Autumn pasture improvements to boost sward productivity.

Lancashire dairy farmer Richard Corlett wants to increase the ratio of milk from grass for his 160-cow herd, and improve his silage quality by raising protein levels. Following practical help and advice from the Grassright Group, white clover was oversown into leys earlier this year. This autumn further pasture improvement has been made: a sward-lifting operation to remove compaction and improve aeration of the soil. However, the original plan to reseed worn out leys has been postponed until spring.

At Home Farm near Ormskirk, Richard has already seen improvements in sward quality after oversowing pelleted clover blend Cloverplus into grass-only leys in May, once a cut of silage had been taken. Despite the dry conditions at sowing, the Headstart-treated seed with its protective coating germinated well and produced a big show of clover through July and August, boosting protein content of the grazing. Protein levels in next summer’s silage should also be higher, and fertiliser input will be lower.

The next step in grassland improvement has been to remove soil compaction to improve drainage and allow earlier turnout and/or muck spreading, and improve soil aeration to boost plant growth.  

OPICO’s Nick Rider explains: “To check for compaction, simply take a spade and dig out asquare clod of earth. Drop this onto the ground and vertical fissures should appear. In compacted ground, only horizontal fissures will be seen.

“Also, on examining the clod, look out for areas of rusty-coloured soil which smells of iron and sulphur. This denotes iron oxidation, where compaction has starved the soil of oxygen, another limit to grass growth.”

An OPICO Sward-Lifter was used to remove soil compaction. It is designed specifically for use on grassland with presses to replace the surface after subsoiling, so minimising damage to the sward.

“On arable land, compaction runs much deeper due to the weight of machinery used,” explains Mr Rider. “For grassland, setting the subsoil leg at 10-12cm below ground level is sufficient to shatter the pan 20cm either side. Setting it any deeper just uses more fuel.

“Subsoiling operations are best carried out when the soil is dry enough to crack a bit, but not so dry it collapses. Autumn is the ideal time for sward-lifting per se, as wet weather will follow and support grass growth again. Alternatively, do this in the spring before rain is expected.

“Sward-lifting oxygenates the soil and grass roots, and improves nutrient uptake from the soil, so Richard can expect to see grass which is a darker green.”

Dow Agroscience’s Duncan Connabeer commented: “Richard has taken the policy of reducing the dock population using a non clover-safe herbicide, for more effective weed control. Clover has then been added afterwards. The oversown clover has taken very well, and already achieved a ground cover of 15-20%. This will increase next year as the plants become more established.”

A few docks were evident in some of the fields. Duncan advises: “Herbicides need to be applied to plants that are in a state of healthy and active growth. This ensures the active chemical components are taken down into the root to give effective control. So it’s too late to do any spraying this year, and Richard should wait until the spring to control weeds in his established leys.

Richard has planned to reseed two of his grazing fields, however the arrival of cold wet weather forced him to defer until the spring.

Duncan advises: “When reseeding new grassland after old, there is a high risk that the new ley may fail due to frit fly and leatherjackets.
“Anyone who has drilled new leys this summer/autumn, without taking the precaution of using a pesticide, should be extra vigilant for the presence of these insects coming out of the old sward and affecting the new ley. On seeing signs of damage, then Dursban WG can be sprayed, unless soil temperatures have fallen below 5° C, in which case, wait until the spring.

“Also, be on the look out for chickweed which can grow over the winter months and stifle new sown leys. Farmers should contact their crop advisor or agronomist for options to combat weed ingression.”  

Richard Corlett has been receiving technical advice and input on his grassland management from the Grassright Group, which consists of: OPICO, advising on machinery for seeding and cultivation; Advanta Seeds (soon to be Limagrain UK), for choice of Monarch seed mixture; Dow Agrosciences for weed and pest control; and GrowHow for nutrient analyses and fertiliser planning.