The effect of stage and height of cutting on the herbage yield of irrigated lucerne was investigated over four years at the Dohne Research Institute. Five cutting stages were used, namely when the lucerne was 12, 24 and 36 cm high as well as at 10% and full bloom stages. Each stage was harvested at four cutting (stubble) heights, namely at ground level and 4, 8 and 12 cm above ground level. The herbage yield increased markedly with stage of development and reached a maximum at the 10% and full bloom stages with the former producing the better quality herbage. Cutting heights from 0 to 8 cm above ground level did not materially affect the yield when cut each time the crop became 24 cm tall or at later stages of development. The 12 cm cutting height reduced the yield at the 36 cm tall and full bloom stages. UITTREKSEL Die invloed van snystadiums en-hoogtes op die hooi-opbrengs van besproeide lusern is oor vier jaar op die Dohne-navorsingsinstituut ondersoek. Die lusern is gesny wanneer hoogtes van 12, 24 en 36 cm bereik is asook op die 10% blom en vol blom-stadium. Die gewas is elke keer op vier hoogtesafgesny naamlik op die grond en 4, 8 en 12 cm bo die grondoppervlakte. Die hooi-opbrengs was opvallend hoër namate die gewas op 'n latere groeistadium gesny is. Opbrengs was die hoogste by die 10% en volblomstadia met die beste kwaliteit voer verkry op eersgenoemde snystadium. Snyhoogtes van 0 tot 8 cm bo grondoppervlakte het die opbrengs nie merkbaar beïnvloed wanneer die gewas op 'n 24 cm hoogte of latere stadium gesny is nie. Die 12 cm snyhoogte het die opbrengs verlaag by die 36 cm en volblom -stadia.

The light-proof box method was used to measure the potential vigour of cocksfoot and lucerne plants which had previously been subjected to different cutting frequencies. The yields of etiolated regrowth in cocksfoot plants that were well supplied with soil moisture declined with each successive harvest. In the lucerne trial the soil moisture content varied over a wide range and the etiolated regrowth yields correlated well with soil moisture content. The amount of etiolated regrowth made during the first twenty days in both species was olosely correlated with the total amount for the different treatments and therefore it was unnecessary to continue harvesting plants until growth ceased. Weight per growing organ was shown to be the most sensitive measure of plant vigour. UITTREKSELDie potensiële groeikrag van kropaargras en lusern, wat eers aan verskillende snyfrekwensies onderwerp was, is met behulp van die ligdighouermetode bepaal. Die hoeveelheid geëtioleerde hergroei van kropaargras, onder gunstige grondvogtoestande, het met elke snysel verminder. In die lusernproef waar 'n wye reeks grondvogtoestaride geheers het, is die opbrengs van geëtioleerde hergroei goed met grondvog gekorreleer. Geëtioleerde hergroei van albei gewasse gedurende die eerste 20 dae is sterk gekorreleer met die totale geetioleerde hergroei van die verskillende behandelings. Dit is dus nie nodig om aan te hou met sny totdat die plante opgehou het met groei nie. Gewig per groei-orgaan blyk die mees sensitiewe maatstaf van groeikrag te wees.

Results of sodseeding experiments have indicated that, provided adequate attention is given to the lime and fertilizer requirements, lucerne and white and red clovers can be successfully established in Dohne sourveld by sodseeding in the autumn. The need for further research on weed encroachment, sodseeding equipment and management of veld reinforced with legumes, is indicated. UITTREKSEL Resultate van veldproewe het aangetoon dat lusern, witklawer en rooiklawer met welslae in die herfs in Dohnesuurveld ingesaai kan word mits aan die kalking en bemestingvereistes van die peulplante voldoen is. Die behoefte aan verdere navorsing op die gebiede van onkruidindringing, geskikte masjienerie vir insaai in die veld, en die beheer van veld wat deur die insaai van peulplante versterk is, word aangedui.