Corn yield response to phosphorus and potassium fertilization in Arkansas. Issue 2 (9th September 2021)

• Record Type: Journal Article
• Authors: Drescher, Gerson L.; Slaton, Nathan A.; Roberts, Trenton L.; Smartt, Alden D.
• Is Part Of: Crop, forage & turfgrass management. Volume 7:Issue 2(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-09-09
• Subjects: Crop science -- Periodicals; Agronomy -- Periodicals; Forage -- Periodicals; Turf management -- Periodicals; Agronomy; Crop science; Forage; Turf management; Periodicals; Electronic journals; 633
• DOI: 10.1002/cft2.20120
• Languages: English
• ISSNs: 2374-3832

Abstract

Abstract: Phosphorus and potassium are key nutrients for plant physiological processes and are required in large amounts for adequate corn ( Zea mays L.) production. Corn is a major row crop, and up‐to‐date soil test‐based fertilizer recommendations are required to enhance production and profitability. The results from 32 P and 42 K field trials evaluating irrigated corn response to fertilizer P and K rates were used to (i) correlate corn's relative yield response to Mehlich‐3 soil test P and K, (ii) determine the frequency and magnitude of the yield response to fertilization, and (iii) calibrate fertilizer P and K rates to soil test P and K. The quadratic and linear models identified 36 parts per million (ppm) P ( r 2 = .68, P < .0001) and 110 ppm K ( r 2 = .36, P < .0001) as the Mehlich‐3 soil test P and K values needed to produce 95% of maximum yield without fertilization. Additional research is needed on soils with P < 15 and > 35 ppm and K < 60 and > 120 ppm to enhance the scope of data in the analyses and improve our understanding of corn's response to P and K fertilization. The current thresholds defining soil test K levels perform well in interpreting soil K availability and corn's response to K fertilization. Mehlich‐3 soil test P level definitions should be modified to improve the accuracy of soil test‐based decisions for irrigated corn. The calibration results suggest the recommended P2 O5 and K2 O rates are greater than needed to maximize yield. Core Ideas: The Mehlich‐3 soil test P producing 95% relative yield (RY) without fertilizer P was 36 ppm. Existing soil test‐based P recommendations should be modified to improve their accuracy. The critical Mehlich‐3 soil test K to produce 95% RY without fertilizer K was 110 ppm. The frequency and magnitude of corn yield response to P fertilization are correlated. The greatest yield benefit from P and K fertilization occurs in soils testing very low and low .