03164naa a2200253 a 450000100080000000500110000800800410001902400310006010000190009124501510011026000090026152024280027065000090269865000090270765000120271665000190272865000100274765000110275765000230276865000090279165000090280065000100280977300910281912124522022-04-04       2001    bl uuuu     u00u1 u    #d7 a10.1081/CSS-1001042202DOI1 aFAGERIA, N. K.  aAdequate and toxic levels of copper and manganese in upland rice, common bean, corn, soybean, and wheat grown on an oxisol.h[electronic resource]  c2001  aCopper (Cu) and manganese (Mn) play an important role in many biochemical functions of plants. Knowing their adequate and toxic levels in soil and crop plants can be helpful in better fertilizer management and improving crop yields. Ten greenhouse experiments were conducted to determine adequate and toxic levels of Cu and Mn in upland rice (Oryza sative L.), common bean (Phaseolus vulgaris L.), corn (Zea mays L.), soybean (Glycine max L.), and wheat (Triticum aestivum L.) grown on an Oxisol. The Cu levels used were 0, 2, 4, 8, 16, 32, 64, and 96 mg kg-1 of soil applied through Cu sulfate. Similarly, the Mn levels used were 0, 10, 20, 40, 80, 160, and 320 mg kg-1 of soil. Ninety percent maximum relative dry matter yield of shoot was used to determine adequate level and decrease in 10% dry matter yield after achieving maximum value was used to determine toxic level. Adequate Cu application rate was 3 mg kg-1 for upland rice, 2 mg kg-1 for common bean, 3 mg kg-1 for corn, and 12 mg kg-1 for wheat. For soybean, there was no necessity to apply Cu to achieve 90% of maximum yield. Copper toxicity was observed when rice received 51 mg Cu kg1, common bean 37 mg Cu kg1, corn 48 mg Cu kg1, soybean 15 mg Cu kg1, and wheat 51 Cu kg1 of soil. Adequate soil test level of Cu was 2 mg kg-1 for upland rice, 1.5 mg kg-1 for common bean, 2.5 mg kg?1 for corn, 1 mg kg-1 for soybean, and 10 mg kg?1 for wheat, when Mehlich-1 extracting solution was used. Toxic level for the same extractor was 48 mg kg-1 for upland rice, 35 mg kg-1 for common bean, 45 mg kg-1 for corn, 10 mg kg-1 for soybean and 52 mg kg-1 for wheat. When DTPA extracting solution was used, the adequate soil test level was 1 mg kg-1 for upland rice, 0.5 mg kg-1 for common bean, 1.5 mg kg-1 for corn 0.5 mg kg-1 for soybean, and 8.5 mg kg-1 for wheat. For the same extractant, the toxic level was 28 mg kg-1 for upland rice, 18 mg kg-1 for common bean. 32 mg kg-1 for corn, 6 mg kg-1 for soybean, and 28 mg kg-1 for wheat. Adequate plant tissue level was 15 mg kg-1 for upland rice, 6 mg kg-1 for common bean, 7 mg kg-1 for corn and soybean, and 14 mg kg-1 for wheat. Toxic level in plant tissue was 26 mg kg-1 for upland rice, 10 mg kg-1 for common bean, 11 mg kg-1 for corn, 10 mg kg-1 for soybean, and 17 mg kg-1 for wheat. These results suggest that crop species differ in adequate and toxic levels of Cu in soil and plant tissue for maximum yield.  acorn  arice  aFeijão  aFitotoxicidade  aMilho  aOxisol  aPhaseolus Vulgaris  aSoja  aSolo  aTrigo  tCommunications in Soil Science and Plant Analysisgv. 32, n. 9/10, p. 1659-1676, 2001.