The temporary grasslands, leys, are mainly utilized for silage production, either only cut or cut in combination with grazing. The leys are established by sowing a mixture of species, and approximately 90% of the total seed mixtures sold are used for establishing leys intended for silage production (Table 2). The most important grassland species are the grasses timothy, meadow fescue, perennial ryegrass (Lolium perenne L.) and smooth meadow grass (Poa pratensis L.) and the legumes red clover (Trifolium pratense L.) and white clover (Trifolium repens L.). Except for smooth meadow grass and white clover, all these species are introduced species. Establishment of grassland by sowing was started early in the 19th century and was not a common practice until the second half of that century (Daugstad 2008). The three species timothy, meadow fescue and red clover are used in most mixtures (Table 2). In addition, perennial ryegrass is widely used in coastal and lower altitudes of Southern Norway, often sown in pure stands. About 70% of the pure grass seed mixtures sold in 2012 (Table 2) was sold by Felleskjøpet Rogaland Agder, supplying southwestern Norway, and most of this consisted of perennial ryegrass variety mixtures. In addition, Felleskjøpet Agri sells annually around 55 Mg of perennial ryegrass seed, which is mainly used for repairing winter-damaged leys (Jon Atle Repstad, personal communication). Cocksfoot (Dactylis glomerata L.) and festulolium (×Festulolium) are used in intensive managed grasslands. In leys used for combined grazing and cutting, smooth meadow grass and white clover are included in the seed mixtures, in addition to species included in mixtures utilized only for cutting (Table 2). In dry areas, in the mountain rain shadow, Bromus inermis Leyss. is used, often in pure stands.
Timothy and meadow fescue account for 70 and 15% of the annual sale of grassland seeds produced in Norway, respectively (Table 3). More than 60% of the total sale of timothy seeds are of the cultivar ‘Grindstad’, a landrace that celebrated 100 years of use in 2015 (Nesheim 2015). ‘Grindstad’
is a heterogenous population that has changed over the course of time, due to changes in harvesting management imposed before seed collection.
There is a tendency that the importance of meadow fescue is declining, and that the popularity of perennial ryegrass is increasing. Norwegian ryegrass varieties are now available, the domestic seed production has increased (Table 3), and the import of seed is high. Likewise, there are domestic red and white clover Table 2. Proportions of species in seed mixtures and total seed mixture sales (Mg) in 2012 by the suppliers Felleskjøpet Agri, Felleskjøpet Rogaland Agder and Strand Unikorn (Sources: Jon Atle Repstad, Geir Paulsen and Bjørn Molteberg, personal communication).
Seed mixture type Species proportion in mixture, % weight basis1 Total, Mg
Phleum pratense Festuca pratensis Poa pratensis Lolium perenne
Trifolium pratense
Trifolium repens
Silage for cutting 60-90 10-20 – 0-10 10-15 – 838
Combined silage and grazing 40-60 10-20 10-20 0-10 0-10 5-15 462
Grazing 30-40 10-25 15-30 0-10 – 5-15 59
Hay 80-90 – – – 10-20 – 49
Only grasses 0-100 0-30 0-20 0-100 – – 233
1 These figures vary both within seed mixture type (regional differences) and between suppliers and they are just indicative. For instance, Felleskjøpet Rogaland Agder uses more perennial ryegrass in their mixtures and they sell much more pure grass mixtures than the other suppliers.
varieties, but the domestic production of clover seeds is less than the consumption so that seeds needs to be imported, mostly from Sweden and Denmark.
The age distribution of temporary grassland has changed over the last decade, during which the area of short-term leys has decreased whilst the area of leys that are renovated every fifth year or at longer intervals has increased (Figure 3).
On average, grassland used for cutting receives in total 177 kg N, 20 kg P and 107 kg P per ha annually as mineral fertilizer and animal manure (Bye et al., 2016). The proportion of the total input attributable to animal manure is 0.38, 0.58 and 0.63 for N, P, and K, respectively. The application rate of both mineral fertilizer and animal manure differs greatly, and depends mainly on the length of the growing season, the number of cuts per year and the livestock density. For instance, the average livestock density is 3.3, 1.4 and 0.9 livestock unit ha-1 arable land in the counties of Rogaland (southwestern Norway), Nord-Trøndelag (Central Norway) and Troms (northern Norway), respectively. These are counties where ruminant production is important.
Much of the manure (57% of total) applied to grassland is spread using slurry tanks equipped with splash plates (Gundersen and Heldal, 2015). Ammonia emissions are significantly reduced when manure is applied by band spreader or direct ground injection, and the proportion of manure spread by using such equipment increased from 7% in 2000 to 19% in 2013. Most of the dairy cow manure is stored as slurry in cellars under the byres (75%) or in outdoor manure pits (23%). A larger proportion of the manure from beef cows is stored as solid dung, with 12% stored outdoors directly on the ground, 12% indoors as deep litter and 4% outdoors as deep litter.
The harvesting frequency ranges from one cut per season in marginal areas at higher altitudes and latitudes, to three and four cuts of the most intensively manged short-term leys in southwestern Norway.
However, the predominant cutting system consists of either two cuts or two cuts plus one grazing per season. Nearly 80% of the harvested grass is preserved in round bales, 18% in tower or bunker silos and 2% as hay (SSB, 2016).
Table 3. Annual sale of grassland seeds (Mg year-1) produced in Norway in 2003 and 2013 (Hans Jacob Lund, Graminor AS, personal communication).
Plant species 2003 2013
Phleum pratense L. 882 1,039
Festuca pratenis Huds. 356 218
Dactylis glomerata L. 15 15
Lolium perenne L. 0 35
Bromus inermis Leyss. 30 11
Poa pratensis L. 4 34
Festuca rubra L.1 18 62
Agrostis capillaris L.1 15 12
Other grasses 12 3
Trifolium pratense L. 131 48
Trifolium repens L. 4 5
Other legumes 9 3
1 Mainly used in seed mixtures for lawns and golf courses.
Of all the silage samples that were analysed for feed quality over the last three years (2013-2015), 35%
were ensiled without any additives, 50% contained a formic acid based additive, 8% with combined lactic bacteria and enzyme based additive and 6% with salt based additives (Ingunn Schei, TINE Rådivning and Medlem, personal communication). The silage quality analyses show that the first and second cuts are on average fairly similar in feed value, and they are characterized by having medium levels of organic matter digestibility, crude protein and NEL (Table 4). The analyses indicate that the first cut is taken between the growth stages ‘inflorescence emergence’ and ‘inflorescence emerged’ of the dominant grass species timothy.
The statistics on grassland yields are based on estimates with a high degree of uncertainty, but they nevertheless give an indication and are presented for three counties, from south to north, in Figure 5.
The figures indicate that the yields have not improved during the last decade, rather they have declined for the country as a whole. The estimated grassland yield potential is about twice as high in central and southwestern Norway and 3.5 times higher in northern Norway than the figures presented in Figure 5, even when 20% losses during harvesting and ensiling are accounted for (Bakken et al., 2014). The reasons for the yield stagnation are not unequivocal. Lunnan (2012) suggested that more efficient farm operations with heavier tractors, harvesting machinery and manure spreading equipment have impaired drainage and soil structure and, consequently, grassland productivity. The farm structural changes with Table 4. Silage quality in Norway, averaged over 2013-2015 (Ingunn Schei, TINE Rådgivning og Medlem, personal communication).1,2
Variable 1st cut 2nd cut 3rd cut
n Mean SD n Mean SD n Mean SD
DM, g kg-1 14,265 317 114 8,745 333 125 926 341 118
CP, g kg-1 DM 14,189 152 25 8,693 161 27 915 175 27
NDF, g kg-1 DM 14,186 536 48 8,691 508 47 916 458 45
ODM, % 14,270 70.7 7.6 8,746 71.0 4.3 926 74.6 4.0
NEL20, MJ kg-1 DM 14,270 5.99 0.45 8,746 6.03 0.41 926 6.33 0.39
1 Of all the samples analysed, 76% were from round bales, 10% from tower silos and 8% from bunker silos.
2 DM = dry matter; CP = crude protein; NDF = neutral detergent fibre; ODM = organic matter digestibility; NEL20 = net energy lactation estimated at standardized total DM intake of 20 kg day-1; SD = standard deviation.
Figure 5. Average grassland dry matter yields (kg ha-1 year-1) in the counties of Rogaland (southwestern Norway, grey dotted line), Nord-Trøndelag (central Norway, black line) and Troms (northern Norway, black dashed line) (SSB, 2016).
increased size of farm management units, where a high proportion of the agricultural area is rented, exacerbates reduced soil quality as investment incentives are low in e.g. drainage. All together 44% of all agricultural land is rented and 62% of all farm units rent land. The agriculture subsidy policy of area payments rather than payments connected to production, stimulates farmers to simply keep land in production rather than invest in management factors that improve yield. For instance, the leys are renovated less frequently than before (Figure 3). Another important reason is the cheap concentrate prices relative to product prices. For instance, the milk to concentrate price ratio increased from 1.3 in 2003 to 1.4 in 2013 (Budsjettnemnda for jordbruket, 2016). Besides, many farmers find that they have higher costs per unit NEL for their home-grown forage than for purchased concentrate (Thuen et al., 2015).