Recycling paper to recarbonise soil.

Soil organic carbon can be increased through sympathetic land management and/or directly by incorporating carbon rich amendments. Herein, a field experiment amended paper crumble (PC) to soil at a normal deployment rate of 50 t ha ^-1 , and at higher rates up to 200 t ha ^-1 . The nominal 50 t ha ^-1 PC amendment resulted a mean increase in soil carbon of 12.5 g kg ^-1 . Using a modified Roth-C carbon fate model, the long-term (50 years) carbon storage potential of a 50 t ha ^-1 PC amendment was determined to be 0.36 t _{O C} ha ^-1 . Modelling a rotational (4 yearly) 50 t ha ^-1 PC amendment indicated 6.65 t _{O C} ha ^-1 uplift would accrue after 50 years. Contextualised for the average farm in the East of England (~120 ha, with 79 % as arable), PC derived increases in SOC would be equivalent to 2310 t CO ₂ e. These results support the use of PC to deliver significant levels of soil recarbonisation. Beyond carbon, PC was observed to influence other soil properties. Benefits observed included, decreased bulk density, increased water holding capacity, and increased cation exchange capacity. While PC amendment did not significantly increase wheat (Triticum aestivum) crop yield, manifold benefits in terms of increased SOC, long-term carbon storage potential, and improved soil quality sustain PC as a beneficial soil conditioner.
Competing Interests: Declaration of competing interest Brian Reid reports financial support was provided by Research England.
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