3068

2947

كارشناسي ارشد

خاكشناسي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي

1384

چهارده، 103، [II]ص.: مصور، جدول، شكل، نمودار

فرشيد نوربخش

حسين شريعتمداري

اميرحسين خوش گفتار منش، مهدي كديور

1396/03/01

كتابنامه

كشاورزي

مهندسي كشاورزي

ID2947

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

AbstractCrop residues supply organic matter to soil and playa major role in nutrient cycling inagroecosystem Incorporation of low quality corn residues results in N immobilization insoil and deteriorate N uptake by plant consequently The objectives of this study were toinvestigate the effect of corn residue application on N mineralization immobilization andsoil enzyme activities in a calcareous soil with contrasting fertilization history For thispurpose composite soil sa ples were collected from the plots of previously establishedfarm experiment in which manure had beenapplied at the rates of 0 50 and 100 Mg ha 1y 1in 3 replication for last 5 years Soil samples were supplied with corn roots and shootresidues separately at the rate of 0 and 10 g C kg I soil In a parallel experiment similartreatments were applied instead the initial concentration of N in soil increased by 50 mgUrea N kg 1soil The soil samples were incubated at 25 C and 50 WHC Destructive soilsampling was performed at 10 time occasions Inorganic N was measured in the soilsamples Some of enzymes activities were measured before and after incubation Resultsindicated that regardlessof manure fertilization history net N mineralization was observed In residue applied treatments a loss in inorganic N in first 2 weeks followed by a gradualincreaserevealing N immobilization and mineralization respectively Manure applicationhistory significantly influenced the rate ofN transformation in residue applied soils after 14weeks of incubation The presence of urea could not affect the pattern of N dynamics Alltreatments including manure application history control 50Mg ha l 100 Mg ha I residue application corn root and corn shoot control and urea application Control 50mg Urea N kg I soil significantly influenced N mineralization Manure applicationincreased enzyme activities either before or after the incubation The enzyme activities theshowedto be more affected by manure application history than that of residue application Initial urea application could not influence J3 glucosidase however amidohydrolasesshowedto be increased at higher rate of urea application Multiple regressionindicated that91 6 percent of final inorganic N variation could be described by the concentrations ofinorganic N at 16 0 and 13 weeks of incubation On the other hand urease activityaccountedfor 67 2 of inorganic N Overall net N immobilization was occurred in residueapplied soil during first 2 weeks of incubation followed by net N mineralization Soilenzymeactivities showed to be affected by manure application in a greater extent than thatresidueand urea application j f llI jf V I A11 i

فرشيد نوربخش

حسين شريعتمداري

اميرحسين خوش گفتار منش، مهدي كديور