Abstract: 【Objective】Northeast China is an important commodity grain base and the place of animal husbandry production in China. The mass production of farming and animal husbandry products influences the trend of nutrient flow, and the nutrient flow in different areas exists some differences. To make clear the characteristics of nutrient flow in different areas, and to reveal their problems, the reasonable and optimal strategy for different flow characteristics was put forward, which will provide a theoretical basis for nitrogen and phosphorus nutrient management in regional farming and animal husbandry system.【Method】With statistical data and literatures collection from 1984 to 2014 taking the farming and animal husbandry system in the three provinces of Northeast China as the research object by NUFER model (nutrient flows in food chain, environment and resources use). The flow and loss of nitrogen and phosphorus in the farming and animal husbandry system in each province were estimated. And the comprehensive evaluation of nitrogen and phosphorus nutrient utilization, loss path and utilization efficiency in each province was made. the trends and characteristics of nitrogen and phosphorus flow in thefarming and animal husbandry system were studied.【Result】In 1984, the total nitrogen input of the farming and animal husbandry in Jilin, Liaoning, Heilongjiang area was 669, 746 and 716 Gg, respectively. the total phosphorus input of them was 121, 222 and 169 Gg, respectively. In 2014, the total nitrogen input increased to 1 899, 1 572 and 2 256 Gg; and the phosphorus input reached 471, 393 and 769 Gg in the areas, respectively. The input amounts of nitrogen and phosphorus nutrients were as follows: Heilongjiang＞Jilin＞Liaoning. The loss rates of nitrogen nutrition in Jilin area and phosphorus nutrition in Liaoning area were the highest. The recycling rate of nitrogen and phosphorus was the highest in Jilin, and the lowest in Liaoning. In the past 30 years, the nitrogen use efficiency of farm system in Jilin, Liaoning and Heilongjiang decreased by 10%, 11%, and 32%, respectively. The use efficiency of phosphorus decreased by 16%, 2% and 23%, respectively. In the livestock and poultry production system, the utilization of nitrogen nutrient increased by 3%, 11% and 10%, respectively; and the utilization of phosphorus content increased by 0.8%, 1.9% and 3.2%, respectively. Nitrogen use efficiency in farming and animal husbandry system decreased from 26%, 36%, 52% in 1984 to 13%, 21%, 22% in 2014, respectively. The overall trend was Heilongjiang＞Liaoning＞Jilin; phosphorus use efficiency decreased from 25%, 25%, 31% in 1984 to 9%, 14%, 10% in 2014, respectively. The trend was as following: Liaoning＞Heilongjiang＞Jilin.【Conclusion】The input of nitrogen and phosphorus in farming and animal husbandry system in Northeast China increased significantly from 1984 to 2014. There were obvious differences among different areas. The total available nitrogen and phosphorus nutrients were the highest in Heilongjiang, while the recycling efficiency of nitrogen and phosphorus was the highest in Jilin. In Northeast China, the efficiency of nitrogen use in Heilongjiang was higher than that in other areas, and the efficiency of phosphorus use in Liaoning was higher than that in Jilin and Heilongjiang. The loss rates of nitrogen and phosphorus in Jilin and Liaoning were higher than those in other areas. Therefore, it is necessary to make reasonable suggestions for the management of farming and animal husbandry according to the characteristics of nutrient flow in different regions, so as to provide a basis for the sustainable development of farming and animal husbandry in Northeast China.

Key words: Northeast region, farming and animal husbandry system, NUFER model, nitrogen and phosphorus flow, nutrient management