Kuraklığın Doğal Mera Alanları Üzerine Muhtemel Etkileri

Bir bölgede tarımsal üretim toprak koşulları, iklim ve bitki üçgenine bağımlı olarak şekillenmekte olup, o bölgede yetiştirilebilecek bitki türleri ve bu türlerin verimlilikleri üzerine bölgenin ekolojik koşulları, özellikle iklim faktörleri önemli derecede belirleyici olmaktadır. Uzun dönemlere ait ortalama yağış değerlerine göre, daha düşük yağışın gerçekleşmesi durumu olan kuraklık sonucu ortaya çıkan su kısıtlığı, insan, hayvan ve vejetasyonlar üzerine olumsuz etkilerde bulunmaktadır. Kuraklığa bağlı olarak verimdeki azalmanın yanı sıra vejetasyonunun tür kompozisyonu, kapalılık derecesi ve yem kalitesi de olumsuz yönde etkilenmektedir. Mera alanlarımızın büyük bir çoğunluğu yıllık toplam yağış miktarı düşük ve yağışın yıl içerisindeki dağılımı da düzensiz olan Doğu ve İç Anadolu bölgeleri gibi kurak veya yarı kurak olarak kabul edilebilecek bölgelerde bulunmaktadır. Bu gibi bölgelerde uzun süreli kuraklık meralarda verimi önemli ölçüde azaltmaktadır. Kuraklığa ilaveten zamansız ve ağır otlatma meraların hayvan otlatılarak değerlendirilemeyecek bir duruma gelmesine sebep olabilmektedir. Bu yüzden kurak dönemlerde otlatma uygulamalarının yeniden planlanması mera bitki örtülerinin devamlılığı açısından önem arz etmektedir.

Anahtar Kelimeler:

Mera, İklim faktörleri, Kuraklık

The Possible Effects Of Drought On Natural Pastures

Agricultural production in a region, depending on soil conditions, climate and plant species is being shaped triangle, plant species that can be grown in the region and ecological conditions, especially climatic factors are significant determinants of the region on the productivity of this species. The drought is defined as lower rainfall values than the long-term average precipitation values, the water restriction that results from drought have negative effects on human, animal and plant vegetation. As well as the reduction in yield, species composition of the vegetation, canopy coverage and forage quality is also affected negatively due to drought. The majority of our rangelands are located in East and Central Anatolian regions considered as arid or semi-arid because in these regions annual total rainfall is low and rainfall distribution is irregular. In such areas, prolonged drought, the production of rangeland decreases significantly. In addition to drought, untimely and heavy grazing in the pasture can cause to come into a situation that cannot be evaluated animal grazing of rangelands. So rearrangement of grazing practices in during dry periods is important for the maintenance of pasture vegetation.

Keywords:

Rangeland, Klimatic factors, Rought.,

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Batima P. Bat B. and Tserendorj Ts (2006) Evaluation of Adaptation Measures for Livestock Sector in Mongolia. AIACC Working papers, available at: www.aiaccproject.org. (18.12.2009)
Borman MM, Johnson DE and Krueger WC (1992) Soil moisture extraction by vegetation in a Mediterranean/maritime climatic region. Agron. J., 82, 1093-1098.
Charney J, Stone PH and Quirk WJ (1975) Drought in the Sahara: a biophysical feedback mechanism. Sci.187,434-435.
Ganskopp DC, and Bedell TE (1981) An assesment of vigor and production of range grasses following drought. Journal of Range Manag., 34,137141.
Hafercamp MR, Volesky JD, Borman MM, Heitschimidt RK and Currie PG (1993) Effect of mechanical treatments and climatic factors on the productivity of Northern Great Plains rangelands. J. Range Manage., 46, 346-350.
Hanson CL and Lewis JK (1978) Winter runoff and soil water storage as affected by range condition. Proc. First Int. Rangel. Cong., 1978. USA, 284-287.
Herbel CH and Pieper RD (1991) Grazing Management. In Semiarid Lands and Deserts: Soil Resources and Reclmation (Ed. J. Skujin). Marcel Dekker, New York, 361-385.
Herbel CH and Gibbens RP (1989) Metric potential of clay loam soils on arid rangelands of the Southwestern United States. Proc. XVI. Int. Grassl. Cong., 1989, France, 519-520.
Holechek JL, Pieper RD and Herbel CH (2004) Range Management: Principles and Practicies. Prentice Hall, New Jersey 607 p.
Jensen ME (1989) Soil climate and plant community relationship on some rangelands of Northeastern Nevada. J. Range Manage., 42, 275-278.
Klages KHW (1942) Ecological crop geography. The Macmillan Company, NY.
Koç A (1995) Topoğrafya ile Toprak Nem ve Sıcaklığının Mera Bitki Örtülerinin Bazı Özelliklerine Etkileri (Doktora Tezi). Atatürk Üniv. Fen Bil. Enst. Tarla Bit. Anabilim Dalı, Erzurum.
Koç A (2001) Autumn and spring drought periods affect vegetation on high elevation rangelands of Turkey. J. Range Manage., 54, 622-627.
Le Houerou HN (1984) Rein use efficiency: a unifying concept in arid-land ecology. J. Arid Environ., 7,213-247.
McDonald Jr MB, Copeland LO, Knapp AD and Grabe DF (1996) Seed development, germination and quality. In: L.E. Moser, D.R. Buxton and M.D. Casler(eds.) Cool-season grasses, p.15- 17. Amer. Soc. Agron. No:34, Madison, Wis.
Moldenhauer L (1998) Drought, no fear! Rangelands 20,30-31.
Ogden PR, (1980) Meeting The Phisiological requirements of a plant with grazing systems. Proc. Grazing Manage. Systems SW Rangel. Symp., 1980, New Mexico, 37-48.
Peterson PR, Sheaffer CC and Hall MH (1992) Drought effects on perennial legume yield and quality. Agron. Journal. 84,774-779.
Pieper RD, Donart GB (1975) Drought on the range: Drought and southwestern range vegetation. Rangeman’s j., 2,176-178.
Pittock AB (1995) Climate change and world food supply: special issue of global environmental changes and food policy. Environment, 37, 25-30.
Rickart WH, Murdock JR (1963) Soil moisture and temperature survey of a desert vegetation mosaic. Ecology, 44, 821-824.
Smoliak S (1956) Influence of climatic conditions on forage production of shortgrass rangeland. J. Range Manage., 9, 89-91.
Snyman HA, Fouche HJ (1993) Estimating seasonal herbage production of a semi arid grassland based on veld condition, rainfall and evapotranspiration. Afr. J. Range For. Sci., 10,21-24.
TeKrony DM, Egli DB (1991) Relationship of seed vigor to crop yield: a reviev. Crop Sci., 31, 816- 822.
Thurow TL, Charles A, Taylor Jr (1999) Vievpoint: The role of drought in range management. Journal of Range Manag., 52 (5), 413-419.
Tuvaansuren G, Bayarbaatar B (2003) Future climate change impacts on livestock. Vulnerability and Adaptation Assessment for Grassland Ecosystem and Livestock Sector in Mongolia project. AIACC annual report. Ulaanbaatar.19 pp.
Vallentine JF (1990) Grazing Management. Academic Pres Inc., 533 p
Weaver JE, Albertson FW (1936) Effect of the great drought on the prairies of Iowa, Nebraska and Kansas. Ecology, 17,567-639.