Lachover, D.

A study of the causes of typical disorders found in dwarf gladiolus grown as a cash crop in many fields in Israel, had two basic objectives: to determine whether the characteristic malnutrition symptoms were due to iron deficiency; and to compare the effectiveness of different iron treatments, based on the soluble and plant-mobile chelate FeEDDHA, from two production sources. A pot experiment was carried out on the effect of the chelates on two characteristic soil types, differing widely in their lime content. Dwarf gladiolus grown without iron application, or receiving treatment to the corms only, showed stunted development and a gradual typical chlorosis, similar to that observed in the fields with the iron chelates applied as top dressing in the irrigation water. The results obtained show the importance of iron in the crop's nutrition. However, the data indicate that the severity of iron hunger signs or the level of response to iron dressings is related to the level of lime in the soil. No significant advantage in response was obtained with the various frequencies as compared with a single top-dressing. A good correlation was found between the criteria for evaluation the nutritional status of the crop and certain 'commercial qualities' of the flowers. Interesting findings were obtained concerning the fluctuations in yield levels from the different cuttings during the blossom period. In no respect was there any significant difference between the imported product Sequestrene 138, and the locally produced Chelafer. © 1979 Dr. W. Junk b.v. Publishers.