Make life easier by calculating in elements

Paul Milham Thanks for the advise. You're not getting my point. My question was, what is the minimum and maximum ratio of organic and inorganic fertilizers, if, there is recommendation and/or no recommendation of P-fertilizer.

We Indians are far ahead of others in terms of calculations.

We usually calculate dose of FYM on N- equivalent ratio. But what you are enquiring is perhaps out of the context of any soil testing , if I have understood your question correctly...

Our fertilizer recommendations are based on the status of N, P and K and i don't think it is based on organic matter/carbon content. On the other hand, the status of N, P and K is the reflection of the OC content. You can follow uniform FYM for both soils.

In case you follow STCR based target yield your question is pertinent and nowadays the calculations are included with soil carbon content. Dr Subba Rao may correct me , if i am wrong

I think we have to measure the N, P, K contain in the FYM. As I know we have to give FYM, along with RDF. So we have to give both based on the specific dose.

Biggest problem with use of FYM while equating the dose on nutrient equivalent basis , is the amount of potassium , unless added from other nutrient source , in addition to its residual effect experienced over a period of time . Unfortunately , soil test - based manuring takes very little account of it...

Yes I do agree with Dr Srivastava sir

Actually possibility we can do one thing,

All the recommended doses are formulated on crop response basis and along with that we usually recommend the doses of OM also because we try to make the treatment as integrated with organic and inorganic.

While testing of soil samples we focus on nutrients and organic carbon and on that basis we categorize that specific Nutrient on which category it comes. For ex. If available nitrogen content of soil sample is very low then we recommend to add 50 % more nitrogen dose through organic or inorganic form nutrient source. That means we have already formulated the doses of NPK and organic manures also on the basis of Crop responses.

So the same thing we can do with Organic manures also

We can rate the content of organic carbon

Then we can recommend the addition of organic matter on the of existence. For example if it comes in medium range then we should stick up with the recommended dose of FYM which we have already specified for a specific crop.

Thanks