A 6-year comparison of nitrate leaching from grass/clover and N-fertilized grass pastures grazed by sheep

1998 ◽  
Vol 131 (1) ◽  
pp. 39-50 ◽  
Author(s):  
S. P. CUTTLE ◽  
R. V. SCURLOCK ◽  
B. M. S. DAVIES
Keyword(s):  
European Union ◽  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Nitrate Leaching ◽  
White Clover ◽  
N Fertilizer ◽  
The European Union ◽  
Fertilizer N ◽  
Leaching Losses ◽  
High Spatial Variability

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.

Leys and soil organic matter:III. The accumulation of macro-organic matter in the soil under different swards

1972 ◽  
Vol 78 (2) ◽  
pp. 333-341 ◽  
Author(s):  
E. A. Garwood ◽  
C. R. Clement ◽  
T. E. Williams
Keyword(s):  
Organic Matter ◽  
Soil Carbon ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Arable Land ◽  
N Fertilizer ◽  
Plant Debris ◽  
Total Soil ◽  
Grazed Swards ◽  
Mesh Sieve

SUMMARYMacro-organic matter (roots and partially decomposed plant debris retained on a 0·25 mm mesh sieve) was measured in soils under various swards. Under a grazed perennial ryegrass/white clover sward, sown on arable land, macro-organic matter in the top 15 cm of soil rose steadily in the first 8 years to 15·8 t/ha, but subsequently declined. Under arable cropping there was great variation with crop and season. Under grass, most of the macro-organic matter accumulated in the top 2 cm of soil, particularly during the first 3 or 4 years. More macro-organic matter was found under perennial ryegrass/white clover than under cocksfoot/white clover swards.After 3 years under grass macro-organic matter accounted for 10% of the total soil carbon, and represented about half the increase in soil carbon.Half, or less, of the nitrogen which accumulated in soil under grass was in the macroorganic matter fraction. The differences between swards which received no N fertilizer and those which received 940 kg/ha over 3 years was small, 16–40 kg N/ha respectively for cut and frequently grazed swards. The ratio of C:N in macro-organic matter under different swards averaged 22:1.

scholarly journals Nitrate leaching and N2-fixation in grasslands of different composition, age and management

2004 ◽  
Vol 142 (2) ◽  
pp. 141-151 ◽  
Author(s):  
J. ERIKSEN ◽  
F. P. VINTHER ◽  
K. SØEGAARD
Keyword(s):  
Perennial Ryegrass ◽  
Nitrate Leaching ◽  
Dry Matter ◽  
Grazing Intensity ◽  
Dry Matter Production ◽  
Leaching Losses ◽  
N Removal ◽  
Matter Production ◽  
Over Time

Grass-legume associations may offer a way of improving the N efficiency of dairy farming, but may also have an adverse impact on the environment by increasing leaching losses. Nitrate leaching from four cropping sequences with different grassland frequency and management (long-term grazed, long-term cut, cereals followed by 1 and 2-year grazed leys) were investigated on a loamy sand in central Jutland for both unfertilized grass-clover (perennial ryegrass (Lolium perenne L.)/white clover (Trifolium repens L.)) and fertilized perennial ryegrass (300 kg N/ha) swards during 1997–2002. Furthermore, 1 year (2001) of N2 fixation in 1-, 2- and 8-year-old grass-clover pastures was determined. Nitrate leaching from grazed unfertilized grass-clover was always considerably lower than from grazed fertilized ryegrass. The effect of grassland age on nitrate leaching was insignificant in grass-clover but clear in grazed ryegrass, where levels increased dramatically with sward age. In production years 6–8, leaching from grass-clover was only 9–13% of the comparable losses from ryegrass. Under the cutting regime grass-clover showed a significant reduction in both yield and N-removal with increasing sward age, whereas for ryegrass these figures did not show any decreasing trend. N2 fixation was lower in 8-year-old swards compared with fully established 2-year-old swards as a consequence of lower dry matter production, lower clover content and a lower proportion of clover-N derived from the atmosphere. The results from the present study indicate that the higher leaching losses observed in fertilized grass compared with unfertilized grass-clover systems were caused by (1) a reduction in N2-fixation in grass-clover over time and (2) a reduction in dry matter production in grass-clover over time, lowering the grazing intensity and the recycling of grassland N via animal excreta.

The effects of red clover (Trifolium pratense var. redhead), white clover (Trifolium repens var. S 100) or perennial ryegrass (Lolium perenne var. S 23) on the reproductive performance of sheep

1973 ◽  
Vol 80 (2) ◽  
pp. 323-327 ◽  
Author(s):  
J. E. Newton ◽  
J. E. Betts
Keyword(s):  
Litter Size ◽  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Reproductive Performance ◽  
White Clover ◽  
Trifolium Pratense ◽  
Red Clover ◽  
The Third ◽  
S 100 ◽  
The Mean

SummaryDuring 3 years, three groups of 20 Scottish half-bred ewes were grazed on perennial ryegrass, white clover or red clover. During this period the two legumes were oestrogenic, in terms of teat-length extension of wethers, but the perennial ryegrass was not. The white clover was only markedly oestrogenic when there was a high proportion of diseased leaves. The mean litter size and lambing percentage of the ewes grazed on red clover was significantly reduced. White clover, although it was oestrogenic, had no effect on mean litter size or lambing percentage. The mean litter size of the ewes on the perennial ryegrass was 2·35, 2·30 and 2·24, on the white clover was 2·20, 2·33 and 2·23 and on the red clover was 1middot;60, 1·67 and 1·78 for the three lambings. Lambing percentage of the ewes on the perennial ryegrass was 175, 225 and 218, on the white clover was 210, 222 and 189, and on the red clover was 160, 128 and 118 for the three lambings. The lambing date of the ewes grazing on the red clover was significantly later at the third lambing.

Some effects of canopy height on perennial ryegrass and white clover in a field sward

1985 ◽  
Vol 105 (1) ◽  
pp. 79-84 ◽  
Author(s):  
D. Wilman ◽  
S. K. Shrestha
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Trifolium Repens ◽  
Lower Proportion ◽  
Canopy Height ◽  
N Content ◽  
Fixed Area ◽  
Leaf Extension ◽  
Dead Tissue

SUMMARYEight canopy heights, maintained by weekly cutting, were compared during summer and early autumn on a perennial ryegrass (Lolium perenne L.)-white clover (Trifolium repens L.) sward.Perennial ryegrass adapted to a taller canopy by increasing the length of its leaf blades much more than it increased the length of its leaf sheaths, and by increasing the length of its blades proportionately more than their width. White clover adapted by increasing the length of its petioles much more than it increased the length of its leaflets. Canopy height did not affect the number of ryegrass leaves emerging or dying per tiller or the number of live, emerged leaves maintained by a tiller. The amount of herbage harvested at the weekly cuts was largely unaffected by canopy height once the swards had adapted to the particular management. Leaf blades in the taller canopies, therefore, lost a much lower proportion of their length to defoliation than those in the shorter canopies. Consequently, the length of blade dying per tiller per week was more strikingly affected by canopy height than was the rate of leaf extension. The increasing amount of material lost by death with increasing canopy height was confirmed by the weights of senescent and dead tissue collected weekly from a fixed area in each plot. Herbage in the lower compared with the upper layers of the taller canopies was much less digestible and lower in N content.

Effects of chitin amendment of soil on microorganisms, nematodes, and growth of white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.)

1996 ◽  
Vol 22 (3) ◽  
pp. 221-226 ◽  
Author(s):  
S. U. Sarathchandra ◽  
R. N. Watson ◽  
N. R. Cox ◽  
M. E. di Menna ◽  
J. A. Brown ◽  
...  
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Trifolium Repens ◽  
Lolium Perenne L ◽  
Trifolium Repens L
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