The Effect of Liquid and Conventional Fertigation Treatments on Commercial Tomato Production
Researchers compare liquid and conventional fertigation treatments for impact on yields of ‘Roma’ and ‘Beefsteak’ tomatoes.
Customized products work better for consumers because they meet their specific needs. Tomato nutrition is no different. Customized fertility programs are effective because they meet the specific nutrient requirements of the tomato crop. Fertigation is a good way to implement a customized nutrition program for commercial tomato production, especially when liquid fertilizers are used.
Many tomato growers use drip systems to provide plant nutrition through irrigation water, a process known as fertigation. Drip systems can accommodate both water-soluble granules and liquid fertilizers, but there are some definite advantages to using liquid over water-soluble granular formations. This article will discuss three of them.
According to a study performed by AgroLiquid, fertigation treatments using liquid fertilizer have a greater impact on tomato yields than conventional treatments. For the experiment, researchers compared the effects of liquid and conventional fertigation treatments on the yield of fresh market ‘Beefsteak’ and ‘Roma’ type tomatoes.
Materials and Methods
Soil preparation included banding liquid fertilizer down the center of the plots or broadcasting dry fertilizer into the area. A swath of plastic mulch covered the center 2 ft. of each 5 ft. wide plot.
Growers doused the soil around each transplant with approximately 4.2 oz. of transplant solution (~300 GPA) which contained the fertilizers described in Table MT1. The rest only had water. For early season disease and insect management, Ridomil and Admire were added to the transplant water.
Drip applications started at early bloom and continued until mid-September. Eight weekly treatments occurred during the season. Upon maturity, ripe fruits were counted and weighed to determine yields. Spring rains delayed planting and harvesting, so a majority of the yields for all treatments occurred during the final portion of the season. Six harvests took place throughout the season; the initial harvest occurred on Aug. 13 and the last on Oct. 18.
When 100% of the fertilizer was applied pre-plant, the AgroLiquid base program (Trt. #2, See Figure MT1) surpassed the conventional program (Trt. #1) for the yield of ‘Beefsteak’ and ‘Roma’ type tomatoes.
During the growing season, drip applications (Trt. #4-#6) supplied 40% of total nitrogen, and in some cases (Trt. #5 and #6), nearly half of the potassium. These changes in the application timing improved tomato yields without using any additional fertilizer when compared to the Agro-Liquid base program (Trt. #1). Table MT1 shows these changes in application timing and volumes.
Kalibrate, listed here as K-10 (Trt. #3 and #6), matched the performance of Sure-K® (Trt. #2 and #5) when it was used in a similar manner. Kalibrate has some winter storage advantages over Sure-K®.
Flexibility and Uniformity
Fertigation allows the grower to apply smaller applications on a frequent basis with greater uniformity. Conventional fertilizer programs can be hit or miss because they usually consist of two or three applications per season. Depending on a plant’s stage of development, it may receive too much or too little fertilizer, or it may not be able to utilize the nutrients at all.
Fertigation improves nutrient uptake because it targets the active root zone; plants have easy access to the nutrients they need. Application rates can also coincide with a crop’s nutrient needs at different growth stages. For instance, growers can start with smaller doses at planting, increase the dose during the vegetative stage, and then decrease the dose as the crop nears the fruiting stage and maintain crop health at the end of a plant’s lifecycle.