Slow-release urea fertilizers ? effect on floodwater chemistry, ammonia volatilization and rice growth in an alkali soil

1987 ◽  
Vol 13 (3) ◽  
pp. 209-221 ◽  
Author(s):  
D. L. N. Rao
Keyword(s):  
Ammonia Volatilization ◽  
Slow Release ◽  
Rice Growth ◽  
Alkali Soil ◽  
Slow Release Urea

scholarly journals Ammonia volatilization from enhanced-efficiency urea on no-till maize in brazilian cerrado with improved soil fertility

2016 ◽  
Vol 40 (2) ◽  
pp. 133-144 ◽  
Author(s):  
Eduardo Lopes Cancellier ◽  
Douglas Ramos Guelfi Silva ◽  
Valdemar Faquin ◽  
Bruno de Almeida Gonçalves ◽  
Leandro Lopes Cancellier ◽  
...  
Keyword(s):  
Controlled Release ◽  
Ammonia Volatilization ◽  
Slow Release ◽  
Urease Inhibitors ◽  
N Accumulation ◽  
Nitrogen Use ◽  
No Till ◽  
Use Efficiency ◽  
Slow Release Urea ◽  
Controlled Release Urea

ABSTRACT High nitrogen losses by ammonia volatilization are expected when urea is used as the source of N. The use of controlled-release urea and urease inhibitors are possible strategies to reduce such losses and increase nitrogen use efficiency. This study aimed to evaluate nitrogen losses by ammonia volatilization from stabilized, slow and controlled release urea and its absorption by maize grown under no-till in an improved Cerrado soil. Four N sources were used: conventional urea, urea + N-(n-butyl) thiophosphoric triamide (NBPT), urea + Cu and B and urea coated by sulfur + polymers. These N sources were surface applied along the rows using three N doses of 100, 150 and 200 kg ha-1. No N was added to the control. Data were collected regarding N losses by volatilization, the N contents accumulated in the stubble and grains, and the yields of the stubble and grains. Stabilized urea and slow release urea were efficient for postponing the ammonia volatilization peaks. The urease inhibitors postponed the peaks for up to two days, reducing the accumulated volatilization by 18% when compared with common urea. Polymer sulfur coated urea resulted in a 37% reduction in ammonia volatilization. Increasing the N application rate to 200 kg ha-1 resulted in 16% greater yields and 37% greater N accumulation in the plants relative to the control. However, the stabilized and slow-release urea did not improve the N accumulation or yield. Consequently, the nitrogen use efficiency of maize was not improved relative to the use of conventional urea.

Effects of Slow-Release Urea Combined with Conventional Urea on Rice Output and Growth in Soils of Different Textures

2013 ◽  
Vol 38 (8) ◽  
pp. 1494-1503 ◽  
Author(s):  
Xiao-Cui ZHANG ◽  
Qi-Gen DAI ◽  
Xing-Xing HU ◽  
De-Jian ZHU ◽  
Xiu-Wen DING ◽  
...  
Keyword(s):  
Slow Release ◽  
Slow Release Urea

Effect of slow-release urea microencapsulated in beeswax and its inclusion in ruminant diets

2019 ◽  
Vol 179 ◽  
pp. 56-63 ◽  
Author(s):  
A. de B. Carvalho ◽  
A.L. da Silva ◽  
A.M. de A. Silva ◽  
A.J. Netto ◽  
T.T.B. de Medeiros ◽  
...  
Keyword(s):  
Slow Release ◽  
Ruminant Diets ◽  
Slow Release Urea

scholarly journals Ruminal fermentation and digestion of cattle diets with total and partial replacement of soybean meal by a slow-release urea product

2019 ◽  
Vol 64 (No. 7) ◽  
pp. 294-301
Author(s):  
S Gonzalez-Munoz ◽  
J Sanchez ◽  
S Lopez-Aguirre ◽  
J Vicente ◽  
J Pinos-Rodriguez
Keyword(s):  
Soybean Meal ◽  
Degradation Rate ◽  
Slow Release ◽  
In Vitro Assay ◽  
Partial Replacement ◽  
Vitro Assay ◽  
Dietary Substitution ◽  
Slow Release Urea

One in vitro assay and one in vivo trial with ruminally cannulated Holstein steers were conducted to evaluate the effects of a dietary substitution of soybean meal by a urea and slow-release urea source of fermentation and degradation of diets for cattle. The experimental diets consisted of the total mixed rations defined as the control with soybean meal (SBM), U (urea), SRU (slow-release urea), and SRU+U+AA (0.42% + 0.42% + 1% amino acids methionine and lysine). The dietary substitution of SBM by U or SRU reduced (P < 0.05) the total gas production (V), microbial mass and degradation at 72 h incubation under the in vitro conditions, as well as the degradation rate (c) and the total volatile fatty acids (VFA) in the rumen of the steers; however, when the dietary substitution of SBM was by U+SRU+AA, those values did not decrease. In the steers, the dietary substitution of SBM by U and SRU reduced the ruminal degradation rate and the total VFA, and increased the ammonia N, but when SBM was substituted by U+SRU+AA in the diets, these changes were not observed. No advantage of SRU over U was found. The dietary substitution of SBM by U, SRU, U+SRU+AA did not modify the molar proportion of the VFA in the rumen nor were there changes in the nutrient digestion or excretion. Both the in vitro assay and the in vivo trial indicated that replacing SBM with U or SRU increases the ruminal ammonia N concentrations and reduces the degradation rate in the rumen, although those undesirable findings were not found when the SBM was replaced by U+SRU+AA. Therefore, it is feasible to replace the SBM with a combination of urea, slow-release urea, lysine and methionine in the diet for the ruminants.

Effect of slow-release urea on the composition of ruminal bacteria and fungi communities in yak

2018 ◽  
Vol 244 ◽  
pp. 18-27 ◽  
Author(s):  
X.T. Yan ◽  
B.Y. Yan ◽  
Q.M. Ren ◽  
J.J. Dou ◽  
W.W. Wang ◽  
...  
Keyword(s):  
Slow Release ◽  
Ruminal Bacteria ◽  
Bacteria And Fungi ◽  
Slow Release Urea

scholarly journals Effect of combinations of feed-grade urea and slow-release urea in a finishing beef diet on fermentation in an artificial rumen system

2020 ◽  
Vol 4 (2) ◽  
pp. 839-847
Author(s):  
Daryoush Alipour ◽  
Atef Mohamed Saleem ◽  
Haley Sanderson ◽  
Tassilo Brand ◽  
Laize V Santos ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Fatty Acid ◽  
Volatile Fatty Acid ◽  
Dry Matter ◽  
Slow Release ◽  
Neutral Detergent Fiber ◽  
Microbial Protein ◽  
Microbial Protein Synthesis ◽  
Microbial Nitrogen ◽  
Slow Release Urea

Abstract This study evaluated the effect of combinations of feed-grade urea and slow-release urea (SRU) on fermentation and microbial protein synthesis within two artificial rumens (Rusitec) fed a finishing concentrate diet. The experiment was a completely randomized, dose–response design with SRU substituted at levels of 0% (control), 0.5%, 1%, or 1.75% of dry matter (DM) in place of feed-grade urea, with four replicate fermenters per dosage. The diet consisted of 90% concentrate and 10% forage (DM basis). The experiment was conducted over 15 d, with 8 d of adaptation and 7 d of sampling. Dry matter and organic matter disappearances were determined after 48 h of incubation from day 9 to 12, and daily ammonia (NH3) and volatile fatty acid (VFA) production were measured from day 9 to 12. Microbial protein synthesis was determined on days 13–15. Increasing the level of SRU quadratically affected total VFA (Q, P = 0.031) and ammonia (Q, P = 0.034), with a linear increment in acetate (L, P = 0.01) and isovalerate (L, P = 0.05) and reduction in butyrate (L, P = 0.05). Disappearance of neutral detergent fiber (NDF) and acid detergent fiber (ADF) was quadratically affected by levels of SRU, plateauing at 1% SRU. Inclusion of 1% SRU resulted in the highest amount of microbial nitrogen associated with feed particles (Q, P = 0.037). Responses in the efficiency of microbial protein synthesis fluctuated (L, P = 0.002; Q, P = 0.001) and were the highest for 1% SRU. In general, the result of this study showed that 1% SRU in combination with 0.6% urea increased NDF and ADF digestibility and total volatile fatty acid (TVFA) production.

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