MICRONUTRIENTS USE EFFICIENCY IN TROPICAL COVER CROPS AS INFLUENCED BY PHOSPHORUS FERTILIZATION
2015
NAND KUMAR FAGERIA | ENDERSON PETRÔNIO DE BRITO FERREIRA | ADRIANO MOREIRA KNUPP
Deficiency of micronutrients is increasing in the recent years in cropping systems in many parts of the world and cover crops are important components of cropping systems. A greenhouse experiment was conducted to evaluate copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn) use efficiency in 14 tropical leg-ume cover crops grown on an Oxisol. The P levels used were low (0 mg kg-1), medium (100 mg kg-1) and high (200 mg kg-1). The P X cover crops interactions were significant for Cu, Fe, Mn, and Zn use efficiency (tops dry weight/unit nutrient uptake). Hence, cover crop species varied in nutrient use efficiency with change in P levels. The micronutrient use efficiency was in the order of Cu > Zn > Mn > Fe. Higher Cu use efficiency was associated with lower uptake of this element, in the cover crop tops compared to other micronutrients. Similar-ly, lower efficiency of Fe and Mn was associated with their higher uptake in the tops of cover crops. Overall, Cu and Mn use efficiency was decreased when P level was raised from low to medium level and then it was constant. Iron use efficiency was increased with increasing P level but Zn use efficiency was constant with the addition of P fertilizer
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