Fertilizer Addition Modifies Utilization of Different P Sources in Upland Rice on Strongly P-fixing Andosols

Area of Science:

• Agricultural Science
• Plant Physiology
• Soil Science

Background:

• High phosphorus (P) efficiencies, including internal P utilization efficiency (PUE) and P acquisition efficiency (PAE), are critical for upland rice, especially in P-fixing soils like Andosols.
• While root traits for PAE are studied, the source of P (native soil vs. fertilizer) in relation to P efficiency is less understood.

Purpose of the Study:

• To evaluate the efficiency of different upland rice genotypes in acquiring both native soil-P and fertilizer-P.
• To investigate how P fertilization levels influence the uptake of native soil-P and fertilizer-P.

Main Methods:

• Four upland rice genotypes were cultivated in Andosols under low and high P fertilization levels.
• Fertilizer-P was labeled with 33P to differentiate P uptake from native soil and fertilizer sources at 9 and 34 days post-emergence.

Main Results:

• Increased fertilizer supply enhanced native soil-P uptake across genotypes.
• Under low-P conditions, DJ123 demonstrated superior PAE and native soil-P acquisition, while AB199 showed higher PUE.
• Genotype DJ123 acquired significantly more native soil-P per root unit than other genotypes, particularly under high-P conditions.

Conclusions:

• Genotypic variations in PAE are linked to the ability to access native soil-P.
• Genotype DJ123 is highly effective at acquiring sparingly soluble native soil-P.
• Further research into rhizosphere processes is needed to understand enhanced PAE of native soil-P.