NITROGEN MINERALIZATION IN SEMIARID SOILS OF MOROCCO - RATE-CONSTANT VARIATION WITH DEPTH

This study was conducted to determine the influence of soil depth on N-mineralization rate, total N, and amino acid N contents for eight representative soils of the subarid zone of Morocco. Nitrogen-mineralization ability within the profiles was evaluated through long-term soil incubation/leaching experiments. Total N and amino acid N were measured by the Kjeldahl method and acid hydrolysis, respectively. A hydrolysable-N-production rate was also evaluated, through successive acid hydrolysis of samples from two soil profiles. Results suggest that the decrease of N mineralization with depth may be attributed to a recondensation of amino acids in complex biochemical compounds more resistant to biodegradation. -from Authors