TILLAGE EFFECTS ON LABILE POOLS OF SOIL ORGANIC NITROGEN IN A SEMI-HUMID CLIMATE OF ARGENTINA: A LONG-TERM FIELD STUDY

MARTINEZ JUAN MANUEL; GALANTINI J.A; DUVAL M.; LÓPEZ, F. M.

SOIL & TILLAGE RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 169 p. 71 - 80

0167-1987

Tillage systems strongly affect nitrogen (N) mineralization. However, there is still only limited information on the relationship between N in labile soil organic matter (SOM) fractions and crop N uptake under different tillage systems in areas with poor water availability. This study discusses the long-term effect of two tillage systems on i) the N-content in labile organic matter fractions and their relationship with the N mineralization potential at three depths (0-5; 0-10 and 0-20 cm), ii) the factors that affect the N mineralization potential, and iii) the relationship between potentially mineralizable N (N0) and crop N uptake in a semi-humid climate. In a long-term experiment, a Typic Argiudoll was sampled under two contrasting tillage systems: no-tillage (NT) and conventional tillage (CT). The soil sampling was performed over four years of the crop sequence (2003, 2009, 2010 and 2011) when the plots were sown with winter wheat (Triticum aestivum L.). They were analyzed for N0 in the form of anaerobic N, soil organic nitrogen (SON), physically separated SOM fractions and crop N uptake. Higher values of SON and labile soil N fractions were observed under NT at all three depths. Significant differences in N0 were found between the tillage systems, with greater values under NT. Significant (P