Organic water-retaining substrate for eucalyptus nursery stocks as well as preparation method and application of organic water-retaining substrate

The invention belongs to the technical field of organic substrates, and particularly discloses an organic water-retaining substrate for eucalyptus seedlings as well as a preparation method and application of the organic water-retaining substrate. The organic water-retaining substrate for the eucalyptus seedlings comprises the following raw material components in parts by weight: 50-60 parts of eucalyptus bark and sawdust, 5-10 parts of pine bark, 5-10 parts of a fertilizer, 3-5 parts of a modifier, 1.5-2 parts of a fermentation inoculant and 1.5-2 parts of a functional inoculant, wherein the modifying agent is prepared from biochar and hydroxyapatite, and the functional microbial agent is prepared from nitrogen-fixing bacteria, trichoderma, glomus mosseae and phosphate solubilizing bacteria. The invention also provides a corresponding preparation method and application of the water-retaining substrate. The water-retaining matrix not only can play an effective water-retaining role, but also can provide nutriti