Grassland reseeding: establishment methods

Our decision tree will help you to decide which reseeding method to choose. We’ve also got information on using a pre-cultivation spray and results from our reseeding survey.

Which establishment method should I choose?

Achieving a level, uniform seedbed is important to ensure a consistent sowing depth. It is vital to select the right technique to suit the farm and soil conditions. Under correct conditions, the impact of reseeding technique on sward productivity is small.

Recent research undertaken in Ireland has shown comparable yield benefits to reseeding with discing, one-pass cultivation and ploughing (see graph below).

Results from Irish work on the impact of cultivation technique on grass yield

Graph showing that ploughing increased year 2 grass yield comparable to discing. Source: Creighton et al. 2012.

Choosing the correct cultivation technique

Cultivation technique can be selected based on various factors, such as soil type and existing sward conditions. The cost of the technique needs to be taken into consideration. Each technique has several advantages and disadvantages.

A decision tree for choosing a cultivation technique

Example costs of different reseeding techniques (£/ha)

	Full cultivation	Minimum-till cultivation	Overseeding
Soil analysis	3	3	3
Spray	30	30
Spraying	27	27
Plough	61
Power harrow	50	50
Power harrow	50
Land leveller	17	17
Seed	161	161	79
Sow	22	79	79
Roll	17	17	17
Fertiliser–100 kg 18:14:14 + spreading	94	94	94
Lime-2 t +application	126	126	126
Leatherjacket control	12	12	12
Slug pellets	20	20	20
Total cost (£/ha)	689	636	430

The pros and cons of cultivation techniques

	Pros	Cons
Ploughing	Good seed-soil contact Can remove compacted layers in topsoil Achieves level even seedbed Buries pests and trash Most reliable method	Expensive due to the number of cultivations Deep ploughing removes nutrient-rich soil from surface Light soils can dry out quickly Disturbs seed bank of weeds in soil
Minimum cultivation, e.g. discing, one-pass	Cheaper than full plough Fertile soil remains at surface Limited disturbance of soil structure	Difficult to remove trash Decaying trash can release organic acids, hindering germination Takes longer to achieve an even level finish across field
Direct drill into existing sward	Opportunity to maintain existing sward No cultivation reduces costs No disturbance of soil structure	Hard for cultivars to compete against existing sward Not suitable for dry, hard ground Results can be variable

Pre-cultivation spray

Before reseeding, applying herbicide to the existing sward can remove any existing weeds and reduce competition for the new ley. Trials undertaken in New Zealand achieved a plant count of 400 plants/m² in the reseed when using a pre-cultivation herbicide. This was reduced to 120 plants/m² when the herbicide was omitted.

It is important to allow sufficient time between herbicide application and sowing the seed.

Contact between the seed and chemical may negatively affect germination rates
Cultivations can usually begin seven to ten days after spraying, but it is important to check the product recommendations

Pesticide legislation

Everyone applying pesticides is required to have a certificate of competence and the sprayer must have passed a test. More information can be found at: voluntaryinitiative.org.uk

Always wear appropriate protective clothing and take care when handling pesticides. More information can be found at: hse.gov.uk/pesticides

Reseeding survey results

A survey looking into current reseeding practices on farm was conducted by AHDB during 2016, with technical assistance from Field Options. Some of the findings from the survey show:

Before reseeding, 58% of respondents treated the existing sward with glyphosate
About 46% of respondents ploughed and cultivated, another 19% cultivated but did not plough
Around 12% surface-seeded, with about 10% using a direct drill

Useful links

Grassland reseeding: top tips for ploughing, cultivation and overseeding

Topics:

Grassland Management

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Beef & Lamb Cereals & Oilseeds Dairy

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grass grassland reseeding re-seeding new reseed pasture improvement grass in arable rotation improving grass grassland management Soil