JOURNAL OF NATURAL RESOURCES ›› 2011, Vol. 26 ›› Issue (6): 943-954.doi: 10.11849/zrzyxb.2011.06.005

• Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS • Previous Articles     Next Articles

Nitrogen and Phosphorus Balance of Cropland at Regional Scale for Integrated Crop-Livestock Farming System in Two Different Areas

WU Lan-fang1, OUYANG Zhu1, XIE Xiao-li2   

  1. 1. Yucheng Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China;
    2. Institute of Subtropical Agriculture, CAS, Changsha 410125, China
  • Received:2010-03-25 Revised:2011-03-01 Online:2011-06-20 Published:2011-06-20

Abstract: The nitrogen (N) and phosphorus (P) balances of cropland within two different areas of crop-animal mixed farming system, Yucheng County, Shandong Province and Taoyuan County, Hunan Province were taken as the case study. The result shows that N and P input to the cropland has been increased since 1980, so is the case of N and P export. However, a large amount of N and P surplus was produced owing to the increasing input of N and P to cropland which is greater than the export, and there were differences between the two areas. In the cropland of Yucheng County, the surplus of N and P has been increasing year by year, annual N surplus per hectare of farmland was greatly increased from 133.8 kgN·hm-2 to over 450.0 kgN·hm-2, and annual P surplus per hectare farmland was increased from 6.2 kgP2O5·hm-2 to 148.9 kgP2O5·hm-2. As a result, in 11 villages and towns of Yucheng, 10 of them show N surplus and 9 of them have P surplus to different extent of which the largest amount of N surplus reaching 841.8 kgN·hm-2 and the P surplus 297.8 kgP2O5·hm-2. In the cropland of Taoyuan County, the surplus amount of both N and P were increased till 2002, and then began to decline. The N surplus increased from about 100.0 kgN·hm-2 to the ceiling amount of 253.7 kgN·hm-2, then decreased to the present about 150.0 kgN·hm-2, and the P surplus increased from about 20 kgP2O5·hm-2 to the peak of 95.9 kgP2O5·hm-2 and then decreased to about 34.4 kgP2O5·hm-2 at present. In 40 village and towns of Taoyuan County, 36 of them exhibit N surplus and 26 of them appear P surplus to different extent, of which the highest amount of N surplus is 561.7 kgN·hm-2and the highest amount of P surplus is 171.1 kgP2O5·hm-2. A great deal of N and P surplus resulted from either overuse of fertilizer or overload of manure within cropland, and the surplus amount of both N and P in Yucheng County is greater than that in Taoyuan County. To cut down N and P surplus and loss, fertilizer should be minimized as much as possible according to crops need, besides manure should be applied inside and outside the area according to the carrying capacity of cropland to manure.

Key words: nitrogen and phosphorus balance, cropland, Yucheng, Shandong Province, Taoyuan, Hunan Province

CLC Number: 

  • S143