[Relationship between Fe, Al oxides and stable organic carbon, nitrogen in the yellow-brown soils].
The stable organic carbon and nitrogen of the different particles were gained by oxidation of 6% NaOCl in the yellow-brown soils. The relationships between the contents of selective extractable Fe/Al and the stable organic carbon/nitrogen were investigated. It shown that amounts of dithionite-citrate-(Fe(d)) and oxalate-(Fe(o)) and pyrophosphate extractable (Fe(p)) were 6-60.8 g x kg(-1) and 0.13-4.8 g x kg(-1) and 0.03-0.47 g x kg(-1) in 2-250 microm particles, respectively; 43.1-170 g x kg(-1) and 5.9-14.0 g x kg(-1) and 0.28-0.78 g x kg(-1) in < 2 microm particles, respectively. The contents of oxalate-(Al(o)) and pyrophosphate extractable (Al(p)) were 0.08-1.34 g x kg(-10 and 0.11-0.47 g x kg(-1) in 2-250 microm particles, respectively; 2.96-6.20 g x kg(-1) and 0.38-0.78 g x kg(-1) in < 2 microm particles, respectively. And amounts of selective extractable Fe are generally higher in paddy yellow-brown soils than in arid yellow-brown soils, and that of selective extractable Al are lower in the former than in the latter. Amounts of the stable organic carbon and nitrogen, higher in paddy yellow-brown soils than in arid yellow-brown soils, were 0.93-6.0 g x kg(-1) and 0.05-0.36 g x kg(-1) in 2-250 microm particles, respectively; 6.05-19.3 g x kg(-1) and 0.61-2.1 g x kg(-1) in < 2 microm particles, respectively. The ratio of the stable organic carbon and nitrogen (C(stable)/N(stable)) were 9.50-22.0 in 2-250 microm particles and 7.43-11.54 in < 2 microm particles, respectively. The stabilization index (SI(C) and SI(N)) of the organic carbon and nitrogen were 14.3-50.0 and 11.9-55.6 in 2-250 microm particles, respectively; 53.72-88.80 and 40.64-70.0 in < 2 microm particles, respectively. According to SI, it is lower in arid yellow-brown soils than in paddy yellow-brown soils. The organic carbon and nitrogen are advantageously conserved in paddy yellow-brown soil. An extremely significant positive correlation of the stable organic carbon and nitrogen with selective extractable Fe/Al is observed. The most amounts between the stable organic carbon and nitrogen and selective extractable Fe/Al appear in clay particles, namely the clay particles could protect the soil organic carbon and nitrogen.
Engineering Research Center of Agricultural Resources and Environment, Colleges and Universities of Henan Province, Henan Agricultural University, Zhengzhou 450002, China. lishaheng@126.com
Li-Sha
LS
Heng
Dai-Zhang
DZ
Wang
Xin
X
Jiang
Wei
W
Rao
Wen-Hao
WH
Zhang
Chun-Yan
CY
Guo
Teng
T
Li
D000537:Aluminum Oxide / Q000737:chemistry*; D000538:Aluminum Silicates / Q000737:chemistry; D002244:Carbon / Q000737:chemistry*; D000077215:Clay; D005290:Ferric Compounds / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry; D012987:Soil / Q000032:analysis*
D000538:Aluminum Silicates; D005290:Ferric Compounds; D009930:Organic Chemicals; D012987:Soil; C000499:ferric oxide; D002244:Carbon; D000537:Aluminum Oxide; D009584:Nitrogen; D000077215:Clay