Analysis of data obtained from samples collected in the Delta area of Mississippi showed that the potassium concentration of young mature and old mature cotton leaf‐blades correlated better with soil test potassium than did that of the apical immature leaf‐blades. Results from field studies indicated that the old mature petiole was the most sensitive indicator of the potassium status of the cotton plants. The potassium concentration in both leaf‐blades and petioles decreased with stage of maturity from early square to early half‐grown boll. Potassium concentration did not fluctuate with sampling at different times of the day. The rate of decline of potassium concentration was greater in petioles of mature cotton leaves than in the leaf‐blades. For mature leaves, the potassium concentration of leaf‐blades was highly correlated with that in petioles, but for immature leaves, the correlation was poor. The rate of decline of potassium concentration in both cotton leaf‐blades and petioles was not affected by potassium fertilization but was a function of maturity stage. Key words: PotassiumPlant AnalysisCotton Notes Contribution from the Agronomy Dept., Mississippi State Univ., Mississippi State. Graduate Research Assistant, Professor, and Assistant Professor of Agronomy, Agronomy Dept., Mississippi State Univ., Mississippi State.

Soil Samples (72) were collected from the Delta, Hill, and Northeast Blackland areas of Mississippi. Chemical analyses for manganese, magnesium, and calcium were made using the Mississippi Soil Test Solution (MSTS) and several other extracting solutions chosen for comparison. For the determination of available soil manganese, the MSTS proved to be as effective as either the Double Acid (0.025 N HCl in 0.05 N H2SO4) or 0.1 N H3PO4. The acid extractants removed more manganese than 1 N NH4OAc (pH 7.0) and therefore included forms that are not exchangeable. The methods studied for magnesium determinations were equilibrium extraction with 1 N NH4OAc, MSTS, Double Acid, 0.25 N CaCl2, and leaching with 1 N NH4OAc. All methods were highly correlated and therefore would be equally effective in determining available soil magnesium. Since MSTS and equilibrium extraction with 1 N NH4OAc removed similar amounts of magnesium from the soil, the same calibration can be used. Calcium determinations were made using equilibrium extraction with 1 N NH4OAc, MSTS, and Double Acid, and by leaching with 1 N NH4OAc. All methods proved effective in measuring available soil calcium on acid soils.

AbstractField experiments were conducted with rates and methods of application of B to cotton. Broadcast was as effective as drilled, foliar application was as good as soil application, and there was no advantage to a combination of soil and foliar application. A highly soluble source of B was superior to a more slowly soluble one.Young leaves, the third or fourth node from the growing point, were found to have a critical level of about 15 ppm B. Mature leaves occurring at the fifth and sixth nodes from the growing point had a B content of 5 to 10 ppm higher. The critical level of hot‐water soluble B in the top 15 cm of soil was in the range of 0.10 to 0.16 ppm.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhosphorus Components, Crop Response to Water-Soluble and Water-Insoluble Phosphorus Components of Granular FertilizersG. L. Terman and J. D. LancasterCite this: J. Agric. Food Chem. 1965, 13, 6, 500–505Publication Date (Print):November 1, 1965Publication History Published online1 May 2002Published inissue 1 November 1965https://pubs.acs.org/doi/10.1021/jf60142a004https://doi.org/10.1021/jf60142a004research-articleACS PublicationsRequest reuse permissionsArticle Views57Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts