Methods of measuring forms of available soil nitrogen. 2. Effect of cropping on the mineralization of soil native organic nitrogen and residual effect of fertilizer nitrogen In six croppings of tobacco
Taki, M.; Yamashita, T.
Bull. Hatano Tob. Exp. Stn 60: 80-88
Cropping with tobacco accelerated the mineraliza-tion of soil organic N. After soil incubation, N mineralization was greater in cropped soils than in fallow soils, suggesting the occurrence also of N immobilization. N uptake from fertilizer N decreased rapidly with increasing number of crops; after the third it was small. The cumulative recovery of fertilizer N by the plant up to the 6th crop was up to 80%. N uptake from native soil N showed little decrease with increasing number of croppings.