging problems during the winter and early spring. Water-logging not only means that stock cannot be grazed in these fields, it also stops oxygen getting to the roots of the sward preventing early spring growth. This reduces yields and can also kill off hybrid grasses allowing less productive indigenous grasses to take over the ley.

Water logging occurs when a layer of compaction has been created, either by heavy machinery or livestock. With mechanical compaction, the compacted ground layer can be as deep as 12 inches. However, with compaction caused by livestock being kept on the field in damper conditions, then commonly this layer is between 3 and 5 inches below the surface. It’s important to look at how best to prevent water-logging in future, rather than just treating the problems arising from it.

To break up this compacted ground, sward-lifting can be carried out. Right now ground conditions are approaching ideal in many parts of the country to do this. Use a grassland subsoiler which is set an inch or so below the compaction, any deeper than needed is a waste of horsepower and diesel. When the subsoil is starting to dry the action of a grassland subsoiler will crack and fissure the soil much better providing channels for water movement down through the soil profile when wetter times come again. Ensure that the surface is rolled and the subsoiler leg slot is closed after the job has been done to prevent the ground drying out too much and grass being killed off.

Where water logging has killed off the grass, then overseeding to patch up the ley should be carried out when rainfall is expected.

Weed control

With rising input costs, livestock farmers need to maximise the return from fertilisers. Weeds, particularly docks, are great robbers of this resource, having both a direct impact on yield, quality and grazing of swards, plus leading to a shortened life of the sward in the long term.

To get the maximum return from any herbicide treatment, weeds should be treated before first cut silage. Forefront now has an extended timing to allow use on established leys in the autumn, allowing docks to be treated later in the season. The same rules apply – weeds must be actively growing and stress-free. Grass treated with herbicide in September has shown remarkable powers of recovery, taking advantage of residual nitrogen in the soil (see treated/ untreated below), to thicken out and fill in the gaps left by weeds.

The images below show before treatment and after treatment in autumn 2007 of a 2 year old ley that had been badly scalped allowing the docks to establish, and a close up of the untreated and treated areas spring 2008. Notice how the grass continues to suffer the impact of the docks .

Introducing white clover to leys

The inclusion of white clover in any grass ley brings both nutritional and financial benefits and after second cut silage is an ideal time to be adding this valuable plant to your swards.

White clover is commonly included in grass seed mixtures but is often lost through the use of herbicides applied for broad-leaved weed control. After second cut silage reduced competition due to slower grass growth means the young clover plant has a better chance of good establishment. This combined with warm soils and the likelihood of sufficient moisture makes it one of the best times to think about introducing clover into your swards.

White clover will enhance the sward digestibility, increase protein levels, improve mineral intake and can in many cases increase sward palatability. This in turn leads to both lambs and beef cattle fattening faster, and improvements in milk yield and quality.

Maintaining a good clover content in your swards will also dramatically reduce your fertiliser bills due to the plant’s ability to fix atmospheric nitrogen. Conservative estimates suggest that clover can fix the equivalent of 200kg N/ha which at today’s prices relates to a saving of at least £157 per hectare.

However, standard clover seed is very small, and as well as making calibration of drills and spreaders very tricky, it can easily be blown off course when broadcast making accurate application difficult. So for best results, the pelleted clover mixture Cloverplus should be used which adds size and weight to the seed. This overcomes these problems and the extra weight of the seed also increases the chance of good soil to seed contact which is vital for good establishment.

Rapid germination is necessary to help the young clover plant compete with the existing sward which is why Cloverplus is also treated with Headstart. This is a combination of seaweed enzymes, natural bio-nutrients and trace elements which enhance vigour and root development to help the seedling overcome any symptoms of stress and ensure that a higher proportion of seeds sown are able to develop into mature, nitrogen-fixing plants.

Autumn reseeding

Now is also the time to start thinking about which fields may need reseeding in the autumn. Taking a walk across your fields should give you an idea of the amount of broad-leaved weeds present, the ground cover of the sward and the levels of less productive weed grasses which may have become established. A judgement of how much extra production can be achieved by reseeding a particular field, can then be made.

Grazed grass continues to be one of the cheapest forms of feed available to farmers with production costs of around £69 per tonne of dry matter compared with bought-in feeds which can be double this price or more. Reseeding at more regular intervals ensures that you get the most from your grass and will help towards keeping your feed costs down. That said, grass prices like many other inputs, look set to continue to rise, so there will never be a cheaper time to buy seed!

Farmers thinking of sowing new leys later this year should consider a number of  issues: if grass follows grass what are the risks of Frit fly and leather jackets? A spray of Dursban WG may be required. Also what weed issues can be expected? This may effect the decision to include clover or not. For example, chickweed is difficult to control well with existing clover safe materials. So if it is likely to be a major problem, it may pay to exclude clover initially and use a product such as Pastor with excellent activity on both common and mouse-eared chickweed. Clover can then be overseeded at a later date once certain that a weed-free ley has been established.

The value of muck

With the costs of autumn fertiliser at around £600/tonne, the full utilisation of soil nutrients is on everyone’s agenda.

For those farmers considering swapping their muck for straw from neighbouring arable farmers, do be aware of how much your slurry and muck is worth today. Straw removes about 40 units of Potash K and 8 units of Phosphate P from the soil, which at £19.50 for K and £6.13 for P, makes it worth £26.63 per acre (before baling costs).

However, 1 tonne of cattle manure if applied to crops in the autumn, contains: 1.2 units of N, 4 units of P and 14 units of K. This equates to a total of £9.58/tonne worth of available nutrients to the crop to which it is applied.

A good average application to match Potash requirements for a cereal crop would be at least 6-7 tonnes of FYM, which is worth £67 in nutrient. So a straight swap on an acre basis, would mean a loss of £40 (£67-££26.63) to the farmer giving the muck.

Also, appreciate the value of slurry. Taking a typical sample of dairy slurry at 6% DM, applied in the autumn, this is worth 8: 5.4: 28 of NPK units respectively. This equates to £19.50/1000 gallons. (If applied in the spring, it will be worth slightly more at £21.50 due to the improved nitrogen availability).

So a slurry pit with a capacity of 500,000 gallons represents a value of £10,750 worth of nutrient towards first cut and grazing.

With plant nutrients costing so much, and with little outlook of prices falling, it makes sense to think carefully about all aspects of where to put this valuable asset to get the best return.

Cost saving on nutrients can be achieved in most cases, with the use of Growhow’s Encompass Management package, available at a cost now equivalent to just over a tonne of fertiliser. Using the data from the farm’s soil and slurry analyses, this ensures yields of silage and grazing are achieved without sacrifice of feed quality, especially protein. By taking into account all aspects of nutrient availability and requirements, Encompass allows targeted nutrient planning and ensures maximum return on the money spent.