Nutrient resource quantity of animal manure and its utilization potential in China

Objectives Combined application of inorganic and organic fertilizations can enhance productivity of agricultural ecosystem and improve health of soil ecosystem, and that is also necessary for the sustainable agriculture. Clarifying the quantity of manure and the contained nutrient resources in China is the prerequisite for making full use of manure resources, improving fertilizer use efficiency, achieving zero growth of chemical fertilizers and ensuring national food security.

Methods The research focused on manures from draft ox, beef cow, draft cow, sheep, horse, donkey, mule, pig, rabbit and poultry in China. The involved crops were rice, wheat, corn, soybeans, potatoes, peanuts, rape and cotton. Based on agricultural statistics and the data published in literatures, the amounts of manure and the contained nutrient resources were estimated in 2015, the quality of organic fertilizers applied to different crops in different regions and the percentages of manure nutrients for substitution of chemical fertilizers were calculated.

Results The manure resource in China was about 3158.4 million tons in 2015, the contained nitrogen (N), phosphorus (P₂O₅) and potassium (K₂O) nutrient resources were 14.78 million tons, 9.01 million tons and 14.54 million tons, respectively. The largest manure was from pigs, followed by beef cows and draft cows, accounting for 36.8%, 24.8% and 9.9%, respectively. The largest manure nutrient resources was from pigs, followed by beef cows and sheep, accounting for 28.2%, 22.8% and 15.0%, respectively. The highest quantity of animal manures and manure nutrient resources were respectively in Southwest and Northcentral of China, accounting for 22.3%, 21.5% and 21.3%, 21.9%, respectively. The applied amounts of nitrogen, phosphorus and potassium from manures were 8.12 million tons, 8.57 million tons, 8.50 million tons, accounting for 37.3% (N), 87.6% (P₂O₅) and 65.9% (K₂O) of chemical fertilizers, respectively, when all the animal manure was returned to field.

Conclusions The amount of animal manure and the contained nutrient resources are enormous, and there is great potential of returning to field in China. Making full use of animal manure nutrient resources may replace chemical N, P and K input by rate of 37.3% (N),87.6% (P₂O₅) and 65.9% (K₂O).