Submitted to: American Society of Limnology and Oceanography
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2011
Publication Date: 3/9/2011
Citation: He, Z. 2011. Water extractable phosphorus in soils as impacted by cropping system, tillage practice, and amendment history. American Society of Limnology and Oceanography. February 13-18, 2011, San Juan, Puerto Rico. p. 106.
Technical Abstract: Water extracted phosphorus (P) is the most labile P pool in soil. Thus, the level of water extracted P is an important parameter in evaluating the runoff potential of soil P. This work compared the water extracted inorganic P (WEPi) and organic P (WEPo) levels in three soils as impacted by crop management, tillage and long term poultry litter (PL) application. In a Caribou sandy loam soil, 3-y crop rotations of disease suppressive, soil conserving, and soil improving systems increased the level of WEPi. Irrigation increased WEPi in soil under continous potato production. The distribution of pattern of WEPo was somewhat like that of WEPi, but on a smaller scale. In a Cecil sandy loam soil with cotton-corn production, 10-y application of PL increased WEPi and WEPo by 6.3 and 8.5 mg per kg soil under conventional tillage, and by 8.3 and 10.0 mg per kg soil under no-tillage, respectively. Similarly, in a Hartselle soil under pasture, WEPi increased rapidly with increasing history of PL application, and reached 29.9 mg per kg soil following 20 years of PL application. Further correlation analysis indicated that the increase in water extracted P from PL was related more to the number of years of PL application, than annual application rate or cumulative amount of litter applied. This research showed that amendment history and management practices on a given soil must be considered for managing P in an environmentally responsible manner.