The writer of this article knows nothing of farming. Why is the soil acidifying? Because the farmers aren't rotating their crops in order to replenish and balance the soil. At the least they can spray it with an alkali neutralizer, but by far the most effective technique is just simple crop rotation.

Of course the other part of the problem is that many of China's waterways are horribly polluted because of the lack of any kind of standards or responsibility for dumping waste products of all kinds into it. If you take a picture of the Yellow River (one of the longest in the world), the color just makes you ill to look at - especially around Beijing.