N management in San Joaquin Valley Acala cotton: soil profile N responses to management

摘要

The response of Acala cotton (Gossypium hirsutum L.) in California to a range of applied nitrogen treatments were investigated in a five year, multi-site experiment. Goals of this portion of the large field trial were to identify patterns of changesin soil nitrate-N status with depth within fields used in the experiments and identify the degree to which residual soil nitrogen in the soil profile could impact crop responses. Site by site analysis of soil nitrogen patterns in the soil profiles indicate varying degrees of potential for downward movement of soil nitrate N not utilized by the cotton plants during the season, and wide variation in residual soil N across sites.