Dry-matter yield, nodulation and nutrient uptake by soybean (Glycine max (L.) Merrill), as a function of levels of P and Zn, in soils of Minas Gerais

Abstract

The effects of levels of phosphorus and zinc on dry matter production, nodulation and nutrient uptake by soybean (Glycine max (L.) Merrill cv. 'UFV-l') were determined in greenhouse. Three levels of phosphorus, corresponding to 0, 200 or 400 kg P2O5/ha, and three of zinc, corresponding to 0, 15 or 30 kg of zinc sulfate/ha were tested in three soils. Plants were grown in clay pots containing 7 kg of either a Red-Yellow Latosol (LV), a Dark-Red Latosol, medium texture (LEm), or a Dark Red Latosol (LE. Seeds were inoculated with strains of Rhizobium japonicum during planting. Phosphate fertilization increased dry matter production and nodulation while zinc fertilization did not. Less dry matter was produced on LEm while most nodulation occured on this soil and the LV, The concentrations of N, Ca, Mg and Zn decreased with phosphate fertilizer suggesting a dilution effect as evident in plant growth intensity. The largest dose of phosphate decreased level of K in old leaves but increased K in young leaves and stems through translocation.