Soil Com­paction: Facts and Fig­ures

It is par­tic­u­lar­ly hard to assess the dam­age caused by com­paction in deep­er soil lay­ers. But research data and sta­tis­tics indi­cate a con­sid­er­able impact on agri­cul­tur­al pro­duc­tiv­i­ty.

LONG-TERM LOSS OF YIELD OF COMPACTED AREAS COMPARED WITH NON-COMPACTED REFERENCE AREAS

In Reck­en­holz, Switzer­land, a study by the Swiss Agro­scope Insti­tute and ETH Zurich is inves­ti­gat­ing the long-term effect of soil com­paction on pro­duc­tiv­i­ty. In 2014, tri­al areas were com­pact­ed under wet soil con­di­tions with a machine weight of 32 t and high tyre pres­sure in order to be able to mea­sure yield changes in the course of crop rota­tion. In addi­tion, the oxy­gen and CO2 con­tent, water and gas exchanges and bio­log­i­cal activ­i­ty in the soil were inves­ti­gat­ed in sub­se­quent years. The results show that the soil has not recov­ered sev­er­al years after com­paction. Loss­es in yield remain con­sis­tent. This is due on the one hand to sub­soil com­paction, which can hard­ly be influ­enced by machines, and on the oth­er hand to the top­soil, which has not regen­er­at­ed in four years despite repeat­ed plough­ing.

 

 

FACTORS INFLUENCING COMPACTION


 
Axle load


 
Num­ber of
pass­es on the field


 
Soil mois­ture


 
Soil pres­sure in
con­tact area


 
Num­ber and
type of tyres


 
Soil type
and struc­ture

 

 

COMPACTION IN DEEPER SOIL LAYERS IS HARD TO MANAGE

Using wider tyres, total load can be almost dou­bled with­out increas­ing soil pres­sure on the sur­face. How­ev­er, the pres­sure reach­es much fur­ther down.

 

Total weight of machin­ery

300 t

Total weight of machin­ery used in a bio­gas crop rota­tion over three years.

 

 

SOIL DEGRADATION FROM COMPACTION (MILLION HA)

33Europe10Asia4Aus­tralia18Africa3Amer­i­c­as

 

 

Com­paction risk of Euro­pean soils

36 %

Per­cent­age of Euro­pean soils with
high or very high com­paction risk.

Sources: FAO, Inra, Europäis­che Umwelt­a­gen­tur, Thomas Keller / Agro­scope, Ter­ran­i­mo, North­ern Illi­nois Uni­ver­si­ty, Bio­gas Forum Bay­ern