Should I use Rhizobium culture for black gram and green gram and how to apply.
6 Answers
Yes, Rhizobium seed treatment is very important for urad, moong and most pulses because these bacteria form nodules on the roots and fix atmospheric nitrogen, cutting your nitrogen fertiliser need and improving yield and soil health. Use the correct Rhizobium strain for the crop along with PSB (phosphate solubilising bacteria). Apply it last, after any fungicide or insecticide seed treatment, by mixing the culture with a little jaggery or rice gruel solution, coating the seed gently, drying it in shade, and sowing the same day. Do not mix Rhizobium directly with chemicals or expose treated seed to sunlight, as that kills the bacteria. One packet usually treats the seed for one acre; follow the packet instructions.
Since I started using Rhizobium and PSB on my moong and urad, nodulation is clearly better and I use almost no extra urea. It costs very little for one acre.
Check the expiry date and storage of the culture packet before buying. A packet that has been lying in a hot shop is often dead and gives no benefit. I buy fresh from the KVK or a reliable dealer and keep it in a cool shaded place until sowing morning.
The shade drying step is the one people skip. The first time I coated seed and left it in the sun the treatment did nothing. Now I mix it in the morning shade, dry the seed on a cloth under a tree, and sow the same day, and the nodules are plenty when I dig a plant later.
If your field has never grown that pulse before, Rhizobium is even more important because the right bacteria may not be in the soil yet. My new plot showed a clear difference in greenness and pod set between the treated and an untreated test strip in the first year itself.
Dig out a few plants at flowering and cut open the nodules to check the treatment worked. Healthy active nodules are pink inside; white or green ones are not fixing nitrogen well. This simple check told me whether my culture was good before I judged the whole crop.