Annangi Subba RAo
Advisor R&D Coromandel International
Indian Institute of Soil Science
There are as many as 12 ways to define nutrient use efficiency including nitrogen use efficiency . This is available on-line at the website of IPNI. I am enclosing an excellent review on nutrient use efficiency in plants describing various components of nutrient use efficiency. Hope , it will be useful.
You can try this publication: Agronomy 2014, 4, 470-477; doi:10.3390/agronomy4040470
Title: A Calculation Tool for Analyzing Nitrogen Use Efficiency in
Annual and Perennial Crops
Dr.Sarker,Dr.Abhishek has given a lot of references which will help you . I am adding one more reference which will explain the formulae in a better way. Improving plant nitrogen-use efficiency by Pathak ,RR and others.Comprehensive Biotechnology,Second Edition,2011,vol 4,209-218 .pdf is available on line.
As suggested in the various publications provided by the previous contributors, there are many ways to calculate nitrogen use efficiency. Some are easy and more direct while others are more complicated. The more complicated a method is the less reliable it will be (from Okhams rule) partly because with complication comes assumptions and estimation of many parameters. For practical application, I prefer the partial factor productivity of N (PFPN) and agronomic efficiency of N (AEN) which are easy to calculate from crop yields and N fertilizer applied. PFPN is the only index of nitrogen use efficiency that can be estimated reasonably well. PFPN is also the broadest measure as it constitutes aggregate production efficiency. See Doberman and Ladha
Dr.Sarker,the pdf of Dobermann2005 nitogen use efficiency is good reference provided by Dr.Gudeta.When you have data on crop yield,nutrient uptake and fertilizer N applied,It would be better to calculate the agronomic efficiency,crop recovery efficiency and physiological efficiency of applied N.The last term one way indicates the actual utilization efficiency of applied N by the crop for yield formation.All the formulas are in table 2 of Dobermann pdf.
For working out integrated nutrient management prescription for a particular crop, we need to know the fertilizer equivalents of previous legume crop grown or manure applied to the current crop .Biofertilizer contribution is also to be taken into consideration.The residual effects of nitrogen fertilizer applied to a crop may be considerable in only one or two seasons .The residual effects of P and Zn can there for for more years.But the effects will diminish with time making it difficult to measure over time.But cumulative effects of several years applications can be measured through soil testing. Fertilizer rates can be adjusted as per soil tests for a particular nutrient.
For calculating nutrient / nitrogen use efficiency under different crop production systems, we use different use efficiency formulae viz. agronomic use efficiency, partial factor productivity, physiological use efficiency, agro-physilogical use efficiency, N harvest index etc. These information in details is available in the attached articles.
Article Effect of Nitrogen Levels and Coated Urea on Growth, Yields ...
The Nitrogen Utilization Efficiency (NUE) can be expressed as agronomic efficiency (AE), recovery efficiency (RE) and physiological efficiency (PE).
Agronomic Efficiency (AE)
Agronomic efficiency refers to the increase in crop yield per unit of applied nitrogen. It can be calculated as follows:
Where,
AE = (YNA - YN0)/NRN
AE : Agronomic efficiency
YNA : Yield (kg/ha) with nitrogen addition
YN0 : Yield (kg/ha) without nitrogen addition
NRN : Rate of nitrogen addition (kg/ha)
Recovery Efficiency (RE)
Recovery efficiency (RE) refers to the increase in nitrogen uptake by plants per unit of applied nitrogen. It can be calculated as follows:
RE = (NUNA - NUN0)/NRN
Where,
RE : Recovery efficiency
NUNA : Nitrogen uptake (kg/ha) with nitrogen addition
NUNO : Nitrogen uptake (kg/ha) without nitrogen addition
NRN : Rate of added nitrogen (kg/ha)
Physiological Efficiency (PE)
Physiological efficiency (PE) refers to the ability of a plant to transform a given amount of acquired nitrogen into grain yield. It refers to the grain yield per unit nitrogen uptake. It can be calculated as follows:
PE = (YNA - YN0)/(NUNA - NUN0)
Where,
PE : Physiological efficiency
YNA : Yield (kg/ha) with nitrogen addition
YN0 : Yield (kg/ha) without nitrogen addition
NUNA : Nitrogen uptake (kg/ha) with nutrient addition
NUNO : Nitrogen uptake (kg/ha) without nitrogen addition
There are as many as 12 ways to define nutrient use efficiency including nitrogen use efficiency . This is available on-line at the website of IPNI. I am enclosing an excellent review on nutrient use efficiency in plants describing various components of nutrient use efficiency. Hope , it will be useful.
Uttam, the other colleagues have already given to you several publications you can look at. However, the 'purpose' of your work or evalution will rule the formula or method you want to choose for determining N use efficiency. If you want to make a mass balance (plant uptake (absorption) + soil stock + leaching + other N losses) you may use the 'apparent fertilizer N use efficiency or FUE', while if you want to determine the efficiency of applied N to generate plant products (yield) or to be metabolized in the biomass you may probably use the 'agronomic efficiency' or the 'physiological efficiency'. Attached you will find other classic publication.
The same question was recently discussed in detail. As mentioned above, a number of components, including agronomic efficiency, apparent N recovery, physiological efficiency, agro-physiological efficiency and N utilization efficiency, are considered to evaluate NUE of crop species and varieties. Of which efficiency of N uptake and utilization are the major components of NUE. Both grain and straw N concentration of a particular crop are required to calculate the NUE. Sources and rates of N applied to soils need to be considered in the evaluation of NUE of crops. You may find a number of references in this area.
Fageria, N., Baligar, V., 2005. Enhancing nitrogen use efficiency in crop plants. Adv. Agron. 88, 97-185.
Bingham IJ, Karley AJ, White PJ, Thomas WTB, Russell JR (2012) Analysis of improvements in nitrogen use efficiency associated with 75 years of spring barley breeding. Eur J Agron 42:49-58.
Xu G, Fan X, Miller AJ (2012) Plant nitrogen assimilation and use efficiency. Annu Rev Plant Biol 63:153-182
Very interesting discussion indeed. After going through this discussion and the earlier ones on such issues, How does different definitions of NUE really translate the eaxct behaviour of crop in field with respect nutrient absorption , translocation and utilization?. Do we need to redefine such definitions with respect to annual crops versus perennial crops in the context of root configuration etc?.
We debated this issue at length through following question , hope you find it wholesomely interesting :
https://www.researchgate.net/post/Can_high_nutrient-use-efficiency_NUE_guarantee_high_crop_yield_and_vice-versa
Dear Uttam, you can find a number of article on N use efficiency.
The utilization/physiological efficiency represents the fraction of plant acquired N to be converted to grain yield, which denotes the ability of a plant to transform N acquired from fertilizer into grain yield.
UtE (kg/kg) = GYf-GYu/Nf-Nu
Where GYf is the grain yield of the fertilized plot (kg), GYu is the grain yield of the unfertilized plot (kg) for each replicate. Nf is the N uptake (grain plus straw) of the fertilized plot (kg). Nu is the N uptake (grain plus straw) of thE unfertilized plot (kg) for each replicate. The article attached may be useful.
You can get help from Fertilizer Recommendation Guide-2012, published by Bangladesh Agricultural Research Council (BARC). There is detailed description and way of calculation of Nutrient Use Efficiency in the Guide.
Endorsing an excellent feedback from my friend Dr Getachew, The term nitrogen use efficiency indicates the ability of the plant to use nitrogen to produce biomass or yield , often called as nitrogen efficiency ratio, evaluated by total plant dry weight divided by nitrogen absorbed as g plant dry weight or kg yield per mg N absorbed. Rightly said, there are plenty of literature on this very important issue relating a variety of crops.
Three NUE, environmental NUE, Agronomic NUE and economic NUE have been described in literature. Agronomic efficiency may be defined as the nutrients accumulated in the above-ground part of the plant or the nutrients recovered within the entire soil-crop-root system. Economic efficiency occurs when farm income is maximized from proper use of nutrient inputs, but it is not easily predicted or always achieved because future yield increases, nutrient costs, and crop prices are not known in advance of the growing season. Environmental efficiency is site-specific and can only be determined by studying local targets vulnerable to nutrient impact. Though perspectives vary, agronomic nutrient use efficiency is the basis for economic and environmental efficiency. As agronomic efficiency improves, economic and environmental efficiency will also benefit. Certainly NUE will contribute towards high crop yield.
In the calculation of Agronomic efficiency, especially for nutrient omission trials we need to be very explicit when we say AE is the difference between Grain yield of N applied plot and Grain yield of plot where N was not applied over the amount of N applied. I say this since the the grain yield of N omitted plot or control plot could be considered.
NUE = [(N uptake in Fertilized Plot (kg/ha) - N uptake in unfertilized plot(kg/ha))]/ Fertilizer N applied (kg/ha) x 100
The best information on this topic is available from the review paper published in Advances in Agronomy by Ladha et al. (2005). The pdf of the paper is attached herewith.
We should carefully see the terms. Nutrient efficiency could be due to uptake efficiency (amount of nutrients taken up per unit of nutrient applied) and /or utilization efficiency ( the efficiency by which the acquired elements are utilized to generate vegetative biomass or edible parts of plants). You can refer literature which you can access thorough doi:10.1093/jxb/erv162
Article Chloride Improves Nitrate Utilization and NUE in Plants
here I leave you my material and Methodsgood luck!
the best method to calculate the Nitrogen use efficiency is stable isotope of Nitrogen. with this method you can determine the % of nitrogen dirived from fertilizer in plant. but you should be have a nitrogen labled with 15N
There are different nitrogen use indices which can be calculated based on data available of yield and nitrogen uptake. Please see the attached files for the further details.
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