Role and Deficiency Symptoms of Potassium in Tomato

Introduction Potassium is used in carbohydrate metabolism and increases water-use efficiency It is essential for protein synthesis and activates enzymes and controls their reaction rates It promotes flower and fruit production and is vital for maintaining growth and helping plants resist diseases K management should be considered part of long-term soil fertility management because K is not easily lost from or added to the root zone

Role of Potassium in Plants Involved in osmoregulation and enzyme activation Regulates transpiration by stomata and transport of assimilates Increases leaf area and chlorophyll content Delays leaf senescence and thus contributes to greater canopy photosynthesis and crop growth Improves the plant’s tolerance of adverse climatic conditions, lodging, insect pests, and diseases. 

Sources of potassium Chemical fertilizers Potassium chloride (Muriate of potash) Potassium nitrate Potassium sulfate

K deficiency symptoms Woody stems and slow growth. Stems become weak and fall down Leaves are blue-green in color and the interveinal area often fade to a pale grey 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 Older leaves may look scorched around the edges and/or wilted. Symptoms first appear on older leaves

Deficiency symptoms in leaves Source: http://5e.plantphys.net/article.php?ch=t&id=289

Potassium deficient tomato fruit Source:http://extension.umass.edu/vegetable/diseases/tomato-blotchy-ripening

Causes of K deficiency Lower K-supplying capacity of soil Low recovery efficiency of applied K fertilizers because of high K-fixation capacity of soil or leaching losses Complete removal of previous crop straw/ residues Wide Na:K, Mg:K, or Ca:K ratios in soil and sodic/saline conditions. Presence of excessive amounts of reduced substances in poorly drained soils (e.g., H2S, organic acids, Fe2+) causing retarded root growth and hence K uptake. Imbalanced fertilization especially excessive use of N or N and P fertilizers with insufficient K application.

Let us sum up Potassium is used in starch and sugar synthesis so is more important in vegetables and fruits Potassium is naturally found in wood ash Prevention and cure can be achieved in short term by adding potassium-specific fertilizer called potash Adequate moisture is necessary for effective potassium uptake; low soil water reduces K uptake by plant roots Limiting acidic soils also increase K retention in the soil by reducing leaching

THANK YOU