Root morphology of greenhouse produced muskmelon under sub-surface drip irrigation with supplemental soil aeration

A fractional factorial experiment was designed to study the response of greenhouse-produced muskmelon root system to 3 levels of sub-surface drip irrigation in combination with drip-tubing placed at 3 different depths in the soil, and 4 frequency levels of supplemental soil aeration. Drip irrigation (I) levels were 70, 80, and 90% of field capacity (170,180, 190) in combination with sub-surface tubing placement depth (D) at 10, 25, and 40 cm (D-10, D-25, D-40). Supplemental aeration frequency levels were none, daily, and at 2 and 4-day intervals (A(N), A(1), A(2), A(4)). Total root length, surface area, and root volume and their distribution by diameter of the root system were measured using the WinRHIZO image analysis software. The results showed that the total length and surface area for D-40 increased by about 48% and 24%, respectively than D-10. The two root parameters for A(1) increased by 83% and 63%, respectively than A(N). For the I-70 treatment, the two parameters increased by 10% and 20%, respectively than Igo. These effects were primarily due to changes in these morphological parameters for the <= 1 mm diameter roots. (C) 2016 Published by Elsevier B.V.