Premium
Evaluation of Chemical Indices of Soil Organic Nitrogen Availability in Calcareous Soils
Author(s) -
Serna M. D.,
Pomares F.
Publication year - 1992
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/sssaj1992.03615995005600050025x
Subject(s) - soil water , loam , calcareous , mineralization (soil science) , agronomy , organic matter , chemistry , nitrogen , environmental science , environmental chemistry , soil science , botany , biology , organic chemistry
Because most of the N in soils is in organic form, information about the rate of N mineralization is required to estimate N availability during a cropping season. Biological and chemical methods to predict the level of plant‐available N in soils were investigated under laboratory and growth chamber conditions. Two biological methods (maize [ Zea mays L.] plants grown in pots and soils incubated aerobically) and four chemical methods (autoclave, 0.5 M KMnO 4 , 6 M HCl, and 0.01 M NaHCO 3 ) were compared using 27 different soils from Valencia. Total N mineralized during the incubation periods ranged from −6.1 to 128 mg N kg −1 dry soil, representing from 0 to 9.57% of the soil organic N. The available soil N, defined as the amount taken up by maize, ranged from 12 to 87 mg kg −1 , representing from 1.03 to 6.57% of the total soil N; the highest values were obtained from loamy soil. Modified autoclave and HCl methods were more suitable for predicting N availability in these soils than the KMnO 4 and NaHCO 3 methods. In general, the different extraction methods were not suitable for the clay soils. Prediction of soil N availability to plants in the growth chamber improved if initial mineral N of soils and several chemical and biological methods were combined in a multiple regression analysis; particularly, the multiple regression analysis markedly improved the suitability of the KMnO 4 and NaHCO 3 methods to predict N uptake by maize.