Effects of Drain Depth of Vertisols, Nitrogen Source

Vertisols, characterized by low soil nitrogen content and low-basic water infiltration rate are prone to waterlogging in highland areas with abundant rainfall. In view of these, this field study was conducted at Ambo Agriculture Research Center experimental site, with the aim of determining the effects of drain depth on temporal and spatial soil moisture variation, and rooting depth (RD) and yields of maize grown on Vertisols and to identify appropriate nitrogen source and time of application for maize production. The experiment involved complete factorial arrangement of five drain depths (0, 15, 30, 45 and 60 cm), two nitrogen (N) sources (urea and ammonium sulfate) and two timings of N applications (twice and thrice) laid out in Randomized Complete Block Design (RCBD) with three replications. The results revealed that the drains, 45 and 60 cm deep, resulted in lower soil moisture content within the 0-45 cm layer, deeper rooting system, and higher grain and stover yield than did the 0, 15 and 30 cm deep drains.