Short‐term incubation method for mineralizable nitrogen

Abstract

Soil N supply plays an important role in the N nutrition of cereal crops under dryland agriculture conditions in the semiarid tropics, where the use of chemical fertilizers is low. Mineralizable N was determined in the profiles of a benchmark Vertisol and Alfisol in the semiarid zone of India using three versions of a water‐logged incubation method: incubation at 30°Cfor 14 days, at 40°C for 7 days, and at 50°C for 2 days. Mineralized N decreased with depth in the profile and increased with increase in temperature from 30° to 50°C. The mineral N released in the soils at 40°C in 7 days and at 50°C in 2 days were significantly correlated with the mineral N released in 14 days at 30°C. The results indicate that short‐term water‐logged incubation test using incubation for 2 days at 50°C may be employed for assessing the potentially mineralizable N in these soils.

Key words:

• Alfisol
• N mineralization
• semiarid
• temperature coefficient
• Vertisol
• waterlogged incubation