Loss of nitrogen from maturing plants

Abstract

Loss of nitrogen from maturing subterranean 'clover and soft brome plants was measured in both field and pot experiments. In subterranean clover, nitrogen loss commenced after seed setting. In soft brome grass, the loss began at flowering and continued until senescence. Nitrogen loss from herbage may be due to translocation to burrs and seeds, to leaching by rain and dew or to volatilization to the air. The practical implications of this nitrogen loss in terms of animal production are discussed.

Nitrogen and Phosphorus Dynamics and Budgets in Annual Grasslands

“…During the period from PSC until the June 1973 harvest date, 14% of the N and 12% of the P were apparently lost from the system (Tables 1 and 2). Although we might assume that N was volatilized as NH3 (Lapins and Watson 1970), no such gaseous loss pathway exists for P. Therefore, we suggest that the decrease during the very dry periods of late May and June may have been caused by disintegration and loss of plant parts during sampling and processing and therefore does not represent a real loss from the ecosystem.…”

“…Rossiter (1966) estimated that seeds contained 10% of the aboveground biomass in a grazed pasture at the end of the season. Other pathways for loss of N and P from tops might be by translocation of N and P to roots (an unlikely process in annual range plants) and by volatilization of NH3 from senescing plant parts (Lapins and Watson 1970). Neither of these processes appeared to be important during the late spring periods.…”