Potassium Deficiency (plants) - Symptoms of Potassium Deficiency

Symptoms of Potassium Deficiency

Typical symptoms of potassium deficiency in plants include brown scorching and curling of leaf tips as well as chlorosis(yellowing) between leaf veins. Purple spots may also appear on the leaf undersides. Plant growth, root development, and seed and fruit development are usually reduced in potassium-deficient plants. Often, potassium deficiency symptoms first appear on older (lower) leaves because potassium is a mobile nutrient, meaning that a plant can allocate potassium to younger leaves when it is K deficient. Deficient plants may be more prone to frost damage and disease, and their symptoms can often be confused with wind scorch or drought. The deficiency is most common in several important fruit and vegetable crops; notably potatoes, Brassicas, tomatoes, apples, currants, gooseberries, and raspberries. Sugar beets, cereals, and clover are commonly affected by potassium deficiency as well. Specific symptoms for each of these plants are as follows:

In potatoes, tuber size is much reduced and crop yield is low. The leaves of the plant appear dull and are often blue-green in color with intervenal chlorosis. Leaves will also develop small, dark brown spots on the undersides and a bronzed appearance on the upper surfaces.

In Brassicas, leaves are blue-green in color and may have a low degree of intervenal chlorosis. Scorching along the outside edges of leaves is common, and leaves are often tough in texture due to slow growth.

In tomatoes, the stems are woody and growth is slow. Leaves are blue-green in color, and the intervenal area often fades to a pale gray color. Leaves may also have a bronzed appearance and yellow and orange patches may develop on some of the leaflets. Fruits often ripen unevenly and sometimes have green patches near the stalks.

In apples, leaves are scorched around the edges, and intervenal chlorosisis common. Apple fruits often have a slightly acidic or woody taste.

In gooseberries, currants, and raspberries, dieback of shoots and branches is common and although the plant may produce many blossom buds in the early stages of deficiency, fruit yields turn out low and the fruits are of poor quality.