5
Pastureland Conservation Practices
Soil and Water Effects
1. A 6-year comparison of nitrate leaching from
grass/clover and N-fertilized grass pastures grazed by
sheep.
Cuttle, S. P.; Scurlock, R. V.; and Davies, B. M. S.
Journal of Agricultural Science 131(1): 39-50. (1998)
NAL Call #: 10 J822; ISSN: 0021-8596
Descriptors: grazing/ pastures
Abstract: Nitrate leaching was measured over a 3-year
period from rotationally grazed perennial ryegrass (Lolium
perenne L.) pasture receiving 200 kg fertilizer-N/ha and
from similarly grazed ryegrass/white clover (Trifolium
repens L.) pasture that received no N fertilizer. The results
are discussed together with those from the same plots in
the preceding 3 years when. they were stocked
continuously. Under both managements, the numbers of
grazing sheep were adjusted on the basis of the quantity of
herbage available on the plots. During the whole 6 years,
mean nitrate concentrations in soil water collected by
porous cup samplers remained below the European Union
limit of 11.3 mg N/l except for the fertilized grass plots in
year 5 of the study. Quantities of nitrate leached ranged
from 6 to 34 kg/ha per year from the grass/clover plots and
2-46 kg/ha from the fertilized plots. Leaching losses from
both types of pasture were positively correlated with the
numbers of lamb grazing days in the later part of the
grazing season. This relationship and the high spatial
variability associated with the measurements indicated that
N derived from excreta was the main source of leached
nitrate. It was concluded that, where pastures of equal
productivity are compared, similar quantities of N are likely
to be leached from grass/clover swards as from grass
swards receiving N fertilizer.
© The Thomson Corporation
2. Acidification under grazed annual and perennial
grass based pastures.
Ridley, A. M.; Slattery, W. J.; Helyar, K. R.; and Cowling, A.
Australian Journal of Experimental Agriculture 30(4):
539-544. (1990)
NAL Call #: 23 Au792; ISSN: 08