Croplands measured on new map

A new interactive map which details croplands worldwide in the highest resolution yet, has been released. It is expected to assist in ensuring global food and water security in a sustainable way.

The map establishes that there are 1.87 billion hectares of croplands in the world, which is about 20%, or 250 to 350 million hectares, higher than former assessments.

This is due to a more detailed understanding of large areas that were never mapped before, or that were inaccurately mapped as non-croplands.

Earlier studies indicated that China or the United States had the highest net cropland area, but this study shows that India ranks first, with 179.8 million hectares (9.6% of the global net cropland area). Second is the United States with 167.8 million hectares (8.9%), China with 165.2 million hectares (8.8%) and Russia with 155.8 million hectares (8.3%). Statistics of every country in the world can be viewed on the interactive map.

For a comparison, Namibia has 1.2 million hectares of croplands, which is 0.065% of the global net cropland area.



High freshwater use

Croplands only make up 1.5% of Namibia's total geographic area of more than 82.3 million hectares.

South Asia and Europe can be considered as the agricultural capitals of the world due to the percentage of croplands of the total geographic area.

The study was led by the American Geological Survey and is part of the Global Food Security-Support Analysis Data @ 30-m (GFSAD30) Project.

The map is built primarily from Landsat satellite imagery with 30-metre resolution, which is the highest spatial resolution of any global agricultural dataset.

The project, and the creation of the map, both aim at helping to understand global croplands, both rain-fed and irrigated, how they are used, their extent and how they can be better managed, particularly since they account for nearly 80% of all freshwater abstractions. Here, technologies such as remote sensing can play an increasingly critical role – providing new spatial information to help manage croplands in a more productive and sustainable way.

“The map clearly shows individual farm fields, big or small, at any location in the world,” said Prasad Thenkabail, USGS research geographer and principal investigator for the project.

“Given the high resolution of 30 metres and 0.09 hectares per pixel, a big advantage is the ability to see croplands in any country and sub-national regions, including states, provinces, districts, counties and villages.”



Need for monitoring

With the global population nearing the 7.6 billion mark and expected to reach 10 billion by 2050, it is of increasing importance to understand and monitor the state of agriculture across the world in great detail. This new research is useful to international development organisations, farmers, decision-makers, scientists and national security professionals.

“This map is a baseline and starting point for higher level assessments, such as identifying which crops are present and where, when they grow, their productivity, if lands are left fallow and whether the water source is irrigated or rain fed,” said Thenkabail.

“Comparisons can be made between the present and past years as well as between one farm and another. It is invaluable to know the precise location of croplands and their dynamics to lead to informed and productive farm management.”

Not only does this map and accompanying data have significant food security implications, but it is also critical as a baseline for assessing water security.

Nearly 80% of all human water use across the world goes towards producing food, and this research provides insight on “crop per drop,” which is an assessment of the amount of crops produced per unit of water.

Access the map at croplands.org and there is also an application for mobile phones.

ELLANIE SMIT