The Freundlich adsorption isotherm constants and prediction of phosphorus bioavailability as affected by different phosphorus sources in two Kansas soils.
Phosphorus (P) adsorption onto soil constituents influences P bioavailability from both agronomic and environmental perspectives. In this study, the P availability from different P sources along with utility of Freundlich adsorption coefficients on the predictability of various crop growth parameters were assessed. Two soils were amended with 150mgPkg(-1) each from six different P sources comprised of manures from two types of ruminants animals, three types of monogastric animals, and inorganic P fertilizer. Corn (Zea mays) was grown and harvested seven times under greenhouse conditions to remove P from the P amended treatments. The application of all P sources reduced the value of Freundlich K and increased the value of Freundlich 1/n and equilibrium P concentration (EPC0) in both soils compared to the un-amended control before cropping. The swine (Sus scrofa) manure (HM) resulted in significant smaller values of Freundlich K and larger values of 1/n in the P deficient Eram-Lebo soil compared to other P sources while, the opposite was true for the turkey (Meleagris gallopava) litter (TL) in the Ulysses soil. The corn biomass, tissue P concentration and P uptake were significantly influenced by all P sources during the first harvest and the total P uptake during seven harvests in both soils compared to the control treatment. Both Freundlich coefficients had strong relationships with the aforementioned corn parameters in the P deficient Eram-Lebo soil while, strength of the association was weak or missing in the Ulysses soil which had optimum levels of antecedent P.
Department of Biosciences, COMSATS Institute of Information Technology, Park Road, Chak Shahzad, Islamabad, Pakistan; Department of Agronomy, Kansas State University, Manhattan, KS 66506, USA. Electronic address: insebat@yahoo.com.
Mustafa N
MN
Shafqat
Department of Agronomy, Kansas State University, Manhattan, KS 66506, USA.
Gary M
GM
Pierzynski
D000327:Adsorption; D000818:Animals; D018533:Biomass; D005308:Fertilizers / Q000706:statistics & numerical data; D007615:Kansas; D008372:Manure; D008956:Models, Chemical; D010758:Phosphorus / Q000032:analysis* / Q000737:chemistry; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry; D013552:Swine; D003313:Zea mays / Q000254:growth & development
D005308:Fertilizers; D008372:Manure; D012987:Soil; D012989:Soil Pollutants; D010758:Phosphorus
Animal manure phosphorus; Corn phosphorus uptake; Freundlich adsorption coefficients; Soil phosphorus bioavailability