Nitrogen Transformations in Broiler Litter-Amended Soils

Abstract EN

Nitrogen mineralization rates in ten surface soils amended with (200 μg N g-1 soil) or without broiler litter were investigated.

The soil-broiler litter mixture was incubated at 25±1C° for 28 weeks.

A nonlinear regression approach for N mineralization was used to estimate the readily mineralizable organic N pools (N0) and the first-order rate constant (k).

The cumulative N mineralized in the nonamended soils did not exceed 80 mg N kg-1 soil.

However, in Decatur soil amended with broiler litter 2, it exceeded 320 mg N kg-1 soil.

The greatest calculated N0 of the native soils was observed in Sucarnoochee soil alone (123 mg NO3 − kg-1 soil) which when amended with broiler litter 1 reached 596 mg N kg-1 soil.

The added broiler litter mineralized initially at a fast rate (k1) followed by a slow rate (k2) of the most resistant fraction.

Half-life of organic N remaining in the soils alone varied from 33 to 75 weeks and from 43 to 15 weeks in the amended soils.

When N0 was regressed against soil organic N (r=0.782**) and C (r=0.884***), positive linear relationships were obtained.

The N0 pools increased with sand but decreased with silt and clay contents.