|CAMBERATO, JAMES - Purdue University
|WIETHORN, MATTHEW - Purdue University
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/2022
Publication Date: 12/28/2022
Citation: Penn, C.J., Camberato, J., Wiethorn, M. 2022. How much phosphorus uptake is required for achieving maximum maize grain yield? Part 1: Luxury consumption and implications for yield. Agronomy Journal. 13(1).Article:95. https://doi.org/10.3390/agronomy13010095.
Interpretive Summary: Improved precision in phosphorus (P) crop recommendations will increase agronomic and economic efficiency and conserve geologic phosphate reserves. The purpose of this study was to determine the minimum P uptake required to achieve maximum grain yield in corn. Three corn hybrids were studied in a sand-culture hydroponics system in which all non-P nutrients were supplied at sufficient levels through fertigation. Six different levels of P was applied. Corn was harvested after reaching full maturity and separated into root, stem, leaf, tassel, cob, husk, and grain, followed by analysis of plant nutrients to calculate nutrient uptake into each plant part. Grain yield and total biomass increased with P uptake, however, grain yield reached maximum at 580 mg uptake per plant. Corn continued to uptake P beyond that level with no additional increase in grain yield, while total biomass continued to increase. This illustrated that corn can experience luxury consumption of P. In addition, grain yield actually decreased with P uptake beyond 580 mg per plant. Luxury consumption of P by corn ultimately translates to reduced economic efficiency for over-fertilized soils. The optimum value of 580 mg P uptake per plant provides an uptake goal for developing future nutrient management recommendations.
Technical Abstract: Development of a more precise and process-based tool for making phosphorus (P) recommen-dations 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.