3. Soil Health-Definition
A healthy soil would ensure proper retention &
release of water & nutrients, promote & sustain
root growth, maintain soil biotic habitat,
respond to management, resist degradation &
act as a buffer for environmental pollution
(Brevik & Sauer 2015).
4. Concept of soil health
Healthy soil is an essential component of a
healthy environment,
It is the foundation upon which sustainable
agriculture is built..
In simplest terms, soil health or soil quality
can be defined as the ‘fitness of soil for use”.
Fnctions include biological productivity of
soil, maintaining quality of surrounding air &
water & promote pt, animal & human health.
It emphasizes the integration of biological
with chemical & physical measures of soil
quality that affect farmers profit & the
environment.
5. Soil Quality
It is the capacity of a specific kind of soil to
function within ecosystem & land-use boundaries
SQ is to sustain biological productivity,
SQ is to protect/maintain environmental quality
SQ is to sustain plant, animal & human health
(Doran and Parkin, 1994).
6. Soil Quality vs Soil Health
SQ is usefulness for a particular purpose over
a long time scale, equal to static soil quality.
SQ is related to soil function
SH as state of a soil at particular time,
equivalent to the dynamic soil properties that
change in short time.
7. Sustain biological productivity
Store & cycle water & nutrients
Decompose OM
Inactive toxic compounds
Suppress pathogens
Protect water quality
Production of food & fibre
Functions of Healthy soil
8. protect the soil surface & low erosion rates
high soil OM ; high biological activity &
biological diversity
high avail. moisture storage capacity
favourable soil pH; deep root zone
balanced stores & supply of avail. Nutrients
resilient & stable soil structure,
adequate internal drainage
favourable soil strength and aeration
favourable soil temp.
Properties of Soil Health
9. low levels of soil born pathogens
low levels of toxic substances;
good soil tilth; sufficient depth
large population of beneficial org.
low weed pressure
resistant to degradation
10. Ideal soil quality indicators should be
well correlate with ecosystem processes
integrate soil physical, chemical & biological
properties & processes
accessible to many users;
sensitive to management & climate
components of existing databases;
interpretable
11. Measure of Soil Health
Governed by a number of
physical, chemical and
biological attributes and
processes.
Expressed by different
quantitative and qualitative
measures of these attributes
as also by outcomes that are
governed by the soil such as
productivity, nutrient and
water use efficiencies and
quality of produce.
SOIL
HEALTH
INDICATORS
CHEMICAL
ENVIRONMENT
ORGANIC
MATTER
BIOLOGICAL
ENVIRONMENT
PHYSICAL
ENVIRONMENT
12. SQ or its capacity to function, is evaluated
using inherent & dynamic soil properties.
These properties serve as indicators of soil
function because it is difficult to measure
function directly & observations may be
subjective.
Soil Quality Measurement
13. i. Physical Indicators :
Physical indicators are related to arrangement of
solid particles & pores. Ex. Soil depth, bulk density,
porosity, aggregate stability, texture, crusting &
compaction.
They primarily limits the root growth, seedling
emergence, infiltration & affect crop performance
through various soil physical parameters:
BD, Texture, WHC & sub-surface hard pan etc.
Soil physical properties also influence the soil water
& plant-water relationships.
14. Physical indicators used for
determining soil health
Phy. Indi. provide information about soil hydrologic
characteristics, such as water entry & retention, that
influences availability of water to plants.
Some indi. are related to nutrient availability by
their influence on rooting volume & aeration status.
Other measures tells us about erosional status.
That indicators include measures of:
15. Aggregate Stability
Available Water Capacity
Hydraulic conductivity
Bulk Density
Infiltration
Slaking
Soil Crusts
Soil Structure and
Macropores
16. 1. Aggregate stability:
It refers to the ability of soil aggregates to
resist disintegration when disruptive
forces associated with tillage & water or
wind erosion are applied.
Wet aggregate stability suggests how well
a soil can resist raindrop impact & water
erosion.
Dry aggregate stability can be used to
predict resistance to abrasion & wind
erosion.
17. 2. Available water capacity:
AWC is the water held in soil between its
field capacity & permanent wilting point.
It is an indicator of a soil’s ability to retain
water & make it sufficiently available for
plant use.
3.Bulk Density :
It is the dry weight of soil divided by its
volume.
It is an indicator of soil compaction, ability
to function for structural support, water &
solute movement & soil aeration.
18. 4. Infiltration :
It is the downward entry of water into the
soil
It is an indicator of the soil’s ability to allow
water movement into & through the soil
profile.
Soil temporarily stores water, making it
available for root uptake, plant growth &
habitat for soil organisms.
19. 5. Slaking :
when the soil aggregates are suddenly immersed in water,
the breakdown of larger sized (>2.5 mm) air-dry soil
aggregates into smaller sized (<0.25 mm) micro-aggregates
is called as ‘Slaking’.
Slaking indicates the stability of soil aggregates,
resistance to erosion.
6. Soil Crusting :
A surface crust indicates poor infiltration, a problematical
seedbed and reduced air exchange between the soil and
atmosphere.
It can also indicate that a soil has a high Na content that
increases soil dispersion when it is wetted by rainfall or
irrigation.
21. ii. Chemical indicators
pH, salinity, organic matter, phosphorus concentration,
CEC, nutrient cycling and concentration of elements.
Decrease in soil pH increases solubility of elements such
as Al, Zn, Cu & Fe. At pH value < 5.5 induces toxicity of
these ions.
These chemical condition of soil affects soil-plant
relation, water quality, buffering capacity, availability of
nutrients & water to plants & other organisms, mobility
of contaminants & tendency to form crust.
Soil chemistry & its influence on the availability of
nutrients to plants play a key role in soil quality.
22. Chemical indicators used for determining soil health
Chemical indicators give information about the equilibrium
between soil solution (soil water, nutrients) & exchange sites (clay
particles, OM);
These indicators include measures of:
Soil organic carbon
Soil soluble salts (EC)
Soil nitrate & other macro & micronutrients
Soil reaction (pH)
