بررسي اثر مصرف مس بر عملكرد و تركيب شيميايي برنج و تعيين حد بحراني مس در تعدادي از خاك هاي آهكي استان فارس

Effect of Cu Application on Yield and Chemical Composition of Rice and Determination of Critical Limit of Copper in Some Calcareous Soils of Fars Province

There is little, if any information available regarding Cu availability in calcareous soils of Iran. The availability of this nutrient is generally low in such soils and further reduced by waterlogging. Therefore, it is very important to assess study effect of applied Cu to rice plant. In this study, Nineteen surface soil samples (0 - 30 cm) were collected from different fields in Fars Province with a wide range of physical and chemical properties. DTPA-TEA used to extract available Cu. Furthermore, the effects of two levels of Cu (0, 2.5 mg kg"1 as CuS04 . 5 H20) on the growth and Cu concentration and uptake in vegetative and reproductive stages were studied in a completely randomized design with 3 replications. Thousand grain weight, harvest index, biological yield and chemical composition of plant were also determined. Mean top dry weight, grain and straw yield, Cu concentration and uptake, thousand grain weight, harvest index and biological yield were significantly higher in Cu-treated soils than those in untreated soils. Application of Cu decreased concentration of Fe, Mn and Zinc by plant. Furthermore, The critical level of Cu in these soils with DTPA was calculated 1M,g/g with Cate-Nelson method and for obtaining 80%, 85% and 90% relative yields with Mitscherlich- Bray method, critical levels of Cu in soils were obtained 1.40,1.65 and 2 (Mg/g, respectively. Whereas, critical level of Cu in grain was determained 5.93 Mg/g.