Urine should work better than urea, since decomposers are limited not only by N, but also by Na (urine is source of Na, urea - not). See papers below:

Kind regards!

Michał

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The wide C/N ratio of your plant leaf materials require addition of mineral N to narrow down the C/N ratio for rapid decomposition during composting. You may incorporate fertilizer N like ammonium sulphate or urea @0.5 to 1.0% of raw materials hastens the decomposition. Addition of fertilizer N serves as starter. Beside moisture content, which you dont want to touch, the other factor that affect in compost are temperature, pH, C/N ratio. aeration and inoculation. These are some of the factors that affect the entire composting process.Well decompose compost should have a neutral pH, C/N ratio < 20 and contain more than 16% C, 0.5% N, 0.5% P2O5 and 1% K2O (on w/w basis). The nutrient content of compost is low. Hence, enriched compost can be prepared by adding N, low-grade minerals like rock phosphate and waste mica during composting to increase the nutrient value of the final product.

Yes.  Add urea as suggested and some minerals.  Kitchen scraps contain microbially available carbohydrates that boost the reaction rate.

Yes, three important factors should be considered which are; N source (N fertilizer), Temperature and moisture for better composting.

Adding N source plus moisture will definitely speed up decomposition. It is altering the C:N ratio. If the N source is an inorganic N (Urea, NH4NO3, (NH4)SO4, NH4Cl, etc.) then the compost cannot be used in organic farming in the USA. It may be different in other country - differs from country to country

Dear sirs,

Thank you very much for your answers and papers attached. It is very useful indeed!

Yes urea can be added to increase the decomposition rate, because the basic reason to reduce the C and N ratio. However moisture is also an important parameters. Optimum moisture level is also very much required.

Particle size and surface area. Shred or chip it.

A nitrate or sulphate based fertilizer source would be preferred N source over urea as there would be less risk of N loss through volatilisation to ammonia through the enzyme ureaze, leaving more N available for microbial breakdown of the litter given adequate moisture,aeration and temperature conditions. Addition of a carbohydrate waste,such as vinasse will accelerate the reaction and rate of decomposition. 

mixed with organic materials containing higher nitrogen, such as sludge and manure

Given the lignocellulosic nature of the material it is advisable to biostimulate decomposing microorganisms by the addition of nutrients such as N and P, urea may be a convenient alternative but attention should be paid to the generation of acidity, which may be inconvenient for the process. You can also consider an alternative source of nitrogen such as leaves of legumes, or other organic waste rich in nitrogen

Cattle dung mixed with water (1 kg fresh dung diluted with 10 litres of water) can be sprayed thrice a week for four weeks in succession to decompose the leaf litter to get a good organic fertilizer.  

 Addition of urea to agricultural waste can be adjusted C/N ratio  at suitable level for microorganisms  ,on the other hand provide energy and nitrogen for microbes.For accelerating composting addition of cellulolytic microorganisms recommended.

My specific concern is whether or not  addition of urea defeats the objective of organic farming principles in which synthetic chemicals are barred notwithstanding the merits of urea use. 

A small quantity of urea, leaves of legumes or some diluted cow dungs will give good results.

Urea is N-rich organic compound produced in mammals and human beings as well.In urine (containing 2.5% urea) it also goes to farmyard manure pit along with animal dung.Synthetic urea is also structurally similar to urea produced in living system.Also undergoes similar hydrolysis by urease enzyme and forms NH4-N and bicarbonate( which decomposes into water and CO2).Then what is the difference in NH4 ion formed from cow urine derived urea and chemical fertilizer derived urea.As I understand, urea whether cow derived or fertilizer plant manufactured should be allowed in organic farming.

If urea is allowed in organic farming,the productivity in organic  farming will increase.To meet the P requirement of crops various modifications/improvements in rock phosphate and  K bearing minerals and crude salts including their integrated use with organics are available.Incidental addition of micro and secondary nutrients through mineral and crude salt sources will also supplement those nutrients in addition to the supply from organic manures and other organic sources.Over all with better crop nutrition the organic produce productivity and quality will increase.

I don't think, there is any harm in adding small quantity of urea to accelerate the pace of litter decomposition, eventually the better soil fertility ensuring elevated crop response. Dr Reddy has a point to see such addition of urea jeopardizing the objectives of organic farming and decomposed litter as a natural product.. 

Urea is organic nitrogen and so are those in the organic matter. I'm not sure which will attrack microbes the most but both urea and organic matter will be sourced as resources, therefore, decomposition will depend on which the attention of the soil microbes are. We have seen addition of organic matter in the form of leucerne more effective in changing soil chemistry (pH, Eh, sulfate content) than addition of urea. This might properly suggest that organic matter induces a conducive environment which becomes a niche for microbes to settle in quickly and act to decompose. The question we have now is, how would a small amount of urea accelerate decomposition? Urea as an N source might increase buck population, hence a faster act on the OM.