Nitrogen, salinity, and acidity distribution in an irrigated orchard soil as affected by placement of nitrogen fertilizers
Felizardo, B.C.; Benson, N.R.; Cheng, H.H.
Soil Science Society of America Proceedings 36(5): 803-808
A 10-year old apple orchard on loamy sand was fertilized with 112 kg/ha N as (NH4)2SO4, NH4NO3 or Ca(NO3)2 broadcast or banded to give a fertilizer concentration of 10 or 100 times that of the broadcast plot. The NH4- and NO3-N contents of the soil decreased rapidly even under narrow band placements. There was considerable NO3-N movement. After 1 year, neither the total nor the inorganic N level in the fertilized plots was significantly different from the control. High conductivity occurred under narrow bands 5 months after application (10, 6 and 3 mmho/cm for Ca(NO3)2, (NH4)2SO4 and NH4NO3, respectively) but the effect rapidly diminished with time. All three fertilizers decreased soil pH.