Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/4/2001
Publication Date: 4/1/2002
Citation: CODLING, E.E., MULCHI, C.L., CHANEY, R.L. BIOMASS YIELD AND PHOSPHORUS AVAILABILITY FOR WHEAT GROWN ON HIGH PHOSPHATE SOILS AMENDED WITH PHOSPHATE-INACTIVATING RESIDUES. II. IRON RICH RESIDUE. COMMUNICATION IN SOIL SCIENCE PLANT ANALYSIS. 2002. Interpretive Summary: The potential for reduction in crop yield and P deficiency when iron rich byproducts are used to inactivate P in high P soils from the poultry producing area of Maryland Eastern shore is a concern to the farmers in the area. A pot study was conducted to determine: 1) the effect of three high P soils amended with a iron rich residue (IRR) on wheat yield and P uptake; and 2) the change in soil characteristics as a result of IRR application. Both biomass yield and tissue P concentration were significantly reduced with increased rate of IRR. Tissue P concentration; however, were in the range considered sufficient for wheat for all the treatments. Water soluble and Mehlich 3 extractable P concentration in the soil decreased with increased application of IRR for each soil. Both water soluble and Mehlich 3 extractable P were positively correlated with tissue P concentration. DTPA extractable Mn increased with addition of IRR, however, DTPA Fe concentration decreased with the addition of IRR. Soil pH and electrical conductivity increased with the increase rate of IRR for the three soils. Applied at rates needed to reduce potential runoff of soil phosphate to surface waters IRR was effective and yield was reduced only at higher application rates.
Technical Abstract: Reducing the environmental risk of soluble Phosphorus (P) in long-term poultry manured fields involves increased use of chemical soil amendments such as iron. Iron salts have been proven effective in removing soluble P from waste water; it is also been used to inactivate P in poultry litter and litter amended soils. The potential for yield reduction for crops grown non these amended soils is a concern to farmers. A growth chamber experimen was conducted using three high P soils (Matapeake, Evesboro, and Woodstown) amended with Fe-rich residue (IRR) in order to: 1) determine the effects (IRR) on crop yield and on plant P, Mn and Fe levels; and 2) Examine pH, electrical conductivity (EC), P, Mn and Fe concentrations in soils after three cropping cycles with wheat. IRR was mixed with the soils at rates of 0, 10, 25 and 50 g kg-1 and incubated for 7 weeks. Three crops of wheat (Triticum aestivum) were grown in succession. Yield and tissue P concentration were significantly reduced with the additions of IRR for all three soils; however, P levels were within the range considered sufficient for wheat for all treatments. Tissue Mn and Fe concentration increased with increased application of IRR, but were below the levels considered to be toxic to plants. Water soluble P and Mehlich 3 (M3-P) concentrations were lowered with increased IRR application rates for each soil and correlated positively with tissue P for the three soils. DTPA extractable Mn increased, but Fe concentration reduced in the three soils. Applied at rates needed to reduce potential runoff of soil phosphate to surface waters IRR was effective and yield was reduced only at higher application rates.