Nitrous oxide emissions -- fall banded -- urea -- fertilizer use efficiency.

Nitrogen (N) losses in the form of ammonia volatilization limit the efficiency of urea-based fertilizers world-wide. Urease inhibitor, N-(n-butyl) thiophosphoric triamide (NBPT) is a promising additive to reduce this N loss. Studies were conducted to test the efficacy of a relatively new NBPT formulation, ARM U (18% NBPT m/v), containing a proprietary polymer that allows for a low NBPT application rate in reducing ammonia volatilization from urea-based fertilizers. The results showed that ARM U reduced ammonia volatilization by an average of 85% across three soils and its effectiveness was not significantly different from other commercial NBPT formulations whose NBPT concentrations were 33-67% greater than ARM U. Further studies showed that delaying N fertilizer application until late-fall, as recommended on the Canadian prairies, did not stop ammonia volatilization from urea-based fertilizers. Across 4 site-year, total ammonia volatilization (% of applied N) from untreated urea-based fertilizers applied in the fall and spring were 14 and 16%, respectively. We found that the reduction of ammonia volatilization by NBPT was significantly greater in the fall (65%) than in the spring (40%) across 4 site-year and the addition of NI with NBPT (double inhibitor, DI) reduced the efficacy of NBPT in decreasing ammonia volatilization from spring-applied urea by 27%. The conserved N by NBPT and DI improved the crop N use efficiency at one of the two sites in this study. Investigation on the interaction between NBPT and NI on urea hydrolysis in five soils at 21 oC and six soils at 5, 15, and 25 oC showed that while NBPT reduced the rate of urea hydrolysis across soils and temperatures, the addition of NI reduced the inhibitory effect of NBPT on urea hydrolysis. Hence, reduction in ammonia volatilization is less with DI than only NBPT. Overall, the research shows that (i) NBPT effectively reduced ammonia volatilization even at a low concentration (ii) significant ammonia volatilization could occur from urea-based fertilizers even at soil temperature below 3 oC (iii) use of NBPT to bridge crop urea use efficiency is site-specific (iv) NI impaired the effectiveness of NBPT in suppressing urea hydrolysis and ammonia volatilization.

It is the aim of this book to present reviews on a wide range of aspects of bacterial respiratory systems. Because the on-going publication elsewhere of reviews on bacterial respiration, ablanket coverage of the field has not been attempted. Rather, a range of topics have been selected, either because they are of special current interest, they have not been reviewed recently, or they have never been reviewed.

This eBook presents highlight papers from the 17th International conference of the Recycling of Agricultural, Municipal and Industrial Residues to Agriculture Network (RAMIRAN) that was held in Wexford, Ireland in September 2017. The book contains a broad range of papers around this multidisciplinary theme covering topics including regional and national organic resource use planning, impact of livestock diet on manure composition, fate and utilisation of excreta from grazing livestock, anaerobic digestion, overcoming barriers to resource reuse, hygienic aspects of residue recycling and impacts on soil health. The overarching theme being addressed is the sustainable recycling of organic residues to agriculture, to promote effective nutrient use and minimise environmental impact.

The purpose of our present work is to review the fundamental studies on inhibition of soil urease activity and the applied studies on improving efficiency of urea fertilizers by inhibition of soil urease activity. The general literature on these topics covers 65 years, and the patent literature comprises a period of nearly 40 years. Studies related to inhibition of soil urease activity were performed in a great number of countries' well representing all the continents. Full texts of the papers describing these studies were published in one of 18 languages·'. The literature data reviewed are structured into 10 chapters, 81 subchapters, and 224 sections. The bibliographical list consists of 830 papers cited. ·In alphabetical order: Argentina, Armenia, Australia, Austria, Belgium, Belorussia, Brazil. Bulgaria, Canada, China, Costa Rica, Cuba. Czech RepUblic, Egypt, Estonia, France, Georgia (Gruzia), Germany, Hungary, India, Iraq, Ireland, Israel, Italy. Japan, Kazakhstan, Lithuania, Malaysia, Moldova, Netherlands, New Zealand, Pakistan, Philippines, Poland, Romania, Russia, Saudi Arabia, Slovakia, South Africa, South Korea, Spain, Sri Lanka. Sudan, Sweden, Thailand, Turkey, Ukraine, United Kingdom, United States of America. Uzbekistan .

A two-year field study was initiated in the fall of 2000 to investigate the effects of application date, landscape position and a urease and nitrification inhibited formulation of urea on the transformation and efficiency of fall-banded nitrogen (N) fertilizer for Canadian Western Red Spring wheat (Triticum aestivum L. cv. AC Barrie) production under Manitoba conditions. Granular urea fertilizer at a rate of 80 kg N ha-1 was banded at three application dates in the fall, between mid-September and mid-October, and once in the spring at planting. In addition, there was a treatment where urea formulated with a urease and nitrification inhibitor (NBPT and DCD respectively) was banded in the early fall. During the fall, landscape position did not significantly influence the conversion of banded-urea to nitrate under the moisture conditions present at the intensive sites. However, delaying the date of application of fall-banded urea fertilizer N into the late fall and the presence of NBPT and DCD slowed nitrification and increased the percent recovery of fertilizer N as NH4+-N in the soil prior to freeze-up. Date of application, soil temperature on the date of application, the accumulation of soil heat units (SHU) and nitrification heat units [NHU) were all linearly related to the percent of recovered fertilizer N as NH4+-N. Accumulated SHU and NHU best described the relationship with the proportion of fertilizer N recovered as NH4+-N at the end of the fall, with and without inhibitors... In the spring, large over-winter losses of fall-banded N were observed in the first year of the study, with greater losses of apparent fertilizer N in the low landscape positions than in the high landscape positions... At harvest, the effects of landscape position were apparent at three of the four sites, with significantly greater grain yields, straw yields and total recovery of N in the high landscape positions than in the low landscape positions... In general, the efficiency of fall-banded urea was not affected by application date, soil temperature on date of application, cumulative soil heat units or cumulative nitrification heat units in the high landscape positions. In the low landscape positions, delaying application until late in the fall, when soil temperatures had cooled to 5 or 6oC, increased grain yelds and total N uptake by the crop relative to early fall-banded N. Soil temperature at application gave the best correlation with crop responses to N (relative grain yields, total N uptake, grain yield increases and N use efficiency) in the low landscape positions (r=-0.79**,-0.75**,-0.78** and -0.72** respectively); date of application gave slightly lower correlations (r=0.66*, 0.66*,0.64* and 0.62* respectively). Soil heat units and nitrification heat units accumulated from date of application until freeze-up gave inferior correlations (r=-0.56ns, -0.62*, -0.56ns and -0.58*, and r=-0.49ns, -0.59ns, -0,49ns and -0.51ns respectively). These results suggest that date of application and soil temperature at application are simple, robust approaches for estimating the effect of weather conditions on the efficiency of fall-banded N in southern Manitoba. The results also suggest that selection of suitable timing for application of fertilizer N to optimize crop yields is much more critical in wet years, for poorly drained fields, and for poorly drained areas within a field, than for better drained land.