Effects of Liquid Organic Fertilizers on Plant Growth and Rhizosphere Soil Characteristics of Chrysanthemum

Organic fertilizers are generally thought to be an effective way to sustain soil fertility and plant growth. To promote the productivity of chrysanthemum, five sources of liquid organic fertilizers (L1–L5), as well as a chemical fertilizer, were applied at an early stage of the growth cycle to investigate their effects on plant growth. In the short-term pot experiment, the liquid organic fertilizers significantly promoted root and aboveground growth by 10.2–77.8% and 10.7–33.3%, respectively, compared with the chemical fertilizer. The order of growth promotion was: L1 (shrimp extracts) > L2 (plant decomposition) > L4 (seaweed extracts)/L5 (fish extracts) > L3 (vermicompost). Morphological and chemical analyses indicated that, compared with other organic fertilizers, the treatment with shrimp extract (L1) produced the greatest increases in root dry weight, total length, surface area, volume, tips, and thick root length, respectively. Furthermore, the shrimp extract treatment significantly increased the nutrient contents and altered the soil’s functional microbial community at the rhizospheric level compared with the chemical fertilizer treatment. Thus, the shrimp extract liquid organic fertilizer could be part of an effective alternative to chemical fertilization during the early stage of chrysanthemum growth.