wAbstract
@Lime was investigated as a soil amendment to decrease phosphorus
(P) loss in runoff from two Delaware sandy loam soils, one high
and one low in P. Soils were limed at three rates (control and
target pH values of 6 and 6.8, respectively), packed into runoff
boxes (2,000 cm2) and received simulated rainfall (80
mm h-1 for 30 min). Lime showed potential to decrease
P loss in runoff, but its effectiveness was soil specific and
dependant on other management factors also. Lime decreased dissolved
reactive P (DRP) and dissolved organic P (DOP) loss by 20-25 and
52-93“, respectively, for the high-P soil and particulate P (PP)
by 13“ for the low-P soil. The majority of P lost in runoff was
DOP (3-29“) or PP (64-96“). Lime increased PP losses from the
finer-textured soil following P application, indicating that increased
P sorption can lead to increased losses if P is sorbed to more
erodable particles. Initial soil P status was more important than
liming in determining P loss. While amendments may decrease P
losses in the short term, addressing nutrient imbalances at the
field scale is clearly necessary in the long term. Losses increased
significantly following inorganic P application. Although P was
sorbed rapidly, with less than 2“ of added P removed in runoff,
mean concentrations in excess of 700 ƒÊg l-1 DRP, 2,500
ƒÊg l-1 OP and 6,500 ƒÊg l-1 PP were recorded
for both soils immediately following P application.
Keywords: Phosphorus; Lime; Phosphorus source measure; Phosphorus
loss in runoff; Organic phosphorus; Soil pHx
1. Introduction
2. Materials and methods
@2.1. Soil characterisation
@2.2. Runoff experiment
@2.3. Statistical analysis
3. Results
@3.1. P solubility and soil chemistry
@3.2. P mobility in runoff
4. Discussion
@4.1. Dissolved reactive P
@4.2. Dissolved organic P
@4.3. Particulate P
5. Conclusions
Acknowledgements
References