Despite of some studies reported that about 50% of the photosynthates were transferred to the soil during the early growth stage of plant, little information is available concerning how the combination or individual effect of organic carbon and mineral nitrogen fertilizer on soil organic carbon derived by rice photosynthesis and the role of these nutrients in paddy soils during different growth stages.

Combining continuous ¹³C labeling method with phospholipid fatty acids (PLFAs) analysis were made by a team of researchers from the Institute of Subtropical Agriculture (ISA) of Chinese Academy of Sciences in cooperation with Georg-August University of Gottingen, Germany.

Scientists study the dynamics of photosynthesis-derived C, microbial communities and priming effect in paddy soil as affected by mineral nitrogen (ammonium sulfate 100 mg N kg-1) and organic carbon (2000 mg C in the form of carboxymethyl cellulose (CMC) kg-1) fertilization in addition to the interaction between them.

Their results indicated that application organic carbon combination with mineral N increased ¹³C assimiulated by shoot (1.39-fold) and decreased that by root (0.75-fold) in comparison to no fertilizer.

They found that the nitrogen and C addition decreased the root biomass and also PLFA biomarker contents for most microbial groups either single or combined application, thereby less ¹³C incorporation into rhizodeposits .

Single application of CMC released portion of Nitrogen stored in Soil organic carbon because of positive N priming effect.

The study entitled "Carbon and nitrogen availability in paddy soil affects rice photosynthate allocation, microbial community composition, and priming: combining continuous ¹³C labeling with PLFA analysis" was published in Plant Soil. Details can be found at https://link.springer.com/article/10.1007/s11104-018-3873-5.

The study was supported by the National Natural Science Foundation of China and Youth Innovation Team Project of CAS, ISA.