Significant acidification in major Chinese croplands.
Soil acidification is a major problem in soils of intensive Chinese agricultural systems. We used two nationwide surveys, paired comparisons in numerous individual sites, and several long-term monitoring-field data sets to evaluate changes in soil acidity. Soil pH declined significantly (P < 0.001) from the 1980s to the 2000s in the major Chinese crop-production areas. Processes related to nitrogen cycling released 20 to 221 kilomoles of hydrogen ion (H+) per hectare per year, and base cations uptake contributed a further 15 to 20 kilomoles of H+ per hectare per year to soil acidification in four widespread cropping systems. In comparison, acid deposition (0.4 to 2.0 kilomoles of H+ per hectare per year) made a small contribution to the acidification of agricultural soils across China.
College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
J H
JH
Guo
X J
XJ
Liu
Y
Y
Zhang
J L
JL
Shen
W X
WX
Han
W F
WF
Zhang
P
P
Christie
K W T
KW
Goulding
P M
PM
Vitousek
F S
FS
Zhang
D000383:Agriculture; D002412:Cations; D002681:China; D018556:Crops, Agricultural / Q000254:growth & development* / Q000378:metabolism; D005308:Fertilizers; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen; D012987:Soil; D013997:Time Factors
D002412:Cations; D005308:Fertilizers; D012987:Soil; D009584:Nitrogen