Ground conditions have improved significantly and with dry weather forecast in the week ahead, there will be some farmers looking to reseed less productive grassland.

Before going to the expense of reseeding grassland, there a few things to consider first, some of which are outlined as follows.

1 Lime and soil fertility

Grass growth can be heavily curtailed if soil fertility is poor. There is little point reseeding a sward without correcting soil pH along with P (phosphate) and K (potash) levels beforehand.

If fields have recently received fertiliser or currently being grazed, there is little merit in taking a soil sample at this stage of the year, as fertility levels will be heavily distorted.

Grass needs a soil pH of 6.0 to 6.5 to grow to its potential. Spreading lime before reseeding is always recommended.

Where P and K levels are low, getting farmyard manure, slurry or some form of organic matter on to the soil is essential.

Building P and K levels takes several years. But getting plenty of organic matter spread will condition soils and gradually improve fertility with regular applications.

2 Drainage and compaction

Poor drainage and compaction will also limit growth. Again, these issues will need correcting before reseeding.

Drainage is expensive when using pipe and stone systems, but it more effective and has a longer lifespan. Mole ploughing is an option to cut costs, but is only effective on soils with a high clay content.

When digging new drains, it is a good time to think about moving water troughs

Ploughing can also help alleviate compaction problems that affect drainage, as will sub-soilers and sward lifters. These machines improve soil aeration, soil temperature and grass growth.

When digging new drains, it is a good time to think about moving water troughs to a more central location in fields to suit paddocks as water pipe can be buried before sowing out new grass.

3 Ploughing or stitching method

Ploughing opens up soils and buries older grasses and weeds. However, it takes longer to get the field back into production.

Also, as the soil surface is softer, grazing new swards requires careful management to avoid poaching from livestock.

If fields are rarely reseeded, the more fertile soil will be ploughed down. Weeds are also a bigger problem after ploughing.

Swards need to be grazed shortly after stitching in new grass

Minimum tillage works well on stonier, or shallow land and it is a much faster reseeding method than ploughing and sowing out new swards.

As the soil surface is not disturbed, there are usually fewer problems with weeds and poaching is less of an issue once the new sward is grazed for the first time.

Swards need to be grazed shortly after stitching in new grass to keep older grasses from re-establishing.

4 Burning off the old sward

Burning off the old sward before reseeding is recommended, especially if using a stitching method to establish new grass.

This stops the existing sward competing for soil nutrients and smothering newly established grass seedlings.

5 Choosing a suitable grass mix

Choose a grass mix that will suit both the soil and general use of the field. For example, on heavier soils, choose a mix with mainly diploid grasses as they tiller out more.

Tetraploid grasses grow tall and erect but do not tiller out as well, so they suit silage swards better than grazing swards.

Spring and autumn growth, along with heading dates are also something to consider. There is also an increasing trend to using mixed species swards for grazing and deserves some consideration.

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