«: AGROCHEMICALS: FATE IN FOOD AND THE ENVIRONMENT PROCEEDINGS OF A SYMPOSIUM, ROME, 7 - 1 1 JUNE 1982 JOINTLY ORGANIZED BY IAEA AND FAO l^J I N T E R ...»
, POSTGATE, J.R., HILL, S., "Nitrogen fixation", Microbial Ecology: A Conceptual Approach (LYNCH, J.M., POOLE, N.J., Eds), Blackwell, Oxford (1979) 91.
REICHARDT et al.
HENZEL, E.F., NORRIS, D.O., "Processes by which nitrogen is added to the soil-plant", Commonwealth Bureaux Pasture Field Crops, A Review of Nitrogen in the Tropics with Particular Reference to Pasture, Bulletin No.46, Aberystwyth (1962) 18.
BODDEY, R.M., DOBEREINER, J., Proc. 12th Int. Congr. Soil Sci., New Delhi, Symp.
Papers I, (1982) 28.
Associative N-fixation, Vols I and II (VOSE, P.B., RUSCHEL, A.P., Eds), CRC Press, Boca Raton (1981).
RENNIE, R.J., Ibid (1981) 253.
RUSCHEL, A.P., "Fixaçâo biológica do nitrogênio", Fisiología vegetal, (GUIMARÂES FERRI, M., Ed.), Vol.1, EDUSP, Sào Paulo (1979) 167.
NEY, P.H., GREENLAND, D.J., The Soil under Shifting Cultivation, Commonwealth Agricultural Bureaux,Bucks., Technical Communication, No.51 (1960).
LIBARDI, P.L., REICHARDT, K., Destino da uréia aplicada a um solo tropical, Rev.
Bras. Cienc. Solo 2 (1978) 40.
ADRIANO, D.C., TAKATORI, F.H., PRATT, P.F., LORENZ, O.A., Soil nitrogen balance in selected row-crop sites in Southern California, J. Environ. Quai. 1 (1972) 279.
FRIED, M., TANJI, K.K., VAN DE POL, R.M., Simplified long term concept for evaluation leaching of nitrogen from agricultural land, J. Environ. Qual. 5 (1976) 197.
LIBARDI, P.L., VICTÓRIA, R.L., REICHARDT, K., CERVELLINI, A., "The fate of urea applied to tropical bean (Phaseolus vulgaris L.) crop", Workshop on Nitrogen Cycling in Ecosystems of Latin America and Caribbean, Cali, 1981, CIAT, Cali (in press).
LUND, L.J., ADRIANO, D.C., PRATT, P.F., Nitrate concentrations in deep soil cores as related to soil profile characteristics, J. Environ. Qual. 3 (1974) 78.
PRATT, P.F., JONES, W.W., HUNSAKER, V.E., Nitrate in deep soil profiles in relation to fertilizer rates and leaching volume, J. Environ. Qual. 1 (1972) 97.
REICHARDT, K., LIBARDI, P.L., VICTORIA, R.L., VIEGAS, G.P., Dinámica do nitrogênio num solo cultivado com milho, Rev. Bras. Cienc. Solo 3 (1979) 17.
CAMERON, K.C., WILD, A., "Comparative appraisal of simple equations or models for predicting nitrate movement in the soil profile", Seminar on Isotope Techniques in Studies of the Useful Conservation and the Pollutant Potential of Agricultural Nitrogen Residues, Vienna, 1980, IAEA, Vienna (1980) 17 (abstract only).
FRISSEL, M.J., VAN VEEN, J.A., "Review of mathematical models on the behaviour of nitrogen in soil, its uptake by plants and release to the environment", Ibid (1980) 16 (abstract only).
NIELSEN, D.R., WIERENGA, P.J., BIGGAR, J.W., "Movement of nitrate in the soil profile", Ibid (1980) 15 (abstract only).
PRATT, P.F., LUND, L.J., RIBLE, J.M., "An approach to measuring leaching of nitrate from freely drained irrigated fields", Nitrogen in the Environment, Vol.1 (NIELSEN, D.R., MacDONALD, J.G., Eds), Academic Press, New York (1978) 223.
ROSE, C.W., "Nitrate movement in the soil profile resulting from successive irrigation/ rainfall and drying events", Seminar on Isotope Techniques in Studies of Useful Conservation and the Pollutant Potential of Agricultural Nitrogen Residues, Vienna, 1980, IAEA, Vienna (1980) 18 (abstract only).
SCOTTER, D.R., Preferential and solute movement through larger soil voids. I. Some computation using simple theory, Aust. J. Soil Res. 16 (1978) 257.
WILD, A., Nitrate leaching under bare fallow at a site in Northern Nigeria, J. Soil Sci. 23 (1972)315.
TERRY, D.L., McCANTS, C.B., Quantitative prediction of leaching in field soil, Soil Sci.
Soc. Am. Proc. 34(1970) 271.
IAEA-SM-263/36 289  PRATT, P.F., LUND, L.J., WARNEKE, J.E., "Nitrogen losses in relation to soil profile characteristics", Seminar on Isotope Techniques in Studies of the Useful Conservation and the Pollutant Potential of Agricultural Nitrogen Residues, Vienna, 1980, IAEA, Vienna (1980) 22 (abstract only).
 SOTIRIOU, N.. KORTE, F., "Balance and fate of nitrogen-15-fertilizer in soil/plant systems under outdoor conditions", Ibid (1980) 24 (abstract only).
 YOUNGDAHL, L.J., AUSTIN, E.R., VLEK, P.L.G., GRASWELL, E.T., "The evaluation of the loss potential of modified urea fertilizer for rice using 1S N", Ibid (1980) 23 (abstract only).
 GOLDEN, D.C., "Nitrification and movement of the nitrate after application of ammonium sulphate in a red-yellow podzolic tea soil in Sri Lanka", Ibid (1980) 27 (abstract only).
 REICHARDT, K„ LIBARDI, P.L., MEIRELLES, N.M.F., FERREYRA, H.F.F., ZAGATTO, E.A.G., MATSUI, E., Extraçao e análise de nitratos em soluçàfo do solo, Rev. Bras. Cienc. Solo 1 (1977) 130.
 REICHARDT, K„ GROHMAN, F., LIBARDI, P.L., QUEIROZ, S.V., Spatial variability of physical properties of a tropical soil. I. Geometric properties, Centro de Energia Nuclear na Agricultura, Piracicaba, Bol. Téc. No.4 (1976).
 REICHARDT, K., GROHMANN, F., LIBARDI, P.L., QUEIROZ, S.V., Spatial variability of physical properties of a tropical soil. II. Soil water retention curves and hydraulic conductivity, Centro de Energia Nuclear na Agricultura, Piracicaba, Bol. Téc.
 NASCIMENTO, V.F., REICHARDT, K., LIBARDI, P.L., Deslocamento miscivel do ion cloreto em solo Terra Roxa Estruturada (Alfisol) saturado em condiçoes de campo, Rev. Bras. Cienc. Solo 3 (1979) 67.
 REICHARDT, K., LIBARDI, P.L., NASCIMENTO, V.F., Condutividade hidráulica saturada de um perfil de Terra Roxa Estruturada (Alfisol), Rev. Bras. Cienc. Solo 2 (1978)21.
 MEIRELLES, N.M.F., LIBARDI, P.L., REICHARDT, K., Absorçâo e lixiviaçâo de nitrogênio em cultura de feijâo (Phaseolus vulgaris L.). Rev. Bras. Cienc. Solo 4 (1980) 83.
 CERVELLINI, A., RUSCHEL, A.P., MATSUI, E., SALATI, E., ZAGATTO, E.A.G., FERREYRA, H.F.F., KRUG, F.J., BERGAMIN, H.F., REICHARDT, K., MEIRELLES, N.M.F., LIBARDI, P.L., VICTORIA, R.L., SAITO, S.M.T., NASCIMENTO, V.F., "Fate of 1SN applied as ammonium sulphate to a bean crop", Soil Nitrogen as Fertilizer or Pollutant (Proc. Panel Piracicaba, 1978), IAEA, Vienna (1980) 23.
 CADIMA, A., LIBARDI, P.L., REICHARDT, K., Variabilidade espacial da condutividade hidráulica de um Latossolo Vermelho Amarelo textura média, no campo, Rev. Bras.
Cienc. Solo 4(1980) 63.
 CALVACHE, A.M., Absorçâo, translocaçâo e eficiência de utilizaçâto do nitrogênio fertilizante CO( 15 NH2)2 por dois cultivares de milho (Zea mays L.), M.S. Thesis, University of Sâo Paulo, Piracicaba, 1981.
 ARAÚJO SILVA, J.C., Movimento e perdas por lixiviaçâo de nitrogênio - CO( 15 NH2)2 em um Alfisol cultivado com milho (Zea mays L.), M.S. Thesis, University of Sîo Paulo, Piracicaba, 1982.
 URQUIAGA, S.C., Dinámica do nitrogênio no sistema soloplanta na cultura de feijâo (Phaseolus vulgaris L.) cultivar Carioca, Ph.D. Thesis, University of Sâo Paulo, Piracicaba, 1982.
290 REICHARDT et al.
 LAL, R., Soil erosion and shifting agriculture, FAO (Food Agrie. Organ. UN) Soils Bull.
2 4 ( 1 9 7 4 ) 48.
[51 ] LAL, R., KANG, B.T., MOORMAN, F.R., JUO, A.S.R., MOOMAW, J.C., "Soil management problems and possible solution in Western Nigeria", Soil Management in Tropical America (BORNEMISZA, E., ALVARADO, A., Eds), North Carolina State University, Raleigh (1975) 372.
 BERTONI, S., PASTANA, I., LONBARDI, F., BENETTI, R., Conclusses gérais das pesquisas sobre conservaçîo de solos no Instituto Agronómico, Instituto Agronómico, Campinas, Circular No.20 (1975).
 GASSER, J.K.R., Fertilizer urea, World Crops 3 (1964) 1.
 TERMAN, G.L., Volatilization losses of nitrogen as ammonia form surface-applied fertilizers, organic amendments and crop residues, Adv. Agron. 31 (1979) 189.
 ANJOS, J.T., TEDESCO, M.J., Volafflizaçâo de amónia proveniente de dois fertilizantes nitrogenados aplicados em solos cultivados, Cient. Jabot. 4 (1976) 49.
 THENABADU, M.W., "Pollution of the environment due to nitrogen fertilization in Sri Lanka", Seminar on Isotope Techniques in Studies of the Useful Conservation and the Pollutant Potential of Agricultural Nitrogen Residues, Vienna, 1980, IAEA, Vienna (1980) 25 (abstract only).
 WETSELAAR, R., FARQUHAR, G.D., Nitrogen losses from tops of plants, Adv. Agron.
Poster Presentation IAEA-SM-263/1
E. H A A K Department o f Radiobiology, The Swedish University o f Agricultural Sciences, Uppsala, Sweden Tracer methods used f o r r o o t studies e m p l o y either the plant injection or soil injection approach [ 1 ]. The first involves injection o f the radiotracer at the stem base o f the plant and subsequent analyses f o r its presence in the soil profile [2, 3 ] ; the second involves injection o f the radiotracer in the soil profile at various locations and subsequent analysis f o r its presence in above-ground parts o f the plant . A special version o f the latter approach, developed and applied t o estimate the nutrient uptake f r o m the plough layer and sub-soil [5, 6], is described here.
The m e t h o d consists o f h o m o g e n o u s l y contaminating the plough layer with a tracer, radioactive or stable, in t w o treatments: in a reference treatment without c o n n e c t i o n with the sub-soil, and in an experimental treatment where the sub-soil is freely available for r o o t penetration and r o o t uptake o f water and nutrients;
uptake o f the latter causes increased dilution in the shoot. Based on the specific activities or isotope ratios in the s h o o t o f both treatments, and according to inverse isotope dilution and the A-value c o n c e p t [ 7 ] as extended f o r determination o f biological dinitrogen fixation [8, 9], nutrient uptake f r o m the plough layer and sub-soil can be quantified as percentages (yield independent criteria) as well as in absolute units per hectare (yield dependent criteria).
The tracers used to label the nutrient source in the plough layer o f b o t h treatments were 32P f o r phosphorus, R b or stable rubidium for potassium and 8 5 Sr or stable strontium for calcium. Regarding the nutrients studied, phosphorus and potassium are highly m o b i l e in plants and are adsorbed by y o u n g as well as older roots, while calcium is slightly m o b i l e and is mainly transferred f r o m y o u n g roots towards the shoot. Owing to this different behaviour uptake o f calcium was considered to correlate with water uptake in the soil profile, whereas this was n o t the case for phosphorus and potassium.
292 POSTER PRESENTATIONS
Sampling o f the spring-sown cereals grown at different times during the growing season showed that uptake o f nutrients from the sub-soil varied with many factors but usually increased with the growth stage and especially during stem elongation [5, 6]. At tillering or early jointing uptake from sub-soil ranged from 0—25% for phosphorus and potassium and 10—40% for calcium; at heading or early maturing it ranged from 10—50% for phosphorus and potassium and 40—80% for calcium. It was usually lower for phosphorus than for potassium at all growth stages, and lower for potassium than for calcium. Clay sub-soils were usually superior to sandy sub-soils as the nutrient sources of all three elements investigated. A high uptake o f sub-soil calcium, indicating a high utilization o f the sub-soil as a water source, usually led to a high uptake o f subsoil potassium. As shown by cultivating soils from long-term phosphate fertilizer experiments, a good phosphorous state of the plough layer was a pre-requisite for a high dry matter yield and for a high utilization o f the sub-soil as a nutrient and water source.
Experiments carried out on many sites in Sweden showed that the nutrient uptake from the plough layer and sub-soil varied with the soil type and location, the year and sowing date, and the time and cereal grown. Uptake o f sub-soil potassium was usually higher in eastern Sweden than elsewhere, while uptake o f sub-soil phosphorus usually increased from the north to south of the country.
Early sowing in spring induced early penetration o f the sub-soil. Barley, and early rather than late varieties, was usually more aggressive in establishing contact with the sub-soil early in the season than oats and wheat. Later in the season oats was comparable with barley, while wheat was still inferior. A wheat cultivar with a normal straw length showed a higher nutrient uptake from the sub-soil than a dwarf cultivar o f the same variety.
The results obtained show the value o f optimizing cereal root development in the soil profile, and the value o f certain cultivation measures to increase the nutrient, and especially the water uptake, from the sub-soil. Early root penetration o f the plough layer provides a later extensive root activity in the sub-soil, which enhances shoot development. The main conclusion is that increased shoot development by itself is a driving force to use distant sources in the soil profile such as water and nutrients from the sub-soil. The method, based on inverse isotope dilution and the A-value concept, is useful to estimate the nutrient uptake from the plough layer and sub-soil, with the plough layer as a reference or standard. Applying the method under field conditions gives quantitative information on percentage and absolute uptake o f calcium, phosphorus and potassium from the two compartments, integrated over the time elapsed from the start o f the experiment to sampling the crop.
293 POSTER PRESENTATIONS
INTERNATIONAL ATOMIC ENERGY AGENCY, Tracer Manual on Crops and Soils, Technical Reports Series No 171, IAEA, Vienna (1976) 149.
ERIKSSON, À., KARLSTRÔM, F., Landbrukshoegskolan, Uppsala, Report SLU-IRB-38 (1977).
HAAK, E„ PALTINEANU, I.C. (unpublished data).
HALL et al., A Tracer Technique to Measure Growth and Activity of Plant Root Systems, North Carolina Agrie. Exp. Sta. Tech. Bull. 101 (1953).
HAAK, E., Landbrukshoegskolan, Uppsala, Report SLU-IRB-43-44-45 (1978).
HAAK, E., Proc. 16th Coll. Int. Potash Inst. Bern (1981) 87.
FRIED, M., DEAN, L.A., Soil Sci. 73 (1952) 263.
FRIED, M.J., Agrie. Food Chem. 2 (1954) 241.
FRIED, M., MIDDLEBOE, V., Plant Soil 47 (1977) 713.