Data from: Soil functions are amplified along increasing planting densities via nutrient trade-off driven by rhizobacteria in drought-prone environment
Abstract
It is unclear how plant growth-promoting rhizobacteria (PGPR) affect soil multifunctionality (SMF) and production function (SPF) along planting densities. To address this issue, Bacillus licheniformis (PGPR) was inoculated in maize fields with five planting densities (D1–D5 from low to high) in the drought-prone region of the Yunnan Plateau, southwest China, from 2022 to 2023. Data indicated that under non-inoculation (CK), SMF tended to increase from D1 to D4 (p<0.05) and then stabilize in D5 across two growing seasons. Yet, SPF was observed to elevate steadily with increasing densities. PGPR inoculation significantly improved SMF (0.129) and SPF (0.508) under increasing planting densities. Meanwhile, soil carbon and phosphorus cycling indices significantly improved by 0.272 and 0.069 (p<0.05), respectively, whereas no significant change was observed in the nitrogen cycling index (p>0.05), relative to CK. Increased carbon cycling index was significantly associated with improved soil soluble organic carbon (2.26%) concentration, and enhanced carbon-related extracellular enzyme activities (9.57%). Similarly, phosphorus-related extracellular enzyme activity significantly increased by 10.51% (p<0.05). Interestingly, no significant changes were observed in the levels of soil total nitrogen, ammonium nitrate,n and nitrate nitrogen, and the activities of nitrogen-related enzymes across planting densities. The above-mentioned phenomenon can be mechanistically explained by the variations in rhizosphere microbiomes, and the accelerated carbon exchanges with nitrogen/phosphorus, which amplified SMF for higher SPF by reshaping the nutrient trade-off in the plant-soil-microbe system through PGPR-enhanced microbial activity.
Dataset DOI: 10.5061/dryad.t76hdr8dv
Description of the data and file structure
During harvest in both maize growing seasons, destructive sampling was performed in every plot, and three soil cores per plot were pooled to create a composite sample. For the first set, rhizosphere soil adhering to fresh maize roots at a depth of approximately 20 cm was gently brushed off with sterile fine nylon brushes and tweezers. All samples were immediately placed in a portable low-temperature freezer and subsequently transferred to a laboratory freezer for storage. Soil bacterial community samples were preserved at –80 °C for two weeks. In parallel, samples for the determination of soil microbial biomass carbon and nitrogen and enzyme activities were stored at –20 °C for one week to ensure sample stability (Ren et al., 2021). A second set, representing bulk soil, was collected with a 5 cm diameter auger at the same depth between plants in each plot. After passage through a 2 mm sieve, the bulk soil was air-dried for subsequent determination of physicochemical properties.
Files and variables
File: DATA.csv
- Year: Year of cultivation
- Number: Sample index
- Inoculation PGPR: Plant Growth-Promoting Rhizobacteria (Bacillus licheniformis) inoculation treatment, non-inoculated (CK), inoculated (PGPR)
- Planting densities: Maize planting densities were D1 (40,950 plants·ha⁻¹), D2 (50,505 plants·ha⁻¹), D3 (58,275 plants·ha⁻¹), D4 (65,880 plants·ha⁻¹), and D5 (75,765 plants·ha⁻¹)
- pH: Soil pH
- SWS: Soil water storage (mm)
- SOC: Soil organic carbon (g·kg⁻¹)
- DOC: Dissolved organic carbon (mg·kg⁻¹)
- TN: Total soil nitrogen (g·kg⁻¹)
- NO₃⁻-N: Nitrate nitrogen (mg·kg⁻¹)
- NH₄⁺-N: Ammonium nitrogen (mg·kg⁻¹)
- AP: Available phosphorus (mg·kg⁻¹)
- MBC: Soil microbial biomass carbon (mg·kg⁻¹)
- MBN: Soil microbial biomass nitrogen (mg·kg⁻¹)
- BG: β-1,4-glucosidase (nmol·g⁻¹·h⁻¹)
- CB: Cellulase (nmol·g⁻¹·h⁻¹)
- LAP: Leucine aminopeptidase (nmol·g⁻¹·h⁻¹)
- NAG: β-1,4-N-acetylglucosaminidase (nmol·g⁻¹·h⁻¹)
- PHOS: Acid phosphatase (nmol·g⁻¹·h⁻¹)
- Plant Biomass: aboveground + belowground maize biomass (t·ha⁻¹)
- Yield: Maize yield (kg·ha⁻¹)