Effect of Soil pH and Related Acidity Factors on Yields of Sweetpotatoes and Soybeans Grown on Typical Soils of the Humid Tropics

Abstract

The effects of soil pH and related acidity factors on the yields of sweetpotatoes, Miguela var., and soybeans, Jupiter var., were determined on typical Oxisols and Ultisols of Puerto Rico. The study revealed no significant effect of pH and acidity factors on the yield of the sweetpotato variety, which was quite tolerant to high soil acidity and exchangeable Al. Yields were similar to those obtained by other researchers who worked with other varieties. Soybeans, although relatively tolerant to high levels of exchangeable Al, were adversely affected when values surpassed 5.5 meq/100 g of soil in a clayey Ultisol. Exchangeable base content was directly related to soybean yield grown on a light textured Oxisol. Yields obtained are considered excellent. Highly significant correlations between soybean leaf N content and yield was found in the clayey Ultisol.

Selection of Sweet Potato For Tolerance to Aluminum Toxicity: Screening Procedures and Field Test

“…The first (and most likely) is that sweet potatoes are not particularly sensitive to pH or AI toxicity and that the field conditions were not as severe a test as the greenhouse screening and thus, less likely to detect differences. This explanation is supported by previous reports that sweet potato is not very exacting with respect to soil acidity (14) and confirms a report of no significant differences in yield of sweet potato in three soil types despite wide variations in pH, exchangeable Al, and per-cent Al saturation (12). Despite the lack of significant soil treatment effects, the clones grown under the lime-treated plot with pH 5.4 had higher marketable root weight than those grown in sulfur-treated soil with pH 4.2 (Table 8).…”

“…Sweet potatoes can be grown over a wide range of environmental conditions, including regions with long periods of drought and severe typhoons, and those with soils of low fertility, poor drainage, and relatively low pH (16). Perez-Escolar (12) found no significant effect of pH and acidity factors on yield of sweet potato "Miguela' on tropical oxisols and ultisols of Puerto Rico. Abruna et al (1) reported that yield of 'Yoga' sweet potato increased with increasing soil pH, decreasing exchangeable Al content, and decreasing exchangeable Al/base ratio, indicating that variability in response to soil acidity may exist among sweet potato cultivars.…”