The timing of phosphorus availability to corn: what growth stages are most critical for maximizing yield

Authors: AMPONG, KWAME - Purdue University; Penn, Chad; CAMBERATO, JAMES - Purdue University

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/13/2024
Publication Date: 11/19/2024
Citation: Ampong, K., Penn, C.J., Camberato, J.J. 2024. The timing of phosphorus availability to corn: what growth stages are most critical for maximizing yield. Agronomy. https://doi.org/10.3390/agronomy14112731.
DOI: https://doi.org/10.3390/agronomy14112731

Interpretive Summary: Phosphorus (P) is necessary for growing field crops, yet excessive concentrations transported from agricultural land to surface waters can lead to degradation of water quality. Fertilizer P is also a finite geologic resource which requires much energy for extraction. Thus, increases in the efficiency of P uptake (i.e., making more with less) can help to improve economics, reduce P consumption, and protect water quality. This research focused on measuring the impact of P application timing to corn, on corn growth and yield. Corn was grown in a sand-culture hydroponics system to separate the impacts of soil-plant interactions. All nutrients were added through drip irrigation; two treatments of P concentrations were applied (low and sufficient) at three different growth phases: germination to 6-leaf vegetative stage (V6), V6 to the first reproductive growth stage (R1), and R1 to maturity (R6). Every combination of P concentration and growth stage was tested, resulting in eight different combinations. Growth stage V6 to R1 was the most critical for receiving P. In fact, if low P concentrations were applied before V6 and after R1, grain yield was not compromised if V6 to R1 stage received sufficient P. These results have implications for management and water quality. It suggests that soil P could be kept at low levels without compromising yield if P was side dressed at V6 instead of application at pre-planting. This would directly reduce the risk of P lost to surface waters.

Technical Abstract: Phosphorus (P) is critical for maximizing agricultural production and represents an appreciable input cost. Geologic sources of P that are most easily mined are a finite resource, while P transported from agricultural land to surface waters contributes to water quality degradation. Improved knowledge of P timing needs by corn (maize) can help to inform management decisions that increase P use efficiency, which is beneficial to productivity, economics, and environmental quality. The objective of this study was to evaluate P application timing on growth and yield components of corn. Corn was grown in a sand-culture hydroponics system that eliminated confounding plant-soil interactions and allowed for precise control of nutrient availability and timing. All nutrients were applied via drip irrigation and therefore 100% bioavailable. Eight P timing treatments were tested using “low” (L) and “sufficient” (S) P concentrations. At each of three growth phases, solution P application levels were changed or maintained, resulting in eight possible combinations: LLL, LLS, LSL, LSS, SLL, SSL, SLS, and SSS, where the first, second and third letter indicates P solution application level from planting to V6, V6 to R1, and R1 to R6, respec-tively. All other nutrients were applied at sufficient levels. Sacrificial samples were harvested at V6, R1, and R6 and evaluated for various yield parameters. Plants that received sufficient P between V6 and R1 produced significantly higher grain yield than plants that received low P between V6 and R1 regardless of the level of P supply before V6 or after R1. The grain yield of plants that received sufficient P at least once after V6 did not differ significantly from plants that received only sufficient P (SSS) due to; (1) greater ear P concentration at R1; (2) efficient remobilization of as-similates from stem and leaf to grains between R1 and R6 (source-sink relationship); (3) Higher kernel/grain weight; (4) less investment into root biomass.