The aim of this study was to evaluate the effect of two grazing regimes: the usual for the area
and late spring grazing, and three rates of N fertilisation, on dry-matter (DM) yields and nutritive
value in three mountain meadows (Anthemido-Cynosuretum cristati, Gaudinio-Agrostietum
cristati and Bromo-Cynosuretum cristati). The results showed that the lowest DM yield was
obtained on Bromo-Cynosuretum cristati meadow. Dry matter yields increased significantly with
N fertilisation in all meadows, independent of grazing regimes. The highest nutritive values occurred
at the beginning of spring, and decreased during the year as a result of maturation. This
effect was favoured by N fertilisation and it was independent of grazing regimes. Nutritive values
were sufficient to meet the daily requirements of beef cattle during the study

Aguiar, Carlos

Fernandes, Adelaide

Fernández-Núñez, E.

Galvão, Lurdes

Moreira, Nuno

Pires, Jaime

Pires, João

Fernández-Núñez, Esther

Biblioteca Digital do IPB

EGF 2012Lublin PolandGrassland – a European Resource?Edited byPiotr GolińskiMarianna WardaPiotr StypińskiVOLUME 17GRASSLAND SCIENCE IN EUROPEGrassland – a European Resource?GRASSLAND SCIENCE Grassland – a European Resource? 311Grazing regimes and fertilisation rates: effects on dry matter yields, crude protein content and digestibility of meadows in the Northeast of PortugalFernández-Núñez E.1, Pires J.M.1, Fernandes A.2, Pires J.1 Aguiar C.1, Galvão L.1  and Moreira N.31 Mountain Research Centre (CIMO), IPB, 5300 Bragança, Portugal2 DRAPN, Largo do Toural, 5300 Bragança, Portugal3 School of Agriculture & Veterinary Sciences, UTAD, 5001-801 Vila Real, PortugalCorresponding author: esther.fernandez@ipb.ptAbstractThe aim of this study was to evaluate the effect of two grazing regimes: the usual for the area and late spring grazing, and three rates of N fertilisation, on dry-matter (DM) yields and nutri-tive value in three mountain meadows (Anthemido-Cynosuretum cristati, Gaudinio-Agrostietum cristati and Bromo-Cynosuretum cristati). The results showed that the lowest DM yield was obtained on Bromo-Cynosuretum cristati meadow. Dry matter yields increased significantly with N fertilisation in all meadows, independent of grazing regimes. The highest nutritive values oc-curred at the beginning of spring, and decreased during the year as a result of maturation. This effect was favoured by N fertilisation and it was independent of grazing regimes. Nutritive values were sufficient to meet the daily requirements of beef cattle during the study.Keywords: grazing management, fertilisation, nutritive valueIntroductionThe growing season in Mediterranean mountains limits the production of meadows to spring and autumn (Pires and Moreira, 2000). Nevertheless, meadows are grazed during the year, beyond the usual cut for hay in spring. In the Northeast of Portugal, the hay cut represents more than 50% of yearly DM yields (Pires et al., 2000), even in summer irrigated meadows, but with relative low nutritive value. Since the hay cut cannot be taken much earlier than the usual date, because of rainfall occurrence, the only way to improve its nutritive value is to reduce the period of growth and to close up meadows later. In this situation, dry mat-ter (DM) yields and nutritive value of meadows must be studied because when the hay yield is increased, its nutritional value decreases due to advancing maturity in plants (Vázquez Aldana et al., 2000). On the other hand, the effect of N fertilisation on DM yield and nutri-tive value, both as a direct or indirect effect through the changes it induces in the relative proportion of legumes and grasses (Sun et al., 2008) must be studied too. The objective of the present study was to evaluate the effects of two grazing regimes, and three rates of N fertilisation, on dry matter (DM) yields and nutritive value in three mountain meadows.Materials and methodsIn 1998 and 1999, three meadows were studied in the North-east of Portugal: Anthemido-Cynosuretum cristati (M1), Gaudinio-Agrostietum cristati (M2) and Bromo-Cynosuretum cristati (M3). The treatments consisted of two grazing regimes: usual for the area (G) and a late spring grazing (LG) period with meadows closed up for hay three weeks later; and three rates of N fertilisation (N0-0; N1-75 and N2-150 kg ha–1 year–1). The experimental design was a hierarchical completely randomised split-split plot, where meadows (M) were the main plots, and grazing regimes (G and LG) the subplots and N fertilisation (N) the sub-subplots. Three samples were harvested inside exclosure cages of 0.25 m × 0.25 m 312 Grassland Science in Europe, Vol. 17within sub-plots, at the beginning of spring (March/April), at the hay cut (June), and at the end of autumn (November). Samples were dried to constant weight at 60ºC (48 h). Dry-matter yields and nutritive value (crude protein content (CP), and digestibility (IVOMD)) were determined. CP content was analysed after macrokjeldahl digestion and the IVOMD was determined according to Marten and Barnes (1980). General linear models procedure (SYS-TAT 12) was used for ANOVA, and the difference among means was detected by Tukey’s HSD test at the 0.05 probability level. Multiple regressions for CP yields and metabolizable energy (ME) were carried out. These models were adjusted by stepwise regression for each meadow taking the grazing treatment (G-LG), and the nitrogen fertilization (N) as independ-ent variables. Only the independent variables with P < 0.05 were retained in the model.Results and discussionAnthemido-Cynosuretum cristati (M1) had the highest DM yields in spring and autumn, whilst Agrostietum cristati (M2) had the highest DM yields in the hay cut (Figure 1). The high N rate (N2) combined with late spring grazing (LG) significantly increased DM yields in M1 in spring (Figure 1). In this harvest, DM yields increased significantly in all meadows (P < 0.001) and in the usual grazing (G) with fertilisation (N1 and N2). Additionally, DM yields significantly increased by the late spring grazing (LG) but only in M1 in hay cut and in M3 in autumn.In the no-fertiliser treatment (N0), the proportions of the annual DM yields harvested in the hay cut accounted for 66–78–50% in G, and 64–70–55% in LG for meadows M1-3, re-spectively. In the case of the high N-rate treatments (N2) the proportions were 64–70–55% (G) and 63–79–58% (LG) in M1-3, respectively.It is well documented that maturation causes changes in chemical composition resulting in a decline in CP content and IVOMD (Vázquez Aldana et al., 2000). Our results showed that the lowest nutritive values (CP content and IVOMD) were obtained in the hay cut and in autumn in all meadows, independent of N rate and grazing regimes, but values were suf-ficient to meet the daily requirements of beef cattle (NRC, 1996). Additionally, there was a significant interaction of fertilisation × grazing for nutritive value in spring (P < 0.001 and P < 0.01 for CP content and IVOMD, respectively) whereby late spring grazing (LG) com-bined with high N rate (N2) significantly increased CP content (Figure 2). While IVOMD content tended to be lower in LG regimen, a significant difference was detected only in the N1 treatment (Figure 2). On the other hand, the highest nutritive value was achieved with the highest N rates (N2) in all meadows. It is know that N fertiliser greatly increases the CP content and herbage digestibility (Duru, 2003). A different effect of grazing regimes (G) was obtained on ME and CP yields (Table 1) in meadows M1 and M2.&/;KGNFUEDEDECDCD0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0URTKPI JC[EWV CWVWOP URTKPI JC[EWV CWVWOP URTKPI JC[EWV CWVWOP/ / /6TGCVOGPVUV&/JC).)(KIWTG  &/ [KGNFU KP VJG VJTGG JCTXGUVU &KHHGTGPV NGVVGTU KPFKECVG UKIPKHKECPVFKHHGTGPEGU R  DGVYGGP 0 HGTVKNKUGT VTGCVOGPVU 0 0 CPF 0 MI0 JC CPF ITC\KPI TGIKOGP ) WUWCN ITC\KPI .) NCVG URTKPI ITC\KPI KP VJG UCOGOGCFQY/CPFKPVJGUCOGJCTXGUVFigure 1. DM yields, in the three harvests. Different letters indicate significant differences (P < 0.05) be-tween N fertlilser treat-ments (N0-0; N1:-75 and N2-150 kg N ha–1), and grazing regimem (G: usual grazing, LG: late spring grazing) in the same meadow (M1-3), and in the same harvest Grassland – a European Resource? 313While ME and CP yields increased with LG regimen and N fertilisation in M1, the opposite response was obtained in M2. This different response could be explained by the fact that the proportion of grasses in M1 was favoured by G regimen (and reduced the presence of legumes and other species) whilst on M2 the late spring grazing increased the presence of grasses (data not shown). Additionally, N fertilisation favours the presence of annual grasses (Sun et al., 2008), e.g. Gaudinia fragilis (L.) Beauv on M2, which contributed to a reduc-tion in ME yields. Yields of ME and CP increased significantly with N fertilisation of M3 and this effect was independent of grazing.Table 1. Adjusted models for CP yields and ME in hay cut in meadows M1-3 taking the independent variables: grazing: 0 (G), 21 (LG) and N: 0–150 kg N ha–1. (n = 36)CP (t ha–1) R2 S ME (MJ ha–1) R2 SM1 0.494+9.1 × 10–5 × N × G 0.36 0.15 33143+497 × G+99 × N 0.42 9808M2 0.548–7 × 10–3 × G+4.2 × 10–3 × N–1.5 × 10–5 × N2 0.63 0.1247454–590 × G+159 × N 0.54 11011M3 0.179+1.2 × 10–5 × N2 0.45 0.14 18072+0.7364 × N2 0.32 10475ConclusionsWhen changes are introduced in meadow management it is important to note the initial community botanical composition. In our case, the change in spring management was more suitable for Anthemido-Cynosuretum cristati meadow, and less suitable for Gaudinio-Agrostietum cristati. N fertiliser increased DM yields and nutritive value in all meadows.ReferencesDuru M. (2003) Effect of nitrogen fertiliser rates and defoliation regimes on the vertical structure and composition (crude protein content and digestibility) of a grass sward. Journal of the Science of Food and Agriculture 83, 1469–1479.Marten G.C. and Barnes R.F. (1980) Prediction of energy digestibility of forage with in vitro rumen fermen-tation and fungal enzyme systems. In: Pidgen W.C., Balch C.C. and Graham M. (eds) Standardization of Analytical Methodology for Feeds, IDRC, Ottawa, pp. 61–71.NRC. (1996) Nutrient Requirements of Beef Cattle. National Academy Press. Washington, DC, USA.Pires J. and Moreira N. (2000) Meadow pastures: Biomass yield and nitrogen response in the Northeast of Portugal. 11th FAO Meeting of the FAO working group of Mountain Grasslands: Quality and valorisations of mountain animal products. Luz St Sauver, Francia, pp. 25.Pires J.M., Trindade H., Martins V. and Moreira N. (2000) Produção ao longo do ano de pastagens de montanha sob o efeito da adubação azotada e do prolongamento do pastoreio na Primavera. I- Produção de matéria seca na zona de Vila Real. III Reunião Ibérica de Pastagens e Forragens, Portugal-España, pp. 301–308.Vázquez Aldana B.R., García-Ciudad A., Pérez-Corona M.E. and García-Criado B. (2000) Nutritional quality of semi-arid grassland in western Spain over a 10-year period: changes in chemical composition of grasses, legumes and forbs. Grass and Forage Science 55, 209–220.Sun X., Luo N., Longhurst B. and Luo J. (2008) Fertiliser Nitrogen and factors affecting pasture responses. The Open Agriculture Journal 2, 35–42.+81/&DCCD) .) ) .) ) .) ) .) ) .) ) .) ) .) ) .) ) .)0 0 0 0 0 0 0 0 0URTKPI JC[EWV CWVWOP6TGCVOGPVU+81/&IMI&/%2%2IMI&/(KIWTG  %2 EQPVGPV CPF +81/& KP VJG VJTGG JCTXGUVU &KHHGTGPVNGVVGTU KPFKECVG UKIPKHKECPV FKHHGTGPEGU R DGVYGGP ITC\KPITGIKOGP ) WUWCN ITC\KPI .) NCVG URTKPI ITC\KPI KP VJG UCOG 0HGTVKNKUCVKQP VTGCVOGPV 0 0 CPF 0 MI 0 JC CPFJCTXGUVFigure 2. CP content and IVOMD in the three harvests. Different letters indicate significant differences (P < 0.05) between grazing regimem (G: usual grazing, LG: late spring grazing) in the same N fertililsation treatments (N0-0; N1-75 and N2-150 kg N ha–1) and harvestIVOMD (g kg-1 DM)

Grazing regimes and fertilisation rates: effects on dry matter yields, crude protein content and digestibility of meadows in the Northeast of Portugal

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Grazing regimes and fertilisation rates: effects on dry matter yields, crude protein content and digestibility of meadows in the Northeast of Portugal

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