Adaptation of “PourThru” for evaluation of substrates with different granulometries

Abstract

Periodic monitoring of the substrate solution allows the nutritional control of plants to be done more quickly and conveniently. In order to this monitoring become a routine among the producers of potted flowers, a standardization of non-destructive methods and easy application are required. This study was conducted in order to adapt of the “PourThru” methodology for substrate evaluation with different particle sizes. It was conducted on substrates with different particle sizes. Two tests were performed to define the amount of water to be applied, the time between irrigation and the collect of the leachate. Both tests were done using substrates with grain size 4-2 mm, 2-1 mm <4 mm <2 mm <1 mm and four repetitions. For the test I, we used the factorial 5 x 4 (5 particle sizes and 4 volumes of water), with volumes of 50, 75, 100 and 125 mL. For test II, we used the 5 x 5 factorial (5 granulometry balance and 5 times), with times of 30, 60, 90, 120 and 150 minutes. The leach solution was evaluated for electrical conductivity and pH. The methodology presented showed constraints when the substrates had particle sizes between 4 and 2 mm, and less than 1 mm. The larger the particle sizes is, the greater is the formation of preferential channels that leads to the possibility of mixing the water used as carrier and the solution to be leached is. The smaller the particle size is, the greater is the tendency of adsorption of the nutrients by the particles. For the pine bark substrate and vase with 1.3 L, it is suggested 60 minutes as settling time and the application of 75 mL of water for leaching the displacement.