Effect of neem (Azadirachta indica Juss.L) products on nitrification in rice growing soil

摘要

A pot experiment was conducted, during wet season using three types soils, namely typic haplusters-clay loam, aridic hap lus tepts-sandy loam and typic haplustalfs-sandy loam with rice as test crop. Four neem (Azadirechta indica) products as neem cake(NC) @ 20% of urea, neem oil (NO) @ 1% volume by weight of urea, Nimco (NI) @ 2% and Neemagold (NG) @ 1% by weight, blended with prilled urea alone were tested in a factorial randomized block design with S replication. The nitrifying capacity of soil was significantly decreased due to the application of neem products coated urea than prilled (control) in typic haplusterts, aridic haplustepos and typic haplustalfs at tillering, booting and harvesting stages of paddy. Among the neem products, neem oil coated urea treatment significantly proved superior to reduce the activity followed by neemgcold nimco and neem cake also. All soils were found to have significantly reduced the nitrification among the Aeem products. Irrespective soil types the mineralizable N in soils was higher in control at tillering stage than the later stages. The coating of urea with neem oil @ 1.0 per cent would be promising to reduces the nitrifying capacity of soil and control the mineralization ofNin typic haplusterts, aridic haplustepts and typic haplustalfs as compared to neemgold, nimco and neem cake, respectively.