Abstract:
Biosolid applications based on crop nitrogen (N) demand have been widely adopted to attenuate nitrate leaching.
However, due to the dependence of N supply on the mineralization rate and the early release of the majority of
the mineralizable N, there are concerns about a compromise in crop yield and groundwater. A two-year field
lysimeter study was conducted to verify whether higher nitrate leaching from biosolid at the early growth stage
would compromise maize yield compared to a two-split inorganic N fertilizer application. Four treatments
(biosolid + humid rainfall, inorganic fertilizer + humid rainfall, biosolid + subhumid rainfall, inorganic fertilizer
+ subhumid rainfall) replicated three times were randomly allocated to 12 lysimeters. Overall, the cumulative
nitrate leaching from biosolid application was comparable to inorganic fertilization. Nitrate leaching at the
early (V0–V14) growth stage of maize from biosolid was lower than inorganic fertilizer, except in the second year
under humid rainfall. However, nitrate leaching did not compromise maize yield. Thus, biosolid application
based on crop and site specificity can replace inorganic fertilizer in maize cultivation. Further studies may need
to ascertain the findings in the humid agro-ecological zone because of the high soil N residue observed under
biosolid-humid rainfall treatment.
