Brazil Soybean Area Estimation Based on Average Samples Change Rate of Two Years and Official Statistics of a Year Before

摘要

Comprehensive, reliable and timely information of Brazil's soybean area is necessary for China to make decisions on agricultural related problems. Spatial sampling method which combined remote sensing and sampling survey is widely used. Due to limitations of width and revisit cycle of medium resolution satellite, This study designed a typical investigation method about Brazil soybean area based on average samples change rate of two years and official statistics of a year before, typical samples were selected to survey, sampling frame was constructed on soybean planting state, the sampling unit was designed as 40 km × 40 km, the sampling proportion was 2 %, average samples change rate of two years were 2013 and 2014. Estimated area was compared with Brazil official harvested area in 2014 (published on 2015 April by Brazilian Institute of Geography and Statistics), the relative error is 2.37 %.