Spatially precise reconstruction of cropland areas in Heilongjiang Province, northeast China during 1900–1910

Abstract

Abstract:It is necessary to reconstruct past changes in land use and land cover to understand the historical effects of humans on climate and the local environment. We collected information from historical documents on the cropland area at the county level for Heilongjiang Province, northeast China during 1900-1910. The original records from different historical documents were calibrated with each other. We then defined an agricultural suitability index quantified by the distance from settlements, the slope and complexity of the topography, and the distance from rivers. Following the order of the agricultural suitability index from high to low values, the documented areas of cropland at the county level were then allocated into 1 km  1 km cells. The area of cropland in 2009 was then retrieved from Landsat ETM+ images and compared with the areas of cropland during 1900-1910 to determine the human-induced changes in land use and land cover. In this period, the total area of cropland was about 25,397 km 2 and this mainly occurred in the mid-southern part of Heilongjiang, in particular the six counties of Hailun, Bayan, Wuchang, Hulan, Shuangcheng and Wangkui. In 2009, the total area of cropland had increased to about 163,808 km 2 and had spread over the southwestern part to the central and northeastern parts of Heilongjiang. The area of cropland had therefore increased by about 138,411 km 2 during the 20th century. The proportion of land used as cropland increased from about 5.6% during 1900-1910 to about 36.2% in 2009, indicating that about 30.6% of the natural land surface in Heilongjiang was replaced by cropland. A total of about 44% (60,962 km 2 ) of the cropland was converted from forest, mainly on the western edge and in the northeastern part of the present-day agricultural area. These areas of cropland reconstructed from historical records for the period 1900-1910 could be used as a basic data set to study the effects of agricultural development on climate and the local environment.

Impacts of Agricultural Expansion (1910s–2010s) on the Water Cycle in the Songneng Plain, Northeast China

“…Annual precipitation has a range of 350-700 mm, most of which occurs in the growing season from May to September. Northeast China is well known for its unique, highly productive Black Soil [23,24], in which the Songnen Plain (our study region), Sanjiang Plain and the Liaohe Plain compose the three primary plains from north to south. Historically converted from vast areas of grasslands since the 1800s, croplands dominate the plains with major crop types of corn, soybean and spring wheat.…”

Present‐day and future contribution of climate and fires to vegetation composition in the boreal forest of China

“…The summers are usually hot and humid, while the winters are cold and dry. The annual average temperature is between À4 and +5°C from north to south, and the annual precipitation ranges from 400 to 700 mm from west to east (Zhang et al 2015). The main vegetation types include evergreen needleleaf forest (ENF), deciduous needleleaf forest (DNF), deciduous broadleaf forest (DBF), and cultivated and managed areas/ grassland (see Fig.…”

The Effects of Forest Area Changes on Extreme Temperature Indexes between the 1900s and 2010s in Heilongjiang Province, China

“…Among them, 39 images cover Heilongjiang province (paths 113-123; rows [23][24][25][26][27][28][29][30]. We subjected this 30 m × 30 m image to geometric and radiation correction, as well as coordinate transformation, image enhancement, and band combination using the software ERDAS 8.7 in order to obtain a final standard false color composite image.…”

“…To do this, we extracted information on the area of cultivated land from the report Spatial Distribution Reconstruction of Cultivated Lands in Heilongjiang Province in the Late 1900s [27], and added areas of water surface, wetland, and unutilized via backtracking and filling methods. In particular, The Economic Geography in Northeast China [28] includes a 1959 land use map for this region at a scale of 1:3,000,000; the ten land use types included in this map are primary and secondary forest, dry land, paddy fields, cities and main settlements, salterns, grassland and bare land with stones, sand dunes and sandy beaches, marshlands, and water bodies.…”