Nitrogen Management Planning in California.

1.0 NM CEU

Register Now: http://agronomy.peachnewmedia.com/store/seminar/seminar.php?seminar=80709

California has among world’s most intensively managed agricultural production systems in which high value fruit, nut, and vegetable crops are grown under irrigation with year-round cropping in some areas.   Historically, these high value crops received large amounts of nitrogen (N) fertilizer to assure top yields of high quality crops leading to groundwater in some basins becoming contaminated with N.   The State Water Control Board (SWCB) is mandated to protect the groundwater in California.  The SWCB, working with the Regional Water Control Boards (RWCB), has implemented mandatory N management planning in which growers must account for all sources of N including preplant soil test N, N mineralized from soil organic matter, and N in irrigation water as well as soil and foliar applied N sources.  The total N available to the crop must correspond with the amount of N that will be removed in the crop, based on anticipated yield and typical N concentration in the portion of the crop that is removed from the field.  Nutrient management plans must be developed by a Certified Crop Adviser (CCA).  Each management unit (field and crop) must have its own N management plan; thus, fields in some areas will have up to four management plans per year.  These plans are reported to the RWCB annually and are available for public inspection. This intense N management has increased grower costs to create and implement these plans while creating opportunities for closer collaboration and ties between fertilizer dealers and growers.  There are many unanswered questions about liability for groundwater contamination and the possibility of ‘citizen lawsuits’ against farmers and crop advisers.  The situation is still unsettled and will likely not be settled until current and future lawsuits work their way through the courts.