The invention belongs to the field of recycling of agricultural wastes and production of organic fertilizers, and provides a
calcium-
magnesium-rich
organic fertilizer for macadimia nut gardens as well as a preparation method and application thereof, and the
calcium-
magnesium-rich
organic fertilizer is prepared from the following raw materials in parts by
dry weight: 100 parts of macadimia nut green peels, 25-50 parts of
phosphate tailings, 10-20 parts of oil cakes, 3-5 parts of
charcoal and 1.4-2.8 parts of a compound
microbial agent. The components contained in the
organic fertilizer have a synergistic effect, insoluble
phosphorus,
calcium and
magnesium nutrients contained in the
phosphate tailings are dissolved by
organic acid generated by degrading organic matters of the
macadamia nut green peels and the oil cakes, and the added
biochar provides a
carbon source for microorganisms, intercepts the nutrients and adsorbs heavy
metal elements in the
phosphate tailings, so that the yield of the phosphate tailings is increased. And a compound
microbial agent is inoculated to promote the composting process, so that resource recycling is realized, the
orchard is fed back, the production cost is low, the environmental
pollution is reduced, the problems of lack of trace elements and low
organic matter content in the existing
orchard soil are effectively solved, and the
fertilizer retention capacity of the soil is improved, thereby improving the yield and fruit quality of Australian fruit trees.