| JUNE 2009 -- There are visual signs of deficiencies of the different minerals in plants which show up in the organs of the plant, including the roots. Nitrogen, phosphorous and magnesium always begin at the bottom of the plant leaves and work upward.
The most common symptoms of nitrogen deficiency are the restricted growth of both tops of roots, spindly plants, small leaves which are yellowish green when young, but orange, red or purple when mature. Reduction in the number of flowers with a reduction in yield of grain and fruits and a delay in spring as the opening of bulbs and the development of leaves and flowers.
Phosphorous deficiency has the same traits as nitrogen deficiency, but the leaf color is usually a dull, bluish green with a tint of purple rather than yellow or red.
Calcium deficiency is expressed in the growing tips, in the young leaves particularly and in the roots. The young leaves are severely distorted and maybe rolled forward along the margins or curved backward toward the under surface. The edges of the leaves are irregular in form so they often appear ragged and may have thin yellowish marginal bands or show brown scorching. The roots do not develop properly.
In potatoes, the leaflets near the stem tips are very small and blanched and are rolled toward the upper surface parallel with the microbe. Tuber formation is effected and may fail to develop at all.
The effects of a deficiency vary somewhat, depending on the severity. The leaf symptoms are rather striking and variable but is different on the tips of the plant. The leaves may assume a dull bluish green color and often show some yellowing in the areas between the veins, followed by brown spots in the leaves, especially near the margins.
There is also stunting of the plants with poor root grown and poor development of flowers, fruits and seeds. Magnesium is the only element which is used in the building up of chlorophyll, the green pigment which enables plants to make sugars and starches. When deficient, the leaves tend to turn yellow and assume brilliant tints and drop prematurely, first in the older leaves and then in the younger ones. |
