N- Mineralization of Organic Residues in Flooded and Aerated Saline Soils under Different Temperature

Abstract

Serious of incubation studies were conducted at Department of soil Science and Water Resources, College of Agriculture, university of Basrah to study the effect of temperature incubation and soil salinity levels (3, 6, 12 and 24) dS.m-1 on N mineralization of cow manure and alfalfa residue under aerobic and flooded conditions. Fifteen gram of air dry soil with salinity levels of 3, 6, 12 and 24 dS.m-1 treated with 5% of cow manure or alfalfa residue were incubated at 10, 20 or 30 ?C for 28 days. Moisture level of incubated soil was kept at either field capacity or flooded condition. NH4+ -N and NO3--N concentration of incubated samples were determined at the end of incubation period. Results showed that organic residues added to soils of all salinity levels increased NH4+ -N and NO3- - N. Concentrations of both ions were higher in alfalfa residue treatment than those of cow manure at all treatments. Highest concentrations of NH3+ -N and NO3-- N ions in all treatments obtained at samples incubated at 30 ?C and E.C. of 3 dS.m-1. Organic N mineralization under F.C. was higher than under logged water for all treatments.