Alkalinity exacerbates phosphorus deficiency in subtropical red soils: Insights from phosphate-solubilizing fungi |
| |
Authors: | Mu Su Jiajie Mei Gilberto de Oliveira Mendes Da Tian Limin Zhou Shuijin Hu Zhen Li |
| |
Affiliation: | 1. College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China;2. Laboratório de Microbiologia e Fitopatologia, Instituto de Ciências Agrárias, Universidade Federal de Uberlândia, Monte Carmelo, Minas Gerais, Brazil;3. Anhui Province Key Lab of Farmland Ecological Conservation and Pollution Prevention, School of Resources and Environment, Anhui Agricultural University, Hefei, China Engineering and Technology Research Center of Intelligent Manufacture and Efficient Utilization of Green Phosphorus Fertilizer of Anhui Province, College of Resources and Environment, Anhui Agricultural University, Hefei, China;4. College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China Department of Entomology & Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA |
| |
Abstract: | Red soils in subtropical regions are often low in available phosphorus (P), a vital plant nutrient. Phosphate-solubilizing microorganisms (PSMs) can release P from phosphate reservoir, making it accessible to plants. However, the complex interactions between PSMs and minerals in red soils are not yet fully understood. In this study, we investigated the effects of Aspergillus niger, a typical phosphate-solubilizing fungus (PSF), on phosphate dissolution in two representative red soils – an acidic soil and an alkaline soil. In the acidic red soil, the fungal abundance reached 3.01 × 10 7 cfu g−1 after a 28-day incubation period, with respiration of ~2000 mg C kg−1. The secretion of oxalic acid promoted P release from inorganic phosphate (from ~1 to 187 mg kg−1). Additionally, the contents of amorphous Fe/Al oxides decreased, which otherwise could have contributed to P sorption in the soil. In contrast, P availability declined in the alkaline red soil after the addition of A. niger, regardless of the P source (inorganic or organic phosphate). Meanwhile, the fungal respiration decreased to ~780 mg C kg−1. Therefore, alkaline red soils with abundant carbonates are susceptible to P deficiency due to both the diminished function of PSMs and strong soil buffering. These findings have important implications for sustainable agriculture on alkaline red soils, as they suggest that the use of PSMs to improve P availability may be limited. |
| |
Keywords: | alkalinity, phosphate Fe oxide phosphate-solubilizing fungi red soil |
|
|