Nitrogen transformation data in rice-faba bean systems
Description
This dataset contains raw and processed data from a long-term field experiment on organic substitution management (OSM) in rice-faba bean rotations in Yunnan, China. It includes: Crop yields and nitrogen recovery efficiency (NRE) for rice and faba bean seasons (2018–2022) across five treatments: CK (no fertilizer), CF (100% chemical N), OF1 (20% organic + 80% chemical N), OF2 (60% + 40%), OF3 (100% organic N). Soil properties (0–20 cm depth): total N, available N, NH4+-N, NO3--N, microbial biomass N. Nitrogen transformation rates from 15N-labeled incubations (2022): mineralization, nitrification, immobilization under saturated/unsaturated conditions. Metagenomic data: abundances of N-cycling genes from soil samples.
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This dataset was generated from a long-term field experiment initiated in 2015 at the Songming Agricultural Environment and Soil Observation and Research Station, Yunnan Province, China (25°21′N, 103°06′E; 1,920 m altitude). The site features a subtropical highland monsoon climate (avg. 15.5°C, 1,100 mm precipitation) and Anthrosols soil (loamy: 19% sand, 32% silt, 49% clay). A rice-faba bean rotation was used, with five fertilization treatments in a randomized complete block design (3 replicates, 15 plots of 6×10 m each, separated by cement walls): CK (no fertilizer), CF (100% chemical N), OF1 (20% organic N + 80% chemical N), OF2 (60% + 40%), OF3 (100% organic N). Total N rates: 150 kg/ha (rice), 75 kg/ha (faba bean); P2O5: 300/150 kg/ha; K2O: 150/112.5 kg/ha. Chemical fertilizers: urea, calcium superphosphate, potassium sulfate. Organic: rapeseed oil cake. Rice (Yun Geng 37) transplanted April, harvested October; faba bean (Yundou 459) sown October, harvested April. Flooding irrigation for rice; drip irrigation for faba bean in November/February. Crop yields (2018–2022) were measured by harvesting aboveground biomass at maturity, drying at 80°C, and calculating dry matter. Nitrogen recovery efficiency (NRE) used Eq. (1): NRE = [(NU - N0)/NF] × 100, where NU/N0 = N uptake in fertilized/CK, NF = N applied. Nitrogen use efficiency (NUE) followed OECD (2013) balance method, accounting for inputs (fertilization, deposition, fixation, irrigation) and outputs (biomass removal). Soil properties (0–20 cm) and N transformation rates (2022) involved sampling at harvests, sieving (<2 mm), and storing at 4°C. For rates, 20 g soil incubated at 60% (unsaturated) or 100% WHC with 15NH4NO3/NH415NO3 (60 mg N/kg each, 10.2 atom% 15N) at 25°C for 96 h. Extracts analyzed for NH4+/NO3- via continuous flow analyzer (AA3, Bran+Luebbe, Germany); 15N via isotope ratio mass spectrometer (Delta V Advantage, Thermo Scientific, USA). Rates calculated per Davidson et al. (1991) Eqs. (5–6). For N-cycling genes, soil DNA extracted using FastDNA Spin Kit (MP Biomedicals, USA), quantified via Nanodrop ND-1000 and gel electrophoresis. Sequencing: 150 bp paired-end on Illumina HiSeq 2000 (Shanghai Majorbio). Processing: adapters removed with SeqPrep, quality-filtered with Sickle; assembly via Megahit (k-mer 21–53); quality via Quast; ORFs via Prodigal; genes identified against NCycDB (Tu et al., 2019). Statistical analyses used R 4.0.3: ANOVA/Tukey HSD (emmeans), regression (ggplot2/ggpmisc), PLS-DA (ropls), PLS-PM (plspm).
Institutions
- Yunnan Academy of Agricultural SciencesYunnan, Kunming