Search

English: Variation in, and changing of climatological patterns, especially rainfall, as well as grazing intensity and frequency has the biggest influence on rangeland productivity and sustainable animal production in the Nama-karoo Biome. This study was conducted to quantify whole-plant productivity, nutritive value and morphological adaptations of Karoo shrubs to defoliation along a soil-water deficit gradient. Two Karoo shrubs, Nenax microphylla and Pentzia incana were investigated. The watering treatments included the following: 0 - 25% depletion (non-stressed), 25 – 50% depletion (mildly stressed), 50 – 75% depletion (moderately stressed) and 75 – 100% depletion (severely stressed) of field capacity. The defoliation treatments were defoliation intensity to a height of 50 mm, 125 mm and 200 mm; and defoliation frequencies of three-monthly, six-monthly and twelve-monthly which was also used as the control. Water availability proved to be the single most important factor influencing both above- and belowground rangeland productivity. Defoliation intensity had the lowest impact on productivity, while the impact of defoliation frequency was markedly higher on both above- and belowground phytomass production. The root:shoot ratio increased with increased water deficit as a means to improve the water absorption of the shrubs. Determination of water-use efficiency (WUE) included both above- and belowground phytomass, while it excluded evaporation which gave a more accurate estimation of WUE. This is of the few studies where root growth is also included in calculating WUE. The expression of WUE in terms of transpiration as was done in this study, is more sensitive for describing ecosystem functioning than evapotranspiration, as was done in most studies in the past. In general, the WUE of the shrubs increased when exposed to water stress and higher grazing pressure. The more frequent and intensely the plants were defoliated, the higher the nutritive value of the produced, Afrikaans: Variasie, en verandering in klimaatspatrone, veral reënval, sowel as intensiteit en frekwensie van beweiding het die grootste invloed op weiveldproduktiwiteit en volhoubare diereproduksie in die Nama-karoo Bioom. Hierdie studie is uitgevoer om die geheel plant se produktiwiteit, voedingswaarde en morfologiese aanpassings van Karoo bossies tydens ontblaring en blootstelling aan ‘n grondwaterstremming gradiënt te kwantifiseer. Twee Karoo bossies, naamlik Nenax microphylla en Pentzia incana is ondersoek. Die waterbehandelings het die volgende ingesluit: 0 - 25% versadiging (nie gestrem), 25 - 50% versadiging (effens gestrem), 50 - 75% versadiging (redelik gestrem) en 75 - 100% versadiging (volkome gestrem) van veldkapasiteit. Die ontblaringsbehandelings het ingesluit, intensiteite van 50 mm, 125 mm en 200 mm hoogtes; en ontblaring frekwensies van drie-maandeliks, ses-maandeliks en twaalf-maandeliks wat ook as die kontrole beskou is. Beskikbaarheid van water is die enkele faktor wat die grootste impak op beide bo- en ondergrondse weiveldproduktiwiteit gehad het. Ontblaring intensiteit het produktiwiteit die minste beïnvloed, terwyl die impak van ontblaring frekwensie merkbaar hoër is op beide bo- en ondergrondse fitomassaproduksie. Die wortel:stingel verhouding het toegeneem met toename in waterstremming om sodoende die water opname van die bossies te verbeter. Vir die berekening van waterverbruiksdoeltreffendheid (WVD) is beide die bo- en ondergrondse fitomassa gebruik, terwyl evaporasie ook uitgeskakel is, wat sodoende ‘n meer akkurate WVD bepaling tot gevolg het. Hierdie is een van die min studies waar wortelproduksie tydens die bepaling van WVD in berekening gebring is. Die uitdrukking van WVD in terme van transpirasie, in plaas van evapotranspirasie soos in meeste studies in die verlede uitgevoer, lewer ‘n akkurater bydrae tot ekosisteem funksionering. Oor die algemeen is daar ‘n toename in WVD indien plante aan waterstremming en beweidingsdruk blootgest

English: Up to the 1980’s marginal soils were successfully ploughed for crop production, but unfortunately those soils soon proved to be marginal. Due to high input costs, the Department of Agriculture soon implemented the “soil conversion scheme” to promote the conversion of those ploughed marginal soils to permanent pastures. It was especially the low maize prices that triggered the conversion scheme in the 1980’s. Regardless the implementation of the soil conversion scheme, many farmers unfortunately just abandoned some of these marginal fields which resulted in many hectares of unproductive previously cultivated fields, being referred to as abandoned fields. The aim of this study was to investigate a few abandoned fields at a single location in the semi-arid central Free State in an attempt to gather information on the dynamics of such disturbed ecosystems and identify their restoration potential. The study investigated the interaction between plant and soil variables to quantify the impact of different soil physical and chemical characteristics on vegetation dynamics (species composition and density). The species richness, as well as the influence of different soil characteristics were determined to identify which might have the biggest influence on the recovery potential of the disturbed area. The soil seed bank was also investigated to quantify the survival potential of climax grass species on abandoned fields, and why these species do not establish voluntarily on these disturbed areas. The main aim of the study was to quantify the influence of soil characteristics on the vegetation dynamics of abandoned fields. The results clearly showed that marginal soils, withdrawn from cash-crop cultivation, are among the most seriously degraded areas with low soil fertility (N and C content). It is creating a more favourable habitat for pioneer grass species. This study sheds more light on the poor natural rehabilitation rate of abandoned fields in the semi-arid Free St, Afrikaans: Marginale gronde was tot en met die 1980’s ekonomies suksesvol omgeploeg vir kontantgewasproduksie, maar was kort voor lank as onekonomies (marginaal) beskou. Hoë insetkostes het veroorsaak dat die Departement van Landbou ‘n grondomskakelingskema geïmplementeer het om die omgeploegde marginale gronde weer terug te skakel na natuurlike weiding. Dit was veral die lae mieliepryse wat die omskakeling teweeg gebring het. Ongeag die implementering van die grondomskakelingskema het sekere boere steeds geen restourasie aksies op van die marginale gronde toegepas nie. Die gevolg hiervan was dat baie hektare voorheen bewerkte lande onproduktief agtergelaat is sonder om aangeplante weidings daarop te vestig. Hierdie studie het ten doel gehad om hierdie onproduktiewe oulande, wat geleë is in die sentrale Vrystaat, te bestudeer ten einde die dinamika van versteurde ekosisteme te verstaan en dan die restorasie potensiaal daarvan te identifiseer. ‘n Studie oor die interaksies tussen plant en grond veranderlikes is onderneem om sodoende die impak van die grond se fisiese en chemiese karaktereienskappe te kwantifiseer. Die plantegroei dinamika, naamlik spesie samestelling en digtheid is ook gekwantifiseer. Die spesie samestelling, asook die invloed van grondeienskappe is bepaal om sodoende die komponente te identifiseer wat die grootste invloed op die herstelpotensiaal van die versteurde area sou hê. Die saadbank is ook bestudeer om sodoende te bepaal of daar wel klimaksgrassade teenwoordig is in die oulande, asook waarom die oulande nie natuurlik herstel nie. Die hoofdoel met die studie was om die invloed van grondeienskappe op die plantegroei dinamika van die oulande te kwantifiseer. Die resultate wys duidelik dat marginale gronde, wat onttrek is van kontantgewasverbouing, ernstige gedegradeerde areas is, met ‘n lae grond vrugbaarheid (C en N inhoud). Dit skep ‘n meer gunstige habitat vir pionier grasspesies. Die studie het ook meer lig gewerp op die swak natuurlike res

English: For farm managers to utilize their pastures more efficiently, it is essential to estimate both herbage biomass and botanical composition. Therefore, there is a need to estimate herbage biomass and botanical composition of cultivated pastures with simple, accurate and cost-effective methods instead of the more accurate, but time-consuming destructive methods. The objective of this study was to evaluate non-destructive methods for estimating herbage biomass and/or botanical composition on different mixed-species pastoral systems for beef and/or dairy cattle and to identify the method, if any, that would be most accurate in each particular pastoral system. A comparison of the rising plate meter, the comparative yield method and the meter stick was conducted to determine the predictability of these non-destructive methods for estimating herbage biomass. Furthermore, the dry-weight-rank method for determining species composition was compared to hand clippings. The accuracy of the different non-destructive methods for estimating herbage biomass was compared using the coefficient of determination (r2) values between cut material and herbage biomass estimates. The study indicated that the meter stick (r2 = 0.79 – 0.85) provided the most accurate values for the dairy pastoral systems. In the beef pastoral systems the rising plate meter (r2 = 0.76 – 0.83) resulted in the most accurate method, for three out of four of pastoral systems. It was clear that species composition of the stand was an important factor affecting the accuracy of herbage biomass estimates. Based on the results of this study, all of the non-destructive herbage biomass estimation methods tested are suitable for use on both farm-level and pasture studies on larger areas. However, in grazing studies that are conducted on relatively small areas and with a relatively small number of animals, these methods may be less accurate and where accurate herbage biomass is desired, cutting is still recommended., Afrikaans: Suksesvolle weidingbestuur vereis dat die beskikbare plantmateriaal vir beweiding en die botaniese samestelling daarvan akkuraat gemeet moet word. Hierdie inligting moet vervolgens doeltreffend in die bestuur verreken word. Daarom bestaan die behoefte om die staande droëmateriaal en botaniese samestelling van aangeplante weidings met eenvoudige, akkurate en koste-effektiewe metodes te bepaal in plaas van die meer akkurate, maar tydrowende kwadraatmetode waar die plante wel gesny word (destruktiewe metode). Die doel met hierdie studie is om verskillende nie-destruktiewe metodes vir die bepaling van staande droëmateriaal en/of botaniese samestelling op verskillende weidingstelsels, bestaande uit gemengde plantspesies, vir vleisbeeste en/of melkbeeste te evalueer en om die metode wat in elke besondere weidingstelsel die akkuraatste sou wees, te identifiseer. ‘n Vergelyking van die skyf-weiveldmeter, ‘n visuele metode en die meterstok is uitgevoer om die voorspelbaarheid van hierdie nie-destruktiewe metodes vir die bepaling van staande droëmateriaal te bepaal. Verder is die droëmassa-rangordemetode vir die bepaling van spesiesamestelling met geoeste (destruktiewe) waardes vergelyk. Die akkuraatheid van die verskillende nie-destruktiewe metodes vir bepaling van staande droëmateriaal is vergelyk deur die bepalingswaarde koëffisiënt (r2) tussen die geoeste materiaal (destruktief) en bepalings deur die verskillende nie-destruktiewe metodes te gebruik. Die studie het aangetoon dat die meterstok (r2 = 0.79 – 0.85) die akkuraatste waardes vir die melkbeesweidingstelsels verskaf. In die vleisbeesweidingstelsels was die skyf-weiveldmeter (r2 = 0.76 – 0.83) vir drie uit vier van die weidingstelsels die akkuraatste metode. Dit was duidelik dat die spesiesamestelling van die verskillende stelsels ook ‘n belangrike faktor mag wees wat die akkuraatheid van die bepalings beïnvloed. Gebaseer op die resultate van hierdie studie, is die getoetste nie-destruktiewe metodes vir d

The study was conducted in the Somali region of eastern Ethiopia, with an arid to semiarid climate. The study aimed at the characterization of the rangeland resources, assessing the current condition of the rangeland, understanding pastoral perceptions on rangeland degradation and developing drought feeding strategies for livestock. Three experimental sites, representative of the three predominant vegetation types of eastern Ethiopia were selected. They were the arid Asbuli grassland (used as grazing area for large and small ruminants), the arid Aydora open savanna (bush-grassland: entirely used for grazing/browsing by all types of livestock), and the semi-arid Hurso closed savanna (bushland: selected for its importance as browsing for camels and goats). A degradation gradient was identified in each of the three vegetation types, where the botanical composition was surveyed and the rangeland condition assessed. The perceptions of the pastoralist on rangeland degradation were also quantified. The dry matter production of both the herbaceous and woody layer was determined, while the grazing and browsing capacity calculated. Key forage species were identified and the grazing pattern of various livestock species along the degradation gradient studied. The soil seed bank regeneration potential was assessed in a greenhouse experiment and the response of cattle, sheep and goats to a simulated drought, in terms of reduced fodder, was conducted under controlled conditions. The results of the study confirmed the existence of severe rangeland degradation that occurred since 1944 and which was aggravated after the 1974 drought. This contributed to an increase in the number of poor households. The average livestock holding per household declined from 809 Tropical Livestock Units (TLU) before 1974 to 483 TLU after 1974. Livestock holding shifted from a predominance of cattle to small ruminants, which are able to utilize the degraded rangeland more effectively. Camels are now the

English: Over the last few years a great interest in cactus pear was shown in terms of both fresh fruit and fodder production. However, there is a lack of knowledge on roots and therefore this study aimed at determining the root dynamics in relation to soil-water content and to quantify or characterise the different root types for two Opuntia species namely Opuntia ficus-indica (cultivar Morado) and 0. robusta (cultivar Monterey). This was carried out in the glasshouse (pots and root boxes) as well as in the field. Cactus pear planted in asbestos pots were used to determine the impact of soil-water content on root development and also their short time of recovery after rewetting the soil. The water treatments included 0 to 25% depletion of plant available (PAW) (not stressed), 25 to 50% depletion of PAW (mildly stressed), 50 to 75% depletion of PAW (moderately stressed) and 75 to 100% depletion of PAW (severely stressed). The root mass and root/shoot ratio decreased (P<0.05) with water stress for both species. Water-use efficiency decreased for 0. ficus-indica and increased for 0. robusta with water stress. The root length, root length/root mass ratio and amount of water needed to fill the cladodes increased (P<0.05) with water stress for both species. The root boxes were used for observation and characterizing the different root types and their response to soil drying and rewetting. Main roots grow up to 42 and 36 mm per day for Opuntia ficus-indica and 0. robusta respectively. The rain roots, which develop after only one hour of rewetting the soil, grow only for three days until dying due to soil drying. The side roots also emerge in response to soil-water but diners from rain roots in that they continue to grow until they die back as soil dries. Only 10 to 14 mm water is needed to fill the cladodes after a water stress. The rain roots therefore play an important role in rapid water up-take, which can fill the cladodes overnight. The root distribution with depth a, Afrikaans: Die afgelope aantal jare het daar 'n geweldige belangstelling in die turksvybedryf ontstaan, wat beide vrugte en voerproduksie aanbetref. Ongelukkig bestaan daar 'n groot gebrek aan kennis oor die wortelontwikkeling van die turksvyplant en daarom was die doel met hierdie studie om die dinamika van wortelontwikkeling 111 verhouding tot grondwater status te ondersoek. Die verskillende worteltipes IS gekarakteriseer en die wortelontwikkeling gekwantifiseer vir twee Opuntia spesies naamlik Opuntia ficus-indica (kultivar Morado) en 0. robusta (kultivar Monterey). Hierdie navorsing is in die glashuis (potte en wortelkaste), asook in die veld uitgevoer. Turksvyplante gevestig in asbespotte is gebruik om die impak van grondwaterinhoud op wortelontwikkeling, asook hulle herstel na opheffing van waterstremming oor die korttermyn te ondersoek. Die waterbehandelings het ingesluit 0 tot 25% onttrekking van plantbeskikbare water (PBW) (nie gestrem), 25 tot 50% onttrekking van PBW (matig gestrem), 50 tot 75% onttrekking van PBW (redelik gestrem) en 75 tot 100% onttrekking van PBW (erg gestrem). Die wortelmassa en wortel/blad verhouding het afgeneem (P<0.05) met waterstremming VIr beide spesies. Die watrverbruiksdoeltreffendheid het afgeneem vir O. ficus-indica, maar is verhoog vir O. robusta met waterstremming. Die wortellengte, wortellengte/wortelmassa verhouding en die hoeveelheid water benodig om 'n blad te vul, het toegeneem (P<0.05) met waterstremming vir beide spesies: Die wortelkaste is gebruik vir die monitering en karakterisering van die verskillende worteltipes en dié se reaksie op gronduitdroging en herbenatting van die grond. Die hoofwortels groei soveel as 42 en 36 mm per dag vir onderskeidelik O. ficus-indica en O. robusta. Die reënwortels wat na slegs 'n uur na opheffing van waterstremming begin ontwikkel, groei vir slegs drie dae totdat dit weens gronduitdroging verkurk. Die sywortels wat ook ontwikkel in reaksie tot waterstremming, verskil van die reënw, Lesotho Government

English: 1. The objectives as determined for this study are; * to classify the main land types in the central and southern Free State into homogenous plant communities; * the quantification of rangeland condition in every homogenous plant community by means of degradation gradients; * to develop easily and quick implementable techniques which can be used by land users te determines rangeland condition (these techniques must be scientificaily acceptable) and * to determine correlations between rangeland condition and grazing capacity. 2. The study was performed in the semi-arid region of the central and southern Free State and includes 35 different land types in the magisterial districts of Zastron, Rouxville, Wepener, Smithfield, Dewetsdorp, Reddersburg, Bloemfontein, Brandfort, Excelsior, Theunissen, Winburg, Thaba Nchu, Senekal, Petrusburg, Boshof, Bultfontein, Edenburg, Trompsburg, Bethulie, Jagersfontein, Fauresmith, Philippolis, Koffiefontein, Jacobsdal, Ventersburg, Virginia, Hennenman and Hoopstad, also includes bordering areas in the magisterial districts of Kimberley and Barkly West in the North Cape province. The study area forms part of a summer rainfall area with a long term average rainfall from approximately 300 mm in the west to 680 mm in the east. 3. With the use of multivariate analysis the study area was classified into 13 different homogenous plant communities which vary from a sour grass- to a mixed sour grass- to sweet grass- to false karoo- to karoo- to a savanna veld type. Degradation gradients were described by means of the ISPD system for every homogenous plant community. This degradation gradients varied from poor denuded rangeland, around water troughs, to well-managed rangeland on the first axis, while degradation on account of selective grazing also occurred on single occasions. 4. The ecological value of species was determined by means of the Gaussian distribution curve. To facilitate the ecological value of species, an index was set up, Afrikaans: 1. Die doelwitte wat vir die studie gestel is, is om; * die belangrikste landtipes in die Sentrale en Suid-Vrystaat in homogene plantgemeenskappe in te deel; * die kwantifisering van veldtoestand in elke homogene plantgemeenskap deur middel van degradasiegradiënte; * die ontwikkeling van eenvoudige en vinnig uitvoerbare tegnieke wat grondgebruikers kan toepas om veldtoestand te bepaal, maar tegnieke wat wetenskaplik aanvaarbaar sal wees en * die vasstelling van verwantskappe tussen veldtoestand en weidingkapasiteit. 2. Die studie is uitgevoer in die semi-ariede gebiede van die Sentrale en Suid-Vrystaat en sluit 35 verskillende landtipes in wat in die landdrosdistrikte Zastron, Rouxville, Wepener, Smithfield, Dewetsdorp, Reddersburg, Bloemfontein, Brandfort, Excelsior, Theunissen, Winburg, Thaba Nchu, Senekal, Petrusburg, Boshof, Bultfontein, Edenburg, Trompsburg, Bethulie, Jagersfontein, Fauresmith, Philippolis, Koffiefontein, Jacobsdal, Ventersburg, Virginia, Hennenman en Hoopstad geleë is, terwyl dit ook oorgangsgebiede in die landdrosdistrikte Kimberley en Barkly West van die Noord-Kaap insluit. Die studie-area is in In somerreënvalgebied geleë met In langtermyn gemiddelde jaarlikse reënval wat varieer vanaf ongeveer 300 mm in die weste tot so hoog as 680 mm in die ooste. 3. Met behulp van meerveranderlike tegnieke is die gebied in 13 homogene plantgemeenskappe ingedeel, wat gewissel het vanafh suurgras- tot 'n gemengdesuurgrastot soetgras- tot skynkaroo- tot karoo- tot 'n savannaveldtipe. Degradasiegradiënte is met behulp van die ISPD pakket vir elke homogene plantgemeenskap beskryf. Hierdie gradiënte het gewissel vanaf swak uitgetrapte veld, rondom waterpunte, tot goed bestuurde veld op die eerste as, terwyl degradasie as gevolg van selektiewe beweiding in enkele gevalle ook voorgekom het. 4. Ekologiesewaardes van spesies, is vir elke gradiënt met behulp van die Gausiese verspreidingskromme bepaal. Om die ekologiesewaarde van spesies te vergemaklik i

English: The aim of this investigation was to quantify the spring-, summer-, autumn and annual DMproduction, botanical composition, nutritional value and milk production potential of kikuyu that is over-sown with annual ryegrass, mixtures of perennial white- and red clover or a mixture of perennial ryegrass and white and red clover, within a sustainable management system. Guidelines around the cultivation practices of these over-sowing techniques were determined. The investigation was executed on the Outeniqua Experimental farm near George in the Western- Cape. Three separate pastures under permanent irrigation over nine hectares during three years were compared in a pasture system study. The experimental design was a randomized complete block design with three treatments being repeated in eight blocks. Perennial white clover (Trifolium repens) cultivars (Haifa and Waverley) and perennial red clovers (Trifolium pratense) cultivars (Kenland and Cherokee), annual westerwold ryegrass (Lolium multiflorum: cultivar Energa) and perennial ryegrasses (Lolium perenne: cultivars Yatsyn and Dobson) were over-sown onto existing kikuyu pasture by making use of three implements, namely a Rotovator, Mulcher and a Land roller. The botanical composition (grass-, clover- and herb content), nutritional value (IVOMD-, TDN-, ME-, CP-, NDF-, ADF-, Ca-, P-content) and DM-content of the different pastures were determined on a monthly basis. The Ellinbank rising plate pasture meter was used to determine the DM-production, DM-production rate and the DM-intake of the pastures. A put-and-take system of grazing, using 36 mid-lactation Jersey cows in three groups (12 per group) for each season (90 days), was implemented. The cows received new strips of pasture after each milking. Cows were moved every second day to a new sub-camp and were absent from any sub-camp for a period of 30 days. Concentrate which contained at leat 120 g crude protein kg-1 DM and 12.5 MJ ME kg1 DM was fed at 4 kg cow' da, Afrikaans: Die doel van hierdie ondersoek was om die lente-, somer-, herfs- en jaarlikse DM-produksie, botaniese samestelling, voedingswaarde en melkproduksiepotensiaal van kikoejoe wat met eenjarige raaigras, mengsels van meerjarige wit- en rooiklawer of 'n mengsel van meerjarige raaigras, wit- en rooiklawer oorgesaai word, binne 'n volhoubare bestuurstelsel te kwantifiseer. Riglyne rondom die verbouingspraktyke van hierdie oorsaaitegnieke is daargestel. Die ondersoek is op Outeniqua Proefplaas naby George in die Wes-Kaap uitgevoer. Drie verskillende weidings onder permanente besproeiing is deur middel van 'n stelselproef op nege ha oor drie jaar met mekaar vergelyk. Die proefuitleg is 'n ewekansige blokontwerp met drie behandelings wat in agt blokke herhaal is. Twee meerjarige witklawer (Trifolium repens) kultivars (Haifa en Waverley) en twee meerjarige rooiklawers (Trifolium pratense) kultivars (Kenland en Cherokee), is as Trifoilium sp. in dié ondersoek gebruik. Een eenjarige westerwold tipe raaigras (Lolium multiflorum kultivar Energa) en twee meerjarige raaigrasse (Lolium perenne: kultivars Yatsyn en Dobson) was gebruik. Hierdie weidingsgewasse is jaarliks in suiwer of gemengde stande op bestaande kikoejoe oorgesaai. Kombinasies van drie implemente, nl. 'n Kapploeg, Stokkieskapper en LandrolIer was gebruik om raaigras en/of klawer in kikoejoe oor te saai. Die botaniese samestelling (gras-, klawer- en kruidinhoud), voedingswaarde (IVOMV-, TVV-, ME-, RP-, NDF-, ADF-, Ca-, P-inhoud) en DM-inhoud van die verskillende weidings is maandeliks bepaal. Die Elllinbank-skyfmeter was gebruik om die DM-produksie, DM-produksietempo en DM-inname van die weidings te bepaal. Daar is gebruik gemaak van die wisselgetalmetode waar 36 mid-laktasie Jerseykoeie in drie groepe (12 per groep) as proefdiere vir elke seisoen (90 dae) gebruik is. Die koeie het na elke melking 'n vars strook weiding ontvang. Koeie is elke tweede dag na 'n nuwe subkamp verskuif en was afwesig van enige sub

The study was conducted in the Borana rangeland of southern Ethiopia. In the last few decades the Borana rangelands have been degraded while the pastoralists adhered to the traditional grazing strategies. The main aims with this study were to investigate the soil characteristics as well as aboveground plant communities and to assess the condition of the rangeland. In addition, the pastoralists' perceptions and cattle-rangeland management practices were evaluated. The botanical composition of the grass layer, woody vegetation structure, soil and the rangeland condition were studied in four communal grazing areas (Did Yabello, Did Harra, Dubuluk and Melbana), three land use systems (communal land, government ranch and traditional grazing reserve) and along distance gradients from water source. Species composition and basal cover of the grass layer was estimated using frequency of occurrence of plant species. Woody plant data were standardized to tree equivalent ha-l (l TE = 1 tree, 1.5 m high). Rangeland condition was assessed based on ecological condition index, weighted palatability composition of the grass layer, the structure of woody plants and soil compaction. Soil seed bank was studied under three land use systems and along a distance gradient from water source. Survey on cattle-rangeland management practice and pastoral perceptions was conducted on 40 individual households and 118 elders (7 per group). Survey results of the pastoral households and elders indicated that the average household in the study area was 7 members. The percentages of male and female children who attended schools were 26 % and 9 % respectively. Livestock holding per household was estimated to be 14 cattle, 10 goats, 6 sheep and 2 camels. Cultivation is widespread in the study area. Major constraints in livestock production were in order of importance: drought, feed shortage, water scarcity, animal diseases, predators and communal land tenure. According to the pastoralists, contributing, Government of Ethiopia

Pastoralism is the most dominant land use form in the arid rangelands of Sub- Saharan Africa in which Ethiopia is not an exception. However, in Ethiopia and elsewhere, rangeland-based life-styles are in difficulty with the rangeland environment under threat because of both external and internal constraints. The spatial variability of the annual rainfall in these areas also has an affect on the pastoralists livelihood. Accordingly, four studies were undertaken in two neighbouring districts occupied by pastoralists of different ethnic groups living in the middle Awash valley of Ethiopia with the objective of evaluating the condition of the rangelands, which was related to the perception of the pastoralists in order to come up with possible recommendations to minimize further degradation. The pastoralists perceptions of the rangeland resource were studied through group discussions and by using a structured questionnaire where each household was taken as a unit of analysis (90 households from Oromo living in Kereyu-Fantale district and 55 households from Mar living in Awash-Fantale district). The data was analysed using Statistical Package for the Social Sciences (SPSS). The result showed that the average family size per household was about 6.74, with nearly 80% of the people without any kind of education. The main source of income for both pastoral groups was from the sale of animals. The second source of income to the Oromo and Afar pastoralists was from the sale of crops and milk and milk by-products, respectively. Both pastoral groups reported that woody species like Cryptostegia grandiflora, Capparis fascicularis, Erythrina abyssinica and Flueggea virosa) and herbaceous species like Tribulus terrestris, Tephrosia subtriflora and Cynodo are sources of poisons which affect their livestock production. Ninety seven and 3% of the Oromo respondents use Cymbopogon commutatus and Chrysopogon plumulosus for house roofing respectively, while 38.1%, 23.0%, 10.6% and 28.3% of

English: The search for appropriate plant species able to produce with sustainably in arid and semi-arid areas, has been a concern for some farmers living in such harsh environments. Unfortunately there is a lack of information concerning the adaptability of different cactus pear cultivers under a range of environmental conditions. This includes the cultivation for both fodder and fruit production. Cactus pear could be introduced with great success on land presently deemed marginal for other crops. A study was therefore conducted to evaluate the production potential of ten cultivars of the green pad cactus pear species (Opuntia ficus-indicaï and one blue pad cultivar of O . robusta over three growing seasons (2001/02 to 2003/04). The cultivars of O. ficus-indica included Algerian, Gymno Carpo, Morado, Nudosa, Roedtan, Sicilian Indian fig, Tormentosa, Van As, X28 and Zastron. The species O. robusta was represented by the cultivar Monterey. The experimental layout was a randomised block design with three treatments (fodder, fruit and scozzolatura), consisting of 11 cultivars replicated twice on 66 plots. Each plot consisted of 20 plants, of which 10 were used as data plants, planted in two rows. During the study vegetative, reproductive and laboratory measurements were evaluated for the different treatments and cultivars. It was evident from this study that young cactus pear plants could be killed by a combination of frequent successive nights of temperatures below the freezing point (as low as -9°C) and water stress. Shortage of soil nutrients could also influence both fruit and fodder production in young cactus plants. Mechanical weeding near the cactus plants could damage the shallow and widespread roots thus reducing the ability of plants to cope with harsh drought. Therefore, chemical control of weeds is encouraged. This limited study has revealed that Roedtan is the best cultivar for both fodder and fruit production while Morado is also ideal for production of b, CMBSL Project of the Ministry of Environment, Gender and Youth Affairs (Lesotho)

l. Themeda triandra plante is in 0.0039m3 potte in 'n glashuis by gekontroleerde temperature van 32°C (±2°C) in die dag en 18°C (±2°C) gedurende die nag ondersoek om midsomertemperature na te boots. 2. Vier water behandelings, nl. Tl = 75-100% (kontrole) van veldwaterkapasiteit (VWK), T2 = 50-75% van VWK, T3 = 25-50% van VWK en T4 = 0-25% van VWK is toegepas. Die watertoediening is progressief verminder totdat die verlangde stremmingspunt vir elke behandeling bereik is. Hierdie vier waterbehandelings IS toegepas vir die vegetatiewe-, pyp- en reproduktiewe groeistadiums. 3. Plantmateriaal is voor sonop geoes, gedroog, verdeel in wortels, stoppel en blare, gemaal en ontleed vir totale nie-strukturele koolhidrate (sukrose, glukose en stysel) en wateroplosbare proteïen. 4. Die TNK konsentrasie in al die plantdele binne al die groeistadiums neem toe (P<0.05) met 'n toename in die intensiteit van die waterstremming van Tl na T4. 5. Binne hierdie studie is gevind dat die stoppel as die belangrikste sone vir mestrukturele koolhidraat akkumulasie, gevolg deur die wortels, funksioneer. 6. Die WOPK in die stoppel neem toe met 'n toename in die intensiteit van waterstremming vir die pyp (P<0.01) en reproduktiewe (P<0.05) groeifases. Die gebrek aan betekenisvolheid vir die WOPK verhoging vir die vegetatiewe stadium kan hoofsaaklik aan die inherente variasie in die data toegeskryfword. 7. Die toename in nie-strukturele koolhidraat en wateroplosbare proteïen, in die verskillende plantdele, met 'n toename in die intensiteit van waterstremming kan hoofsaaklik aan die inhibering van groei voor die staking van fotosintese toegeskryf word. Dit lei dan tot 'n verhoging in die konsentrasie fotosintate en dus groeireserwes. 8. Ontblaring induseer 'n afname (P<0.01) in die TNK konsentrasie binne die wortels en stoppeloor al die groeistadiums. Groot hoeveelhede koolhidraat word dus vir hergroei gemobiliseer. Die afname (P

English: The nutritive value of maize foggage cultivated on a low yield potential soil in the North Eastem Free State, with special reference to four yellow maize cultivars, was examined in a production study with Dohne Merino ewes and their lambs. Four yellow maize cultivars with the same growth season length, but differing in prolificacy, namely PAN 6364 (high prolific), SNK 2950 (semi high prolific), CRN 4512 (semi low prolific) and CRN 4502 (Iow prolific) were cultivated to be grazed as maize foggage by lactating ewes and their lambs. The experimental plot was fertilized with 35 kg N/ha, according to the planned grain yield of 2.5 t/ha. Normal tilling and production practices were applied during cultivation of the maize. The 120 Dohne Merino ewes used as experimental animals were randomly selected out of the local herd. The maize was grazed at a stocking rate of 15 ewes and lambs/ha during a 90-day grazing period. Dry material yield (DM-yield) and grain yield for cultivars were determined during the first month of the grazing period in order to quantify grazing material available to ewes and their lambs. A determination of residues not utilized by sheep during the grazing period was carried out after completion of the grazing period. The quality of grazing material available to ewes was examined in each of the three months of the grazing period, by use of feed samples collected by esophageal fistulated ewes. The dry material intake (DMI) and organic material intake (OMI) of twenty ewes, five per cultivar, were determined at the end of the first month of the grazing period, by use of the chromium oxide marker technique. The digestible organic material intake (DOMI) and crude protein intake (CPI) of ewes for the first month of the grazing period were calculated from the in vitro digestibility and chemical composition of feed samples collected by fistulated ewes. Ewes were weighed every two weeks and lambs every week from parturition till the end of the grazing per, Afrikaans: Die voedingswaarde van weimielies op 'n lae opbrengspotensiaal grond in die Noord-Oos Vrystaat, is aan die hand van vier geelmieliekultivars in 'n produksiestudie met Dohnemerino lammerooie ondersoek. Vier geelmieliekultivars van dieselfde groeiseisoenlengte, maar wat in hul meerkoppigheid verskil, naamlik PAN 6364 (sterk meerkoppig), SNK 2950 (medium-sterk meerkoppig), CRN 4512 (medium-swak meerkoppig) en CRN 4502 (swak meerkoppig) is aangeplant om as weimielies deur lammerooie benut te word. Bemesting van die proefarea is na aanleiding van die beplanningsopbrengs vir die studie van 2.5 Uha op 35 kg Nlha vasgestel. Normale bewerkingsen produksiepraktyke is tydens die verbouing van die mielies gevolg. Die 120 Dohnemerino ooie wat vir die beweiding van die mielies gebruik is, is volledig ewekansig uit die plaaslike kudde geselekteer. Die mielies is teen 'n veebelading van 15 lammerooie/ha oor 'n 90 dae periode bewei. Die hoeveelheid weiding tot die lammerooie se beskikking is gedurende die eerste maand van die weiperiode deur middel van 'n droëmateriaalopbrengsbepaling (DM-opbrengs) en graanopbrengsbepaling vir elke kultivar gekwantifiseer. 'n Bepaling van die onbenutte reste op elke kultivar is na afloop van die weiperiode uitgevoer. Die kwaliteit weiding wat deur elke kultivar verskaf is, is in elk van die drie maande van die weiperiode met behulp van fistelmonsters, wat deur slukdermgefistuleerde ooie versamel is, bepaal. Die DM-voerinname (DMI) en OMvoerinname (OMI) van twintig ooie, vyf per behandeling, is aan die einde van die eerste maand van die weiperiode deur middel van die chroomoksiedmerkermetode bepaal. Die verteerbare organiese materiaalinname (VDMI) en ruproteïeninname (RPI) van ooie vir die eerste maand van die weiperiode is vanaf die in vitro verteerbaarheid en chemiese samestelling van fistelmonsters bereken. Die ooie is tweeweekliks en lammers weekliks vanaf lamtyd tot aan die einde van die weiperiode geweeg. Die melkproduksie van twinti