The objective of this study (conducted in 1994) was to assess the effects of season and grazing frequency (control, continuous, intermittent during 2 days per week) on vegetation attributes, and animal feeding behavior. Mean standing crop, for which Artemisia herba alba contributed 72%, attained 533 for the control while it was maintained at 394 and 322 Kg DM/ha, for the continuous and the intermittent grazing, respectively. Mean productivity of Artemisia herba alba varied according to treatment and had values of 5.3, 3.0 and 2.5 Kg DM/ha/day, under the ungrazed control, the continuous and the intermittent grazing regimes, respectively. Percent utilization varied according to season, groups of plant species and treatment. Thus, this parameter ranged from 3.3% to 27.6%, and from 28% to 56.1%, for Artemisia herba alba and the perennial grasses, respectively. Mean contribution to sheep diets was similar (34%) for both Artemisia herba alba and the perennial grasses. However, it varied according to availability and the grazing regime. For example, Artemisia herba alba contributed with 27.1% and 41.7%, under the continuous and the intermittent grazing regimes, respectively

Bensalem, C

Berkat, O

Mejjati Alami, M

English

University of Kentucky

Session 29 - Grazing Management 29-167ABSTRACTThe objective of this study (conducted in 1994) was to assess theeffects of season and grazing frequency (control, continuous,intermittent during 2 days per week) on vegetation attributes, andanimal feeding behavior. Mean standing crop, for which Artemisiaherba alba contributed 72%, attained 533 for the control while itwas maintained at 394 and 322 Kg DM/ha, for the continuous andthe intermittent grazing, respectively. Mean productivity of Artemisiaherba alba varied according to treatment and had values of 5.3, 3.0and 2.5 Kg DM/ha/day, under the ungrazed control, the continuousand the intermittent grazing regimes, respectively. Percent utilizationvaried according to season, groups of plant species and treatment.Thus, this parameter ranged from 3.3% to 27.6%, and from 28% to56.1%, for Artemisia herba alba and the perennial grasses,respectively. Mean contribution to sheep diets was similar (34%)for both Artemisia herba alba and the perennial grasses. However, itvaried according to availability and the grazing regime. For example,Artemisia herba alba contributed with 27.1% and 41.7%, under thecontinuous and the intermittent grazing regimes, respectively.KEYWORDSArtemisia herba alba, grazing regime, mean standing crop,productivity, contribution, relative preferenceINTRODUCTIONDeveloping a grazing management plan that is both ecologically andeconomically sound must take into account how the forage resourcewill respond to different levels, timing and duration of use. Thisgrazing plan is dependent upon the combination of applying theseprinciples. The Artemisia herba-alba dominated vegetation is animportant rangeland resource in Morocco. The importance of thisresource and the rate of its degradation have prompted a number ofstudies. Among these: the evaluation of the response of this lowshrubland vegetation to different levels of stocking rates using acontinuous grazing system (El Bare, 1985; Berkat, 1986; N’Grade,1989), the biology of Artemisia herba-alba populations (Berkat1986), the dynamics of its forage production (Benkhalifa, 1988;N’Grade, 1989), the impact of grazing on soils characteristics (ElBare, 1985; Berkat, 1986; Sabir, 1994), and animal performances(El Bare, 1985; Berkat, 1986). Although grazing management hasbeen recognized to be critical in order to improve the managementof these rangelands, only one investigation on the impact of grazingfrequency on this type of vegetation has been carried out (El Haddi,1993). This study is a contribution toward that end and has theobjective of assessing the effect of grazing frequency (control,continuous, intermittent during 2 days per week) on vegetationparameters and on diet composition of sheep during winter, springand summer seasons of 1994.METHODSThis investigation was conducted at the Sagebrush experimental area,located within the Aarid Perimeter in the High Moulouya Valley ofMorocco (32° 64’N, 4° 95’W). Elevation is 1800 m. Soils are ofbrown calcareous type, of a silt-sandy texture, and of a depth notexceeding 30 cm (Berkat, 1986).Climate is arid Mediterranean type with a cold winter. The rainyseason extends from September to June with November and AprilID NO. 1738RESPONSES OF ARTEMISIA HERBA-ALBA ASSO. AND ITS ASSOCIATED SPECIESTO GRAZING FREQUENCY (MIDELT, MOROCCO).M. Mejjati Alami1, O. Berkat1, and C. Bensalem21Professors, Department of Plant Ecology and Range Science, IAV Hasan II, Rabat, Morocco.2Range manager, Tunis, Tunisiapeaks. Mean annual precipitation is 225.7 mm. Mean annualtemperature is 14.2°C. Monthly mean temperature ranges from 6.4°Cin December to 24.1°C in July.Vegetation is a low shrubland dominated by Artemisia herba-albaAsso. Other low shrub species include Artemisia mesatlantica L.,Teucrium polium L., Helianthemum croceum (Desf.) Pers.,Helianthemum virgatum (Desf.) Pers., Thymus hirtus L. and Santolinarosmarinifolia L. Dominant herbaceous species include Dactylisglomerata L., Stipa barbata Desf., Stipa parviflora Desf., Kœleriavallesiana (Honk.) Bert. and various annuals.The experimental units consisted of 6 pastures allocated to 3 grazingtreatments with 2 replications. Treatments were: control with nograzing, grazing every day (continuous), intermittent grazing duringtwo days per week. Grazing was performed two hours per day with81 ewes allocated to the pastures so as to obtain a moderate stockingrate of .75 ewe /ha (El Bare, 1985 and Berkat, 1986). Animalsreceived each day 200 g of barley supplement.Plant cover was determined using 3 permanent ten-meter lines perpasture with 10 cm reading intervals (Pieper, 1978; and Bonham,1989).Ten paired plots per treatment were used to evaluate vegetationparameters and utilization (Pieper, 1978). In each pair, one plot wasprotected by a cage of 2 m2 (1m (2m)). Both quadrats were clippedevery two weeks in order to determine consumable standing crop(from February to July), forage productivity for the April to Julyperiod, determined with the procedure described by Bonham (1989),percent utilization for the April to July period, determined from thedifference between inside and outside cages as described by Pieper(1978). Sheep diets were determined every two weeks for the Aprilto July period using the bite count method (Holechek et al., 1982).For all these parameters, plant species were grouped into 5 categories:Artemisia herba-alba as a group and with its population components(adult vigorous, adult senescent, juveniles, seedlings), other shrubs,perennial grasses, other herbaceous perennials and annuals.Data were subjected to analysis of variance to determine differenceswith regard to period and grazing treatment in a completelyrandomized block design with two replications. A 2 arcsinû%transformation was performed on percent data prior to analysis.Where appropriate, differences between means were separated usingNewman - Keuls test at p<0.05 (Steel and Torrie, 1980).RESULTS AND DISCUSSIONTotal plant cover varied from 21 to 42% with Artemisia herba-albaas the dominant plant species. The adult vigorous plants of this specieswere the dominant life state class within its population. Artemisiaherba-alba mean cover attained 17.7% and was significantly affectedby the grazing treatment only. El Bare (1985), Alaoui (1985) and ElHaddi (1993) reported values at the same site, respectively of 12.2,15.4 and 12.6. These differences could be explained by the climaticconditions and the grazing treatment. Cover of perennial grasses wassignificantly higher (p<0.05) under the control and intermittentgrazing (7.1%) as compared to the continuous grazing (5.9%).Session 29 - Grazing Management 29-168végétation sous un système continu de pâturage : Effets du pâturageà différents niveaux de charge au printemps et en été sur les steppesà armoise blanche en Haute Moulouya. Mémoire de 3ème cycle enAgronomie. IAV Hassan II. Rabat.Benkhalifa, A. 1988. Contribution à l’étude de la variabilité de laproduction de l’armoise blanche à travers l’analyse des réponses descomposantes démographiques à différents régimes pluviométriques.Mémoire de 3ème cycle, IAV Hassan II. Rabat.Berkat, O. 1986. Population structure, dynamics and regenerationof Artemisia herba-alba Asso. Thèse de Doctorat Es-SciencesAgronomiques. IAV Hassan II. Rabat.Bonham, C.D. 1989. Measurements for terrestrial vegetation. Acursery Interscience Publication. John Wiley and Sons, New York.El Bare, B. 1985. Contribution à la connaissance des pâturages àarmoise: utilisation par les ovins et impacts du broutage sousdifférents niveaux de charge. Mémoire d’assistanat, IAV Hassan II.Rabat.El Haddi, M. 1993. Contribution à l’étude de l’impact de la fréquencede pâturage sur la steppe à armoise blanche dans la Haute Moulouya(station expérimentale de l’Aarid). Mémoire de 3ème cycle enAgronomie, IAV Hassan II. Rabat.Holechek, J.L., M. Vavra, and R.D. Pieper. 1982. Botanicalcomposition determination of range herbivore diets: A review. J.Range. Manage. 35:309-315.N’Grade, G. 1989. Evolution saisonnière de la phytomasse et de ladémographie des pousses de l’armoise blanche (Artemisia herba-alba Asso) sous différents niveaux de charge. Mémoire de 3èmecycle, IAV Hassan II. Rabat.Pieper, R.D. 1978. Measurement Techniques for Herbaceous andShrubby Vegetation. New Mexico State University, Las Cruces, N.Mex.Sabir, M. 1994. Impact du pâturage sur l’état de surface et lespropriétés hydrologiques d’un sol dans un milieu steppique marocain(Périmètre de l’Aarid, Haute Moulouya) .Thèse de Doctorat Es-Sciences Agronomiques. IAV Hassan II. Rabat.Steel, R.G.D., and J.H. Torrie. 1980. Principles and procedures ofstatistics. Second edition. McGraw-Hill Book Co., N.Y. 632pp.Consumable standing crop and in particular its Artemisia componentincreased from February to June for all treatments. This increaseresulted from recruitment of a number of herbaceous plant speciesand from development of new shoots by the shrubby species.Consumable standing crop was significantly higher (p<0.05) underthe control (533 Kg DM/ha) as compared to both grazing frequenciesfor which this parameter attained 322 and 394 Kg DM/ha,respectively for the intermittent and the continuous grazing regime(Table 1, a). Artemisia herba-alba contributed by 69% to theconsumable standing crop and its production was significantly(p<0.05) affected by the grazing treatment (Table 1, ). The highestvalue was obtained under the control (361 Kg DM/ha), as comparedto the treatments for which values of 216 and 280 Kg DM/ha wererecorded for the intermittent and the continuous grazing, respectively(Table 1, ). Perennial grasses are the second most important groupof species. Their contribution to the consumable standing crop variedfrom 11 to 14%. All the values obtained for this parameter weresignificantly different (p<0.05) and were 66, 46 and 35 Kg DM/ha,respectively for the control, the intermittent and the continuousgrazing (Table 1, ). These values are twice those reported by ElHaddi (1993). Even though the spring season was particularly dry,the productivity levels in April (for perennial grasses) and May (forArtemisia herba-alba) were high. This can be explained by the overallmoisture regime. In fact, The 1993-94 year was wetter than usualespecially in fall and winter. The grazing pressure did significantlyaffect the productivity of Artemisia herba-alba and the perennialgrasses group (Table 1, ). The utilization and contribution ofArtemisia herba-alba and perennial grasses to the sheep diets weresignificantly affected by the season and the grazing frequencies (Table1, ). Perennial grasses were more utilized than Artemisia plants(Table 1, ), especially late in the season due to their higherpalatability. The relative preference index (RPI) values obtained forthis group of species were 1.8 and 2.0, respectively for the intermittentand the continuous grazing.REFERENCESAlaoui, M. 1985. Contribution à l’étude de l’interface ovins-Table 1Residual phytomass(Kg DM ha-1), productivity(Kg DM ha-1day-1), utilization(%) and contribution(%)of different group of species to sheepdiets during the periods of 2/28 to 7/4/94 at the Aarid experimental station (Midelt, Morocco) for the grazing treatments (Continuous, intermittentand ungrazed control).    Group of species Artemisia Perennial Other Perennial Annuals TotalTreatments herba-alba grasses shrubs forbsIntermittent 216b1 35c 18b 32b 21a 322c Continuous 280c 46b 27b 27b 13a 394b Control 361a 66a 38a 45a 21a 533a    Group of species Artemisia Perennial Other Perennial Annuals TotalTreatments herba-alba grasses shrubs forbsIntermittent 2.5c1 1.2a 0.3a 0.8a 0.7a 5.3b Continuous 3.0b 1.2a 0.4a 0.8a 0.4a 5.9b Control 5.3a 0.5b 0.3a 0.7a 0.4a 7.3a    Group of species ArtemisiaPerennial Other Perennial Annuals TotalTreatments herba-alba grasses shrubs forbsIntermittent 12.3a1 36.8a 2.8b 17.2a 22.4a 17.9a Continuous 9.1b 31.5b 4.8a 20.6a 17.9a 14.5bGroup of species Artemisia Perennial Other Perennial AnnualsTreatments herba-alba grasses shrubs forbsIntermittent 41.7a1 30.3b 6.9a 17.2b 3.9a Continuous 27.1b 38.0a 7.0a 25.5a 2.3b1 Means in a column not sharing a common letter differ significantly (P ( 0.05)

Responses of Artemisia herba-alba Asso. and its Associated Species to Grazing Frequency (Midelt, Morocco)

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Responses of Artemisia herba-alba Asso. and its Associated Species to Grazing Frequency (Midelt, Morocco)

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