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Production Guide: Nitrogen and Water Management for Coastal Cool-Season Vegetables

G.S. Pettygrove, S.R. Grattan, B.R. Hanson, T.K. Hartz,
L.E. Jackson, T.R. Lockhart, K.F. Schulbach and R. Smith.

Publication 21581, Division of Agriculture and Natural Resources, University of California. 1998.

The main cool-season vegetables grown in California are lettuce, broccoli, celery, cauliflower and cabbage. The majority of these vegetables are grown in the central and southern coastal areas in Santa Barbara, San Luis Obispo, Ventura, Santa Cruz, Monterey and San Benito counties. These highly productive systems depend on the use of nitrogen fertilizers and a ready supply of irrigation water. Unfortunately, because of shallow root systems, water and nitrogen use efficiency of these vegetable crops is quite low. This results in leaching of nitrate to the groundwater and increasing nitrate groundwater levels which is the primary source of drinking water supply in much of the coastal area.

This production guide provides important information about ways of managing water and nitrogen more efficiently in order to reduce the problem of groundwater contamination. The measures and practices described in the guide were developed by a group of growers, fertilizer retailers, crop consultants, and University of California research and extension personnel. The purpose of the manual is to provide technical information and recommendations about the management of nitrogen and water to all those involved in the production of cool-season vegetables.

The production guide includes a clear and concise discussion on the nitrogen cycle and how various farming practices can influence it. The authors provide detail on the relative amounts of various forms of nitrogen in the soil, the factors that affect the transformation of nitrogen, as well as its availability for crop uptake. Other topics include nitrogen additions to the soil/plant system, plant uptake and harvest removal, and nitrogen loss pathways. The production guide is supplemented with numerous tables and figures and several appendices on soil and plant tissue testing, cover crops, manure management, and other practices that alter crop nitrogen use efficiency. The recommended practices include aspects of fertilizer management, irrigation system design and operation, and general crop and soil management.

The production guide was prepared with funding from the California State Water Resources Control Board with additional funds from the Fertilizer Research and Education Program of the California Department of Food and Agriculture.

This publication is available for $10 from the University of California DANR Communications Services at (800) 994-8849 or (510) 642-2431.