Growth and Nutrient Uptake of Cotton as Affected by N Source and Dicyandiamide

D.W. Reeves, D.H. Rickerl, and J.T. Touchton


 
ABSTRACT

The nitrification inhibitor dicyandiamide (DCD) offers potential for improving efficiency of N applications to cotton grown on sandy soils of the southeastern Coastal Plain. Research has indicated that cotton is sensitive to DCD. The purpose of this greenhouse experiment was to investigate the effect of DCD on growth and nutrient uptake of DPL 90 cotton grown for 73 days in pots containing a typical Coastal Plain soil (Norfolk sandy loam). Nitrogen (100 lb/ac equivalent) as NaNO3 or urea, and DCD (0, 5, 10, 20, 30 and 40 lb/ac equivalent) were applied to the soil at first true leaf and plants were harvested 58 days later. Sodium nitrate increased leaf dry weight and total dry weight of plants 9.1 and 6.0%, respectively, over urea fertilized plants. DCD reduced linearly leaf area and dry weight and stem dry weight.

Fertilization with urea increased concentrations of leaf P, X, and Mn and reduced the concentration of Mg in leaf tissue. Dicyandiamide increased leaf N, P, and K concentrations but reduced concentrations of Ca, Mg, and Mn. Uptake rates (µg/g fresh root/day) of Ca and Mg were increased 7.5 and 13.7% respectively, with NaNO3 vs. urea, while P uptake rate was 15.5% greater for urea fertilized plants vs. NaNO3 fertilized plants. Dicyandiamide reduced Ca and Mg uptake rates. Phosphorus uptake rates were increased by DCD when urea was the N source. The effects of DCD on cotton growth and nutrient uptake generally resulted from the compound itself and were not an indirect result of nitrification inhibition. Although significant reductions in plant growth did not occur unless DCD exceeded that normally applied with recommended N rates on this soil, these results suggest a need for caution when applying DCD to cotton grown on sandy soils.



Reprinted from 1987 Proceedings: Beltwide Cotton Production Research Conferences pp. 481 - 484
©National Cotton Council, Memphis TN

[Main TOC] | [TOC] | [TOC by Section] | [Search] | [Help]
Previous Page [Previous] [Next] Next Page
 
Document last modified Sunday, Dec 6 1998