How Much Phosphorus Uptake Is Required for Achieving Maximum Maize Grain Yield? Part 1: Luxury Consumption and Implications for Yield

Abstract

Development of a more precise and process-based tool for making phosphorus (P) recommendations requires detailed understanding of plant P uptake needs. Future adaptation of a nutrient uptake model for this purpose must utilize a mass-balance approach. The objectives of this study were to determine the minimum P uptake mass required for achieving maximum grain yield of maize and to evaluate plant P partitioning over a range of P uptake. Three maize hybrids were grown under optimal conditions using sand-culture hydroponics for precise control of the root environment. Plants were grown to maturity with six different P concentrations followed by biomass and nutrient partitioning analysis of various maize parts. Phosphorus uptake occurred in three phases with two steps of luxury consumption; (i) increased uptake with increased grain yield and total biomass until maximum grain yield was attained at 580 mg P uptake, (ii) further P uptake with increase in total biomass until 730 mg P uptake, but with decrease in grain yield; and (iii) additional P uptake with little to no increase in total biomass and continued decrease in grain yield. Luxury consumption of P implies that excess P fertility is an economic drag for grain production.