Bentonite clay with different nitrogen sources can effectively reduce nitrate leaching from sandy soil

Area of Science:

• Soil Science
• Environmental Science
• Agronomy

Background:

• Nitrate (NO3-1) leaching from soils degrades soil fertility, reduces crop yields, and pollutes water sources.
• The impact of bentonite clay on nitrate leaching with different nitrogen fertilizers in sandy soils requires further investigation.

Purpose of the Study:

• To investigate the effects of bentonite clay (0, 2, and 4%) on nitrate leaching from sandy soils.
• To compare nitrate leaching under three nitrogen sources: calcium nitrate, ammonium chloride, and urea.

Main Methods:

• A lysimetric study was conducted using sandy soil treated with bentonite and nitrogen fertilizers.
• Nitrate leaching was measured from soil treated with varying bentonite concentrations and nitrogen sources at 300 kg N ha-1.

Main Results:

• Bentonite significantly reduced nitrate release in leachate, with 4% bentonite showing the highest soil nitrate retention.
• Nitrate leaching varied by nitrogen source: calcium nitrate > ammonium chloride > urea.
• Early leaching showed higher nitrate with ammonium chloride and calcium nitrate, while urea showed increased leaching later.

Conclusions:

• Soil amendment with bentonite is an effective strategy to mitigate nitrate leaching in sandy soils.
• Bentonite application helps prevent nitrogen fertilizer loss and reduces groundwater contamination.
• Understanding nitrogen source behavior is crucial for managing nitrate leaching in amended soils.