Due to the availability of heavily subsidized urea (or neem oil coated urea) in India, in some regions, farmers have developed a tendency to apply overdoses of N to crops like rice and wheat. And due to the same reason, farmers use more N and less P and K fertilizers leading to imbalanced use of fertilizers. Both overdoses of N and imbalanced use of N, P and K result in low fertilizer N use efficiency.
It is very useful questions. Subsidy makes urea relatively cheaper, and this could prompt farmer buy this more compared to P and K fertilizers. Even though many farmers are aware of marginal incremental benefit of after reaching a peak, there can be tendency to over apply N-fertilizer. In the process N-use efficiency can be lower. But this needs to be reviewed thoroughly to ascertain the fact. Thank you.
Any kind of unbalance is harmful to plants. This means farmers must be aware of the side effects. I do not think it will be difficult however, this means, farmers will be aware of the cost too,not just side effects. It will be effective to just say, unbalanced.
Plants always prefer to take the N from natural sources than artificial sources because, all N added to soil has to enter N cycle. So behavior of N is governed by the activity of the Cycle which depends on the soil flora & fauna activity which is directly proportional to SOM.
Thus in a soil with high SOM, no more than 30% of added Urea N is absorbed which is called the N fertilizer use efficiency or recovery. this can be estimated by difference method using the equation pfr = percent fertilizer recovery
pfr= nf-nc/R ratio expressed as %, where nf is total crop N uptake, nc = n up take from control ad R is the rate ofapplied nitrogen to crop.
This is because added N is used by microbiota to make more microbiota and lock them up and some is denitified as plants have not evolved to work outside N cycle. Thus crop get beaten up in absorbtion thru roots due to microbial activity, thus farmers add excess causing not only pollution but soil degradation. Best cheapest method is to use the minimum amounts within recovery efficiency with activated stable biochar + unstable biochar to raise organic matter of soil up to at least 5%. This will make N or anyfertilizer use very efficient which can be further enhanced by adding wormi compost, FMY, Earth Worms + compost
I do not understand why many academicians are not feeling concerned about low fertilizer N use efficiency and fertilizer related government policies in countries like India. We have now reached a stage where governments in developing countries like India, China, Pakistan need to be guided to formulate policies that can not only ensure sustainable food production for the masses but also climate change mitigation and environmental protection.
I fully agree. In the sixties when oceans could act as buffer to GHGs the urea based inorganic served a purpose for the newly reclaimed land from adjoining forest having plenty of SOM could be extremely effective giving 60 to 70 % fertiliser recovery efficiency and inorganic was wonderfully cost effective. But it is not so any more due to loss of som and acidification and loss if biota having a totally inert soil.
Now govt must subsidise to restore soil fertility and use the fertilizer subsidy for long term soil fertility restoration starting with soil conservation including planting lemon grass and lavender grass along the hedges and contour binds and cut fertilizer pits along the contour and bury all prinings, clippings, organic residues and add biochar to raise som to 2.5pc , gym and vermicompost and worms plus inorganic to 30pc of recommended levels now and keep the heap well covered with polythene to retain moisture.
Dr. Nandesiti dharmawaedene
Poor NUE is really a serious concern, however, there are well-proven agronomic practices if followed religiously, a fairly high level of NUE can be achieved but unfortunately very often these are ignored and result in a present mess in NUE.
- Badges
- Science topic
- Similar topics
- Geoscience
- Asia
- India