Amino Compounds in Poultry Litter,Litter-Amended Pasture Soils and Grass Shoots

Amino compounds(ACs),i.e.,amino acids and amino sugars,are the major forms of organic nitrogen(N)in animal manure and soil.To increase our understanding on the effect of long-term poultry litter(PL)application on soil AC pools and turnover,in this study,we determined the contents of 21 ACs in 23 PL samples,15 soil samples collected from 0–20,20–40,and 40–60 cm layers of five pasture plots with 0,5,10,15 and 20 years of PL applications,and 5 grass shoot samples grown on these pasture fields.The contents of 21 ACs were simultaneously determined by methanesulfonic acid hydrolysis/extraction and anion chromatography-pulsed amperometry.PL application increased soil total and individual AC contents with a distribution pattern similar to that of AC in PL.The highest AC-N concentrations were observed in the soils with 10-or 15-year PL applications,inconsistent with the order of annual application rates or cumulative applied PL amounts.Application of PL increased the AC contents in grass shoots whereby the highest increase of most ACs was with the shoots from the fields that received PL for 5 years.These observations suggested that both freshly applied and residual PL had contributions to the soil AC-N,and that PL application also accelerated AC-N transformation in soil.