Crop residue management

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Contents

Theory

Soil physics

Leaving crop residue after harvest in the field can improve the soil structure. The hydraulic conductivity of the soil remains higher than when the crop residue is plowed under, since the root canals remain intact, and no additional cultivation, possibly resulting in compaction, is needed. A higher bulk soil hydraulic conductivity allows better infiltration of rains or pre-plant irrigation for the following season. A higher infiltration amount and deeper water infiltration could result in a more efficient leaching of salts from the root zone, with subsequent storage of salts below the root zone.

Evaporation

Leaving soil residue on the soil surface would create a mulching layer, thus reducing the actual soil evaporation. This mulching layer would reduce the loss of stored soil water, and reduce the upward flow of water through the root zone. A reduction of upward soil water fluxes would reduce salts moving back into the root zone.

Capillary rise

In the presence of shallow groundwater (1-2 m below soil surface) a higher soil hydraulic conductivity could result in higher capillary rise. Capillary rise, or the movement of water from the saturated zone to the unsaturated zone, can result in a large mass of salts moving into the root zone, especially during the fallow period. [1]

Soil chemistry

The presence of crop residue adds organic matter to the soil. This has the effect that .... [to be added]


Applications and results

Tanzania

In Tanzania, a newly cultivated farm was split into two sections. In one section, crop residue remained in the field, while the other section was plowed after harvest. The effect was that.... [Source: Eng. Ahmad Moravvej]


References

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