Effect of current-season application of calcitic lime on soil pH, yield and cadmium concentration in potato (Solanum tuberosum L.) tubers

Abstract

Cadmium (Cd) has accumulated in many agricultural soils in Australia due to fertilization with phosphatic fertilizers that contained Cd as an impurity. Nine field and seven glasshouse experiments using light-textured soils were conducted to investigate the effect of current-season applications of calcitic lime on i) soil pHw, ii) tuber yield, and iii) Cd accumulation in tubers of a range of processing (Russet Burbank, Atlantic, Shepody and Kennebec) and fresh market (Crystal, Pontiac and Desiree) potato cultivars.Liming increased soil pH values by up to 2 units. Yields of potato tubers were generally unaffected by liming. Under glasshouse conditions, significant reductions in tuber Cd concentrations were found after liming of soils. In contrast, in the field, application of calcitic lime at rates up to 20 t ha -z had either no effect or significantly (p < 0.05) increased tuber Cd concentrations. Concentrations of Cd in tubers were closely correlated (R2=0.74, p < 0.001 ) with concentrations of chloride (CI). The lack of any beneficial effect of lime application in reducing tuber Cd concentrations under field conditions is attributed to a combination of ineffective mixing of lime throughout the whole root zone, inadequate time of reaction of lime with soil, competitive desorption of Cd 2+ by Ca 2+ and low soil moisture inhibiting lime dissolution under field conditions. Further work is required to resolve which mechanisms are most important.

Evaluation of Growing Media Containing Farmyard Manure Compost, Household Waste Compost or Chicken Manure for the Propagation of Lettuce (Lactuca sativaL.) Transplants

“…The difference between field trials and pot experiments was stressed by Maier et al (1997). They found decreasing Cd uptake in potato tubers at increasing pH, caused by liming, under glasshouse conditions, but no effect or even increasing Cd uptake with increasing pH in field experiments.…”

“…In field trials (Andersson & Siman, 1991;McLaughlin et al, 1994;Maier et al, 1997), the effects of pH on Cd uptake often seem to be contradictory. The difference between field trials and pot experiments was stressed by Maier et al (1997).…”

Cadmium accumulation in crops

“…Concentration of Cd in oat, ryegrass, carrot and spinach decreased with increasing soil pH in a sandy soil, but Cd concentration of ryegrass increased with increasing pH in a loam soil (He and Singh 1994a,b). In several studies, Cd uptake increased with increasing pH (Andersson and Siman 1991;Sparrow et al 1993a;Maier et al 1997). The Ca 2+ in the soil solution may have competed with Cd for sorption sites, off-setting the effect of increasing pH.…”

Effect of soil pH on cadmium phytoavailability in some New Zealand soils

“…Similarly, Li et al (1996) found that adding limestone to acidic soils had no effect on non-oilseed sunflower {Helianthus annum L.) grain Cd concentration. Liming did not reduce the Cd status in crops studied by Jaakola (1977) and Sparrow et al (1993), and in some instances liming has resulted in increased crop Cd concentrations (Sparrow et al 1993;Maier et al 1997). As a consequence it may be important to evaluate the effect of soil pH on plant Cd concentrations in a field situation to ascertain its true potential as a management strategy.…”

“…A number of studies have shown that with increasing soil pH, there is a corresponding decrease in plant Cd concentrations (e.g., Han & Lee 1996). In contrast, however there have been several field trials in which liming to increase soil pH has resulted in no change in plant Cd concentrations (e.g., Sparrow et al 1993) and in some instances liming soil has increased plant Cd concentrations (e.g., Maier et al 1997;Singh & Myhr 1998).…”