Model-Based Analysis of the Long-Term Effects of Fertilization Management on Cropland Soil Acidification

Area of Science:

• Agricultural Science
• Environmental Science
• Soil Science

Background:

• Agricultural soil acidification in China is primarily linked to excessive nitrogen (N) fertilizer use.
• Long-term effects of various fertilization strategies on intensive cropland soil acidification remain largely uncharacterized.

Purpose of the Study:

• To develop and validate the VSD+ soil acidification model for intensive agricultural systems.
• To quantify the contributions of nitrogen and base cation fluxes to soil acidification.
• To simulate the long-term impacts of different fertilization practices on soil acidification.

Main Methods:

• Development and validation of the VSD+ soil acidification model using data from three long-term Chinese fertilization experiments.
• Simulation of soil pH and base saturation changes over 20 years (1990-2050).
• Quantification of proton production from nitrogen and base cation fluxes.

Main Results:

• The VSD+ model accurately simulated soil pH and base saturation changes over two decades.
• Nitrate leaching and ammonium input accounted for 80% of proton production under N application.
• Base cation uptake contributed one-third of acid production when N was not applied.

Conclusions:

• Balanced nitrogen application combined with manure application prevents soil pH and base saturation reduction.
• Calcium nitrate and liming applications enhance soil pH and base saturation.
• Optimizing nitrogen management to reduce ammonium input and nitrate leaching, alongside increasing base cation input via manure, are effective strategies for mitigating soil acidification in intensive croplands.