Heavy machinery weighing over 1.5-2.5 tons can cause soil compaction by exerting pressures over 12 pounds per square inch. This compaction destroys the soil's crumb structure, reduces porosity and macropores, and increases bulk density. As a result, the soil's infiltration rate decreases, saturated hydraulic conductivity decreases, water stable aggregates are destroyed, and aeration porosity is reduced. Overall, soil compaction decreases the soil's ability to conduct water and air, reducing microbial activity and the availability of nutrients to plants. The negative impacts of compaction tend to be greater for black soils and fine-textured soils compared to red soils and coarse-textured soils.

1. 1

2. UNIVERSITY OF AGRICULTURALSCIENCES
BENGALURU
College of Agriculture
Hassan
NRM 403-FARM MECHANIZATION
2

3. IMPACT OF HEAVY
MACHINERIES ON SOIL
PROPERTIES
3

4. Heavy machinery……..?
Machinery having minimum weight of 1.5-2.5 ton.
Or exerting a pressure of 12 PSI on soil
4

5. Granular or crumby structure is preferred for agriculture.
Due to compaction crumby structure is destroyed, platy structure is formed.
Total porosity of the soil and macropores are reduced due to compaction.

6. Bulk density of the soil increases by using heavy machineries due to compaction of soil.
Normal bulk density of soil -1.3 g/cm3
6

7. Due to loss of MACROPHORES the infiltration rate decreases.
In normal soil infiltration rate 10-20 mm/hr.
In compacted soil infiltration rate is less than 5 mm /hr.
So runoff water increases.
normal compacted
7

8. Unsaturated hydraulic conductivity increases
Saturated H.C. decreases
Easiness with which water moves in the soil
8

9. Water stable aggregates are destroyed due to compaction , so the rain splash will disperse
the aggregates. The fine particles will block the pores and upon drying forms the crust.
Both surface and subsurface crusts are formed.
9

10. Due to destruction of macropores the aeration
porosity of the soil is reduced , it leads to
reduced soil aeration.
Carbon dioxide will accumulate in the soil.
Oxygen diffusion rate decreases.
10

11. WATER HOLDING CAPACITY OF SOIL
Water holding capacity of the soil reduced due to compaction by decrease in porosity.
A small amount of rain may cause saturation or flooding.
11

12. Due to increase in runoff water and loss of water stable aggregates the soil erosion by water increases
12

13. Thermal conductivity of soil increased due to compaction.
It is due to closer arrangement of soil particles.
Heat movement in the soil will be rapid.
Temperature regulation of soil is altered.
13

14. Compaction will decrease the overall activity of soil microbes.
Anaerobes are dominated in compacted soil.
Mineralization of nutrient is reduced.
Denitrification loss will be increased.
Activity of Earthworms , Nematodes are reduced due to
poor aeration.
Root growth will be restricted.
14

15. IMPACT ON
The overall capacity of soil to supply nutrient to plants is reduced.
Plant will suffer from multinutrient deficiency.
Depleted fertility is due to poor structure of soil , reduced aeration
and water holding capacity and reduced biological activity of soil.
15

16. Red soil v/s Black soil
In short run impact of heavy machineries will be high in Black soil.
But in long run impact will be high in red soils because they are
Irreversibly damaged every year.
16

17. Coarse texture v/s Fine texture
Fine textured soil will suffer more from compaction than coarse textured soil.

18. 1.Application of organic manure to soil. 2.Residue incorporation in the soil.
18

19. 3.Field operations at optimum soil moisture content
4.Follow a permanent path for movement of machineries
19

20. REFERENCES
1.SOIL PHYSICS - ARUN KUMAR SAHA
2.NATURE AND PROPERTIES OF SOIL- N.C. BRADY
3. IMAGES-INTERNET
20

21. THANK YOU
21