Effects of Soil Moisture Tensions and of Chloride and Sulfate Treatments upon the Yield, Composition, and Bacterial Soft Rot of Irish Potatoes1
- M. E. Harward,
- W. A. Jackson,
- L. W. Nielson,
- J. R. Piland and
- D. D. Mason2
Greenhouse experiments were conducted over a period of 2 years to determine the effects of soil moisture and of the chloride and sulfate ions upon the growth and quality of potato tubers.
Irish cobbler potatoes were grown in a soil mixture containing equal weights of Bladen fine sandy loam and 18-mesh quartz sand. The anion variables consisted of KCl or K2SO4 applied at the rate of 180 pounds K2O per acre. The different moisture levels consisted of resaturating the soil when tensions of approximately 300, 800, 2,000 and 10,000 cm. of water were obtained. Measurements of yield, chemical composition, dry matter, specific gravity of tubers, and susceptibility of tubers to bacterial soft rot were made at or after harvest.
The yields of U. S. No. 1 tubers from the SO4-treated plots were greater than those receiving Cl. There were some suggestions that the response to high levels of soil moisture may have been related to the source of potassium. Greater vine yields were obtained with the chloride treatments than with the sulfate. A reversal in the curve for growth of tops occurred at the lowest level of soil moisture. The use of chloride as compared to sulfate increased the content of Ca and Mg in the leaves and stems and decreased the content of Mg in the tubers. The K contents of tubers were greater with the SO4 than with the Cl treatments but no differences in K content of leaves were associated with source of potassium. Applications of SO4 as compared to Cl at all moisture levels resulted in increased contents of N in the leaves, stems, and tubers. No significant differences in the specific gravity of tubers as related to Cl and SO4 treatments were found after 6 weeks storage. The mean specific gravities of U. S. No. 1 tubers increased with increasing levels of soil moisture. The dry matter contents of leaves and stems were greater from the sulfate treated plants than from the chloride. Wound infection by bacterial soft rot organisms was less for tubers grown under low soil moisture tensions, than those grown under high tensions. The rate of bacterial decay of tubers grown under low moisture tensions was greater than for those grown under the limiting conditions of low soil moisture.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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