Date of this Version
Thesis (M.A.)—University of Nebraska—Lincoln, 1953. Major: Department of Agronomy.
In 1952 a comprehensive irrigation experiment was conducted at the Scotts Bluff Experiment Station to obtain more information on irrigation practices in relation to the stage of plant development. Thirteen irrigation treatments were included in the experiment to test the importance of a low moisture stress at different stages of growth on the yield of corn. Three irrigation treatments from the experiment were selected for studying the influence of moisture regimen on the growth and uptake of nutrient elements by corn. The irrigation treatments selected were: (1) a high moisture level throughout the season with 6 irrigations; (2) a medium moisture level with 3 irrigations; (3) a low moisture level with no irrigation. Plants were sampled at weekly intervals. Leaves, stalks, husks, grain, and cobs were weighed and analyzed for nitrogen, phosphorus, potassium, and calcium. Magnesium was determined on the leaves and grain, and a few samples were analyzed for sodium.
The results may be summarized as follows:
Height differences were first apparent eight weeks after emergence of the plants. These differences were associated the length of the upper internodes of the plant.
There was greater production of dry-matter with the high than with the medium moisture regimen, and significantly less with the low moisture regimen. Differences in dry-matter production due to moisture level occurred in all plant parts with differences in grain production being especially marked.
A relative rate of growth curve was constructed by plotting the logarithm of total dry-weight against time, which appeared to be related to physiological periods in the plant, e.g. the slowing down of root development, tasseling, silking, and when maximum vegetation growth was reached.
The effect of moisture level upon nutrient composition was generally less than has been reported by other investigators.The amounts of nutrients present in the corn plants per acre were largely related to the amounts of dry-matter produced.
Advisor:Harold F. Rhoades