A 0.5 ha 6-year trial compared 6 grass species x 4
N fertiliser rates x 2 times of closing for summer-saved
standing winter feed. The pre-winter yields
averaged 3.4 t DM/ha from November, closing
with a high browntop/sweet vernal component, as
compared with 1.7 t DM/ha from December
closings with a low browntop/sweet vernal
component. Grasslands Kara cocksfoot was the
highest yielding cultivar, followed by Grasslands
Apanui cocksfoot, Grasslands Wana cocksfoot,
Grasslands Roa tall fescue, Grasslands Nui
perennial ryegrass and Grasslands Maru phalaris,
with decreasing proportions of sown grass.
Nitrogen fertiliser had a limited effect on prewinter
yields but did have a carry-over effect into
spring yields

Pollock Keith, M

Robertson, JS

Scott, D

Lincoln University Research Archive

Proceedings of the NewZealand  Grassland Association 56: 197.200 (1994) 107Factors affecting accumulation of summer grass for winter standing feed in thehigh countryK.M. POLLOCK’,  D. SCOTT and J.S. ROBERTSON2AgResearch,  PO Box 60, Lincoln‘Present address: Department of Plant Science, PO Box 84,  Lincoln University, Canterbury*Present  address: Alex McDonald (Merchants) Ltd, ChristchurchAbstractA 0.5 ha 6-year trial compared 6 grass species x 4N fertiliser rates x 2 times of closing for summer-saved standing winter feed. The pre-winter yieldsaveraged 3.4 t DM/ha  from November, closingwith a high browntoplsweet vernal component, ascompared with 1.7 t DM/ha from Decemberclosings with a low browntopfsweet  vernalcomponent. Grasslands Kara cocksfoot was thehighest yielding cultivar, followed by GrasslandsApanui cocksfoot, Grasslands Wana  cocksfoot,Grasslands Roa tall fescue, Grasslands Nuiperennial ryegrass  and Grasslands Marn phalaris,with decreasing proportions of sown grass.Nitrogen fertiliser had a limited effect on pre-winter yields but did have a carry-over effect intos p r i n g  y i e l d s .Keywords: Dactylis  glomerata, fertiliser, Festucaarundinacea, high country, Lolium perenrte,.- nitrogen-; -Ph&wis  aquati&;  v%ik~ TeedIntroductionWinter feed for stock is one of the main limitations topastoral agriculture in the South island high country.Summer-saved standing pasture is one option. A numberof grasses compared for yields and winter digestibilities(Scott & Maunsell 1986) showed that pre-winter yieldswere more important in determining available winterfeed than the loss of digestibility or dry matter contentof the standing material during the early part of thewinter. Other similar trials, at Tara  Hills (Douglas &Drew 1969; Daly & Allan  1985),  showed that highamounts of standing herbage  going into the winter didnot deteriorate any faster than lesser masses, and thatcocksfoot was likely to be the most useful grass species.In the USA and Britain the main factors affectingthe early winter yields of summer-autumn saved pastureshave been the length of the accumulation period, nitrogen(N) fertiliser and autumn weather (Barker et al. 1965;Archer & Decker 1977; Ocumpaugh & Matches 1977;Rayburn  er  al. 1979). Longer accumulation periodsgenerally gave a lower feed quality but this was usuallyoffset by the increased herbage  mass going into thewinter. Benefits of N fertiliser are dependent on adequatetemperature and moisture during the accumulationperiod.Dryland  pastures in the high country producecomparatively little during the summer and autumnowing to low soil moisture (Scott & Maunsell 1981).The implication is that if grass pastures are to be savedfor standing winter grazing then they may need to beclosed in the late spring or early summer to create a‘feed bank’ (Allan  et al. 1985). The trial looks at anumber of these factors in relation to grass species andcultivars.MethodsThe 0.5 ha trial was conducted at the Mt John trial site,Lake Tekapo, on a Tekapo soil on moraine topography.The site was a mosaic of hieracium (HieraciumpiZosella)and browntop-dominated depleted fescue tussock-;prassland-before-over-drilling-grasses-with-the-rota~hoe drill in September 1984. The trial was a split-splitplot design with fenced main plots of 2 summer closingsx 2 replications with subplots of 6 grass cultivars within4 nitrogen fertiliser levels. The ultimate plot size was 2x 25 m drilled strips.The six grass treatments were cocksfoot (Dactylisglomerata)  cultivars of Grasslands Kara, GrasslandsApanui, Grasslands Wana,  Grasslands Roa tall fescue(Festuca arundinacea), Grasslands Nui perennialryegrass  (Loliumperenne)  and Grasslands Maru  phalaris(Phafaris aquatica). The four N fertiliser levels were;nil, 50 kg N/ha as urea in March; 25 kg N/ha in Septand 50 kg N/ha March; or 50 kg N/ha Sept and 50 kg N/ha March. The two summer closings were spring grazinguntil closing at either mid November or mid December.A common legume mixture of alsike, red and whiteclover were disc-drilled across plots and plots given ayear to establish under a common N fertiliser rate of 50kg N/ha at seedling emergence, 50 kg N/ha in the firstautumn (Pollock 191X9),  and with the differential N andclosing treatments not applied until the second year.Herbage  mass, species composition, and live versusdead proportion in mid-May at the beginning of winter,1 9 9were determined from a combination of calibratedcapacitance probe readings, sub-sample clip quadratsand dissections, and visual rankings. Herbage  mass anddigestibilities in May and July in the third and fourthyear were determined from clip quadrat  samples. Springherbage mass was determined from calibratedcapacitance probe measurements and visual rankings ofspecies composition.Digestibilities were determined in vitro by neutraldetergent and cellulose degradation but with theinclusion of standard reference material regressed togive estimated in vivo values.ResultsThe seedling establishment of all sown grasses in thefirst spring was adequate (Table 1). The higher initialdensity of perennial ryegrass  carried through to itsslightly higher yield than the other sown grasses in thesecond and third spring. However, the relationshipbetween the sown grasses changed once the closingtreatments were imposed in the second and later years.The combined data for the pre-winter standing feedfor the second to sixth year showed significantdifferences related to species or cultivar, time ofclosing,years  and the interaction between years andother treatments (Figure 1).There were marked differences between theaccumulated feed from the two closing dates, with anaverage of 3.4 DMIha  from the November closing and1.7 t/ha from the December closing. The highest yieldswere from cocksfoot cultivars, with the highest fromKara, and similar yields from Apanui and Wana.  Theother species decreased in the cirder  of tall fescue,perennial ryegrass  and phalaris.However, there were important differences inrelation to composition, particularly the contributionby the sown grasses, and the response of the residentbrowntop  and sweet vernal remaining between the drillstrips. The significant treatment effects were the speciesof grass sown and time of closing but not N fertiliserFigure 1 Yield and components of pre-winter standing feed(May) in relation to species or cultivar and time ofclosing.Right hand bar: sown grass (solid) and browntoplsweetvernal  (cross  hatch) ,  legume (open)Left hand bar: living material (hatch), dead (open)Standard error  for  cul t ivar  by closing date difference=0.17 t/haK = Kara cocksfoot R = Roa tall fescueA = Apanui  cocksfoot N = Nui perennial ryegrassW = Wana  cocksfoot M = Maru phalarist DMlhaI K A W R N M K A W R N MNovember DecemberIlevel. There was a general increase in the proportion ofsown grass in the total yield, but this included a largespecies x closing time interaction. Figure 1 includes themean composition for the fifth and sixth year. Sowncocksfoot made up more than three quarters of the totalyield of its plots, tall fescue and perennial ryegrass  onlysmall proportions, and phalaris negligible proportions.Browntop  and sweet vernal substituted for the latterthree sown grasses. Browntop  and sweet vernal alsomade up a higher proportion of the total in the Novemberclosed treatments. Sown legume made up only 2.6% ofthe pre-winter yields in the later years.The species of sown grass was the principalsignificant effect for the digestibilities of the standingfeed. While cocksfoots had the highest total yields theyhad the lowest digestibilities and decreased to a greaterextent between May and July (Table 1). Because ofthese small differences in digesti-bilities the difference in yields ofTable 1 Compar ison  of  seedl ing  dens i ty ,  y ie lds  and  d iges t ib i l i ty  of  spec ies  andcul t ivars .A t t r i b u t e K a r a  A p a n u i  Wana R o a Nui Maru SEdiffF i r s t  s p r i n gSeedling density (no/m) 3 9 2 6 6 1 8 9 164 5 9 7.5Second springTotal yield (t  DM/ha) 0.90 0.93 0.89 0.93 0.97 0.94 0.06DigestibilityMay (%) 5 4 5 7 5 3 5 8 58 5 6 0.6July (%) 48 5 0 5 2 5 5 56 54 0.7digestible organic matter between thesown grasses was somewhat less thanindicated by the total yields.There were significant year, yearx closing, year x N and year x speciesinteractions, probably related toautumn rainfall. The mean pre-winteryields in 1986 were 2.2 t DM/ha,  19874.4, 1988 2.1, 1989 2.6 and 1990 1.5 tDM/ha  with the corresponding totalrainfall December to March being 27 11 9 9mm, 354 mm, 130 mm, 172 mm and 211 mmrespectively. The interaction effects relate to a greaterdifference between treatments in the better growingyears.While the trend was for N fertiliser to increase pre-winter yields, the differences were not large enough toreach statistical significance (P=O.20).  The mean pre-winter yields were respectively 2.3, 2.7, 2.6 and 2.8 tDM/ha  for the 0,50,75  and 100 kg N/ha.The combined data for the October spring yields forthe third to sixth years showed significant effects relatedto species or cultivar, years, N and times of closing.The cocksfoots had the highest spring yield, with againthe cultivar order being Kara, Apanui and Wana  (Figure2). The figure also includes the composition for thefifth year and shows again the high proportion of sowngrass in the cocksfoot treatments, less in the others, andtheir substitution by browntop  and sweet vernal.Legumes made up 7.7% of the spring yields.Figure 2 Combined data for October spring yields for 3rd to6th  years .  Sown grass  (sol id) ,  resident grass (hatch),legume (open)I-t-7DM/ha0K A W R N MThe yields presented in Figures 1 and 2 were onlyfor the mid spring and pre-winter after summer spelling.They do not include the main growth period of latespring/early summer. The growth rates in that periodare indicated by the differences in pre-winter yieldsfrom one month’s difference in closing in eitherNovember or December. They also demonstrate againthat in dryland  conditions, pastures for winter have tobe closed by at least December to accumulate adequatepre-winter yields.The intention of the N fertiliser treatments had beento boost the amount of pre-winter feed available. Theresults have indicated that there may be a relatively lowresponse in the year of application but a significantcarry over effect into the following spring and season.The pre-winter yields were low in some years. Theresponse to additional N was 4.5 kg DM/kg  N for thepre-winter yields and 3.6 kg DMIkg  N for the springyields, i.e., 8.1 kg DM/kg  N, and not including themain growth period of late spring/early summer.The implication is that N applications should not beseen as panic solutions for getting growth in crisisautumns, but as means of raising the mean productivitylevels over a number of years. The carry-over effect oftime of closing on the following spring yieldsdemonstrates the point.While cocksfoots were clearly the superior speciesand cultivars in this particular situation, both in totalyield and contribution of sown grass, the results alsoillustrate another principle: that species like browntopand sweet vernal can respond to the changedenvironment of new inputs and produce to within halfto two thirds of the potential of the changed environment(Scott et  al.  1985). Kara was the superior cocksfootcultivar as it had been in earlier trials (Scott & Maunsell1986). On this  more extreme high country site, perennialryegrass  though performing well in the initial two years,did not persist.There was a significant (P=O.O2) carry-over effectof N fertiliser on spring yields, these being respectively2.1, 2.2, 2.3 and 2.4 t DMIha  for the 0, 50, 75 and 100kg N/ha.DiscussionThe main conclusion, as in other investigations, hasbeen that for standing winter feed based on perennialgrass species, the main requirement is to get adequatepre-winter yields before exploiting the smallerdifferences between species and other propertiesinfluenced by frosting duration (Eddie & Black 1968;Douglas & Drew 1969; Daly & Allan  1985). Cocksfootis the superior species in this regard because of its yieldaccumulation, even though its winter digestibilities aresomewhat below those of other grasses.ACKNOWLEDGEMENTSMr P. Nes for digestibility determinations, Mr B.L.Sutherland for technical assistance, and RavensdownFertiliser Ltd for fertiliser.REFERENCESAllan,  B.E.; Lowther, W.L.; Walton, P.J. 1985. Planning,establishment and management of pastures in highcountry. In Burgess, R.E. & Brock  J.L. (eds) Usingherbage  cultivars. Grasslands research andpracticeseries 3: 17-21.Archer, K.A.; Decker, A.M. 1977. Autumn accumulatedtall fescue and orchard grass. 1. Growth and quality200as influenced by nitrogen and soil temperature.Agronomy journal 69: 601605.Barker, H.K;  Chard, J.R.A.; Hughes, W.E. 1965. Acomparison of cocksfoot and tall fescue dominantswards for out-of-season production. Journal of theBritish Grasslands Society 20: 84-90.Daly, M.J.; Allan,  B.E. 1985. Autumn saved pasture ina high frost environment. Proceedings of the NewZealand Grassland Association 46: 135-40.Douglas, J.A.; Drew, K.R. 1969. Value of cocksfootfor winter grazing in the tussock grasslandenvironment. New Zealand agn’cultural  science 4:23-24.Eddie, J.; Black, J.S. 1968. Herbage  utilization on hillpastures. In Hill-land productivity. BritishGrasslands Society occasional symposium 4: 191-195.Ocumpaugh, W.R.; Matches, A.G. 1977. Autumn-winteryield and quality of tall fescue. Agronomy journal69: 639-643.Pollock, K.M. 1989. Grass establishment andperformance on a high country soil fertilised withnitrogen. New Zealand journal of agriculturalresearch 32: 7-15.Raybum,  E.B.; Blaser, R.E.; Wolf, D.D. 1979. Wintertall fescue yield and quality with differentaccumulation periods and N rates.Agronomyjoumal71: 959-963.Scott, D.; Maunsell, L.A. 1981. Pasture irrigation in theMackenzie Basin. I. Species comparison. NewZealandjournal of experimental agriculture 9: 279-2 9 0 .Scott, D.; Maunsell, L.A. 1986. Winter feed quality ofsome grasses in the high country. New Zealandjournal of experimental agriculture 14: 19-24.Scott, D.; Keoghan, J.M.; Cossens, G.G.; Maunsell,L.A.; Ploate,  M.J.S.; Wills, B.J.; Douglas, G. 1985.Limitations to pasture production and choice ofspecies. In Burgess, R.E.; Brock,  J.L. (eds) Usingherbage  cultivars. Grasslands research andpracticeseries 3.n

Factors affecting accumulation of summer grass for winter standing feed in the high country

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