Determination of Micronutrient Critical Levels in Soil and Plant (Dry land Wheat) in North Western of Iran
2003
Fazi Asl, Vali
In order to determine Fe, Mn, Zn, Cu and B micronutrient critical levels for dry land wheat in Western Azarbayejan, Eastern Azarbayejan, Kurdestan and Kermanshah dry land areas, experiments were conducted in RCBD design with 4 treatments for each micronutrients with three replications for four years (1998-2002). Fe fertilizer rates were 0, 5, 10 and 15 kg.ha -1 from iron chelate (NaFeEDDHA)Mn fertilizer rate 0, 5, 10 and 15 kg.ha -1 from manganese sulfateZn fertilizer rates 0, 5, 10 and 15 kg.ha -1 from zinc sulfateCu fertilizer rates 0, 2.5, 5 and 7.5 kg.ha -1 from copper sulfate and B fertilizer rates 0, 1.5, 3 and 4.5 kg.ha -1 from boric acid sources. The data were used in different models and critical levels were determined in models. Results showed that Fe, Mn, Zn and Cu critical levels for obtaining 90% grain yield by Mitshcherlich model were 8.8, 11.3, 0.88 and 1.8 mg.kg -1 in soil respectively, in all regions. Boron critical level was 0.65 mg.kg -1 determined by an another model similar to Mitshcherlich equation. From the results for the critical levels of cation micronutrients, the best model was Mitshcherlich equation (A=100). But for Boron, the best model was similar to Mitshcherlich equation (A=28.02). In addition, critical levels were also determined by Cate- Nelson 2 classes model for Fe, Mn, Zn and Cu were 8.5, 8, 0.55 and 1.65 mg.kg -1 respectively. Critical levels were determined at two different models, such as Cate- Nelson 2 and 3 class ANOVA models, the results indicated that three class Cate 'Nelson model compared to two class Cate 'Nelson model was effective. It can be concluded critical levels for micronutrients are differed at various models such as Cate- Nelson ANOVA model and Mitshcherlich equation. In addition, critical levels in dryland condition differed with irrigation condition.
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