I suggest to inoculate your plants of Medicago sativa after germination to enhance the probability of interaction between Sinorhizobium meliloti and your plant, you must  adjust to a DO=0.05 (previously your bacterial liquid culture should reach a DO = 0.8 and then adjust to DO=0.05) .

Regards

Thanks a lot for your help. But we want to  inoculate seeds of Medicago sativa because in field condition it is not possible to inoculate seedlings one by one.

Hi Roghaye,

Please take a look at this topic: Inoculation of Legumes for Maximum Nitrogen Fixation at below link, including alfalfa with R. meliloti . It mentions the detailed steps of seed inoculation. Info is from Penn State University (Extension), a good university.

http://extension.psu.edu/plants/crops/forages/successful-forage-establishment/inoculation-of-legumes-for-maximum-nitrogen-fixation

Thank you very much Dr Yuan-Yeu Yau.

The paper from Pen State Uni gives a good outline of the process.  I prefer direct application to the seed coat as described in this paper.  Ensure that a period of drying onto the seed coat occurs - good airflow, but absolutely avoid exposure to high temperature and direct sunlight during this time as rhizobia death can occur.  The 24 hour window between coating and planting into the soil is quite important.  Drilling the rhizobia coated seed into the soil is highly desirable- seed broadcast on the soil surface is likley to result in high rhizobia death rate.  The use of a sticker, especially milk/skim milk as noted in the paper, resulted in improved rhizobia survival rates based on some research here in New Zealand back in the 1960's ( whicjh I can not find just now).

In the event of a failure of the seed coating method, I have had exxperience in intriducing rhizobia into a lucerne sward using the method detailed in the attached paper. 

@Tony,

I have a question: after the rhizobia-treated seeds are buried in the soil, and the next day, it rains. In this situation, will it decrease the effect of the treatment?? Thanks.

Thanks a lot Dr.  Rhodes .

Therefore, in your opinion if we use inoculated seeds, soil must be moist and after planting irrigation is necessary?

Thank you very much Dr. Bhavin Mehta.

But I do not understand, in your opinion  10 8 Rhizobia is enough for a hectare seeds?

Thanks a lot Dr. Bhavin Mehta.

The recommended number of viable rhizobia per lucerne seed is 1,000 organisms.  The suggested loading is 250 gm of commercial peat media per 25 kg of lucerne seed.

Certainly moisture after sowing eg irrigation will only enhance the survival and establishment of both seed and rhizobia.

A good overview if the processes is detaile in the attached document provided by the Australian Legume Innoculant Research Unit (ALIRU).