Effect of Soil Type and Fertilizer Treatment on the Composition of the Soybean Plant1

Abstract

Fertilizer tests with soybeans were located on five soil types from which crops samples were taken periodically for laboratory studies. The samples were analyzed for total ash, calcium, magnesium, nitrogen, sulfur, phosphorus, and potassium. Tests were conducted in the in the greenhouse to study the effect of soil type and fertilization with phosphorus and potassium upon the phosphorus and contents of the cell sap of the plant. The total ash content of the soybean plants was lowest 110 days after seeding, and in many cases it was highest 73 days after seeding. In the young plants the high ash content was associated with smaller growth. The calcium, magnesium, and nitrogen contents of the soybean plant decreased with the age of the plants. There was very little change in the sulfur content during growth or due to the influence of fertilizers or soil type differences. The results of these experiments suggest a tendency for the phosphorus content of the soybean plants to increase during the latter half of the growing period. The potassium content was very irregular, but the variations were small. The effects of fertilizer treatments upon the composition of the plant were small. Fertilizers were more effective in changing the composition of the soybean plants grown on Coloma sand and least effective on Miami loam. Plants on Brookston clay loam had the highest magnesium content (1.08%), one of the highest nitrogen (4.81%) and one of the lowest calcium (2.16%) and ash (9.72%) contents 35 days after seeding, among the plants without fertilizer treatment. Plants on Hillsdale sandy loam and on Coloma sand had the highest ash (10.70%) and 10.12%) and calcium (2.70% and 2.79%) contents and the lowest magnesium (0.58% and 0.69%) and nitrogen (4.41% and 4.17%) contents of the unfertilized plants 35 days after seedings. The phosphorus content of the unfertilized soybean plants varied from 0.46% in the plants on Brookston clay loam to 0.23% in the plants on Hillsdale sandy loam. The Brookston clay loam produced plants that had the lowest calcium (1.79%) the highest magnesium (1.08%) and one of the highest ash (10.61%) and nitrogen (3.46%) contents of the unfertilized soybeans 73 days after seeding. For unfertilized soybeans 110 days after seeding, the plants on Brookston clay loam had the highest ash (8.56%) and magnesium (0.79%) contents, the plants on Coloma sand the highest calcium (2.11%) and phosphorus (0.46%) contents, and the plants on Kewanee loam the highest nitrogen (3.52%), content. Plants on Miami loam contained the lowest ash (6.29%), calcium (1.29%), sulfur (0.22%), phosphorus (0.28%), and potassium (0.53%) contents and one of the highest nitrogen (3.27%) contents of the plants grown on the unfertilized plats 110 days after seeding. All treatments on Fox sandy loam increased the nitrogen content of the plants. The phosphorus and potassium contents of the cell sap of soybean plants were increased by applications of phosphorus and potassium. The phosphorus, potassium, and calcium contents of the cell sap were affected by the type of soil upon which the plants grew. The soil type upon which the soybeans grew was a greater factor in determining the composition of the plants than was the application of moderate amounts of fertilizers.