Greinasafn: The effects of grass species and nitrogen fertilizer onwhite clover growth and mixture yield in a northern maritime environment

The effects of grass species and nitrogen fertilizer onwhite clover growth and mixture yield in a northern maritime environment


Höfundur	Útgefandi	Útgáfuár	Útgáfustaður
Áslaug Helgadóttir, Þórey Ólöf Gylfadóttir, Þórdís Anna Kristjánsdóttir	Hólaskóli, LBHÍ, Rannsóknastöð skógræktar Mógilsá, Veiðimálastofnun, Keldur, Landgræðsla ríkisins, BÍ	2005	Reykjavík

Rit	Árgangur	Tölublað	Bls.
Icelandic Agricultural Sciences		18	75-84

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ABSTRACT

The impact of four contrasting companíon grasses on whíte clover was studíed in a field experiment at Korpa Experimental Station, Iceland, over a four year period. Smooth meadow grass (Poa pratensis L. cv. Fylking), timothy (Phleum pratense L. cv. Adda), perennial ryegrass (Lolium perenne L. cv. Svea) and meadow fescue (Festuca pratensis Huds. cv. Salten) were sown in binary mixtures with white clover (Trifolium repens L. cv. Norstar). The fertilizer treatments were 0 kg N (N1), 20 kg N in the spring (N2) and 20 kg N ha' in the spring and after each harvest (N3) applied for three years after the establishment year. Detailed morphological measurements of the white clover and the different companion grasses were made every autumn and spring during the course of the experiment and herbage yield was measured for three years. The results showed that population size of white clover and dry matter production was greatly influenced by the growth habit of the companion grass. Perennial ryegrass caused the greatest suppression to clover growth, mainly because of high shoot yields and the large leaf canopy as early as in the establishment year. In contrast, smooth meadow grass was the least competitive companion grass. Its low dry matter production per tiller and rhizomatous growth habit led to an open sward, which favoured clover growth. No interaction was found between grass companion and fertilizer treatment.

Key words: compatibility, companion grass, herbage production, morphology, white clover

YFIRLIT

Áhri mismunandi svarðarnauta á vöxt hvítsmára og uppskeru smárablöndu á norðurslóð

Fylgst var með samspili fjögurra ólikra grastegunda við hvítsmára í tilraun á Tilraunastöðinni á Korpu í fjögur ár. Norstar hvitsmára var ýmist sáð i blöndu með Fylkingu vallarsveifgrasi, Öddu vallarfoxgrasi, Svea vallarrýgresi eða Salten hávingli. Áburðarliðir voru 0 kg N (N1), 20 kg N að vori (N2) og 20 kg N ha -1 að vori og eftir hvern slátt (N3). Ítarlegar mælingar voru gerðar á hvítsmáranum og grasinu haunt og vor ár hvert sem tilraunin stóð og þurrefnisuppskera var mæld í þrjú sumur. Niðurstöður sýndu að stofnstærð hvitsmára og uppskera hans ræðst að talsverðu leyti af vaxtarlagi svarðarnautarins. Vallarrýgresi dró mest úr vexti smárans, aðallega vegna mikils blaðvaxtar og uppskeru strax fyrsta haustið. Vallarsveifgras reyndist hins vegar besti svarðarnauturinn því hver grassproti myndar tiltölulega litla þurrefnisuppskeru og saman mynda þeir opna grasþekju sem gefur hvítsmáranum meira rými til vaxtar. Ekkert samspil fannst á milli áburðarliða og svarðarnauta.