Earthworm (Eisenia fetida) Mucus Inspired Bionic Fertilizer to Stimulate Maize (Zea mays L.) Growth

Abstract

Background: Increasing population and food consumption are placing unprecedented demands on crop production. Maize is one of the most important food crops in the world, the improvement of its yield primarily depends on the application of chemical fertilizer. Methods: Earthworm activity is an essential factor in promoting soil fertility and stimulating plant growth. Inspired by amino acids composition of earthworm (Eisenia fetida) epidermal mucus, the liquid fertilizer was developed and prepared by utilizing a bionic approach. The influence of earthworm epidermal mucus (mucus), the mucus-mimicked mixture of amino acids (bionic fertilizer) and urea fertilizer (urea) on maize emergence and growth were studied and compared with the control group (distilled water). Experimental cultivation tests were conducted. The aforementioned three types of liquid fertilizer effects on maize seed vigor index, seedling emergence rate and plant quality were quantitatively evaluated. Results: Based on the conducted research, it was found that the beneficial effects of different fertilizers for maize emergence rate were ranked as follows: mucus > bionic fertilizer > urea. The low concentration treatments were beneficial to the maize emergence, while the high concentration treatments were helpful to the maize growth and root development. Besides, the lower concentration of mucus was the most effective fertilizer treatment for improving seedling quality. In addition, the test results of three types of liquid fertilizer effects on maize growth indicated that the higher concentration treatments provided more nitrogen nutrition than lower concentration treatments. Furthermore, the maize stem height and diameter were significantly promoted (p < 0.05) by the three types of liquid fertilizer. The beneficial influences of liquid fertilizer treatments for plant height, stem diameter, relative chlorophyll content and photosynthetic characteristic of leaves were ranked as follows: bionic fertilizer > urea > mucus. Conclusions: Bionic fertilizer demonstrated significant beneficial fertilizing effects (p < 0.05), which increased soil nutrients, improved maize physiological parameters, promote its growth and improved dry matter accumulation. The tested results verified the effectiveness of bionic fertilizer on stimulating maize growth.