Enhanced nitrogen and phosphorus activation with an optimized bacterial community by endophytic fungus Phomopsis liquidambari in paddy soil

Human activity in the Antarctic requires the use of petroleum hydrocarbons as the main energy source for a variety of operations. In the current study, in situ soil microcosms were constructed in the proximity of the Brazilian Antarctic Station Comandante Ferraz, King George Island, South Shetland Islands, to analyse the effect of oil amendment on the indigenous bacterial community in contaminated and uncontaminated sites to assess the potential for bioremediation. Microcosms were sampled for heterotrophic and hydrocarbon-degrader bacterial counts, pH, temperature, moisture, nutrient levels and petroleum hydrocarbons. Total organic carbon, nitrogen and phosphorus contents were generally low in the Antarctic cryosols. According to statistical analysis based on Colony Forming Unit numbers, significant bacterial populations were present in all microcosms, with larger numbers observed in oil amended than in non-amended soils. Aliphatic and aromatic fractions of diesel fuel were detected in the soil microcosms, and significant quantities were removed during the experiment. These results strongly suggest that the cold-adapted bacterial community present in soils around the Brazilian Antarctic station has the potential to adapt and utilize the oil as a carbon source. This knowledge can contribute both to bioremediation technology and the goals of the the Antarctic Treaty which prohibits the introduction of foreign organisms into the region.

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The effects of the depth of fertilization on losses of nitrogen and phosphorus and soil fertility in the red paddy soil of China

PeerJ ◽

10.7717/peerj.11347 ◽

2021 ◽

Vol 9 ◽

pp. e11347

Author(s):

Kun Hou ◽

Ying Huang ◽

Xiangmin Rong ◽

Jianwei Peng ◽

Chang Tian ◽

...

Keyword(s):

Paddy Soil ◽

Ammonia Volatilization ◽

Soil Column ◽

Nitrogen And Phosphorus ◽

Total N ◽

Optimal Depth ◽

Significant Difference ◽

Research Objects ◽

Minimal Environmental Impact ◽

Red Paddy Soil

Nitrogen (N) and phosphorus (P) losses from agroecosystems are dominant nonpoint pollution. To minimize the losses of N and P, the optimal depth of fertilization was explored using a soil column study with the red paddy soil as the research objects. The losses of N and P were measured under five depths of fertilization (0, 5, 7.5, 10, and 12.5 cm) as well as no fertilization. The results showed that ammonia volatilization was significantly decreased with increasing fertilization depth within 0–10 cm, and there was no significant difference among the 10 cm, 12.5 cm, and no-fertilization treatments. Comparing with surface fertilization (0 cm), N and P losses by runoff could be reduced by 30.7–67.1% and 96.9–98.7% respectively by fertilization at 5–12.5 cm. In addition, deep fertilization (5–12.5 cm) did not increase N and P losses by leaching at the depth of 40 cm. Total N and P contents in the tillage layer of soil were increased by 5.1 to 22.8% and by −1.0 to 7.5%, respectively. Fertilization at 10cm depth has the potential to minimal environmental impact in the red paddy soil of south China, at this depth, NH3 volatilization was reduced by 95.1%, and N and P losses by runoff were reduced by 62.0% and 98.4%, respectively, compared with surface fertilization.

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