Temperature is a limiting factor on legume-Bradyrhizobium symbiosis of subtropical plants in the temperate region. Twelve strains of Bradyrhizobium spp. that nodulate pigeonpea [Cajanus cajan (L.) Millsp], and cowpea [Vigna unguiculata (L.) Walp], were evaluated for tolerance to three temperature regimes (20 • C/10 • C, 30 • C/20 • C, and 38 • C/25 • C day/night temperature) by determining their growth following exposure to the regimes. The five most temperature-tolerant strains were further evaluated for symbiotic effectiveness with pigeonpea and cowpea under controlled temperatures. These strains were USDA 3278, USDA 3362, USDA 3364, USDA 3458, and USDA 3472. Plant heights of both crops were generally independent of Bradyrhizobium strains and were dependent mainly on temperature regimes. Plant heights were the shortest at the lowest temperature. At the lowest temperature regime, biological nitrogen (N) fixation by pigeonpea was almost completely inhibited. Cowpea genotype IT82E-16 inoculated with USDA 3458 formed the most effective symbiosis. The 30 • C/20 • C temperature regime was optimum for effective symbiotic association in both crops, and also for Bradyrhizobium survival.
The United States Environmental Protection Agency (EPA) has the authority to regulate the public water systems. The EPA does not have the jurisdiction to regulate private drinking water wells. This leaves approximately fifteen percent of the nation's population without any regulation being held in place to protect their source of drinking water. With that fifteen percent of the US population having private wells for drinking water, it makes the number of people whose drinking water is unprotected by regulation at a little over 15 million US households. This concern is even more acute in areas with groundwater that is close to the surface. Delaware residents live in a region with low elevation which is very close to the coast with low elevation and the shallow groundwater makes us concern about contaminated well water even more intense. As one of the Water Resources Program partners, we have offered free Drinking Water Quality Clinics to local well owners over the past 4 years in Delaware State University. Since 2009, over 400 Delaware residents have benefited from these clinics. At each clinic, an information session was offered in the evening, with an opportunity to hear from and speak with a drinking water well expert. Participants were given sample bottles and water testing performed the following day included pH, nitrite, nitrate, sulfate, alkalinity, fluoride, hardness, iron, lead, cadmium, arsenic, Total Coliform, and E. coli. Over half of the samples returned out of range values for pH, while 72 returned results positive for Total Coliform and Escherichia coli bacterium. Data are examined for correlations, and improved understanding of local well owners. These tests shared with local well owners insights into what may be wrong with their water. In addition, any tests that came back outside of the normal range were reported to homeowners in writing. Mailed with the written reports were also information specific to what test results were outside of the limits, and actions to take to correct the exact problem the well owners encountered. The data reported here are examined to discuss the correlations of information, and ways that the Drinking Water Quality Clinics have improved our understanding of local wells and ownerships. In conclusion, regular testing on a yearly basis is the most effective way to ensure that public health is maintained.
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