Band placement of lime and superphosphate for ladino clover in an acid oxysol

Abstract

In a pot experiment with the A₁ (topsoil) and B₂ (subsoil) horizons of a Clovelly soil, it was found that although increasing the rate of band‐placed lime from 265 to 2650 kg per ha did not significantly influence the yield of Ladino clover, considerably higher yields were obtained where the pH of the entire soil mass was raised from approximately pH 5.0 to 6.0 by liming.

It is suggested that Al‐toxicity is a major limiting factor in this soil and may largely account for the response to liming. Increasing the band‐placed superphosphate application from 265 to 2650 kg per ha resulted in highly significant yield increases. Considerable root development occurred in the superphosphate bands as compared with limited root development in the lime bands. Significantly higher yields were obtained from the A₁ horizon than from the B₂ horizon. Differences due to depth of placement of the lime and superphosphate, placement of the lime and superphosphate in a single band as opposed to separate parallel bands, and the use of powdered and granular superphosphate were recorded in the first cut but not in the second.

UITTREKSEL

In ‘n potproef met die A₁ (bogrond) en die B₂ (ondergrond) horisonte van ‘n Clovelly grand, is dit gevind dat alhoewel die opbrengs van ladinoklawer nie deur die verhoging van bandgeplaasde kalk van 265 tot 2650 kg per ha vermeerder is, is opbrengste heelwat verhoog deur die verandering van die pH van die hele grondmassa van 5.0 tot 6.0 deur die toediening van kalk. Dit is vaorgestel dat Al‐toksisiteit in die grand die hoof beperkende faktor is en dat dit verantwoordelik is vir din uitwerking van kalk. Die uitwerking van die verhoging van bandgeplaasde supcrfosfaat van 265 tot 2650 kg per ha was ‘n betekenis‐volle verhoging in opbrengs. In vergelyking met die behandeling waar kalk in ‘n band geplaas is, was die ontwikkeling van die wortelstelsel heelwat beter waar superfosfaat in bande geplaas is. Opbrengste van die A₁ horison was ook heelwat hoër in vergelyking met dié van die B₂ horison. In die eerste snysel, maar nie tweede nie, is verskille in opbrengs gevind weens dicpte van plasing van kalk en superfosfaat, plasing van kalk en superfosfaat in ‘n enkele band in plaas van afsonderlike parallel bande en die gebruik van gepoeierde en gekorrelde superfosfaat.

Notes

Present address: University of Fort Hare, Alice.