Inoculation in legumes crops helpful in nitrogen fixation

The term inoculation is defined as the process in which coating of seeds with the desired species of bacteria which is helpful in the fixation of nitrogen.

Inoculation in legumes crops helpful in nitrogen fixationIn simple words, bringing rhizobia in contact with the seed or root of legume crop. Major producing countries are USA, Brazile. Australia, Thailand and New Zealand.

Generally, nitrogen fixation bacteria are present in the soil and help the crop to fix nitrogen. Intensive cultivation and soil erosion have disturbs the fertile land. It is reported that in eroded soils there is sever deficiency of major nutrient Nitrogen (N), removal of upper fertile land and depletion of soil fertility.

Moreover, it also decreases the amount of bacterial species. In this way most of the legume crops are unable to fix nitrogen and ultimately yield reduced. To overcome this problem farmer applied synthetically fertilizers which is expensive and not eco-friendly practice.

From present scenario inoculation is the best technique to tackle the issue because it is cheap source and environmental friendly. Additionally this technique is also applicable for the hilly areas which can increase the soil fertility and farm income of poor farmers. Furthermore inoculation enhances the Nodule number, nodule dry weight, shoot yield and amount of fixed nitrogen.

Suitable crops

Legumes crops (beans, peas and soybeans) are best for the inoculation because they have a structure on their roots which is called Nodule (a swollen structure). Nodule forms a symbiotic relation with nitrogen fixation bacteria.

Qualities of inoculant:

Inoculant should be highly effective on the host plant, competitive, tolerant to soil stress and persistent in the soil.

Types of inoculant:

There are several types of inoculant but most commonly used types are Liquid culture, freeze-dried preparations, oil-dried preparations and solid culture.


Inoculum material can be taken from Soil Biology and Biochemistry section, National Agriculture Research Centre (NARC), Islamabad.  Ayub Agriculture Research Institute (AARI), Faisalabad. Institute of Soil and Environmental Sciences University of Agriculture Faisalabad, (UAF).

Treatment method:

Make sure that before treating of seed with inoculum always done in the shady place. Always use uniform seed size for the equal distribution of inoculant material. Protect inoculant seed from direct sunlight, heat and excessive drying. Sow the inoculated seed as early as possible.

    1. Prepare sticky solution by adding sugar in water 1:9 parts.
    1. Place the seed on a sheet at soil surface.
    1. Sprinkle the sticky material on the seed.
    1. Apply the culture inoculum and incorporate well so that inoculum will contact with each seed.
  1. Dry the seed for 15 minutes.

Keeping in view the above discussion legumes crops must be cultivated after inoculation.  The choice of method for seed and soil inoculation depends on the material available, climate and soil conditions.

Inoculant contain living organism so it should be stored properly otherwise the number of rhizobia in inoculant will decline. Inoculant rhizobium rapidly infects the roots and starts the process of nodulation. In this way it enhances the soil fertility, crop yield and farm income.

Authors: Muhammad Abrar, Amir Maqbool, Haroon Zaman Khan, Muhammad Atif Shabir, Syed Ali Zafar, Ali Mehmood Lakhvi, Ahmad Mukhtar, Muhammad Asad, Samee ullah, Muhammad Amjad and Sadia Altaf.

By Muhammad ABRAR

Muhammad Abrar M.Sc.(Hons.) Agronomy University of Agriculture Faisalabad. Ex.Research Fellowship Nigde Omer Helisdemir University, Turkey. +92 347 0357410