THIS is the time of year when livestock farmer's "top" their grazing land with a grassland-topper to keep the grass lush and to control weeds. Grass becomes fibrous and less nutritious as it forms seed heads or "heads out" at this time of year, so cutting it encourages the growth of lush, nutritious leaves. Perennial weeds like rushes, docks and creeping thistle are weakened by topping, while biennial weeds like Scotch thistles are prevented from seeding.

Of course such weeds can also be controlled by spraying with expensive herbicides, but topping not only improves the quality of the pasture and contains the spread of weeds, it makes the fields look tidier.

My father, ever one to do things the hard way, used to get his men to "chap" the Scotch thistles. That was a soul-destroying task where we chopped or "chapped" them off at ground level with a hoe. A day of that in the sun left many farm-workers wishing they had stuck in at school.

Thicker patches of creeping thistle were cut by scythe, but sharpening that tool properly was an art form that I never mastered. Perhaps the most accomplished scythe sharpeners I knew were the roadmen who cut back the miles of verges on our rural roads. They also cleaned out all the run-offs preventing the flooding that is a common occurrence nowadays.

Another pernicious weed we used to control at this time of year was bracken. The farm I grew up on had about 100 hectares of the stuff that could grow to the height of your chest and reduced the amount of grazing available for the livestock. It was also poisonous to cattle and harboured ticks.

My father cut it back twice a year with a very robust type of topper, while those areas too steep for a tractor, or with outcrops of rock that would have damaged the topper were cut by scythe. He eventually eradicated bracken from the farm.

In more recent years farmers have been spraying bracken with Asulam, either by tractor-mounted sprayers, quad bike-mounted sprayers, knapsack sprayers or by helicopters. Following the ending of the approval to use Asulam for bracken control on 31 December 2012, emergency annual arrangements have been put in place to allow the use of Asulam to continue. Under the new arrangement spraying can commence on 1 July but the herbicide must be used by 31 October, or returned to the supplier.

Other species of weeds have increased over recent years, but often as not that has been down to bad farming practices or bad neighbours.

I think of nettles and cow parsley that spread from railway embankments and badly maintained road verges. Railway operators don't give a damn and councils often wait until those pernicious weeds have seeded before cutting them back.

Docks are also to the fore everywhere I look nowadays. The old practice of composting farmyard manure in a midden used to kill the dock seeds present in bedding straw. The modern practice of storing animal waste as slurry allows seeds that have passed through the cattle in their dung to survive and be subsequently spread on the land.

The only way to get on top of docks is to regularly spray expensive herbicides. Sadly, once established they are difficult to eradicate as their seeds remain viable in the soil for years.

Those readers who graze horses will be well aware of the problems of controlling ragwort. It is a weed I had little experience of because I was a sheep farmer and sheep nibble it out of existence. I have learned a little about this nasty weed in recent years because I retired to a bungalow with a small paddock that is grazed by ponies belonging to a friend, and becomes infested by seeds blowing onto it.

Spraying or cutting it are not options for us, because while ponies and horses tend to ignore ragwort that is growing, as it dies and wilts it becomes sweet and irresistible to them - and of course, as most know, it is poisonous to horses and ponies.

Part of the grazing deal is that my friend has to control the weeds in my paddock, so she pulls that ragwort every summer at this time of year.

It is important to remove all of the root as fragments left in the ground will grow into plants the following year. To help achieve that, my friend uses a special tool called a "rag fork", that helps to ease the roots out - and is particularly useful when the ground is hard and dry.

ENDS