Blossom End Rot (BER)

"I am a tomato farmer in Loitoktok and have a problem with my tomato fruits having a wet /burning appearance. I have been told it's a lack of Calcium, how can I manage this problem."

The problem you refer to is a physiological disorder called Blossom End Rot ( BER ) and occurs in several other crops such as melons and capsicums among others. Indeed this is a problem resulting from a deficiency of Calcium and Boron.

The Role of Calcium and B

Calcium plays a very important role in maintaining the firm structure of cells and is for this reason that a deficiency of Calcium will make the cell walls weak and susceptible to collapsing and cracking, resulting in the typical physiological problems of Fruit cracking and Blossom End Rot.

Boron on the other hand has a role to play in maintaining the flexibility of plant cells while allowing for their expansion. This ensures that the plants/ fruits continue to expand in size without cracking. Boron, therefore, plays a role in making the calcium even more efficient.

The type of Calcium you need :

There are many sources of Calcium, including common fertilizers like CAN and soil amendments such as Lime and Gypsum. Calcium is predominantly taken up by the plants together with water and therefore very important that the Calcium source used to be one that provides SOLUBLE CALCIUM, for it to be efficiently taken up. However, the common sources of Calcium mentioned above -CAN, Lime and Gypsum – provide calcium that is NOT readily soluble and therefore only available to the plants over a long period of time and in relatively small amounts.

Calcium Nitrate on the other hand provides SOLUBLE calcium, readily taken up by crops and therefore effective in helping prevent fruit cracking and Blossom End Rot.

To compare these products, for example, it takes about ONE liter of water to dissolve 1kg of Calcium Nitrate, and you require about 415 Litres of water to dissolve 1Kg of Gypsum and more than 60,000 Litres of water to dissolve 1 kg of Lime!

Calcium Nitrate fertilizer such as NITRABOR will therefore help prevent fruit cracking and Blossom End Rot because it provided Soluble Calcium and Boron for stronger cells in the tomato and other fruits.

By: Vitalis Wafula
East Africa Regional Agronomist - YARA