Among all essential plant nutrients, nitrogen (N) is the most unstable in the soil and also the most yield-limiting nutrient for berry and vegetable crops production in Ventura County. The significant fluctuation of in-season soil N levels occurs due to a combination of factors including numerous biological and chemical processes, variable uptake rates among all crops, uneven rainfall pattern, irrigation inefficiency and soil type, among others. These factors make it challenging to accurately assess soil N throughout the growing season so that fertilization rates can be adjusted accordingly. Mismanagement of N fertilizers very often leads to yield decrease when soil levels are insufficient, and to nitrate leaching when both soil levels exceed immediate crop needs and irrigation and rainfall amounts exceed the field capacity of the soil.
For regulation requirements on N use and reporting, click here.
For accessing soil N with the soil nitrate quick test, click here.
For N management in organic systems, click here.
For N management in conventional systems, click here.