Overuse Of Fertilizers Drops Average Chinese Soil pH By 0.5 In 30 Years - Nature

[hatrack]

Oops!

Chinese farmers' rampant use of fertilizers could soon endanger the nation's ability to feed itself. A survey of more than 8,000 samples from across the country has shown that overuse of nitrogen fertilizers has caused soil pH to plummet over the past 20 years. Left unchecked, the acidification could cripple Chinese agricultural production, says Fusuo Zhang, a soil and plant scientist at the China Agricultural University in Beijing and lead author of the survey, which is published online this week in Science1.

Since the 1980s agriculture yields have grown in China, as has the nation's use of chemical fertilizers. In 2007, China consumed 32.6 million tonnes of nitrogen fertilizer, a 191% increase over 1981. To understand the consequences of this increase, the researchers compiled 8,875 soil pH analyses from existing data to calculate the change in soil acidity between the 1980s and 2000s. The data came from various sources, including a national soil survey carried out between 1980 and 1984, 912 published research papers and long-term field monitoring studies.

The team's results show that extensive overuse has caused the pH of soil across China to drop by roughly 0.5, with some soils reaching a pH of 5.07 (nearly neutral soils of pH 6-7 are optimal for cereals, such as rice and grain, and other cash crops). By contrast, soil left to its own devices would take at least 100 years to acidify by this amount.

The acidification has already lessened crop production by 30-50% in some areas, Zhang says. If the trend continues, some regions could eventually see the soil pH drop to as low as 3. "No crop can grow at this level of acidification," he warns.

EDIT

http://www.nature.com/news/2010/100211/full/news.2010.67.html

[LiberalFighter]

1. What else are they going to screw up because of their restrictive type of government.

[OKIsItJustMe]

3. OK, I cannot help myself

Do you think the US is screwing up a great deal less with our government?

[Dead_Parrot]

4. Hmmm...

http://pnwsteep.wsu.edu/DirectSeed/conf2k2/dscmahler.htm

"Yield reductions because of excess soil acidity occur primarily in the midwestern, southern, and eastern regions of the USA... Soils in eastern Washington and northern Idaho have become increasingly acidified over the last 40 years. This acidification is due to the long-term use of high rates of ammonium-based nitrogen fertilizers."

See? Completely different.

:crazy:

[OKIsItJustMe]

5. I'm sorry. I stand corrected. Stupid Chinese!

http://en.wikipedia.org/wiki/Dust_Bowl
http://en.wikipedia.org/wiki/Love_Canal
http://en.wikipedia.org/wiki/Cuyahoga_River

[izquierdista]

2. Ground zero for the population crash

Something will tip China past the brink of stability, and then instead of supporting a billion people, the land there will only be able to support a few million, at least until the ecosystem recovers. In the meantime, there are going to be a lot of people with relative wealth who will be deserting like the proverbial rats from a sinking ship. In those days, sparsely populated areas like western Australia and even the American west are going to be where the best off people are.

[depakid]

6. Poster child for overshoot and collapse

and it's not the first time down that path.

[Lorien]

7. True. Just look at Easter Island. nt

[tama]

8. Good grief

Nitrogen fertilizers are criminally idiotic where everybody knows there are edible plants (beans, peas etc plus clovers etc.) that tie nitrogen from atmosphere to the soil. Wich don't acidify the soil. Potassium from mines is not exaclty renewable way to treat the pH but ash is. Ask any native forest tribe using slash and burn cultivation. Check Terra Preta of Amazon. And as for phosphorous, just compost the fish bones and bring them back to soil. And to avoid erosion, don't leave the soil uncovered, don't cut the forests down.

The utter idiocy and criminal short sightedness of industrial agriculture - the "Green Revolution" etc. - makes one very very sad.