Nitrogen Use Efficiency and Herbage Production of an Established Grass Sward in Relation to Moisture and Nitrogen Fertilization

Effect of N fertilizer source and timing on yield and N use efficiency of rainfed maize (Zea mays L.) in Kashmir–Pakistan

“…In the plots where NO 3 − -N was added as the N source, DMY was 1760-1870 kg ha −1 , N recovery efficiency was 24%-43%, while in NH 4 + -N added plots, both DMY and N recovery efficiency were increased to 3190-3700 kg ha −1 , and 39%-48%, respectively (Abbasi et al, 2005). The effect of N fertilizer forms or sources on the growth, yield and NUE of maize under field conditions had not been reported extensively.…”

The response of date palm to calcareous soil fertilisation

“…These growing conditions are similar to those of the Zaghloul palms investigated by the present study. The differences in plant yield responses to the various forms of N fertiliser are due primarily to differences in the N losses from the soil rather than to differences in the N assimilated (Abassi et al, 2005).…”

A decision tree approach to modelling nitrogen fertiliser use efficiency in New Zealand pastures

“…The mechanisms underlying this better N response in August/September are not clear. However, it may be attributed to some or all of the following factors: (1) the combination of favourable temperature and soil moisture during the August/September period encourage fast pasture growth which in turn increase N use efficiency (Abassi et al 2005;Smith et al 2000); (2) plant available N in soil is very low in early spring due to the low rate of N mineralization (Bolan et al 2004), and (3) N leaching during this period is lower than in other seasons due to the rapid plant uptake and immobilisation by soil microbial biomass (Ledgard 1989;Ledgard et al 1983).…”

“…8, 14.2, 37.4, 28.5 and 7.1% of the total dataset, respectively. As pasture mainly responds to N fertiliser input in the first 40-50 days and may have some residual effect in the next 30-40 days (Abassi et al 2005;Smith et al 2000), we chose 80 days as a standard period for this normalisation. A second reason for choosing 80 days was that the bulk of the NFUE data corresponded to a measurement period of between 60 and 100 days.…”

“…The NFUE in pasture systems is commonly measured as the amount of forage DM produced for each unit of applied N (kg DM/kg N) (Eckard 1998;Zemenchika and Albrecht 2002), and thus is also referred to as the magnitude of pasture response to N fertiliser. This magnitude is dependent on the severity of the N shortage in the soil, pasture species composition, climate, N fertiliser application rate, soil type and other factors that influence plant growth (Abassi et al 2005;Cassman et al 2002;Ledgard et al 1983;Mundy 1999;Zemenchika and Albrecht 2002). In previous field trials, measured NFUE has ranged from negative to more than 40 kg DM/kg N, but usually it falls between 5 and 15 kg DM/kg N (Mundy 1999;Smith et al 2000;Zhou et al 1993).…”