Nitrogen uptake into unfertilized pasture of the willem pretorius game reserve, central orange free state

Abstract

The herbage yield of five main types of grassland in the Willem Pretorius Game Reserve was measured by clipping five 0,5 m² quadrats taken at random within three 10 m² enclosures in each grassland type at approximately monthly intervals from October 1975 to September 1976. The material was separated into green, standing dead and litter fractions, in each of which nitrogen was measured.

Available grazing (sum of green and standing dead) and herbage yield in the whole Reserve were estimated by weighting for the areas of each grassland type.

Nitrogen uptakes were compared with expectation from nitrogen mineralized in incubated surface soils sampled from each enclosure before the first pasture measurement.

Uittreksel

Die plantmateriaal opbrengs van vyf kenmerkende tipes grasveld in die Willem Pretorius Wildtuin is as volg bepaal. Vyf 0,5 m² kwadrate, na willekeur geselekteer binne drie omheinde areas in elke soort grasveldgebied, is met tussen‐poses van min of meer ‘n maand afgesny gedurende die tydperk Oktober 1975 tot September 1976. Vervolgens is die gesnyde gras gesorteer in drie kategorieë nl. groen, droog en strooi en ‘n stikstofontleding uitgevoer.

Beskikbare weiding (die somtotaal van groen plus droog) en plantmateriaal opbrengs van die Wildtuin as ‘n geheel is bereken deur middel van gewigsbepalings ten opsigte van elke afsonderlike soort grasveld.

Stikstofopname is vergelyk met die hoeveelheid beraamde gemineraliseerde stikstof in die geihkubeerde bogrond‐monsters wat in elke kamp versamel is voor die eerste weidingsopname.