Temporal and spatial distribution of nutrient resource from livestock and poultry feces and its returning to cropland

Abstract: In recent decades, China's livestock and poultry industry developed rapidly, producing plentiful of livestock and poultry manure and urine. But their quantity, nutrient content, rate of returning to cropland in different regions, and the changes of quantity over time have not been fully understood. In this paper, based on official statistical data and literature reviews, we estimated the quantity of animal feces, nutrient resources and their rate of returning to cropland at provincial level in various time slots. Results showed that, in 1980s, 1990s, 2000s and 2010s, the amount of animal feces (fresh) in China was 27.62×108, 39.11×108, 44.59×108 and 42.34×108 metric tons, respectively, increased by 53.32% in 30 years. The total nutrient N, P and K resources of animal feces in 1980s, 1990s, 2000s and 2010s were 2 523.86×104 t (N 1 249.47×104 t, P2O5 230.64×104 t, K2O 1 043.75×104 t), 3 686.59×104 t (N 1 820.79×104 t, P2O5 327.13×104 t, K2O 1 538.67×104 t), 4 296.77×104 t (N 2 124.13×104 t, P2O5 401.29×104 t, K2O 1 771.35×104 t) and 4 089.40×104 t (N 2 017.66×104 t, P2O5 421.17×104 t, K2O 1 650.57×104 t), increased by 62.03% in 30 years and Northeast China had the greatest increase. About 40% of China total amount of animal feces and the corresponding nutrients was derived from Henan, Sichuan, Shandong, Hunan, Yunnan and Inner Mongolia. The ratio of specific animal feces and nutrients in China was in the sequence of cow > pig > sheep > poultry > horse > donkey > mule, but varied in different regions. Northwest China, Southwest China and Northeast China had the higher proportions of cow feces and the corresponding nutrients, the Middle Lower Reaches of the Yangtze River had the highest proportion of pig feces and the corresponding nutrients, the Northwest China had the highest proportion of sheep feces and the corresponding nutrients, the Southeast China had the highest proportion of poultry feces and the corresponding nutrients. The ratios of feces and the corresponding nutrient quantity from horse, donkey and mule were relatively small in various regions. In 1980s, 1990s, 2000s, 2010s the total amount of nutrient N, P and K returning to cropland reached 1 132.73×104, 821.36×104, 1 860.52×104 and 1 709.19×104 t, respectively, accounting for 44.88%, 22.28%, 43.30% and 41.80% of total resources, respectively. About 50% of the total nitrogen, phosphorus and potassium nutrient returning to cropland from animal feces was occurred in Hebei, Henan, Shandong, Hunan, Inner Mongolia, Sichuan, Yunnan and Guangxi. By 2010s, N, P2O5, K2O from animal feces returned to cropland was 615.91×104, 297.70×104 and 795.58×104 t, accounting for 30.53%, 70.68% and 48.20% of the total quantity, respectively. This investigation can provide scientific basis and reference for the rational utilization of nutrient resources from animal feces and nutrient management under zero growth of chemical fertilizer in different provinces or regions in China.