Catchment-Sensitive Farming: Tackling Diffuse Water Pollution from Agriculture in England —Policies and Drivers - Water and Agriculture: Sustainability, Markets and Policies - page 271

Table 3. Summary of the perceived main issues contributing to diffuse pollution of nitrates,
total phosphorus, and faecal indicator organisms for the three
farm system types from England and Wales
(adapted from Defra 2005)

DIFFUSE POLLUTANTS

FARM
SYSTEMS

Faecal Indicator
Organisms

Nitrates Total Phosphorus

Nutrient overload and risk of
leaching
1. Inappropriate fertiliser and
manure management
2. Overstocking
3. Maize

Nutrient overload, incidentals
and detachment
1. Soil phosphorus
accumulation
2. Improper manure and
fertiliser management
3. Maize
4.

Transfer of excreta and
manures
1. Improper manure
management
2. Direct defecation to
steams
3. Uncontained losses
from hard standings
and manure heaps

Intensive
grassland 1

Poaching and compaction

Nutrient overload
1. High stocking rates
2. Lack vegetative cover
3. Nutrient hotspots

Increased runoff and
detachment

Increased runoff and
detachment
1. Poaching and
compaction
2. Lack vegetative cover
3. Foraging damaging
soil structure

Outdoor
pigs 2

1. Poaching and compaction

2. Lack vegetative cover

3. Foraging damaging soil

structure

High nutrient inputs and
high hydrological
connectivity

High runoff soils with
high inputs
1. Soil phosphorus
accumulation
2. Inappropriate fertiliser and
manure management
3. Preferential pathways
through cracks and drains

Manure imports

1. Improper manure
storage
2. Inappropriate manure
application
3. Preferential pathways
through cracks and
drains

Arable
systems
(heavy
soils) 3

1. Injudicious fertiliser
applications and manure
management where
relevant
2. High risk crops i.e. rape
3. Preferential pathways
through cracks and drains

1. Intensive grassland — is characterised by being typically overstocked, leading to poaching, soil erosion, manure
management problems and related losses to watercourses. Soils are often subject to nutrient surpluses. Where maize occurs,
leaching and erosion increases.

2. Outdoor pigs — is characterised by high stocking rates and difficulty in maintaining green cover, leading to capped, poached
soils. Nutrient hotspots such as feeding and defecation areas are a problem in terms of surface runoff and leaching losses
through typically light soils.

3. Arable systems (heavy soils) — is characterised by drainage and surface runoff that can lead to rapid movement of pollutants
to water courses by surface and preferential pathways. Surface runoff can also lead to erosion of exposed soils.

Since 2002 55% of England has been designated a Nitrate Vulnerable Zone. Farmers
in this area have been required to follow an Action Programme to comply with the
requirements of the Nitrates Directive. This means that farmers have to: restrict nitrogen
use to crop need, observe closed periods for inorganic and organic nitrogen subject to risk
of run off, observe spreading controls, use appropriate storage to match closed periods
and keep records of nitrogen use.