NOX fluxes from three kinds of agricultural lands in the Yangtze Delta, China

Static chamber method was adopted to measure the surface exchanges of NO and NO2 between three kinds of agricultural lands and the atmosphere during spring-summer period in the Yangtze Delta, China. The average NO fluxes were 20.9, 27.4 and 21.4ng Nm(-2) s(-1), respectively, for cabbage (CA, cultivation of celery occurred along with cabbage), potato (PO) and soybean (SY) fields. The average NO, fluxes were -1.12, 0.93 and -0.68 ng N m(-2) s(-1), respectively, for the cabbage, potato and soybean fields. Apparently, negative linear correlation was found between the NO2 fluxes from the CK plot (tilled conventionally but did not cultivate any seeds) and its ambient concentrations, and the compensation point was calculated to be 0.92ppbv, The total NO emission from the vegetable lands and SY land in this region during spring-summer period was roughly estimated to be 15.9Gg N, which accounted for about 11.2% of the estimated value of total NO emissions in the July of 1999 from Chinese agricultural fields. (C) 2007 Elsevier Ltd. All rights reserved.