2025-01-16 イリノイ大学アーバナ・シャンペーン校
＜関連情報＞
- https://aces.illinois.edu/news/gene-edited-soil-bacteria-could-provide-third-source-nitrogen-corn-production
- https://acsess.onlinelibrary.wiley.com/doi/10.1002/agj2.21729
トウモロコシの肥料需要を補うための窒素固定細菌の土壌接種 Soil inoculation with nitrogen-fixing bacteria to supplement maize fertilizer need
Logan P. Woodward, Connor N. Sible, Juliann R. Seebauer, Frederick E. Below
Agronomy Journal Published: 28 November 2024
DOI:https://doi.org/10.1002/agj2.21729
Abstract
Nitrogen (N) is an essential plant nutrient, but low and variable plant-available N levels in agricultural soils often limit maximum grain production. The objective of this study was to determine if a free-living nitrogen-fixing bacterial inoculant (NFI) could supply biologically-fixed N as an additional N source and if this enhances maize (Zea mays L.) N uptake and grain yield. Maize was grown at four site-years in Illinois during 2019–2021. The NFI, a mixture of edited Klebsiella variicola and Kosakonia sacchari, was applied in furrow at planting with urea-N rates from 0 to 225 kg N ha−1. Using quadratic regression models, across N rates, the NFI supplemented the fertilizer-N equivalent of 38.5 or 12.1 kg N ha−1 at V8 or R1, respectively. Increases in N accumulation were observed in all plant fractions, and δ15N abundance measurements confirmed that some of this additional N was derived from biological N fixation. The NFI treatment increased N accumulation by an average of 4.8% and 3.7% at V8 and R1, respectively, which was the result of greater biomass, with no effect on plant N concentration. Application of NFI resulted in an average of 1.5% more kernels m−2 and 0.11 Mg ha−1 more grain yield. This work reveals that NFI can provide an additional source of N for maize production but identifies that the season-long benefit of fixed-N from an NFI is yet to be fully optimized.
Plain Language Summary
Nitrogen is often the most limiting nutrient for increased maize yields, but extra fertilizer may be lost to waterways and the air. Nitrogen-fixing bacterial inoculants can convert nitrogen from the air into a usable form in the soil near the plant roots. Yet, maize plants need nitrogen at certain times and amounts to be useful to grow and make yield. We wanted to know if a nitrogen-fixing bacteria inoculation mix can replace some reliance on fertilizer, when maize takes up this nitrogen and where it goes in the plant, and if grain yield changes. Supplying the inoculant at planting in combination with low rates of fertilizer (45–135 kg nitrogen ha−1) increased maize vegetative growth, nitrogen accumulation, kernel number, and yield (on average 0.11 Mg ha−1 more yield) and was equal to 12–38 kg nitrogen ha−1 of fertilizer. This nitrogen-fixing inoculant mix added to the nitrogen fertilizer, mostly early, for small, but significant, increases in maize plant growth and yield.
