New Zealand Journal of Agricultural Research abstracts
Assessment of best management practices to minimise the runoff of
manure-borne phosphorus in the United States
Andrew Sharpley
Peter Kleinman
Jennifer Weld
USDA-ARS
Pasture Systems and Watershed Management Research Unit
Curtin Road, University Park
PA 16802-3702, USA
email: Andrew.Sharpley@ars.usda.gov
Abstract Phosphorus (P), an essential nutrient in
crop and livestock agriculture, can cause and accelerate freshwater
eutrophication. Intensification of farming systems has resulted in
local accumulations of P in some agricultural watersheds with related
increases in P runoff. In most cases, continual land application of
manure at rates exceeding crop P removal is the proximate cause of P
runoff. To mitigate associated water quality impairments, P-based
agricultural best management practices (BMPs) are now becoming a part
of farm nutrient planning. This planning involves the selection,
timing, and implementation of source and transport BMPs at field, farm,
and watershed scales. Source measures include balancing P imports and
exports, improved livestock feed management, chemical and physical
treatment of manures, appropriate rate, method, and timing of land
application based upon regular soil and manure testing, adequate manure
storage and transport infrastructure, and composting. Transport
measures aim to reduce runoff and erosion via practices such as
conservation tillage, contour ploughing, and vegetative filter strips.
To be effective, these measures must be carefully selected and targeted
to areas at greatest risk to P loss. This vulnerability can be
identified and ranked by P indices, which account for source and
transport factors controlling P loss. We demonstrate that the P Index
can provide flexible yet reliable manure management and provide farmers
with options to minimise the risk of P loss from several farms in
Pennsylvania, United States. Overall, a comprehensive and holistic
approach to manure management can decrease P transfers from land to
water.
Keywords eutrophication; leaching; non-point
source pollution; risk assessment; soil conservation; surface runoff;
watersheds
A04025; Received 16 April 2004; accepted 18 August 2004; Online
publication date 15 December 2004
New Zealand Journal of Agricultural Research, 2004, Vol. 47:
461–477
0028–8233/04/4704–0461 © The Royal Society of New Zealand 2004
PDF file of entire paper: Print-quality
(2354K) | screen-quality (837K)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
