The invention relates to a biological
organic fertilizer which can effectively solve the problem of reducing environmental
pollution, improving soil and increasing
crop yield. A method for preparing the biological
organic fertilizer comprises the following steps: crushing
crop straw into 1-5cm sections, putting the crushed
straw into a
cracking device, and
cracking at a temperature of 300-1100 DEG C so as to obtain
biomass straw charcoal; crushing the
biomass straw
charcoal, sieving with a 60-100-mesh
sieve so as to obtain
biomass straw
charcoal powder; in a
sunlight greenhouse with a temperature of 19-25 DEG C, uniformly mixing the biomass straw carbon
powder with
biogas residues, adding a biological
deodorant, fermenting for 7-10 days under the condition of ventilating, turning over the obtained object, and further fermenting for 7-10 days to obtain a blocky mixture; and crushing the blocky mixture, sieving the mixture by using a 40-mesh
sieve, adding
bentonite (as a forming aid), a
nitrogen fertilizer, a
phosphate fertilizer and a
potash fertilizer, spraying a
pyroligneous acid in an atomized mode while stirring, uniformly mixing, and powdering or granulating, thus obtaining the biological
organic fertilizer. The biological organic fertilizer disclosed by the invention is prepared from abundant raw materials, is low in cost, easy to produce, convenient to use, and good in effect, and can effectively reduce the environment
pollution, improve soil, and increase
crop yields, therefore, the biological organic fertilizer has huge economic and
social benefits.