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Accueil du site → Doctorat → États-Unis → 1991 → The impact of grazing on forage quantity, quality and foliar cover of the herbaceous vegetation in the Mamora cork oak forest, Morocco

Oregon State University (1991)

The impact of grazing on forage quantity, quality and foliar cover of the herbaceous vegetation in the Mamora cork oak forest, Morocco

Mejjati-Alami, Mohammed

Titre : The impact of grazing on forage quantity, quality and foliar cover of the herbaceous vegetation in the Mamora cork oak forest, Morocco

Auteur : Mejjati-Alami, Mohammed

Université de soutenance : Oregon State University

Grade : Doctor of Philosophy (PhD) 1991

Résumé
This research was conducted in the Mamora cork oak forest of Morocco to : (1) Describe the impacts of sheep grazing (none, 35% use, 70% use) in March, April, May and June of 1987 and 1988 on seasonal forage production ; (2) evaluate the effects of these factors on annual changes in herbaceous foliar cover and botanical composition ; and (3) determine their effects on seasonal changes in forage quality of the herbaceous vegetation. Neither the month of 1987 nor the degree of use had significant effects on the rate of herbage accumulation. In 1988, the month of grazing, the degree of use and their interaction had significant effects on all rates of herbage accumulation except that between May and June for the March grazed treatment. For the April, May and June treatments, grazing depressed the forage production of the subsequent months. The interaction of the month of grazing and the degree of use had no significant effect on the botanical composition of all groups of species. Averaged over the season, the other forbs were the dominant group of species. Total canopy cover was significantly affected by the year only. The 1988 total vegetative ground cover was significantly higher than the 1987 and 1989 ones as a result of the impacts of the intensity and distribution of rains on vegetative growth, development and distribution. The degree of use had a significant effect on the forage nutrients only for some grazing treatments. It seemed that the effect of the grazing intensity on forage nutrients of the subsequent months is more evident when grazing occurs early in the season. This study developed the first information for this area related to the response of the vegetation to the time and the intensity of grazing. The results suggest that scheduling intensity and timing of grazing livestock might be a key factor in community dynamics. Combined research on grazing management, fertilization and seeding should be undertaken and implemented in the next Mamora management plan.

Mots clés : Range management, Biological sciences

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