Reduced loss of NH3 by coating urea with biodegradable polymers, palm stearin and selected micronutrients

In agricultural lands, the loss of NH3 from surface-applied urea and micronutrient deficiencies are the two most common problems, which can be solved by using coated urea with micronutrients and biodegradable natural materials. These coatings can improve the nutrient status in the soil and simultaneously reduce nitrogen loss from urea. To control ammonia loss and urea’s hydrolysis process, two laboratory studies were conducted to compare the effects of using coated urea with that of using only urea. Both studies consisted of consecutive incubation experiments that were conducted on the same Typic Paleudult soil (Serdang Series). Eight treatments (labeled as Urea, UPS1, UPS2, UPS3, UAG1%, UAG2%, UG1% and UG2%) in study 1 and six treatments (labeled U, UPSCu, UAGCu, UGCu, UCu, and UCuZn) in study 2 were prepared and used to determine the effects of various concentrations of natural materials and the inhibitory effects of micronutrients on both ammonia loss and the hydrolysis process. The NH3 loss was measured by forced draft techniques; the soil’s exchangeable ammonium, available nitrate and urea-N were determined by using standard procedures. The outcomes of the study did not show any significant difference among various concentrations ofnatural material. Coated urea treatments significantly reduced ammonia loss by 30 to 40% in study 1 and by 40 to 67% in study 2 in comparison to urea alone. The same observation was made with respect to urea hydrolysis. All of the coated urea treatments significantly slowed down the hydrolysis process in comparison to urea. The outcomes of the study may improve urea fertilizer by reducing the loss of NH3 volatilization.Key words: Biodegradable polymers, coated urea, CuSO4, NH3 volatilization loss, urease inhibitor, urea

Role of inhibitors and biodegradable material in mitigation of nitrogen losses from fertilized lands

Loss of N, occurring mainly through NH3 volatilization, biological denitrification, and NO3 - leaching, has both economic and environmental implications. Therefore, the economic benefits of reduced environmental pollution and future damage to our environment as a result of the use of urease inhibitors are of higher significance to the production of gains over the long-term. The literature review discussed the role, effectiveness and mechanism of urease inhibitors as well as coating of urea to reduce ammonia volatilization loss from urea fertilizer. Coating with urease inhibitors can improve the bioavailability of N, resulting in increased dry matter yield and N uptake. Such increases result from delayed urea hydrolysis by urease inhibitors and coating materials. The value of inhibitors in mitigating N loss would depend on their rate of biodegradation and persistence in soils. Previous studies has proven that micronutrients could be competent urease inhibitors, but the information about their effects on soil, nutrient uptake of plants and dry matter yield is poorly documented. Some nutrients such as Cu and Zn as urease inhibitors and natural biodegradable material such as agar, gelatin and palm stearin were found effective in reduction of nitrogen losses from nitrogen fertilizer especially from urea fertilizer. The article deals with the importance of use of above mentioned materials and micronutrient.Key words: Nitrogen, urea, fertilizer, inhibitors, biodegradation, land, nitrogen loss