[Effects of selenium fertilization on selenium availability in rice soil.]

Area of Science:

• Agricultural Science
• Soil Science
• Environmental Chemistry

Background:

• Selenium (Se) availability is limited in acidic South China rice soils.
• Understanding Se fertilizer impact on soil Se dynamics is crucial for crop nutrition.

Purpose of the Study:

• To investigate how Se fertilizer affects Se availability in rice rhizosphere and non-rhizosphere soils.
• To analyze Se transformation and translocation within rice plants.

Main Methods:

• Field study comparing Se-fertilized and unfertilized rice soils.
• Analysis of various soil Se fractions (water-soluble, exchangeable, bound, residual).
• Measurement of Se migration coefficients and plant Se concentrations.

Main Results:

• Se application increased rice yield and Se concentration.
• Rhizosphere soil showed lower Se content in most fractions compared to non-rhizosphere soil.
• Se translocation improved from leaves to grains, but not from roots to leaves.
• Organic acid secretion varied with Se application rates and did not significantly alter rhizosphere pH.

Conclusions:

• Se fertilizer application leads to Se fixation in soil, reducing its availability for rice.
• Applied Se primarily converts to less accessible forms in the soil.
• Organic acid secretion's role in enhancing Se availability is complex and not solely pH-dependent.