WATER AND FERTILIZER MANAGEMENT OF MICROIRRIGATED FRESH MARKET TOMATOES

Abstract

ABSTRACT Field studies were conducted to evaluate water and fertilizer management for fresh market tomato production on raised, plastic mulched beds using microirrigation with buried drip lines on a sandy soil. The studies were additionally designed to compare microirrigated tomato production with the typical subirrigation (seepage) production and to provide local growers with management guidelines. Tests were evaluated during two fall crop seasons and one spring crop season. Tensiometers placed at 0.15 m depths were manually monitored and used to aid with irrigation scheduling. Two soil water management levels were used to evaluate a low moisture management (LMM) treatment which was scheduled to maintain soil water tensions no drier than 10 to 15 kPa, and a high moisture management (HMM) treatment which was operated similar to current grower practice and provided water to maintain soil water tensions between 5 and 10 kPa. Two treatment levels of seasonal nitrogen (N) and potassium (K) applications were used to evaluate low (reduced) fertihzer (LF) applied at 224 and 372 kg/ha of N and K and high fertilizer (HF) applied at 336 and 558 kg/ha ofNandK. Spring crop production yields and water requirements were greater than those associated with the fall season. Yields from the HMM schedule were greater than those for the LMM schedule during the spring crop, but not during either of the two fall crops. In addition, the HMM schedule during the spring crop increased the proportion of extra large fruit. Yields from microirrigated plots were equivalent to those from the subirrigated (seepage) plots. No significant benefit was realized by using the HF vs. LF levels of fertilizer from either of the fall crops or from the spring crop. Thus, spring production of microirrigated fresh market tomatoes requires more water than fall production, yet yields are higher and response to irrigation management is more sensitive than fall season production. Improved water and fertilizer management by using tensiometers and fertigation with microirrigation of fresh market tomatoes produced on sandy soils can result in reduced water and fertilizer applications as compared to those associated with current subirrigation (seepage) methods. KEYWORDS. Microirrigation, Tomatoes, Fertilizer.