Raghava apply 50 kgs of urea to the soil and soil gain 23 kgs of Nitrogen where as Aditya applying Ammonium Sulphate to his soil how much Ammonium Sulphate should add by aditya ? (here urea contain 46% , nitrogen Ammonium Sulphate contain 21% of nitrogen
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Fertilizer urea
By Curtis J. Overdahl, George W. Rehm and Harvey L. Meredith
Introduction
In the past decade urea has surpassed and nearly replaced ammonium nitrate as a fertilizer. This has brought about new questions on urea and its use.
Fertilizer urea
Urea, a white crystalline solid containing 46% nitrogen, is widely used in the agricultural industry as an animal feed additive and fertilizer Here we discuss it only as a nitrogen fertilizer.
Physical forms of urea
Commercially, fertilizer urea can be purchased as prills or as a granulated material. In the past, it was usually produced by dropping liquid urea from a "prilling tower" while drying the product. The prills formed a smaller and softer substance than other materials commonly used in fertilizer blends. Today, though, considerable urea is manufactured as granules. Granules are larger, harder, and more resistant to moisture. As a result, granulated urea has become a more suitable material for fertilizer blends.
Advantages of fertilizer urea
Urea can be applied to soil as a solid or solution or to certain crops as a foliar spray.
Urea usage involves little or no fire or explosion hazard.
Urea's high analysis, 46% N, helps reduce handling, storage and transportation costs over other dry N forms.
Urea manufacture releases few pollutants to the environment.
Urea, when properly applied, results in crop yield increases equal to other forms of nitrogen.
Incorporate urea for best use
Nitrogen from urea can be lost to the atmosphere if fertilizer urea remains on the soil surface for extended periods of time during warm weather. The key to the most efficient use of urea is to incorporate it into the soil during a tillage operation. It may also be blended into the soil with irrigation water. A rainfall of as little as 0.25 inches is sufficient to blend urea into the soil to a depth at which ammonia losses will not occur.
Urea losses to air
Urea breakdown begins as soon as it is applied to the soil. If the soil is totally dry, no reaction happens. But with the enzyme urease, plus any small amount of soil moisture, urea normally hydrolizes and converts to ammonium and carbon dioxide. This can occur in 2 to 4 days and happens quicker on high pH soils. Unless it rains, urea must be incorporated during this time to avoid ammonia loss. Losses might be quite low in the spring if the soil temperature is cold. The chemical reaction is as follows:
CO(NH2)2 + H2O + urease → 2NH3 +CO2 (urea)
The problem is the NH3, because it's a gas, but if incorporated the NH3, acts the same as incorporated anhydrous ammonia. Also, half of 28% liquid N is urea and the same thing happens with this half as with regular urea.
Urea losses related to soil temperature and pH
The volatility of urea depends to a great extent on soil temperature and soil pH. Tables 1 and 2 show that after a few days warm temperatures or high pH would cause losses.
Table 1. Percent of surface-added urea volatilized as ammonia at different temperatures and days on the surface.
Temperature (F)Days45 degrees60 degrees75 degrees90 degrees(% of added N volatilized)0000020012422456567108571219106101420Data abstracted from curves in SSSP 24, pages 87-90, 1960. Urea was added on a silt loam soil at 100 lbs N.
Table 2. Percent of surface-added urea volatilized as ammonia at various soil pH levels and days on the surface.
Soil pHDays5.05.56.06.57.07.5(% of added N volatilized)0000000200001541251018206457112330889121830331081013224044Data from SSSP 24, pages 87-90, 1960. Urea added on silt loam soil at 100 lb. N.
Fall application comparisons
Urea can be readily nitrified – that is, converted to nitrate (NO3) – even when applied late in the fall, and can be quite susceptible to denitrification or leaching the following spring. Anhydrous ammonia (AA) applied in the fall does not nitrify as quickly, due to the stunting of microorganisms in the AA application band.
A two-year study conducted at Waseca compared late-October applications of both AA and urea for continuous corn (Table 3). These data show a 6 bu/A advantage for AA over urea when applied in the fall without a nitrification inhibitor. But when N-Serve was added, a 16 bu/A advantage was shown with AA. This indicates that the inhibitor has a better degree of contact with the AA mix than is possible with urea.
Table 3. Corn yield as influenced by N source, time of application, and nitrification inhibitor at Waseca. Malzer & Randall.
By Curtis J. Overdahl, George W. Rehm and Harvey L. Meredith
Introduction
In the past decade urea has surpassed and nearly replaced ammonium nitrate as a fertilizer. This has brought about new questions on urea and its use.
Fertilizer urea
Urea, a white crystalline solid containing 46% nitrogen, is widely used in the agricultural industry as an animal feed additive and fertilizer Here we discuss it only as a nitrogen fertilizer.
Physical forms of urea
Commercially, fertilizer urea can be purchased as prills or as a granulated material. In the past, it was usually produced by dropping liquid urea from a "prilling tower" while drying the product. The prills formed a smaller and softer substance than other materials commonly used in fertilizer blends. Today, though, considerable urea is manufactured as granules. Granules are larger, harder, and more resistant to moisture. As a result, granulated urea has become a more suitable material for fertilizer blends.
Advantages of fertilizer urea
Urea can be applied to soil as a solid or solution or to certain crops as a foliar spray.
Urea usage involves little or no fire or explosion hazard.
Urea's high analysis, 46% N, helps reduce handling, storage and transportation costs over other dry N forms.
Urea manufacture releases few pollutants to the environment.
Urea, when properly applied, results in crop yield increases equal to other forms of nitrogen.
Incorporate urea for best use
Nitrogen from urea can be lost to the atmosphere if fertilizer urea remains on the soil surface for extended periods of time during warm weather. The key to the most efficient use of urea is to incorporate it into the soil during a tillage operation. It may also be blended into the soil with irrigation water. A rainfall of as little as 0.25 inches is sufficient to blend urea into the soil to a depth at which ammonia losses will not occur.
Urea losses to air
Urea breakdown begins as soon as it is applied to the soil. If the soil is totally dry, no reaction happens. But with the enzyme urease, plus any small amount of soil moisture, urea normally hydrolizes and converts to ammonium and carbon dioxide. This can occur in 2 to 4 days and happens quicker on high pH soils. Unless it rains, urea must be incorporated during this time to avoid ammonia loss. Losses might be quite low in the spring if the soil temperature is cold. The chemical reaction is as follows:
CO(NH2)2 + H2O + urease → 2NH3 +CO2 (urea)
The problem is the NH3, because it's a gas, but if incorporated the NH3, acts the same as incorporated anhydrous ammonia. Also, half of 28% liquid N is urea and the same thing happens with this half as with regular urea.
Urea losses related to soil temperature and pH
The volatility of urea depends to a great extent on soil temperature and soil pH. Tables 1 and 2 show that after a few days warm temperatures or high pH would cause losses.
Table 1. Percent of surface-added urea volatilized as ammonia at different temperatures and days on the surface.
Temperature (F)Days45 degrees60 degrees75 degrees90 degrees(% of added N volatilized)0000020012422456567108571219106101420Data abstracted from curves in SSSP 24, pages 87-90, 1960. Urea was added on a silt loam soil at 100 lbs N.
Table 2. Percent of surface-added urea volatilized as ammonia at various soil pH levels and days on the surface.
Soil pHDays5.05.56.06.57.07.5(% of added N volatilized)0000000200001541251018206457112330889121830331081013224044Data from SSSP 24, pages 87-90, 1960. Urea added on silt loam soil at 100 lb. N.
Fall application comparisons
Urea can be readily nitrified – that is, converted to nitrate (NO3) – even when applied late in the fall, and can be quite susceptible to denitrification or leaching the following spring. Anhydrous ammonia (AA) applied in the fall does not nitrify as quickly, due to the stunting of microorganisms in the AA application band.
A two-year study conducted at Waseca compared late-October applications of both AA and urea for continuous corn (Table 3). These data show a 6 bu/A advantage for AA over urea when applied in the fall without a nitrification inhibitor. But when N-Serve was added, a 16 bu/A advantage was shown with AA. This indicates that the inhibitor has a better degree of contact with the AA mix than is possible with urea.
Table 3. Corn yield as influenced by N source, time of application, and nitrification inhibitor at Waseca. Malzer & Randall.
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