Dry-Matter and Grain Yield, Nutrient Uptake, and Phosphorus Use-Efficiency of Lowland Rice as Influenced by Phosphorus Fertilization

摘要

Phosphorus (P) deficiency is one of the most yield-limiting factors in lowland acid soils of Brazil. A field experiment was conducted during two consecutive years to determine dry-matter and grain yield, nutrient uptake, and P-use efficiency of lowland rice (Oryza saliva L.) grown on an acidic Inceptisol. Phosphorus rates used in the experiment were 0, 131, 262, 393, 524, and 655 kg P ha~(-1) applied as broadcast through termophosphate yoorin. Dry-matter yield of shoot and grain yield were significantly (P < 0.01) and quadratically increased with P fertilization. Concentrations (content per unit dry-weight leaves) of nitrogen (N), P, and magnesium (Mg) were significantly increased in a quadratic fashion with the increasing P rates. However, concentrations of potassium (K), calcium (Ca), zinc (Zn), copper (Cu), and iron (Fe) were not influenced significantly with P fertilization, and Mn concentration was significantly decreased with increasing P rates. Phosphorus use efficiencies (agronomic, physiological, agrophysiological, recovery, and utilization) were decreased with increasing P rates. However, magnitude of decrease varied from efficiency to efficiency.