View of Testing grass species and varieties for land reclamation in Iceland

Maataloustieteellinen^Aikakauskirja Vol. 60: ^191—200, 1988

Testing grass species and

varieties

ÄSLAUG HELGADÖTTIR

The Agricultural Research InstituteKeldnaholti, 112 Reykjavik, Iceland

Abstract. During thiscentury,increasingeffort has beenputtothe reclamation of eroded areasin Iceland,bothinthe lowlands along the coast and inthe interior of the^country. The seedingof^grassspecies along with the application of chemical fertilizers has formed thecore of the reclamation work. ^Atleast ⁴⁵⁰different varieties consisting of about 50grassspecies have been testedinvarietytrials,but only fewvarieties, all of northern origin, proved valu- able. Their performance is strongly dependentonenvironmentalconditions,and it is proposed thatamixture of adaptedvarieties,subjected tonatural selection at eachlocation,would yield belter results.

Index words: reclamation, northern areas,grassvarietytrials

Introduction Table 1. Changesinvegetative cover in Iceland over 1,100^years.

Since^thesettlement^ofIceland, 1,100years ^{; :}

, ... . _, At the time Atpresent

ago, much of the formervegetativecoverhas _{of settiement} been lost. At the time of settlement it is be-

r.u ^{. .} Denuded areas 18,000 km² 58,000km²

heved that 60 %of thecountry was covered _{Woodlands 25,000 km}2 1,250km² with lush vegetation, whereas today only 25^% Rangelands 40,000 km² 23,000 km² of thecountry is vegetated (Table 1, Thor- ^{Cultivated land 1,500km2}

STEiNssoN 1978). This loss of around4 million hectars is an extensive degradation of the ecosystem(Arnalds 1987), and the soil ero-

sion still continues. total of ^210,000ha have been fenced ^off, of Since theturnof thecentury,serious efforts

have been made to halt the erosion and reclaim the lost vegetation (Sigurjönsson 1958). Traditionally, the first step has beento protect the land from grazing. Since 1907,^a

total of 210,000 ha have been fenced off, of which 85,000 ha have been protected from grazing since 1974 (Runölfsson 1987). In areas of heavy sanddrift, Icelandic popula- tions of Elymus arenariusare seededtostabi- lize moving sand dunes. After stabilization of JOURNAL OF AGRICULTURAL SCIENCE IN FINLAND

the soil, ^the areas are revegetated either through self-seeding or by seeding commer- cial grassvarieties ^{along with}theapplication offertilizers. Usually, fertilizer is applied for two yearsin succession. The grass swards that are thus established are expected to aid the naturalsuccession ^{of the}nativevegetation by providingmorehospitable microenvironment.

In addition, ^{extensiveareas along new high-} ways andinareasdisturbed by roadconstruc- tionare seeded yearly. There are no official figuresavailable^{for theamount} of grass seed used forreclamation purposes, butit^{is prob-} ably closeto 50 tons per year.

Reclamation by theuse of grass seed and fertilizer is very expensive. Itis, therefore, ^im- portant to seed well adapted grass varieties that canpersist for _anumber of years, while the local vegetation is establishing itself. In this paper, important characteristics of grass varieties for reclamation purposes will be iden- tified in the light of the environmental condi- tions that prevail atthe reclamation sites. A briefaccountwill be given of those grassvar- iety trials in Iceland, where the aim has been to search for well adapted grass varieties for this purpose.

Environmental conditions

Environmental conditions for plant growth are generally harsh in Iceland. This is partic- ularlytrue in thoseareas where effortsare be- ing madeto revegetate erodedsoils, often in the interior of thecountry.

Climate

The climate in Iceland can be defined as maritime, cold-temperate in thelowlands, ^but lowarcticin the highlands and in some parts of the lowlands in northern Iceland (Einars- son 1976). The mean yearly temperature in the lowlands ismostcommonly between 3.0 4.O°C, whereas in the highlands it is only around O°Cor evenless insome areas(Fig. 1).

Precipitation varies geographically in Iceland (Fig. 2), and the annual distribution ^{is such}

that the minimum precipitationoccurs in the spring and maximum in theautumn.

Soils

Soil erosion in Iceland has primarily oc- curred in theareas of active volcanic ^erup- tions. The soil in the areas which have been termed volcanic loess (Sigbjarnarson 1969) is silty, and the mineral fraction has been deposited by eolian processes. The soil pro- file is characterized by layers ofash, ^{and it} erodes very easily(Arnalds 1984). In severe- ly erodedareas, the whole profile has blown away,leaving the glacial pavement orold lava flows behind. The soils in theseareas arethus coarse, poor in organic matterand available nutrients, ^{and water} retention is low (Arn-

alds etal. 1987).

Grazing

The interior of thecountry is divided into grazing areas for each province and within theseareas sheep graze freely for twomonths during the summer. Grazing has adverse ef- fects on the vegetation in the erodedareas, and wherereclamation isin progress the land is protected from grazing by fences. However, fencing is expensive and it would be desirable to be able to revegetate without it.

Important plant characteristics

A grass variety which istobe used for recla- mation purposes ^must possess a number of characteristics. One of themost important is general adaptation to the climatic environ- ment. Under the conditions which prevail in the _areas ofreclamation, winterhardiness is probably themostimportant feature. Poorly adapted varieties most commonly die in the firstorsecond winter after sowing. This can be relatedtothe onset of dormancy in theau- tumn, as a close association between growth cessation and winter survival has been found for latitudinalecotypes of both Poapraten- sis and Festuca rubra (Klebesadel et al.

Fig. I. Mean temperature, 1931 —1960(°C), inReykjavik (50 m

a.

a.

Fig. 2. Mean precipitation, 1931 1960(mm). (Bergthörsson 1988).

1964, ^Habjorg 1979). Small plants canper- sist for ^someyearsbut withoutgiving any sig- nificant contributionto yield. The poorsur- vivalcan be caused by poor growth and lack of sufficient nutrientreservesresulting instar- vation in late winter and spring (Klebesadel

&Helm 1986).However, climatically adapt-

ed material_cansuffer winter damage for var- iousreasons such asdirect frost damage, soil heaving, desiccation ^and icecover(Larsen^&

Ärsvoll 1984).

Also important is the ability^tobind thesoil, especially in_areaswhere soil^movementiscon- siderable. Other desirable characteristics _are the ability to tolerate low fertility orlack ^of chemicalfertilizer application, and persistence under grazing.

Grass varieties that have been used for reclamation in thepast have generally shown poor persistence. Thiswasparticularly_trueof Danish varieties of red fescue⁽Festuca rubra) which_were used almost exclusively for many decades. Even though morepersistent varie- ties have been used recently, reclamation us- ing seed and fertilizer remains haphazardous asthe environmental conditions _{are so}varia- ble. The search for superior grass varieties therefore still continues.

Grass variety trials for reclamation

The search for suitable species and varie- ties for reclamation purposes began over 40

yearsago (Sigurjonsson 1958). Until recent- ly, seed of Icelandic grass varieties has gener- allynot been available. Introduction breeding has therefore been the main approach in the variety testing, _as for example in Alaska (Mitchell 1982),_even though _a few Icelan- dic wild populations and bred varieties have been included in the trials. In the earliertrials,

most of the varieties tried originated from lower latitudes, either in Europe or North- America(Sveinsson 1953). Most of the vari- eties tested, both in the lowlands and the high- lands, survived only two years, with theex- ception of Icelandic wild populations of Festu- ca rubra, Poa pratensis and Deschampsia

caespitosa (e.g. Fridriksson 1952, 1971, Arn-

alds etal. 1978).

In 1975,extensive trialswere begun, where 403 different grass varietieswere sownin small plots at four locations both in the lowlands and the highlands. Aftertwowinters, less ^than 25^% of thevarieties^{sownstill hadsome cover} (Arnalds etal. 1978). The best 46 varieties of six species, mainly Festuca rubra and Poa pratensis, wereselectedon the basis of results from these trials andsown in 1980 in bigger plots ina new trialatthree locations (Fig. 3).

The varieties originated from Scandinavia, Holland, Germany and the UnitedStates, in- cludingAlaska. ^Thelocations ^werechosen^so astogiveavariation in elevation and distance from thesea. In 1981,a smaller trial includ- ing 10 varieties of five grass species was laid out in three places in northern Iceland, all 500 m above sea level. This was carried out in conjunction withahydro-power station de- velopment in the Blanda area, ^where new grazing_{areas are}needed_toreplace rangelands that will go underwater(Helgadöttir 1988).

In the former trial, all plots wereprotected from grazing, but in the latter, one half of each experimental plot was fenced off, whereas the other half_wassubjectedto heavy grazing by sheep. Itwas thus possible to as- sess the effects of grazingonthe performance of the grass varieties. In both trials the effects of fertilizer shortageonthe persistence of the grass varieties werestudied.

Differences

The results from the trial established in 1980 demonstrate that thereareconsiderable differ- ences in performance between varieties, ^but the display of these differences is highly de- pendent on thetest location (Fig. 4).

The test sites provided a gradient of _en- vironmental conditions with least discrimina- tion between varietiesatthe lowestelevation, Gunnarsholt (Fig. ^4a), but greatest at the highest elevation, Hrauneyjafoss (Fig. 4c), wheresummers areshort and cold. Thesnow cover is restricted inthisarea sothat thegrass

is subjectedtoseverefrost. Using suchan en- vironmental gradient makes it possible todis- criminate between varieties subjectedtodiffer- ent levels of stress.

Very few grass varietiesare hardyenough tosurvive the harsh conditions that prevail at the experimental sites, especially those at Hrauneyjafoss. The varieties that did survive areall of northerly origin, namely, Deschamp- sia beringensis, lAS 19 from Alaska, Deschampsia caespitosa, a wild population fromIceland, Festucarubra,Leik from Nor- way and Sturla and 0305 from Iceland. Vari- eties of Poa pratensis were in general inferi- or, but of these Fylking from Sweden had an advantage.

In the smaller trial in the Blandaarea,only the eight mostpromising varieties of the big trial _were included in addition to Festuca rubra Echo from Denmark and Festuca ovi-

naTournament from Holland,both of which soon disappeared. The performance of the other varieties varied somewhat between years and locations (Fig. sa). On the plots which were protected from grazing, D.beringensis and D.caespitosa were generally superior to others and it seems that the Icelandic varie- ties of both F.rubra and P.pratensis had be- come superiorto importedvarieties ^towards the end of the experiment.

These results correspond well with results from variety trials in other northern regions, for example in Alaska (Klebesadel 1985).

Most of the varieties that fail originate from lower latitudes andarethus adaptedto differ- entphotoperiodic conditions inautumn. They

misread the photoperiodic signals and, con- sequently, have not developed adequate

hardeningat the onsetof winter. The climat- ic conditions within thesame latitudearealso

Fig. 3. Grass variety trials at Gunnarsholt. Each plot is100m 2.The plotsonthe rightare fertilized whereas those on the left areunfertilized.

195

Fig. 4. Evaluation of grass varietiesonfertilized plotsin avarietytrial from 1980inIceland,using Principal^Com- ponentsAnalysiscombined for all three locations. The analysis is based ^onsixvariables,and PCIand ^PC IIexplain74^%and 12^% of the totalvariation,respectively. The varieties with the lowestscores on PC 1 showed thegreatestpersistenceand vigour. Varieties of F.rubraarerepresented by ordinaryletters,P.pratensis by italics and other species by capital letters (HelgadOttir 1988),

Fig. 5. Cover (0—9; 0 ⁼ nocover,9 ⁼ full cover) ofgrassvarieties, onfertilized plots ina trial establishedin 1981, in the years 1984(3), 1985 (□) and 1986(■). The varietiesare P.pratensis Fylking(1) and06(2), F.rubra Sturla (3), Leik (4) and0301(5), D.caespilosa Icelandic wild population (6) and D.beringensis lAS

19(7). (HeloadOttir 1988).

Table 2. The effects of fertilizer stress^{on cover}(0—9; 0⁼nocover,9 ⁼full cover) of varieties of Festuca rubra and Poa pratensisin varietytrialsin southern Iceland.

Fertilized plots Unfertilized plots

F.rubra P.pratensis F.rubra P.pralensis

Meancover 5.9 5.6 2.0 3.9

s.e. 1.90 1.21 1.58 1.72

of importance. Varieties that originate from comparable latitudes butare adaptedto con- tinental climates orstablewinters may suffer under Icelandicconditions, where the climate is maritime with repeated freeze-thaw cycles in winter, evenat higher altitudes. This may explain whynot all Alaskan material fare well in Iceland.

D.beringensis from Alaska isaninteresting addition^to the species poorIcelandic flora, which only numbers around 400 species. It wasfirst imported in 1974 and has since been extensively tested, both for reclamation pur- poses and herbage production, with promis- ing results (Tömasson 1984).

Effects of

in the smallertrial, where the varietieswere subjected to severe grazing pressures, their relative performance altered substantially (Fig. sb). The Icelandic wild population of D.caespitosa surpassed all other ^varieties, whereas D.beringensis and P.pratensis 06 from Iceland sufferedmost.The differences between these speciescanlargely be explained by differentrootpatterns. Another study has revealed that D.caespitosa has asignificantly higher root/shoot ratio than D.beringensis (Magnusson ^& Helgadöttir, unpublished results) causing the former_to sit morefirmly in the soil. Plants of D.beringensis and 06, on the otherhand,were^torn up from the soilby the grazing animals. Inaddition,the tillers of D.beringensisareerect and the growing point sits above the soil surface. Thiscontrastswith D.caespitosa, which has densetillers,^agrow- ing point below the soil surface andprostrate leaves. Consequently, the grazing animal is

not abletoreach the whole plant, allowing the remaining leavestocarryon photosynthesis.

Effects of fertilizer

It has been shown that application of chem- icalfertilizer generally affects the persistence ofsown grasses in reclamation (Gunnlaugs-

DöTTiR 1985). This isnot surprising, since the soil is generallypoorin nutrients. In the vari- ety trials of 1980, it appeared that P.praten- siswasgenerallymorepersistent tofertilizer shortage than F. rubra (Table 2) (Helgadött-

ir 1988). The former species has extensive rhizomes, where nutrient _reserves may ac-

cumulate when nutrientsare plentiful. These reserves can then be remobilized at times of nutrient shortage. There is indeed evidence of oldreclamation trials where Icelandic varie- ties of P.pratensis have survived for a num- ber ofyears without any fertilizer (Arnalds etal. 1978).F.rubra, on the other hand, ^has nosuch _storage systemand may therefore be able to tolerate fertilizer shortage less well.

Wild Icelandic populations of D.caespitosa havesurvived ⁱⁿanumber of reclamation tri- als in the highlands without fertilizer (Frid-

riksson 1971) and in themost recent trials ⁱⁿ the Blanda area it surpassed all other varie- ties under fertilizer stress, especially under heavy grazing (Helgadöttir 1988).

Conclusions

Extensive variety trials in Iceland demon- stratethat only grass varieties of northerly ori- gin areadapted tothe conditions that prevail where reclamation is in progress. However, their performance strongly depends on en-

vironmental conditions such as climatic fac- tors, soil type, snow cover and presence of grazing animals. It has, therefore, ^{been pro-} posedtosow amixture of adapted grass vari- eties for reclamation and let nature select the most suitable combinationat each location.

To testthis hypothesis,a newexperiment has been started, where mostlyIcelandic materi- al is seeded in various combinations with different amounts ^of fertilizer, ^{with and} without grazing.

References

Arnalds, A. 1987.^Ecosystemdisturbance andrecovery inIceland. Arct. Alp. Res. 19: 508 —513.

—,Ärnason, Th.Ö., Lawrence, Th.^&Siourbjörnsson, B. 1978.Grass variety trials forreclamation andero- sion control. RALA Report No. 37. 52 ^p.

Arnalds, ^Ö. 1984.Eolian nature and erosion ofsome Icelandic soils. J. Agr. Res. Iceland. 16: 21—35.

—,Aradöttir,Ä.L.^&Thorsteinsson, I. 1987.The^na- tureand restoration of denuded areasinIceland. Arct.

Alp. Res. 19:518—525.

Bergthörsson,P. 1988.The effects of climatic variations onagricultureinIceland. 1.Introduction. In:TheIm- pactof Climatic Variations onAgriculture.Volume 1.

Assessments InCool, Temperate and Cold Regions (Eds. M.L.Parry,T.R.Carter*N.T.Konijn). Kluwer Academic Publishess Group, The Netherlands.

Einarsson, M.Ä. 1976.Veöurfarä Island! (Weatherin Iceland). 150 p. löunn,Reykjavik.

Fridriksson,S. 1952.Comparisonofsomeagronomical- lysignificantpropertiesofgrasses grownatfour sites in Iceland. Report No. 2 from The University of Iceland, Dept,of Agriculture.

1971. Raektunartilraunir ä Kili (Land reclamation studiesinthe district Kjölur, Central Iceland). J. Agr.

Res. Iceland. 2: ^34—49.

Gunnlaugsdöttir,E. 1985.Compositionand dynamical statusof heathland communitiesinIcelandinrelation torecovery measures. ActaPhytogeographica Sueci- ca 75. Uppsala.84p.

Helgadöttir, Ä. 1988. Insearch of suitablegrassvarie- ties for reclamation ^purposesinIceland. Icel. Agr. Sci.

1.In press.

Klebesadel, L.J. 1985.The critical importance of north- latitude adaptation for dependable winter survival of perennial plantsin Alaska. Agroborealis 17: 21 —30.

&Helm, D. 1986.Foodreserve storage,low-temper-

ature injury,wintersurvival,and forage yields of timo- thyinsubarctic Alaskaas^{related to}latitude-of-origin.

Crop Sci. 26: 325—334.

—,Wilton,A.C., Taylor,R.L.^&Koranda,^J.J. 1964.

Fall growth behaviour and winter survival of Fesluca rubra and Poa pratensisinAlaskaasinfluenced by lati- tude-of-origin. Crop Sci.4: 340—341.

Larsen, A.^& Ärsvoll,K. 1984.The impact of biotic andphysical overwinteringfactorsongrassland produc- tion and management. In:The Impact of Climateon GrassProduction and Quality (Ed.H.RileyandA.D.

Skjelväg). Proc. 10th General Meet. EGF, Norway, 268—277.

Mitchell,W.W. 1982.Forage yieldand quality ofin- digenousand introduced grasses atPalmer, Alaska.

Agron. J.74: 899—905.

Runölfsson, S. 1987.Land reclamation inIceland. Arct.

Alp. Res. ^19:514—517.

Sicbjarnarson, O. 1969.^Äfokoguppblastur(The loes- sial soil formation and erosionon Haukadalsheiöi).

Nätturufraeöingurinn.39: 49—128.(English summary).

SiourjOnsson,A.(Ed.) 1958.Sandgraeöslan.Minnst 50 ärastarfs Sandgraeöslu rikisins (Celebration 50thAn- niversary Soil Conservation Serviceof Iceland). Agric.

Soc. Icel. and Soil Cons. Serv. Icel. 359p.

Sveinsson,R. 1953.Amemorandumonsoil erosion and reclamation problems in Iceland. Mimeograph. Soil Cons. Icel.36p.

Thorsteinsson, I. 1978.Grööur oglandnyting (Vegeta- tion and land utilization). Lesörk Landverndar, 3.

Reykjavik. 45p.

Tömasson, Th. 1984.^{A grass} from Alaska gives promis- ing results in Icelandic trials. Agroborealis 1984:

33—36.

SELOSTUS

Maan kasvuunpalauttamisessa käytettävien heinälajien ja -lajikkeiden testaaminen

Islannissa

Äslaug Helgadöttir

The Agricultural Research Institute Keldnaholti, 112Reykjavik, Iceland

Islannissa on 1900-luvun mittaan panostettu lisään- tyvässämäärässätoimenpiteitäerodoituneiden alueiden saattamiseksi uudelleen kasvuston peittoon. Työn perustanonmuodostanut eri heinälajien kylväminen ja viljeleminen kemiallisia lannoitteita käyttäen. Kent- täkokeissa on tutkittu vähintään 450lajiketta noin 50

heinälajista, muttavain muutamat, pohjoista alkuperää olevat lajikkeet ovat osoittautuneet käyttökelpoisiksi.

Lajikkeiden menestyminenonvoimakkaasti riippuvainen ympäristöoloista ja onnistuneen tuloksen saavuttamiseksi suositellaan sopeutuneiden lajikkeiden seosviljelyä eri pai- koilla vallitsevan luonnonvalinnan alaisena.