Plant Cl concentration vs. growth stage relationships

Current, data-bases on critical Cl concentrations in wheat are limited to tissue sampling of the whole plant (above ground) at, or near head emergence (Feekes growth stage 10.1).   Nutrient concentrations in wheat are known to change with crop development.   Nutrient uptake by wheat, including chloride, usually proceeds more rapidly than top growth, with the major of nutrient uptake occurring between tillering and heading.    Whole plant chloride concentrations will typically decrease over the growing season as they did at the site near Huntley,  Montana (Figure 3).   Hence, a wheat plant with a chloride concentration of 0.4% at head emergence will most likely have a higher concentration early during the vegetative growth period.  Interpretation of results from plant analyses requires that careful attention be paid to the growth stage at which the samples were collected.   This is true of chloride, as well as other nutrients.

              

Figure 3.   Whole plant Cl concentrations in irrigated "Rambo" sprng wheat at several stages of plant development and four Cl fertilizer rates (0,10,20, and 60  lbs/a).  Huntley,  Montana.   1994.

Plant Cl uptake vs. growth stage relationships

Chloride uptake (concentration x dry matter) in wheat will typically peak at, or near the heading stage (Feekes growth stage 10.1 to 10.5)    Thereafter,  uptake will drop or remain fairly stable through the grain-fill period as it did at this site near Huntley,  Montana.

Figure 4.   Whole plant Cl uptake in irrigated "Rambo" spring wheat at several stages of plant development and four Cl fertilizer rates (0,10,20, and 60  lbs/a).  Huntley,  Montana.   1994.