Abstract
It has been shown 1 that oral administrations of certain inorganic salts, alone or in combination, are definitely toxic for ducks. The greatest toxicity in these experiments was found in sodium chloride and sodium sulphate mixtures containing in addition either magnesium or bicarbonate together with nitrate ions. The symptoms exhibited by the birds after feeding with these mixtures resembled in many respects those noted in “duck disease”. The salt composition of soils from disease and non-disease areas was studied to attempt to correlate these experimental findings with the naturally occurring condition.
Soil samples were obtained from the following areas:
A. Disease Areas. 1. San Joaquin Valley (West of Pond, Calif.). 2. Tule Lake (Modoc County, Calif.). 3. Government Sump (South of Klamath Falls, Ore.).
B. Non-disease Areas. 1. San Joaquin Valley (Los Banos area). 2. Isolated ponds south of Klamath Falls, Ore.).
All samples were taken near the surface of the soil and within a few yards of the water's edge. Analyses were made on water extracts. Carbonate, bicarbonate, and chloride were determined by titration. Calcium, magnesium, and sulphate were approximated (after precipitation) by comparative turbidity tests. Nitrate was determined by aluminum reduction followed by distillation and titration. Qualitative tests only were made for nitrite. Sodium was computed by difference in the reaction value of basic and acidic ions. The ions were grouped for study as follows: 1. Chloride, sulphate, and sodium. 2. Carbonate and bicarbonate. 3. Calcium and magnesium. 4. Nitrate.
In Fig. 1 are shown the relative per cents of the different groups of ions in relation to increasing amounts of salts in the soil. This chart includes 50 samples from all areas and is presented for the purpose of showing the general character of the soils studied.
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