The quantification of nitrogen (N) supplying capacity of organic amendments applied to a soil is of immense importance to examine synchronization, N release capacity, and fertilizer values of these added materials. The aims of the present study was to determine the potential N mineralization and subsequent nitrification of separate and combined use of poultry manure (PM), wheat straw residues (WSR), and urea N (UN) applied to a loam soil incubated periodically over 140 days period. In addition, changes in total soil N and carbon contents were also monitored during the study. Treatments included: PM100, WSR100, PM50 + WSR50, UN100, UN50 + PM50, UN50 + WSR50, UN50 + PM25 + WSR25, and a control (unfertilized). All the amendments were applied on an N-equivalent basis at the rate of 200 mg N kg-1. Results indicated that a substantial quantity of N had been released from the added amendments into the soil mineral pool and the net cumulative N mineralized varied between 39 and 147 mg N kg-1, lowest in the WSR and highest in the UN50 + PM50. Significant differences were observed among the amendments and the net mineral N derived from a separate and combined use of PM was greater than the other treatments. The net cumulative N nitrified (NCNN) varied between 16 and 126 mg kg-1, highest in UN50 + PM50 treatment. On average, percentage conversion of added N into available N by different amendments varied between 21 and 80%, while conversion of applied N into NO3-–N ranged between 9 and 65%, and the treatment UN50 + PM50 displayed the highest N recovery. Urea N when applied alone showed disappearance of 37% N (N unaccounted for) at the end while application of PM and WSR with UN reduced N disappearance and increased N retention in the mineral pool for a longer period. Organic amendments alone or in combination with UN improved organic matter buildup and increased soil N concentration. These results demonstrate the existence of substantial amounts of N reserves present in PM and WSR that can be utilized efficiently and effectively as potential N source for the management of nutrient poor soils and plant growth.
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机译:对施用于土壤的有机改良剂的氮(N)供应能力进行量化,对于检查这些添加材料的同步性,氮释放能力和肥料值非常重要。本研究的目的是确定将单独施用和组合使用的家禽粪便(PM),小麦秸秆残留物(WSR)和尿素氮(UN)单独施用并在140℃以上温育的壤土中的潜在氮矿化作用和随后的硝化作用天期间。此外,在研究过程中还监测了土壤总氮和碳含量的变化。处理包括:PM100,WSR100,PM50 + WSR50,UN100,UN50 + PM50,UN50 + WSR50,UN50 + PM25 + WSR25和一个对照(未受精)。所有修正案均以200当量N kg -1 sup>的当量氮含量应用。结果表明,从添加的改良剂中释放出大量的氮,进入土壤矿物质池,矿化的净累积氮量在39至147 mg N kg -1 sup>之间,WSR最低,最高在UN50 + PM50中。修正案之间观察到显着差异,单独和联合使用PM产生的净矿物质N大于其他处理。净累积硝化氮(NCNN)在16和126 mg kg -1 sup>之间变化,在UN50 + PM50处理中最高。平均而言,通过不同的修正将添加的N转化为有效N的百分比在21%到80%之间变化,而将应用的N转化为NO 3 sub> - sup> -N的百分比范围为9到90%。 65%,并且处理UN 50 sub> + PM 50 sub>的N回收率最高。单独施用时,尿素氮最终显示出37%的氮消失(N不详),而在联合国施用PM和WSR可以减少氮的消失,并在更长的时间内增加氮在矿藏中的保留。单独使用有机改良剂或与联合国联合使用可改善有机质积累并增加土壤氮浓度。这些结果表明,PM和WSR中存在大量的N储备,这些氮储备可以有效地用作管理营养不良的土壤和植物生长的潜在N源。
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