Studies on potato nutrition III. Chemical composition and uptake of nutrients by kern county potatoes

Summary Comparisons were made on growth and on dry matter, nitrogen,

phosphoric acid, and potash content of the potatoes grown at four different fertilizer levels during 1945 and 1946.

Nitrogen content of plants and tubers was increased by nitrogen fertilization during the early stages of growth but this was not true at maturity.

Nitrogen, phosphoric acid, and potash greatly decreased per unit of dry weight in both plants and tubers as they approached maturity.

The greatest amount of growth and the greatest intensity of nutrient absorption occurred between about 75 and 110 days after planting or between 45 and 80 days after emergence.

An unfertilized crop of potatoes grown in 1945 and producing 119 sacks contained 59 pounds of nitrogen per acre, 17 of phosphoric acid, and 126 of potash. The tubers alone removed 33 pounds of nitrogen, 14 of phosphoric acid and 79 of potash. The highest yielding treatment which in 1946 produced 395 sacks per acre, absorbed 139 pounds of nitrogen, 36 of phosphoric acid and 253 of potash. The tubers alone removed 106 pounds of nitrogen, 31 of phosphoric acid, and 196 of potash.