Effects of different types and rates of organic manures on Egyptian broomrape (Orobanche aegyptiaca Perss.) control in tomato (Lycopersicon esculentum Mill.)

In order to study the effect of different types and rates of animal manure and spent mushroom compost on controlling Egyptian broomrape (Orobanche aegyptiaca Perss.) in tomato (Mill. Lycopersicon esculentum), two studies were conducted on randomized complete block design with three replications at Research green house, College of Agriculture, Ferdowsi University of Mashhad and Nemooneh field of Astane Ghods Razavi during two years of 2009 and 2010. Greenhouse study treatments were consist of poultry, cow, sheep manure and spent mushroom compost, which each one applied at four rates (10, 20, 30 and 40 t.ha-1). Field experiment treatments were included of poultry, cow and sheep manure that each one applied at two rates (20 and 40 t.ha-1). Result of the greenhouse study indicated that poultry manure significantly reduced orobanch infestation and increase tomato dry weight compared to control. But in the field experiment, the maximum fruit yield (68 t.ha-1) with the minimum orobanch dry weight were obtained with sheep manure. The effect of cow manure was similar to poultry manure in all measured traits. In the field study, rates of manure application had no significant effect on orobanch fresh and dry weights. The findings indicated that all treatments of animal manure reduced orobanch infestation. But the mechanism of orobanch growth suppression due to animal manures application is unknown. It seems fermentation of different organic matters can produced heat and the resulting toxic compounds such as certain organic acids, ammonia and ammonium salts that may reduce orobanch growth at proper concentrations.