Change characteristics analysis of farmland in Northern Sanjiang Plain in 2000－2009 based on remote sensing

Based on the remote sensing data, change characteristics of farmland at the Northern Sanjiang Plain in 2000-2009 was analyzed, aiming to provide the basis for land remediation, construction of farmland water conservancy, land resource development and utilization. The results showed that the area of farmland raised from 214.31×104 to 285.10×104 hm2. The reclamation ratio rose to 67.3% and the new increased land was drought land mainly. 73.64×104 hm2 land was cultivated mainly from swamp, woodland and grassland, and the returning farmland area was only 2.84×104hm2. At the same period, 58.67×104 hm2 drought land changed to irrigated land and 9.06×104 hm2 irrigated land changed to drought land. Irrigated land showed a pattern of concentrated distribution and the proportion of irrigated land accounted for 30.10% of the total area of farmland. More farmland increased in the east and north countries and less farmland increased in the west and south countries in the study area. Allocation optimization of water and land resources should be paid more attention in the process of agricultural development especially water conservancy construction in the future. Increasing the effective cultivated land area should be through land remediation frirstly.