Author
Leytem, April | |
Westermann, Dale |
Submitted to: Soil Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/16/2005 Publication Date: 6/1/2005 Citation: Leytem, A.B., Westermann, D.T. 2005. Phosphorus availability to barley from manures and fertilizers on a calcareous soil. Soil Science. 170(6):401-412. Interpretive Summary: Phosphorus (P) is a limiting soil nutrient for many crops; however, P losses in runoff from agricultural lands are implicated in the degradation of water quality in many regions. We conducted a growth chamber study to determine the relative P solubility and plant P availability of manure and fertilizer sources typically land applied in the Pacific-Northwest U.S. Six manure types and four fertilizer P amendments were applied to two Portneuf soils at the same total P rate and incubated for a total of 9 weeks with barley planted after initial 2 week incubation. Soil samples were analyzed prior to barley planting and then at 4 and 7 wk after planting, while plant samples were analyzed at 4 and 7 wk. There was an increase in soil water soluble (WS-P) and Bicarbonate P resulting from P additions which varied by source. The trend of relative extractable WS-P and Olsen P generally followed the pattern [inorganic P] > [liquid manures] > [solid or composted manures]. Plant shoot biomass and plant P accumulation were similar except swine manures were greater than inorganic P sources and beef manure was less than both. Determining relative P solubility of manure and fertilizer sources will be beneficial when estimating P losses from land application of manures and may be used in risk assessments such as a P site index, with limited impact on P availability to crops. Technical Abstract: Phosphorus (P) is a limiting soil nutrient for many crops; however, P losses in runoff from agricultural lands are implicated in the degradation of water quality in many regions. We conducted a growth chamber study to determine the relative P solubility and plant P availability of manure and fertilizer sources typically land applied in the Pacific-Northwest U.S. Six manure types and four fertilizer P amendments were applied to two Portneuf soils at the same total P rate and incubated for a total of 9 weeks with barley planted after initial 2 week incubation. Soil samples were analyzed prior to barley planting and then at 4 and 7 wk after planting, while plant samples were analyzed at 4 and 7 wk. There was an increase in soil water soluble (WS-P) and Bicarbonate P resulting from P additions which varied by source. The trend of relative extractable WS-P and Olsen P generally followed the pattern [inorganic P] > [liquid manures] > [solid or composted manures]. Plant shoot biomass and plant P accumulation were similar except swine manures were greater than inorganic P sources and beef manure was less than both. Determining relative P solubility of manure and fertilizer sources will be beneficial when estimating P losses from land application of manures and may be used in risk assessments such as a P site index, with limited impact on P availability to crops. |