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Nitrogen Mineralization Potential of Arid and Semiarid Soils of Morocco
Author(s) -
El Gharous M.,
Westerman R. L.,
Soltanpour P. N.
Publication year - 1990
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/sssaj1990.03615995005400020024x
Subject(s) - soil water , mineralization (soil science) , soil science , environmental science , arid , nitrogen , organic matter , nitrogen cycle , hydrology (agriculture) , mathematics , zoology , chemistry , geology , ecology , biology , geotechnical engineering , organic chemistry
An accurate estimate of N mineralized from soil organic matter during the growing season is required to make correct N fertilizer recommendations for crops. In Morocco, very little information regarding the N‐supplying power of soils is available. These studies were conducted to determine N‐mineralization potential (N o ) and rate constant ( k ) values, N flux, and instantaneous rate of reaction for soils of the Chaouia region of Morocco. Fourteen soils were selected and net mineralizable N during 16 wk of incubation at optimum moisture and temperature was determined for each soil. Exponential and hyperbolic models were used to describe net mineralization, and N o and k values for each soil were determined using nonlinear least‐squares regression. Values using the exponential model ranged from 120 to 241 mg N kg −1 of soil for N o and 0.06 to 0.274 week −1 for k . The values ranged from 164 to 391 mg N kg −1 of soil for N o and 0.024 to 0.212 week −1 for k , using the hyperbolic model. The lowest average N o values for different soils were shown to occur in Palexerolls, which are shallow soils approximately 35 cm deep that have received very low N input. Calculations using the exponential and hyperbolic models indicated the active fraction of total N in these soils varied from 7 to 22% and 10 to 36%, respectively. This study supported earlier reports that a single exponential model as well as a hyperbolic model can be used to estimate reliable N o and k values in soils if a nonlinear least‐squares fitting technique is used.