Improving lettuce production through utilization of spike wheel liquid injection systems

Spike wheel liquid injection systems were developed in the late 1980's as an improved method for applying fertilizer post emergence. Although studies have shown that use of the system provides measurable yield benefits in a variety of crops, limited studies have been conducted in lettuce production systems. This study addresses this shortcoming. The objectives of the project were to determine if spike wheel injection technology can be used in lettuce to 1) improve plant growth, nutrient uptake efficiency and crop yield and 2) determine if the system can be used to deliver soil applied pesticides post emergence. Replicated field trials were conducted in Yuma, Arizona in 2010 to achieve the stated objectives. Use of the spike wheel injector significantly improved mid-season lettuce plant weight and nitrogen uptake levels as compared to conventional knife blade fertilizer application systems. Despite these early advantages, crop yield was not significantly affected by fertilizer applicator method. The data also showed that the soil applied systemic insecticide Coragen can be effectively delivered post emergence using the point injection system. These data were very promising in that it implies that the system could also be used successfully to deliver other soil applied pesticide chemistries post emergence in lettuce crops. This would benefit the industry by greatly increasing the control options growers have for managing pests post emergence. Additional study is needed to confirm/validate the results of this one year study.