Re­seed­ing can de­liver big re­sults within two years

The in­creased prof­itabil­ity of new swards makes re­seed­ing one of the most cost-ef­fec­tive farm in­vest­ments, writes Deirdre Hen­nessy

Irish Independent - Farming - - RESEEDING -

Less than 2pc of Ire­land’s grass­land area is re­seeded an­nu­ally de­spite grass be­ing our dom­i­nant feed source Swards with low peren­nial rye­grass con­tent are cost­ing farm­ers up to €300/ha/year due to re­duced DM pro­duc­tion and re­duced ni­tro­gen (N) use efficiency.

And while re­seed­ing costs ap­prox­i­mately €750/ha, the in­creased prof­itabil­ity of the new sward would cover the cost in just two years mak­ing re­seed­ing one of the most cost ef­fec­tive on-farm in­vest­ments.

Re­cent Moorepark re­search shows that old per­ma­nent pas­ture pro­duces, on av­er­age 3t DM/ha/year less than peren­nial rye­grass dom­i­nated swards. Old per­ma­nent pas­ture is up to 25pc less re­spon­sive to avail­able nu­tri­ents such as ni­tro­gen than peren­nial rye­grass dom­i­nated swards.

Re­seed­ing will in­crease the over­all pro­duc­tiv­ity of the farm, al­low­ing an in­crease in the stock­ing rate along with higher an­i­mal out­put – 8pc higher milk out­put per hectare rel­a­tive to per­ma­nent pas­ture. It’s also an op­por­tu­nity to in­crease grass qual­ity, in­crease grass util­i­sa­tion and al­low white clover/peren­nial rye­grass pas­tures to es­tab­lish as well as be­ing more re­spon­sive to fer­tiliser.

Tim­ing

The tim­ing of re­seed­ing de­pends to a large ex­tent on weather con­di­tions, and grass sup­ply.

While au­tumn re­seed­ing may make sense from a feed budget per­spec­tive, soil con­di­tions de­te­ri­o­rate as au­tumn pro­gresses; lower soil tem­per­a­tures can re­duce seed ger­mi­na­tion, and vari­able weather con­di­tions re­duce the op­por­tu­nity to ap­ply post-emer­gence spray and to graze the new sward.

Spring re­seed­ing offers farm­ers greater flex­i­bil­ity. Swards re­seeded in spring will have sim­i­lar, or even greater, to­tal herbage pro­duc­tion in the year of re­seed­ing com­pared to old per­ma­nent pas­ture.

Es­tab­lish­ing white clover in a spring re­seed is more re­li­able than in au­tumn due to the sta­bil­ity of soil tem­per­a­tures in late spring, while post emer­gence spray­ing for weed con­trol is usu­ally very suc­cess­ful with spring re­seed­ing due to favourable weather con­di­tions in sum­mer.

Plough­ing

If plough­ing use a shal­low plough and avoid plough­ing too deep (>15 cm) as this can bury the top layer of soil (the most fer­tile soil). Use a land lev­eller un­til an even seedbed is gen­er­ated and aim to de­velop a fine, firm and level seedbed. If the seedbed is cloddy and loose, grass seed (and es­pe­cially white clover seed) will be buried too deep and will not ger­mi­nate.

Disc­ing and One-pass

Aim for 2/3 passes of the disc har­row in an­gled di­rec­tions to break the sod and turn up enough soil to form a seedbed. For­ward speed must not be ex­ces­sive as it can lead to rough, un­even seedbeds

One pass

With a one-pass sys­tem, the slower the for­ward speed of the ma­chine the bet­ter in terms of fin­ish. Of­ten left rough and patchy due to op­er­a­tors mov­ing too fast across fields.

Use a heavy disc har­row to do the pri­mary cul­ti­va­tion fol­lowed by a fi­nal pass with a power har­row that can also be fit­ted with a seed box to till and sow with a ‘Onepass’.

Use shal­low sur­face cul­ti­va­tion with a ro­tary power har­row to pro­duce a seed bed with seed sown us­ing an air seeder at­tached to the power har­row. Di­rect Drill

This can be a dif­fi­cult en­vi­ron­ment for seeds to es­tab­lish in as there is no cul­ti­va­tion of the soil.

A slight ‘cut’ in the ground will al­low more seed/soil con­tact, although re­sults can be vari­able. It’s not suit­able on dry, hard ground and there may be a need to use slug pel­lets. It can also be more sus­cep­ti­ble to scutch grass re-es­tab­lish­ing.

Rolling is very im­por­tant for both full re­seed­ing and min­i­mum cul­ti­va­tion to en­sure seed to soil con­tact for seed ger­mi­na­tion.

Deirdre Hen­nessy is a grass­land re­search of­fi­cer at Tea­gasc Moorepark, Co Cork

Re­sults: Re­seed­ing will in­crease the over­all pro­duc­tiv­ity of the farm, al­low­ing an in­crease in the stock­ing rate along with higher an­i­mal out­put

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