Nutrient Management Research Database

This work discusses strategies for using drip systems to reduce irrigation water use and fertigation to avoid nitrate leaching in processing tomatoes. The installation of Drip requires radical changes in water management strategies, but is also impacts soil fertility management, allowing for the potential reduction in nitrogen leaching losses as irrigation efficiency is increased. This work discusses the ways in which converting to Drip system will require adjustments in fertilizer programs. The pattern of nutrient uptake of high-yield processing tomato plants show that nutrient uptake is slow until fruit set begins. From fruit set until the fruit begins to ripen, fertigation management is critical, with macronutrient uptake being somewhat constant at approximately 5 lbs nitrogen, 0.5 lb phosphorus, and 6 lb potassium per day. Nutrient uptake slows 4 to 5 weeks before harvest. During this period it may be unnecessary to apply fertilizers. This paper includes general guidelines for macro-nutrient applications, timing, and plant monitoring of nutrient status.

This research paper is an overview of drip and fertigation strategies for processing tomatoes in California.

• It is unlikely that converting to fertigation will reduce total applied nitrogen if growers want to achieve maximum yields (50-60 tons per acre).
• 200 lb nitrogen per acre or less should be a sufficient application rates.
• The most critical time for fertigation management is between fruit set and fruit ripening.
• Nitrogen should be fertigated in multiple applications just before and during the rapid uptake phase of tomatoes.
• Phosphorus is normally applied pre-plant or at planting, as phosphorus supply is most limited in the early season.
• Therefore, fertigation may not be the best method for phosphorus application.