Monthly, annual and altitudinal variation of forage production in a mountainous-subalpine grassland

Koutsoukis Ch.^1,2, Akrida-Demertzi K.², Demertzis P.G.², Roukos Ch.¹, Voidarou Ch.¹, Mantzoutsos I.¹ and Kandrelis S.¹

1Technological Educational Institute of Epirus, Department of Agricultural Technologists, Faculty of Agricultural Technology Food Technology and Nutrition, Kostakioi – Arta, 47100 Arta, Greece;

2University of Ioannina, Department of Chemistry, Section of Industrial and Food Chemistry, Food Chemistry Lab., 45110 Ioannina, P.O. Box 1186, Greece; koutsoukis.har@hotmail.com

Abstract

In this study the results of research conducted during the years 2012, 2013, 2014 and 2015, in the mountainous-subalpine grassland ‘Kostilata’, an area of about 950 ha, in Theodoriana, Epirus, Greece, are presented. The grassland area was divided into three zones based on their altitude above the sea level:

zone A (1,100-1,400 m), zone B (1,400-1,800 m) and zone C (1,800-2,393 m). The results showed that:

(A) the quantity of forage production of the mountainous-subalpine grassland was, on average, 1,322.1 kg dry matter (DM) ha^-1; (B) in zones A, B and C, the forage production was, on average, 1,690.1 kg DM ha^-1, 1,622.1 kg DM ha^-1 and 1,017.9 kg DM ha^-1, respectively; and (C) forage production was greatest in zone A during the second half of June 2014 (1,926.1 kg ha^-1), in zone B during the first half of July 2015 (1,817.6 kg ha^-1) and in zone C during the first half of August 2015 (1,250.5 kg ha^-1).

Keywords: mountainous-subalpine grassland, forage production

Introduction

Subalpine grasslands have a rich flora and are utilised primarily for livestock farming during summer. The quantity and quality of the forage produced is affected by climatic conditions, the physical and chemical properties of soil, botanical composition, the type of grazing animal and management (Lemaire et al., 2000). Furthermore, seasonal production is affected by the distribution of precipitation, during the plant growth period (Tallowin and Jefferson, 1999). At a specific point in time, the stage of growth varies between different plant species (Bruinenberg et al., 2002) and the main factors that affect the growth of plants, in natural conditions, are precipitation and air temperature (Frank and Ries, 1990). On the other hand, the change of altitude affects the prevailing climatic conditions, which further affect the properties of the soil and the botanical composition (Oztas et al., 2003).

The aim of this study was to investigate the monthly, annual and altitudinal variation in forage production within three altitudinal zones of the same ecosystem in a subalpine area located in Epirus-Greece.

Materials and methods

The research was conducted in the years 2012, 2013, 2004 and 2015, in ‘Kostilata’ subalpine grassland. The area extends at an altitude of 1,100 to 2,393 m and it is located in Theodoriana, Epirus, in Western Greece.

Sixty fixed experimental cages, 20 in each zone, with dimensions of 4×4 m, were installed, consisting of a 1 m high fence to protect plants from grazing. From each experimental cage, the aboveground biomass was collected in metal frames with dimensions of 50×50 cm placed in five different locations within the cage, according to the method of harvesting described by Odum (1971). Then, the samples were oven-dried until a steady weight and afterwards they were weighted. Forage was sampled every 15 days, when the animals were grazing. In zones A and B forage was sampled from the beginning of May to the end of August while in zone C from the middle of June to the end of August. An existing weather station (at 1,100 m) was used to collect the required climatic parameters (air temperature and precipitation) in zone

A, while for zones B and C, two weather stations were installed in May 2013, at 1,600 m and 2,050 m, respectively. Τhe results were compared for significant differences using a one-way ANOVA test, while mean differences were checked using Tuckey’s test (P<0.05). Statistical analyses were performed with OriginPro 9.0 software.

Results and discussion

In zone A, the largest quantity of forage production occurred during the second half of June 2014 (1,926.1 kg ha^-1), in zone B during the first half of July 2015 (1,817.6 kg ha^-1), and in zone C during the first half of August 2015 (1,250.5 kg ha^-1). The maximum monthly forage production (dry matter (DM)) during the whole period of the study reached in the first half of July, on average, 1,322.1 kg ha^-1. In zones A, B and C the maximum monthly forage production was, on average, 1,690.1 kg ha^-1, 1,621.2 kg ha^-1 and 1,017.9 kg ha^-1, respectively (Table 1).

The statistically significant differences observed in forage production within the same zone, could most likely be explained by the greater precipitation observed during June, July and August, in the years 2014 and 2015. Furthermore, the statistically significant differences in the quantity of forage production between each zone, as well as in the different time periods during which the forage production was greatest, could probably be explained by the different climatic conditions (precipitation, air temperature) prevailing in each zone and the variation in precipitation during the most important months of plant growth, although we did not test these relationships statistically (Table 2). The results of our study agree with those of other researchers who observed significant differences in the annual quantity of grassland Table 1. Forage production per year, zone and dates of sampling, expressed as kg DM ha^-1.^1,2,3

Year Dates of sampling

May June July August

1^st half 2^nd half 1^st half 2^nd half 1^st half 2^nd half 1^st half 2^nd half Zone A 2012 615.5^a1 1,216.7^a1 1,424.5^a1 1,440.4^a1 1,080.4^a13 726.2^a1 800^a1 932.6^ac1

2013 690.9^a1 1.416.9^a1 1,439.2^a1 1,502.6^a1 1,351.5^a1 881.6^a1 549^a1 661.9^a1

2014 609.8^a1 1.544.7^a1 1,770.8^b1 1,926.1^b1 1,882.7^b1 1,606.4^b1 1,420.2^b1 1,325.5^b13 2015 570.2^a1 1.434.6^a1 1,862.2^b1 1,891.4^b1 1,842.9^b1 1,500.5^b1 1,258^b1 1,069.4b^c1

mean 621.6^a 1,403.2^a 1,624.2^a 1,690.1^a 1,539.4^a 1,178.7^ab 1,006.8^a 997.3^a

Zone B 2012 59.1^a2 564^a2 885.4^a2 1,325^a1 1,417.6^a2 1,166.2^a2 1,051.8a^b1 1,157.6^a1

2013 249.1^a2 696.9^a2 1,204.2a^b1 1,409.1^a1 1,469.1^ac2 1,233.6^a1 867^a1 995.9^a2 2014 144.7^a2 831.7^a2 1,460^b1 1,745.1^a1 1,780.7^ac1 1,519.7^a1 1,133.2^ab1 900.7^a2 2015 183.7^a2 849.8^a2 1,423.2^b2 1,722.9^a1 1,817.6^bc1 1,443.2^a1 1,237.2^b1 959.9^a1

mean 159.1^b 735.6^b 1,243.2^b 1,550.5^a 1,621.2^a 1,340.7^a 1,072.3^a 1,003.5^a

Zone C 2012 149.5^a3 397^a2 692.1^a3 999.7^a12 978.9^a1 957.8^a1

2013 207.9^a2 647.1^a2 871.8^a3 1,078.8^a1 955.9^a1 814.7^a2

2014 169.4^a2 523.7^a2 861.8^a2 982.2^a2 1,234.8^a1 1,157.6^a23

2015 190.1^a3 496.2^a2 797^a2 1,010.9^a2 1,250.5^a1 1,105.2^a1

mean 179.2^c 516^b 805.7^b 1,017.9^b 1,105^a 1,008.8^a

Total mean 260.2 712.9 1,015.5 1,252.2 1,322.1 1,179.1 1,061.4 1,003.2

1 Average rates followed by different letter (a, b, c), in the same column, in the same zone differ significantly;^.average rates followed by different exponent (1, 2, 3), in the same column, in the same year, but in different zones differ significantly.

2 Means of each zone followed by different letter (a, b), in the same column, differ significantly.

3 Results differ significantly if P<0.05.

production, which were attributed solely to the climatic conditions that may vary from year to year (Skapetas et al., 2004). Furthermore, in studies conducted in other subalpine grasslands in Greece, the maximum forage production occurred in July and August (Mountousis et al., 2009).

Conclusions

In subalpine grasslands the level of forage production and the period during which the production reaches its maximum level depend on precipitation during the summer months.

References

Bruinenberg M.H., Valk H., Korevaar H. and Struik P.C. (2002) Factors affecting digestibility of temperate forages from seminatural grasslands: a review. Grass and Forage Science 57, 292-301.

Frank A.B. and Ries R.E. (1990) Effect of soil water, nitrogen, and growing degree-days on morphological development of crested and western wheatgrass. Journal of Range Management 43, 257-260.

Lemaire G., Hodgson J., De Moraes A., Nabinger C. and De F. Carvalho P.C. (2000) Grassland Ecophysiology and Grazing Ecology.

CABI publishing, Nosworthy WayWallingford Oxfordshire, UK, 432 pp.

Mountousis I., Papanikolaou K., Stanogias G., Roukos C., Chatzitheodoridis F. and Papazafiriou A. (2009) Mineral content of the herbage material in pastures of Mt. Varnoudas NW, Greece. Agronomy Research 7(2), 837-846.

Odum E.P. (1971) Fundamentals of ecology. W.B. Saunders Co, 3^rd edition, Philadelphia and London, 544 pp.

Oztas T., Koc A. and Comakli B. (2003) Changes in vegetation and soil properties along a slope on overgrazed and eroded rangelands.

Journal of Arid Environments 55, 93-100.

Skapetas B., Nitas D., Karalazos A. and Hatziminaoglou I. (2004) A study on herbage mass production and quality for organic grazing sheep in a mountain pasture of northern Greece. Livestock Production Science 87, 277-281.

Tallowin J.R.B. and Jefferson R.G. (1999) Hay production from lowland semi-natural grasslands: a review of implications for ruminant livestock systems. Grass and Forage Science 54, 99-115.

Table 2. Precipitation and air temperature during the summer months.

G Precipitation (mm)

Year 2012 2013 2014 2015

June July Aug. June July Aug. June July Aug. June July Aug.

Zone A 34.2 24.4 124.8 58.8 36 3.6 108.6 43 49.2 76.4 34.6 99.8

B 72 66.4 7 120.7 75.2 75.9 93.4 72 66.4

C 65.4 63.4 4 140.4 102.4 57.4 180.4 111.8 113.6

Air temperature (°C)

A 20 23 21.3 17.4 19.3 20.9 17.1 18.8 20.7 16.4 21.7 20.3

B 14.8 17.1 18.5 14.6 16.4 18.4 14.2 18.2 18.6

C 10.1 12.9 14.4 10.5 12.9 14.7 10.3 14.1 14.9