Abstract
The current study investigated the short-term physiological implications of plant nitrogen uptake of urea amended with the urease inhibitor N-(n-butyl) thiophosphoric triamide (nBTPT) under both greenhouse and field conditions. 15N labelled urea amended with 0.0, 0.01, 0.1 and 0.5% nBTPT (w/w) was surface applied at a rate equivalent to 100 kg N ha−1 to perennial ryegrass in a greenhouse pot experiment. Root, shoot and soil fractions were destructively harvested 0.75, 1.75, 4, 7 and 10 days after fertilizer application. Urease activity was determined in each fraction together with 15N recovery and a range of chemical analyses. The effect of nBTPT amended urea on leaf tip scorch was evaluated together with the effect of the inhibitor applied on its own on plant urease activity.
nBTPT-amended urea dramatically reduced shoot urease activity for the first few days after application compared to unamended urea. The higher the nBTPT concentration the longer the time required for shoot activity to return to that in the unamended treatment. At the highest inhibitor concentration of 0.5% shoot urease activity had returned to that of unamended urea by 10 days. Root urease activity was unaffected by nBTPT in the presence of urea but was affected by nBTPT in the absence of urea.
Transient leaf tip scorch was observed approximately 7–15 days after nBTPT + urea application and was greatest with high concentrations of nBTPT and high urea-N application rates. New developing leaves showed no visual sign of tip necrosis.
Urea hydrolysis of unamended urea was rapid with only 1.3% urea-N remaining in the soil after 1.75 days. N uptake and metabolism by ryegrass was rapid with 15N recovery from unamended urea, in the plant (shoot + root) being 33% after 1.75 days. Most of the 15N in the soil following the urea+0.5% nBTPT application was still as urea after 1.75 days, yet 15N plant recovery at this time was 25% (root+shoot). This together with other evidence, suggests that if urea hydrolysis in soil is delayed by nBTPT then urea can be taken up by ryegrass as the intact molecule, albeit at a significantly slower initial rate of uptake than NH4 +-N. Protein and water soluble carbohydrate content of the plant were not significantly affected by amending urea with nBTPT however, there was a significant effect on the composition of amino acids in the roots and shoots, suggesting a difference in metabolism.
Although nBTPT-amended urea affected plant urease activity and caused some leaf-tip scorch the effects were transient and short-lived. The previously reported benefit of nBTPT in reducing NH3 volatilization of urea would appear to far outweigh any of the observed short-term effects, as dry-matter production of ryegrass is increased.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Andrews R P 1980 The analysis of human serum and plasma using the LKB 4400 amino acid analyser with a lithium buffer system. Pharmacia Biotech Protein Chemistry note number 12, Knowlhill, Milton Keynes, UK.
Benchemsi-Bekkari, N and Pizelle, G 1992 In vivo urease activity in Robinia pseudoacacia. Plant Physiol. Biochim. 30, 187–192.
Bollard, E G, Cook, A R and Turner, N A 1968 Urea as sole source of nitrogen for plant growth I. The development of urease activity in Spirodela oligorrhiza. Planta 83, 1–12.
Buresh, R J, De, Datta, S K, Padilla, J L and Samson, M I 1988 Field evaluation of two urease inhibitors with transplanted lowland rice. Agron. J. 80, 763–768.
Carmona, G, Christianson, C B and Byrnes, B H 1990 Temperature and low concentration effects of the urease inhibitor N-(n-butyl) thiophosphoric triamide (nBTPT) on ammonia volatilization from urea. Soil Biol. Biochem. 22, 933–937.
Creason, G L, Schmitt, M R, Douglass, E A and Hendrickson, L L 1990 Urease inhibitory activity associated with N-(normal-butyl) thiophosphoric triamide is due to formation of its oxon analog. Soil Biol. Biochem. 22, 209–211.
Dilley K J and Rocek P H 1978 The physiological fluid analysis using the LKB 4400 amino acid analyser with a lithium buffer system. Pharmacia Biotech Protein Chemistry note number 11, Knowlhill, Milton Keynes, UK.
Eskew, D L, Welch, R M and Cary, E E 1983 Nickel: An essential micronutrient for legumes and possibly all higher plants. Science 222, 621–623.
Fahmy, A S, Mohamed, M A and Kamel, M Y 1994 Ureases in the cucurbitaceae, distribution and properties. Phytochemistry 35, 151–154.
Fenn, L B and Hossner, L R 1985 Ammonia volatilization from ammonium or ammonium-forming nitrogen fertilizers. Adv. Soil Sci. 1, 123–169.
Genstat 1993 Design and analysis of experiments. In Genstat 5, Release 3, Reference Manual. Genstat 5 Committee of the Statistics Department, Rothamsted Experimental Station, AFRC Institute of Arable Crops Research, Harpenden, UK. Chapter 9, pp 461–538. Oxford University Press, Oxford, UK.
Harper, J E 1984 Uptake of organic nitrogen forms by roots and leaves. In Nitrogen in Crop Production. Ed. R D, Hauck. pp 165–170. ASA, CSSA, SSSA, Madison, WI, USA.
Hogan, M E, Swift, I E and Done, J 1983 Urease assay and ammonia release from leaf tissues. Phytochemistry 22, 663–667.
Hoult, E H and McGarity, J W 1986 The measurement and distribution of urease activity in a pasture system. Plant and Soil 93, 359–366.
International Atomic Energy Agency 1976 Tracer Manual on Crops and Soils. Technical reports series no. 171, pp 119–148. IAEA, Vienna, Austria.
Joo, Y K, Christians, N E and Blackmer, A M 1991 Kentucky blue-grass recovery of urea-derived nitrogen-15 amended with urease inhibitor. Soil Sci. Soc. Am. J. 55, 528–530.
Krogmeier, M J, McCarty, G W and Bremner, J M 1989 Potential phytotoxicity associated with the use of soil urease inhibitors. Proc. Natl. Acad. Sci. USA 86 1110–1112.
Krogmeier, M J, McCarty, G W, Shogren, D R and Bremner, J M 1991 Effect of nickel deficiency in soybeans on the phytotoxicity of foliar-applied urea. Plant and Soil 135, 283–286.
Liantie, Li, Wang, Z P, Van, Cleemput, O and Baert, L 1993 Urea N uptake efficiency of ryegrass (Lolium perenne L.) in the presence of urease inhibitors. Biol. Fertil. Soils 15, 225–228.
Lowry, O H, Rosebrough, N J, Farr, A L and Randall, R J 1951 Protein measurement with the folin phenol reagent. J. Biol. Chem. 193, 265–275.
Matsumoto, H, Yasuda, T, Kobayashi, M and Takahashi, E 1966 The inducible formation of urease in rice plants. Soil Sci. Plant Nutr. 12, 33–38.
McCarty, G W, Bremner, J M and Chai, H S 1989 Effect of N-(n-butyl) thiophosphoric triamide on hydrolysis of urea by plant, microbial and soil urease. Biol. Fertil. Soils 8, 123–127.
Mengel, K and Kirkby, E A 1982 Nutrient uptake and assimilation. In Principles of Plant Nutrition, 3rd ed. Eds. K, Mengel and E A, Kirkby. pp 109–184. International Potash Institute, Bern, Switzerland.
Ministry of Agriculture, Fisheries and Food 1981 The Analysis of Agricultural Materials. RB427, 2nd ed. HMSO, London, UK.
Ministry of Agriculture, Fisheries and Food 1988 Fertilizer recommendations for agricultural and horticultural crops. RB209, Fifth ed. HMSO, London, UK.
Mulvaney, R L and Bremner, J M 1979 A modified diacetyl monoxime method for colorimetric determination of urea in soil extracts. Commun. Soil Sci. Plant Anal. 10, 1163–1170.
Scheiner, D 1976 Determination of ammonia and Kjeldahl nitrogen by indophenol blue method. Water Res. 10, 31–36.
Tabatabai, M A 1982 Soil enzymes. In Methods of Soil Analysis, no. 9, Part 2. Chemical and Microbiological Properties. 2nd ed. Eds. A L, Page, R H, Miller and D R, Keeney. pp 903–947. ASA, SSSA, Madison, WI, USA.
Tecator 1983 Determination of nitrate nitrogen in soil samples extractable by 2 M KCl using flow injection analysis. AN 65/83.
Tecator 1984 Determination of ammonia nitrogen by flow injection analysis and gas diffusion. AN 50/84.
Turley, R H and Ching, T M 1986 Physiological responses of barley leaves to foliar applied urea-ammonium nitrate. Crop Sci. 26, 987–993.
Wallace, G F and Barrett, P 1981 Analytical method development for inductively coupled plasma spectrometry. Perkin Elmer application note, Perkin Elmer Corporation, Norwalk, CT, USA.
Warden, M R and Kettlewell, P S 1993 Effects of different doses of urea solution applied to the foliage of winter wheat at stem extension on leaf scorch and yield. Ann. Appl. Biol. 122, 114–115.
Watson, C J, Miller, H, Poland, P, Kilpatrick, D J, Allen, M B D, Garrett, M K and Christianson, C B 1994a Soil properties and the ability of the urease inhibitor N-(n-butyl) thiophosphoric triamide (nBTPT) to reduce ammonia volatilization from surface-applied urea. Soil Biol. Biochem. 26, 1165–1171.
Watson, C J, Poland, P, Miller, H, Allen, M B D, Garrett, M K and Christianson, C B 1994b Agronomic assessment and 15N recovery of urea amended with the urease inhibitor nBTPT (N-(n-butyl) thiophosphoric triamide) for temperate grassland. Plant and Soil 161, 167–177.
Whitehead, D C, Lockyer, D R and Raistrick, N 1988 The volatilization of ammonia from perennial ryegrass during decomposition, drying and induced senescence. Ann. Bot. 61, 567–571.
Zonia, L E, Stebbins, N E and Polacco, J C 1995 Essential role of urease in germination of nitrogen-limited Arabidopsis thaliana seeds. Plant Physiol. 107, 1097–1103.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Watson, C.J., Miller, H. Short-term effects of urea amended with the urease inhibitor N-(n-butyl) thiophosphoric triamide on perennial ryegrass. Plant Soil 184, 33–45 (1996). https://doi.org/10.1007/BF00029272
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00029272