Loading...
An assessment of the long-term effects of three phosphorus fertiliser regimes on soil phosphorus and sward condition.
Citations
Altmetric:
Date
1999-04-01
Collections
Files
Loading...
eopr-4231.pdf
Adobe PDF, 537.77 KB
Research Projects
Organizational Units
Journal Issue
Citation
Culleton, N., Murphy, W.E., Carton, O., Cuddihy, A., An assessment of the long-term effects of three phosphorus fertiliser regimes on soil phosphorus and sward condition, End of Project Reports, Teagasc, 1999.
Abstract
A grazing trial using beef animals (mean weight 260 kg) was used
to determine optimum soil phosphorus levels for dry stock farming.
· The trial commenced in 1968. There were three fertiliser P
treatments, 0, 15 and 30 kg P/ha applied annually. There were
two stocking rates, 3300 and 2400 kg liveweight at turn out,
respectively. Animals were rotationally grazed around six
paddocks per treatment and stocking rates were reduced in June
and September to match feed supply. The trial continued until
1998.
¸ Nitrogen was applied at a rate of 220 kg/ha per year to all
treatments.
¹ Liveweight gains/ha/year were monitored annually. Soil P levels
were monitored by sampling to 10 cm depth.
º The distribution of phosphorus in the soil was recorded by
analysing P levels at various depths from 0-2 mm to 100 cm.
Botanical composition was recorded at the commencement of the
trial and again in 1997. Phosphorus levels in herbage were also
recorded.
» An analysis of the liveweight gain data showed that for optimum
output a Soil Index of 3 (Morgans P between 6.1 and 10.0 mg/l) is
the target Soil P Index.
¼ Phosphorus recovery (as expressed by percentage of P fertiliser
recovered in product) in the P30 treatments was low and was
better in the P15 treatments.
½ The vast bulk of P accumulated near the surface of the soil, but
there was some evidence of movement down the profile in the P30
treatment over a 30 year period. The soil P status influenced both the botanical composition of the
sward and the P content in the herbage. The perennial ryegrass
content declined on the zero P treatment, while there were no
significant differences between the P15 and P30 treatments. The P
concentration in the herbage in the zero P treatments were not
sufficient for healthy growth of plants or animals.