ROLE OF IRRIGATION SCHEDULING AND POTASSIUM FERTILIZATION ON SOIL MOISTURE DEPLETION AND DISTRIBUTION OF QUINOA ROOT (IRRIGATION SCHEDULING FERTILIZATION AND THEIR EFFECT ON MOISTURE DEPLETION AND YIELD)

Abstract

A field experiment was carried out during the spring season 2017 in the fields of College of Agriculture, University of Baghdad in Abu Ghraib (25 km west of Baghdad), to study the role of irrigation scheduling and potassium fertilization on the moisture depletion and distribution of quinoa roots with four irrigation treatments (0.8, 1.0, 1.2 and 1.4) PEF and four levels of Potassium fertilization (0, 60, 120 and 180 kg K2O.ha-1). Results showed the effect of irrigation treatments on the water depth applied during quinoa growing season. It was noticed that the lowest value of water used was 302.9 mm.season-1 which was obtained at 0.8 PEF, while the highest seasonal water consumptive use was 325.5 mm season-1 for the treatment 1.4 PEF. The best value of water use efficiency was 1.63 kg m-3 was for 1.2PEF irrigation treatment with seasonal water consumptive use was 323.0 mm and highest grain yield 5.13 ton ha-1 at potassium fertilization level of 120 kg.ha-1. The values of monthly plant factor (Kc) were 0.67, 0.41, 0.70 and 0.55 on February, March, April and May respectively depending on the date of 1.2 PEF treatment. Results also showed the highest distribution percentage of quinoa roots was found at the upper depth of soil (0.00- 0.30 m) and increased with increasing in values of PEF, the same results was found for the moisture depletion for all irrigation treatments approximately, 5.25 ton ha-1 were obtained and consider as the highest yield of quinoa grain for treatment PEF 1.2 at the level of fertilization of 120 kg ha-1