Microbiological attributes, organic carbon, and soil hydrothermal regime under Copernicia prunifera waste application

 This study aimed to verify the effects of the application of carnauba waste on the biological attributes, organic carbon content, and hydrothermal regime of soil.

The experiment was performed in randomized blocks with six treatments and four replicates. The treatments were as follows: (1) NPK (recommended dose of synthetic fertilizers: 100:180:86 kg ha-1 NPK); (2) surface application of 10 t ha-1 carnauba waste; (3) incorporation of 10 t ha-1 carnauba waste; (4) surface application of 10 t ha-1 carnauba waste + NPK; (5) incorporation of 10 t ha-1 carnauba waste + NPK; and (6) bare and unfertilized soil (control).

 Treatments that received carnauba waste showed higher amounts of organic carbon, carbon accumulation, microbial biomass, and CO2 in the surface layer of the soil, from 0.0 to 0.10 m, compared to control treatments. Although there was no difference in the respiration rates between the treatments, the metabolic quotient tended to decrease in the treatments that received carnauba waste. Treatment with carnauba waste resulted in a decreased soil bulk density in the surface layer. Soil covered with carnauba waste maintained higher soil moisture and lower temperatures. Multivariate analysis showed that applying carnauba waste with NPK to the soil surface significantly affected soil quality attributes.

 The use of carnauba residue combined with fertilizer can improve the microbiological attributes of the soil, increase the organic carbon content in the soil, and reduce thermal amplitude, which can help maintain higher levels of moisture in the soil.