Nitrogen mineralization potentials in three tropical soils treated with biosolids

Area of Science:

• Soil Science
• Environmental Science
• Agronomy

Background:

• Biosolids application is a common practice for soil amendment.
• Understanding nitrogen (N) mineralization kinetics is crucial for sustainable agriculture.
• Tropical soils have unique characteristics influencing nutrient cycling.

Purpose of the Study:

• To assess the impact of different biosolids (anaerobic and aerobic) on soil N mineralization in tropical soils.
• To determine the N mineralization kinetics (N0 and k) in treated soils.
• To evaluate the safety of biosolids application rates concerning nitrate accumulation.

Main Methods:

• Incubation of three tropical soils (Lt, Cp, Ca) with anaerobic biosolids (DS) and aerobic biosolids (MS) at 10, 50, and 100 Mg ha(-1) for 48 weeks.
• Measurement of accumulated N mineralized over time.
• Kinetic modeling using first-order kinetics and nonlinear least squares equations.

Main Results:

• N mineralization in biosolids-treated soils followed first-order kinetics.
• Aerobic biosolids (MS) showed significantly higher N mineralization potential (N0) than anaerobic biosolids (DS).
• N mineralization rates (k) varied, with MS generally exhibiting higher rates than DS.
• Limited organic N remained available for mineralization after 48 weeks.

Conclusions:

• Aerobic biosolids offer greater N supply potential for plants compared to anaerobic biosolids in tropical soils.
• Current biosolids application rates are deemed safe for Taiwanese vegetable production, as they do not lead to excessive nitrate accumulation.
• Further research into long-term effects and specific crop N demands is warranted.