Effect of Polymer-Coated Urea and Ammonium Nitrate Application on Nitrogen Behaviour in Sandy Soil and Yield Productivity | ||||
| Journal of Soil Sciences and Agricultural Engineering | ||||
| Article 2, Volume 8, Issue 3, March 2017, Page 101-113 PDF (4.06 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jssae.2017.37228 | ||||
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| Author | ||||
| Mona Osman | ||||
| Soil, Water and Environ. Res. Inst., Agric. Res. Center, Giza, Egypt | ||||
| Abstract | ||||
| A field experiment was carried out at El- Ismailia Agriculture Research Station farm, Agric. Res. Center (ARC), Egypt during two successive seasons (2015/2016). The institute farm is located at 30o 35' 41.9" N latitude and 32o 16' 45.8" E longitude. Wheat plants (Triticum aestivum L., CV. Giza 168) was planted during winter season (2015) and peanut plants (Arachis hypogaea) was planted during summer season (2016) in a sandy soil under sprinkler irrigation system, to improve the soil chemical properties, eliminate or reduce labor intensive of fertilizers losses, as well as increase in apparent nutrient recovery, through improving the nutritional status, minimize nitrogen loss, maintaining growth and yield of both wheat and peanut crops. Two sources of nitrogen fertilization were used, urea and ammonium nitrate with two rates (75% and 100% from the recommended dose) along with four rates of polymer (Hydrogel 0%, Hydrogel 1%, Hydrogel 2%, Hydrogel 3%) as a coating film material. Moreover, samples of the same nitrogen fertilizers were coated with the same four rates of polymers to be then incubated under laboratory condition to study the cumulative released percentage versus time, from both N- sources, along with the different rates of polymers; finally a field experiment was conducted. With regard to incubation experiment, results indicated that, the release of nitrogen from uncoated N-sources showed rapid and highly increase during the first two hours; the increase reached 94.35 % and 98.36% for both urea and ammonium nitrate respectively, uncoated urea being more responded as compared to uncoated ammonium nitrate. Generally, presence of polymer, as a coating material, caused slow gradual increase for soluble nitrogen as time goes up to 15 days as compared to without polymer treatment.The calculation of swelling ratio of hydrogel estimated that every one gram of hydrogel was swollen by uptake of 500 ml of water, this means that every 1 gram coating material from the used polymer absorbed 500 gm from the water. Also, Field Emission Scanning Electron Microscope noted that, the coated urea was smaller diameter, denser, more uniform and much smoother surface as compared to ammonium nitrate. On the contrary, the cross section of the coating shell of ammonium nitrate had a larger diameter, rough surface with large cavities along with both open and closed porosity.With regard to field experiment, results revealed that, the pH values in the soil after harvesting were significantly affected by both coated N-sources, as compared to uncoated treatments, for both tested crops; pH values increased significantly with time in presence of urea as compared to ammonium nitrate. Moreover, increasing the rate of nitrogen fertilization along with increasing the rate of applied polymer caused a significant increase in EC values during both tested seasons. Values representing nitrogen and potassium availability in soil, total contents (straw and grains or seeds) and yield components for both tested crops increased significantly in both coated urea and ammonium nitrate as compared to uncoated treatments. Furthermore, coated urea was more responded as compared to ammonium nitrate. Availability of N and K, total contents, (straw and seeds or grains) and yield components for both tested crops increased significantly by increasing the rate of nitrogen especially in presence of HG 2%. HG 2% ranked the first considering values under both fertilizer sources and rates. In contrast, the high rate of polymer (HG3%) for both N-sources caused a significant decrease in nutrient availability, total contents (straw and seeds or grains) and yield components for both tested crops. Again, the second rate of nitrogen fertilization (100%) was superior as compared to the first rate (75%) regarding increases in the wheat and peanut yield components (straw, grains and seeds). Apparent N and K recovery Efficiency (ANRE) was the highest due to application both nitrogen fertilizer sources coated with polymer as compared to control treatments. Also, increasing the rate of polymers caused a significant increase in ANRE of wheat and peanut plants. Regarding the rate of polymer, values of ANRE for N and K were significantly more stimulated with increasing the rate of polymer as a coating material for both N-sources as compared to un-coating up to HG2% as compared to control. On the other hand, the lowest ANRE was recorded in presence of HG3% as a coating material for both N- sources. Moreover, increasing the rate of polymer for both N-sources caused a positive increase in crude protein in grains and seeds of both crops (wheat and peanut) as compared to control. The highest crude protein (CP) % was obtained with application of high rate of coated urea (N2) with the second rate of polymer (HG2), coated urea was more pronounced as compared to coated ammonium nitrate for increasing the crude protein in grains of both tested crops. In conclusion, the application of both nitrogen fertilizers (urea and ammonium nitrate) coated with polymer at rate of 2 % hydrogel in sandy soil is an effective practice to reduce the losses of nitrogen, helpful to improve the soil chemical properties and positively reflected on total content of macronutrients, crude protein and ANRE as well as yield components of both wheat and peanut crops. Hydrogels act as a slow releasing fertilizers agent in sandy soil, through absorption of the nutrients needed by plants and releases them gradually by time for plants uptake and prevent nutrients from leaching. | ||||
| Keywords | ||||
| Polymer-coated urea and ammonium nitrate-nutritional status-wheat-peanut-yield- apparent nutrient recovery efficiency (ANRE); crude protein; swelling; Scanning Electron Microscope (SEM) | ||||
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