An economic evaluation of steer livemass gain from kikuyu differentially fertilized‐with nitrogen

Abstract

Livemass gain of steers grazing kikuyu fertilized at different levels of nitrogen has not yet been economically evaluated in South Africa. This paper reports the findings of an evaluation of kikuyu in terms of dry matter production, nutrients (crude P, K, Mg and Ca), leaf:stem ratio, animal livemass gain and economics when fertilized at four levels of nitrogen (150, 300, 450 and 600 kg N/ha). Four 1 ha paddocks were allocated to each nitrogen level and rotationally grazed by steers of four breed types: Brahman cross, Simmentaler, Brahman and British types. Dry matter production increased with an increase in nitrogen applied as did gain/ha, but gain/head decreased. Differences in gross returns did not quite cancel differences in costs of the various nitrogen levels and so the marginal returns per ha were R878 and R788 for the low and high nitrogen levels respectively with the other two treatments intermediate.

Uittreksel

‘n Ondersoek is nog nie in Suid‐Afrika uitgevoer op die ekonomie van stikstofbemesting van kikoejoe in terme van die lewende massatoename van osse nie. Kikoejoe is teen vier piele met stikstof bemes (150, 300, 450 en 600 kg N(ha) en waardeer in terme van droë‐materiaalproduksie, voedingstowwe (ruproteïn, P, K, Mg en Ca), blaar: stingel verhouding, toename in liggaamsmassa van osse en die ekonomie daarvan. Vier 1 ha kampe is toegeken aan elke stikstofpeil en ‘n wisselweidingstelsel is gevolg met osse van vier rastipes: Brahmankruise, Simmentaler, suiwer Brahman en Britse vleistipe. Die droë‐materiaalproduksie en gewigstoename per hektaar het toegeneem met toename in peil van stikstoftoediening. Massa toename per kop het egter verlaag. Verskille in bruto opbrengs kon nie die verskil in koste tussen die verskillende bemestingspeile uitkanselleer nie. Gevolglik was die netto opbrengs per ha R878 en R788 in die lae en hoe stikstofpeile respektiewelik, terwyl die ekonomiese opbrengs van die ander tussen die twee uiterstes geval het.