土壤微生物在枸溶性和聚合态磷肥活化利用中的作用

[目的]如何实现磷肥高效利用是农业生产中亟待解决的重要问题.研究土壤微生物在磷肥形态转化与高效利用过程中的作用及机制,为理解作物-磷肥品种-土壤微生物匹配机制提供科学依据.[方法]盆栽试验选用褐土,速效磷为4.53 mg/kg,供试玉米品种为'郑单958'.试验土壤首先进行高温灭菌和不灭菌处理,然后分别施用磷酸一铵(M...

Effects of soil microorganisms on the utilization of citrate soluble and polymerized phosphorus fertilizers

  【Objectives】  Increasing the efficiency of phosphorus fertilizer utilization is a challenge that requires urgent attention in agricultural production. Here, we researched the role and mechanism of soil microorganisms in the morphological transformation of phosphorus fertilizer and utilization efficiency. We aimed to provide a basis for understanding the matching mechanism between crop-phosphate fertilizer types and soil microorganisms.   【Methods】  Cinnamon low-phosphorus soil (Olsen-Pi =4.53 mg/kg) was used for a pot experiment with maize (Zhengdan 958). The experimental soil was treated with high-temperature sterilization and non-sterilization. Further, monoammonium phosphate (MAP), calcium magnesium phosphate (CMP), and ammonium polyphosphate (APP) fertilizers were applied to the soil at an equal nutrient supply of P 100 mg/kg. Also, a control (CK) without phosphorus fertilizer was set up. After maize harvest, soil pH, Olsen-Pi, alkaline phosphatase activity, dry shoot weight, phosphorus content were measured, and calculation of fertilizer rate was carried out. For each index, the difference between phosphorus fertilizer application and control was termed fertilizer effect, and the difference between unsterilized and sterilized was designated as the microorganism effect.   【Results】  The fertilizer use efficiency in sterilized conditions was MAP>APP>CMP, with a significant difference among the treatments. There was no significant difference (P>0.05) in the fertilizer use efficiency of MAP and APP under unsterilized conditions, and the two treatments recorded higher values than CMP. Plant phosphorus content and rhizosphere Olsen-Pi in CMP treated unsterilized soil increased by 116.3% and 128.0% , compared with the sterilized soil. Similarly, fertilizer utilization rate, aboveground dry weight, plant phosphorus content, and rhizosphere Olsen-Pi in APP treated unsterilized soil increased by 40.7%, 34.2%, 41.2% and 38.2%, compared with the sterilized soil. The rhizosphere ΔpH of unsterilized soil treated with CMP was significantly lower than in sterilized soil. In contrast, compared with CK, the increment of alkaline phosphatase (ALP) activity in unsterilized soil treated with APP was significantly higher than that in sterilized soil.  【Conclusions】  We find that the effects of soil microorganisms on different phosphorus fertilizers varies based on the application rate (100 mg/kg) adopted in this study. Soil microorganisms promote the mobilization of citric-acid soluble phosphate fertilizer (CMP) and polymerized phosphate fertilizer (APP). Water-soluble phosphate fertilizer (MAP) can meet plants phosphorus demand. Therefore, soil microorganisms do not play a key role in mobilizing MAP. An improved understanding of soil-phosphate fertilizer matching technology provides theoretical support to develop microbial regulation techniques for phosphate fertilizer application.