Ascensão capilar de água em substratos de coco e de pinus

Abstract

The capillary irrigation in nursery production could give advantages in water use and its correct application demands knowledge about capillary water rise through root growth media, an attribute poorly studied. This research had as objective to evaluate water capillary rise in commercial pine and coconut substrates for two particle size distributions and two moisture conditions, to indicate the substrate with the best physical characteristics for capillary irrigation. The capillary rise determination method was applied on disassembled rings column filled with substrates, evaluating the following contact durations of the column bottom with water surface: 0.25, 0.5, 1, 2, 4, 8, 16 and 24 hours, with 10 repetitions per time. The results showed that the fine pine and coconut substrates had the higher water rise during the 24 hours test. Moreover, the hydrophobic state presented by coconut substrate indicated high irrigation frequencies for this material in comparison to pine substrate, avoiding that drying conditions become irreversible. The pine bark substrate did not show this problem, needing longer irrigation intervals, especially with the fine texture one. Due to the greater water holding and water rise capacity for wet conditions, the fine coconut substrate showed more suitable for capillary irrigation in small recipients.