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Short‐Term Nitrogen Fertilizing Value of Liquid Dairy Manures is Mainly Due to Ammonium
Author(s) -
Bechini Luca,
Marino Pietro
Publication year - 2009
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2008.0217
Subject(s) - mineralization (soil science) , manure , zoology , incubation , ammonium , nitrogen , nitrogen cycle , soil water , chemistry , agronomy , environmental chemistry , environmental science , biology , soil science , biochemistry , organic chemistry
The efficient use of animal manures is important both for environmental and economic reasons. This study was conducted to determine the mineralization of C and N of five liquid dairy manures incorporated in three soils of increasing clay content (102, 209, and 337 g kg −1 ). The manures represent the variability observed in animal farms in northern Italy. Incubation was performed for 181 d at 25°C and −0.05 MPa of soil water potential; respired CO 2 –C and soil inorganic N were measured on 12 sampling dates. For all soil × manure combinations the dynamics of C respiration showed high rates in the first week, and lower rates thereafter. Differences among manures were greater during the initial phase. At the end of the experiment, the total C respired ranged from 40 to 71% of applied C; model extrapolations indicate that part of manure C will be stored in the soil in the long term. Higher respirations were obtained in the soil with the lowest clay content. For most of the treatments, immobilization of mineral N occurred in the first weeks, followed by slow remineralization of immobilized N, resulting in either no or low net mineralization of organic N at the end of the incubation (−7 to 23%). It is concluded that the variability of manure C and N mineralization is high. Nitrogen fertilizing value of the manures during the first year after application must be mainly attributed to ammonium, while organic N is mineralized slowly, and is therefore available later.