Development of a multiplicative model to explore how biological nitrogen fixation responses to multiple edaphic factors in paddy soils.

Various sole edaphic factor has been screened as controlling factor for paddy biological nitrogen fixation (BNF), however, no single factor can interpret different results from different experiments. Paddy BNF might be influenced by several factors simultaneously at various degrees, but we still lack a model to predict BNF as a function of multiple edaphic factors. Developing this model will help us to estimate BNF based on soil properties and improve policy decisions to enhance paddy BNF. In this paper, 27 paddy soil samples with different soil properties were collected from the southwest to the northeast in China. These soils with rice plantations were incubated for 77 days in an airtight, transparent, and ¹⁵N₂ enriched growth chamber to measure BNF. Results showed that BNF amounts ranged from 0.66 to 12.3 kg ha^-1 and had a lognormal distribution. A multiplicative model was developed, the R code and raw data were deposited in this project. This multiplicative model could explain 86% variance of the BNF in various soils. In each site, the controlling factors were screened and corresponding measures to enhance BNF were proposed. Our study provided a systematic framework on how BNF responded to a range of edaphic factors simultaneously in paddy soils, and this work might also give inspiration for the study of other ecological functions.