Data from: Soil functions are amplified along increasing planting densities via nutrient trade-off driven by rhizobacteria in drought-prone environment

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.