Determination and assessment of procedures of the pour-through nutrient extraction procedure for bedding flats and plug trays

Abstract

A study was conducted to develop, demonstrate and assess the Pour-through nutrient extraction procedure for bedding flats and plug trays. The Pour-through technique involves pouring a prescribed volume of water on a recently irrigated medium, then collecting and analyzing the leachate to predict nutrient availability in the medium. The volume of water necessary to collect a Pour-through from a 1204 bedding flat was determined to be 5 ml per cell based on leachate pH and electrical conductivity (EC) at various volumes of water applied. Impatiens wallerana ‘Super Elfin Red’ and Tagetes erecta ‘Apollo’ were grown in 1204 bedding flats at three fertilizer concentrations to assess the overall potential of the Pour-through procedure. Analysis of leachate EC, pH, and macro- and micro-nutrients indicated that the Pour- through method of nutrient extraction was sensitive and effective in extracting available nutrients. Leachate analysis was positively correlated to fertilizer nitrogen concentration, shoot tissue dry weight, and nutrient concentrations of conventional Saturated Media Extract methods. Preliminary studies indicated that evenly applying 200 ml of water per plug tray cells produced adequate leachate (50 ml) for laboratory analysis of EC, pH, and macro- and micro-nutrients. Impatiens wallerana ‘Super Elfin Red’ and Tagetes erecta ‘Apollo’ were grown in plug trays at three fertilizer concentrations to assess the overall potential of the Pour-through procedure. Analysis of leachate EC, pH, and macro- and micro-nutrients indicated that the Pour-through method of nutrient extraction was sensitive and effective in extracting available nutrients. Pour-through leachate analysis was positively correlated to fertilizer nitrogen concentration and to whole shoot tissue.