NOVELTY - Production of boron sludge carbonized nutrient soil involves mixing and extruding boron sludge carbonized nutrient soil raw material containing boron sludge, attapulgite, waste activated clay, peat, bentonite, zeolite, crushed waste, vermiculite and water, carbonizing sheet-shaped particles at 250-450 degrees C for 30-90 minutes in a rotary carbonization furnace, spraying water in the furnace, granulating obtained carbonized semi-finished nutrient soil with moisture content of 25% or less, sterilizing obtained soil particles, drying, cooling obtained soil, and packaging.    USE - Production of boron sludge carbonized nutrient soil used for planting flowers and plants, and nursery-grown plants.    ADVANTAGE - The method enables production of nontoxic odor-free boron sludge carbonized nutrient soil with high quality, fertilizer efficiency and water retention capacity.    DETAILED DESCRIPTION - Production of boron sludge carbonized nutrient soil involves mixing and extruding boron sludge carbonized nutrient soil raw material into sheet-shaped particles having thickness of 8 mm or less, carbonizing sheet-shaped particles at 250-450 degrees C for 30-90 minutes in a rotary carbonization furnace, spraying water in the furnace using high-pressure water spray nozzle, obtaining carbonized semi-finished nutrient soil with moisture content of 25% or less, granulating carbonized semi-finished nutrient soil to particle diameter of 6-12 mm and particle length of 6-20 mm, sterilizing obtained soil particles at low temperature, drying at 60-100 degrees C for 30-90 minutes, cooling obtained soil having moisture content of 20% or less, and packaging. The boron sludge carbonized nutrient soil raw material comprises 15-55 wt.% boron sludge, 10-30 wt.% waste activated clay, 5-25 wt.% peat, 0-20 wt.% attapulgite, 0-15 wt.% bentonite, 2-15 wt.% zeolite, 5-15 wt.% crushed waste, 0.5-5 wt.% vermiculite and 5-45 wt.% water. The boron sludge carbonized semi-finished nutrition soil comprises 45-75 wt.% boron sludge carbonized soil, 5-25 wt.% water retting system wastewater, 0.2-10 wt.% diammonium phosphate, 0.5-5 wt.% expanded perlite, 0.5-8 wt.% ferrous sulfate, 0.1-5 wt.% superabsorbent and 0-35 wt.% water. The water retting system wastewater comprises 35-75 wt.% crushed waste and 25-65 wt.% water, and is prepared by immersing crushed water in water, and performing water retting process for 10-30 days.