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.

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.

Three field trials on the nitrogen fertilisation of the Ermelo cultivar of Eragrostis curvula conducted over seven years were collated and reviewed. Dry matter yields in tons obtained from these trials, excluding first year results, were used to derive the regression equation y = 3.9 x -0.4 x 2 + 1.3 for the yield response to increments of 100 lb of nitrogen per morgen per annum. This response was nearly linear up to 300 lb of nitrogen, and more than 400 lb of nitrogen was required for maximum dry matter production. The crude protein content of the herbage increased progressively with increasing rates of nitrogen. The recovery of fertiliser nitrogen varied from 51 to 70 per cent ; the latter being achieved by (he application of 300 lb of nitrogen. Ammonium sulphate produced considerably higher dry matter yields than urea or limestone ammonium nitrate when applied in a single dressing in the spring. When the nitrogen was applied in three dressings the yields from urea and LAN were increased and no longer significantly different from those due to ammonium sulphate. UITTREKSEL Drie veldproewe oor die stikstofbemesting van die Ermelocultivar van Eragrostis curvula wat oor 'n periode van sewe jaar uitgevoer is, is vergelyk en bespreek. O pbrengste in ton droë materie wat van hierdie proeweverkry is, uitsluitende resultate van die eerste jaar, is gebruik om die regressievergelyking y = 3.9 x -0.4 x 2 + 1.3 vir die opbrengsreaksie op inkremente van 100 lb stikstof per morg per jaar te bepaal. Hierdie reaksie is feitlik lineêr tot by 300 lb stikstof per morg en meer as 400 lb stikstof word benodig vir maksimum droë-materieproduksie. Die rueiwitinhoud van die droë materie het steeds met toenemende peile van stikstof gestyg. Die herwinning van kunsmisstikstof het van 51 tot 70 persent gevarieer ; laasgenoemde is met die toediening van 300 lb stikstof verkry. Ammoniumsullaat het aansienlike hoër opbrengste van droë materie as ureum of kalksteenammoniumnitraat gelewer wanneer alles in een slag in die lente toegedien is. Met drie verdeelde toedienings was die opbrengste met areum en KAN verboog en nie betekenisvol verskillend van die opbrengste met ammoninmsulfaat nie.

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