Cotton Irrigation

Cotton irrigation has been on-going for the past four weeks and will likely continue three to four weeks depending on weather conditions.  Watering schedules vary from grower to grower and field to field.  In addition, watering schedules vary depending on the type of irrigation system in use.  Fields watered with a center pivot system tend to be watered on a more frequent basis than those watering with furrow irrigation.  It is not uncommon for 0.5” to 1.0” per acre to be applied using center pivot irrigation whereas 2” – 3” per acre is commonly applied with furrow irrigation.  Irrigation frequency is often an inexact science and is based on past experience.  Dr. Jason Krutz at the Delta Research and Extension Center is currently evaluating the use of soil moisture sensors to aid in irrigation scheduling.

 Irrigation termination is more well defined than irrigation scheduling.  Generally speaking, irrigation termination occurs in fields that are furrow irrigated at first cracked boll.  However, some prefer to make an additional irrigation application after first cracked boll.  Given the truncated growing season and the potential for boll rot following irrigation applications after first cracked boll, these applications should be approached with caution.  Irrigation termination in fields that are watered using center pivot systems typically occurs a week to ten days after first cracked boll.  The additional time prior to terminating irrigation after first cracked boll using center pivot systems compared to furrow irrigation is directly related to the amount of water delivered per acre with each of these systems.  A center pivot system delivers less water per acre, thus an additional application may be needed to maximize yield.