HONG KONG — Piles of unsold coal line rural roads in north-central China. Some iron ore mines near Beijing are operating at a fraction of capacity. Chinese farm products are even increasingly scorned by the Chinese consumer.

While China remains nearly self-sufficient in all these categories, it is importing more from other emerging markets. Economists and investors around the world have been fretting in recent days about the effects on smaller emerging markets if China’s economic slowdown worsens. Those concerns have driven down share prices and currencies from Jakarta to Istanbul to Buenos Aires, although emerging markets staged a partial recovery on Wednesday. They helped to prod the central banks of Turkey and India to raise benchmark interest rates unexpectedly on Tuesday.

Yet the most vulnerable producers these days may not be the coal mines in Indonesia, palm oil plantations in Malaysia or soybean farms in Brazil, but the farms and particularly the mines in China itself.

China’s role as the largest buyer of a long list of commodities, from iron ore to palm oil, means that emerging markets are heavily exposed to any economic slowdown. But their ability to capture ever-larger shares of the Chinese market at the expense of China’s commodity producers has limited at least somewhat the exposure of emerging markets.