Kelley, Kenneth W.

Murphy, Larry

Kansas State University

Kansas Agricultural Experiment Station Research Reports Volume 0 Issue 12 Keeping up with Research Article 112 1976 Residual Effects of Phosphorus on Dryland, Grain Sorghum (Milo) Kenneth W. Kelley Larry Murphy This report is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Kansas Agricultural Experiment Station Research Reports by an authorized administrator of New Prairie Press. Copyright 1976 Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. Brand names appearing in this publication are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products not mentioned. K-State Research and Extension is an equal opportunity provider and employer. Follow this and additional works at: https://newprairiepress.org/kaesrr Recommended Citation Kelley, Kenneth W. and Murphy, Larry (1976) "Residual Effects of Phosphorus on Dryland, Grain Sorghum (Milo)," Kansas Agricultural Experiment Station Research Reports: Vol. 0: Iss. 12. https://doi.org/10.4148/2378-5977.7349 Residual Effects of Phosphorus on Dryland, Grain Sorghum (Milo) Keywords Keeping up with research; 22 (1976); Kansas Agricultural Experiment Station contribution; no. 1556-S; Phosphorus; Residual effects; Grain sorghum; Milo; Dryland Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 License. This research report is available in Kansas Agricultural Experiment Station Research Reports: https://newprairiepress.org/kaesrr/vol0/iss12/112 JUNE 1978 Residual Effects of Phosphorus on Dryland Grain Sorghum (Milo)1 Kenneth W. Kelley and Larry Murphy2 Southeast Kansas Branch Experiment Station When phosphorus fertilizer is broadcast, it stays within 2 or 3 inches of the topsoil unless mixed deeper with tillage implements. So phosphorus can be stored in the soil without being leached from the root zone by rainfall. Residual phosphate, therefore, is still available for succeeding crops, although a certain por-tion becomes fixed in unavailable form over time so it can not be used by plants. Residual P compared with continued ap-plications of P were studied at the Southeast Kansas Branch Experiment Station (Parsons Field) from 1974 through 1977 to see if heavy, first-year applications (200 pounds P205 acre) would be as effective for grain sorghum as 100 pounds PzOs per acre applied every other year, or as effective as annual applications of SO pounds P205 per acre. 1. Contribution 78·282-s, Southeast Kansas Branch, Kansas Agricultural Experiment Station. 2. Agronomist, Southeast Kansas Branch Experiment Station, Mound Valley, 67354, and former soil Fertility Research Scientist, Dept. of Agronomy. AGRICULTURAL EXPERIMENT STATION Kansas State University, Manhattan Floyd W. Smith, Director This publication from Kansas State University Agricultural Experiment Station and Cooperative Extension Service has been archived. Current information: http://www.ksre.ksu.edu.After 4 years all plots had received the same total amount of P. Phosphorus was broadcast on the soil surface before planting then incorporated with a springtooth. The two P sources used were diammonium or-thophosphate (AOP, 18-46-0) and solid ammonium polyphosphate (APP, 15-62-0). APP was obtained from the Tennessee Valley Authority and contained 80% of the P in the APP form, with the remainder as AOP. Initial soil P levels were very low (6 pounds of available P per acre). Soil series was a Parsons silt loam with 2.3% organic matter. Results and Discussion Results of the 4-year investigation indicated good P response despite moisture limitations in 1974 and 1976. As expected, first-year yields were highest from 100 or 200 pound~ of P per acre. The second year, yields were good from the initial 200-pound application and the annual SO-pound ap-plications. The 100-pound application, only residual in the second year (1975), gave a significantly lower yield than either of the other two. Third-year data (1976) indicated that the initial 200-pound P application was starting to become fixed in the soil. The SO-pound annual treatments and the 100-pound treatments (applied in 1974 and 1976) were both significantly more effective than the first-year 200-pound application. The fourth year showed annual SO-pound ap~ plications slightly superior to 100-pounds every othe year, and 13 bushels per acre superior to 200 pounds the first year only. Means for the 4 years indicate no significant dif-ferences because of first-year (1974) yields. Yield differences between P sources were non-significant throughout the 4-year study. Soil test values at the end of the study indicated that the P treatments had . essentially doubled the available soil P during the study. Soil pH at the end of the study was 6.1. Conclusion Results indicate that heavy, one-time P ap-plications for grain sorghum are not so effective as an-nual applications. Biennial applications were more ef-fective than applications once in four years. For maximum efficiency, phosphorus should be applied annually because phosphorus fixation is quite likely in the acid soils of southeastern Kansas. Comparisons of ortho- and polyphosphate materials indicate no significant difference. Publications and public meetings by the Kansas Agricultural Experiment Station are available and open to the public regardless of race, color , national origin, sex, or religion. Table 1. Residual effects of phosphorus: on dryland grain sorghum yields, 1974-1977. P205 rate Application Yield, bu/ A lbs./A time 1974 1975 1976 1977 Mean Control 28 51 26 63 42 so Annual 40 70 42 79 58 100 1974& 76 45 65 48 76 59 200 1974 48 77 38 66 58 LSD .OS 4 4 2 s n.s. This publication from Kansas State University Agricultural Experiment Station and Cooperative Extension Service has been archived. Current information: http://www.ksre.ksu.edu.

Residual Effects of Phosphorus on Dryland, Grain Sorghum (Milo) (1978)

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Residual Effects of Phosphorus on Dryland, Grain Sorghum (Milo)

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