Plants and microbes' responses to the net nitrification rates of chemical fertilizers in soils

摘要

Various types of chemical fertilizers are used in agricultural production in Bangladesh. However, plants and microbes' responses to the nitrification activity of chemical fertilizers are unknown. The goal of this study was to determine the responses of plants and nitrifying archaea/bacteria and comammox amoA Nitrospira inopinata bacteria to the net nitrification rates (NNRs) of chemical fertilizers in four vegetable soils. The abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), and comammox amoA N. inopinata was determined by q-PCR. The NNRs ranged from 2.96 +/- 0.39 to 10 +/- 1.19 mg kg(-1) h(-1) and were significantly higher (p < 0.05) in the vegetable soils than in the control soils (uncultivated soils). Temperature and pH influenced the NNRs. The abundance of comammox amoA N. inopinata ranged from 9.34E+05 to 4.55E+06 per gram dry soil in the vegetable soils and represented 28 to 72% of the nitrifying amoA genes. Among the vegetable soils, the highest NNRs and abundance of comammox amoA N. inopinata were found in Phaseolus vulgaris soils. The abundance of AOA, AOB, NOB, and comammox amoA N. inopinata was significantly (p < 0.05) higher in the vegetable soils compared to control soils and was correlated positively and significantly with the NNRs. Principal component analysis (PCA) results confirmed the distinct variation present among the vegetable soils according to their components. Finally, it may be concluded that the plants and nitrifying archaea/bacteria, as well as comammox amoA N. inopinata, can also have indirect/direct effects on the nitrification activity of chemical fertilizer among vegetable soils.