Biomass yield and phosphorus availability to wheat grown on high phosphorus soils amended with phosphate inactivating residues. I. Drinking water treatment residue

Abstract

Use of aluminum (Al)-rich compounds to reduce the solubility of phosphorus (P) in poultry litter and litter amended soils is being used as a method to inactivate (precipitate or adsorb) P in high P soils. Previous studies have shown that Drinking Water Treatment Residue (DWTR) rich in Al significantly lowered soluble P in litter amended soils; however, this could result in P deficiency in crops. A growth chamber experiment was conducted using Matapeake, Evesboro, and Woodstown soils containing Mehlich 3 extractable P levels above 800 mg kg⁻¹ in order to 1) determine the effects of DWTR soil treatment on plant dry biomass yield (BM), P and manganese (Mn) uptake; and 2) examine pH, extractable P, Mn, and Al concentrations in soils after three cropping cycles with wheat. DWTR was mixed with the soils at rates equal to 0, 10, 25, and 50 g kg⁻¹ soil, followed by incubation for seven weeks. Three cycles of wheat (Triticum aestivum) were grown in succession. DWTR application significantly reduced plant dry matter yields for Evesboro and Woodstown soils at rates above 10 g kg⁻¹ DWTR, but not in Matapeake. Plant P concentration progressively reduced with increased rates of DWTR during the three cropping cycles for the three soils. Plant tissue P concentrations appeared above sufficiency levels for wheat for all three soils at 10 g kg⁻¹ rate of DWTR during the first cropping cycle. At the 25 and 50 g kg⁻¹ rates, however, tissue P concentrations were either low or deficient for the second and third cycle. Both water soluble and Mehlich 3 extractable P exhibited reductions with increased DWTR application rates and cropping cycle. Significant correlations were found between water soluble, Mehlich 3 extractable P and plant P concentrations for all the soils; however, the r² values were generally higher for water soluble P compared to the Mehlich 3 extractable P. Soil pH values typically increased with DWTR application rate, but extractable Al concentrations, measured after each cropping cycle, remained below 2 mg kg⁻¹ for both the treated and untreated soils. DWTR was capable of reducing water soluble phosphate in these soils without severely impacting soil fertility.

Acknowledgments

The authors thank George Kendel for providing the Drinking Water Treatments Residue for the study. We also wish to thank L. C. Jones, Richard Thomas, Quint Reiley, and Brian Bradford for supplying soil and poultry litter.