Soil research in Europe with special reference to that in Finland A Review Jouko Sippola MTT Agrifood Research Finland, Environmental Research, FIN-31600 Jokioinen, Finland jouko.sippola@surffi.net Abstract The presentation reviews recent European soil research cooperation and areas where Finland has been especially active. The topics include production of European soil map, activities in European Trace Element Network and calculation of soil heavy metal balances. With respect to soil maps after compiling information at a rather rough level, the maps in more detailed scale with related database has been created. In the case of trace element studies, activities have been divided to various areas from general analytical quality control aspects to improve comparability of results to surveys at national and international level. The results of a global investigation revealed the deficiency of zinc to be most common and that of boron in certain countries. More detailed assessment at a country level showed that zinc deficiency may be so serious that no yield is obtained without zinc application. Also, to monitoring of soil pollution development has been paid attention. A way to understand reasons for increased soil pollution has been the making of balance calculations for metals. This serves also in developing control measures. Concerning macronutrients nitrogen has been given much attention because of its high effects on crop yield and environmental pollution. Models have been developed by several groups to understand nitrogen transformations and fate in varying environmental conditions. Key words: soil mapping, soil monitoring, trace elements, nitrogen modelling, 43 MTT Agrifood Research Finland
European Soil Map Early co-operation between European soil scientists started when European share for the soil map of world in scale 1: 5 000 000 was prepared. This work was completed in the beginning of 1970s (Sippola and Yli-Halla 2004). The co-operation continued more intensively when a more detailed map in scale 1:1 000 000 was prepared. Harmonisation of classification was a big problem. Field tours were organised to fit soils of various countries into proper classes of the FAO/UNESCO system and system was developed when needed. At present a preparation of a more detailed map in scale 1: 250 000 and related database is underway. The project is planed to be completed by the end of 2008. Trace Element Study A project which Finland was the organiser was the so called Trace Element Study, which focused on investigation of status of micronutrients in 30 countries worldwide (Sillanpää 1982). The project was done in co-operation with FAO and five countries from Europe participated. Almost 4000 soil and plant samples were analysed for micronutrients boron, copper, iron, manganese, molybdenum and zinc and for macronutrients calcium, manganese, phosphorus and potassium. The much generalized results were that zinc deficiency was most common and deficiency may be suspected in almost every studied country. Boron deficiency was most common in some Far East countries. Problems due to excess of boron occurred in sites with irrigated agriculture. Molybdenum deficiency was connected to acidity of soils and that of manganese with soil alkalinity. Micronutrient Assessment at Country Level A follow-up project of the above worldwide trace element investigation was the Micronutrient assessment at country level where micronutrient fertilizers were tested in field (Sillanpää 1990). In 15 countries in total 190 experiments were carried out. In addition to nitrogen, phosphorus and potassium, micronutrients boron, copper, iron, manganese, molybdenum and zinc were applied in a way that one micronutrient was missing in each treatment. Local crops like barley, oats, wheat, maize, rice or cotton, for example, were the experimental crops depending on local cropping systems. The results verified the findings of Trace Element Study so that zinc deficiency was most frequent when it appeared in 25% of experiments. In some extreme cases no yield was obtained without zinc application. Boron defi- 44
ciency was clear in 10% of the sites although mostly crops which were not susceptible were grown. Copper deficiency was only half that frequent than boron. Status of cadmium, lead, cobalt and selenium in soils and plants of thirty countries Second follow-up work of the global investigation was a study on status of cadmium, lead, cobalt and selenium in soils and plants of thirty countries (Sillanpää and Jansson 1992). Almost 4000 soil and plant samples were analysed for mentioned elements. Results showed that cadmium and lead contents were definitely higher in soils and plants of industrialized than in developing countries (Figs. 1 and 2). Low selenium values were found in Finland were to day selenium is added to mineral fertilizer for remedy. SIERRA LEONE NIGERIA GHANA TANZANIA MALAWI NEPAL ZAMBIA BRAZIL INDIA EGYPT ETHIOPIA SRI LANKA KOREA rep. of TURKEY PHLIPPINES PAKISTAN FINLAND ARGENTINA THAILAND IRAQ MEXICO HUNGARY ITALY PERU SYRIA LEBANON NEW ZEALAND MALTA BELGIUM 0 0.1 0.2 0.3 0.4 AAAc+EDTA-extractable Cd, mg/l soil Fig. 1. Cadmium in soil in various countries (Sillanpää and Jansson 1992). 45
SIERRA LEON MALAWI PHILIPPINES SYRIA IRAK NEW ZEALAND ZAMBIA LIBANON TANZANIA ARGENTINA FINLAND ETIOPIA GHANA NIGERIA THAILAND SRI LANKA EGYPT INDIA NEPAL BRAZIL TURKEY PAKISTAN PERU MEXICO HUNGARY KOREA rep ITALY BELGIUM MALTA 30.3 0 5 10 15 AAAc+EDTA-extractable, mg/l soil Fig. 2. Lead in soil in various countries (Sillanpää and Jansson 1992). European Trace Element Network Trace analysis is a challenging task and using proper quality control measures is essential. Analytical results need to be comparable between laboratories. Reliable results are also likely to promote trace element research. Therefore a network was established to discuss problems and to carry out small scale joint research activities. Laboratories in several European countries making trace element determinations were participating. Analytical quality was improved by preparing reference samples of soil and plant material and establishing certified concentrations for several elements using specified extraction methods. As outcome of this activity the results of European laboratories agree well to day. Nitrogen modelling Nitrogen is very effective plant nutrient affecting crop yield but also environmental pollution. Little nitrogen in root zone results to a small yield but excessive nitrogen causes lodging of cereals or quality problems in other crops. In environment excess nitrogen impairs the quality of drinking water 46
and causes eutrofication in rivers and lakes. To understand nitrogen behaviour and fate in soil several models have been developed in different European countries, in addition to Swedish SOILN (Jansson et al. 1991) and Danish DAISY (Hansen et al. 1990). German and British scientists have been active to develop models, also. One use of results of modelling is to estimate soil mineral nitrogen at time of sowing to adjust the fertilizer nitrogen rate. Variable results have been obtained, however. Results have been best when cereals have been cropped and poorest when organic fertilizers have been used or crop residues have been plown into soil. In practice a maximum deviation of 10 kg/ha of mineral nitrogen from actual amount could be acceptable. Presently, only occasionally this limit is reached and therefore soil analysis is preferred in practical fertilizer advisory work. AROMIS project Assessment and reduction of heavy metal input into agro-ecosystem (AR- OMIS) was an EU-concerted action project aiming at control of pollution of agricultural soils in Europe (Mäkelä-Kurtto and Sippola 2001). Inputs and outputs of metals were estimated based on available data and balance was calculated. Metals included were cadmium, chromium, copper, nickel, lead and zinc. The result obtained for Finland show that for all elements having sufficient data balance is positive leading to higher concentrations in soil over time (Table 1). Table 1. Estimated overall heavy metal balance in agriculture in Finland for the elements Cd, Cu, Pb and Zn. Soil erosion is not taken into account. Cd Cu Pb Zn Flow [g/ha a] Total input 0,60 148 14,0 550 Total dicharge 0,20 23 1,2 123 Load change 0,40 125 12,8 427 Monitoring of arable land Another activity which is practiced in various European countries but independently without coordination is monitoring of arable land. In Finland systematic monitoring started 1974 and two other samplings have been done since then. Local soil testing methods were used so that international comparison is not possible. The results show that soil ph remains at low level 47
(Table 2). Concentration of phosphorus has increased as a result of intensive use of fertilizers. Concentration of water extractable boron had increased from 1974 to 1987 due to general use of boron-containing NPK fertilizers, but no more in the latter period, because the concentration in the fertilizers was adjusted. Copper increased by 32% in 1974-1987 and the rate was about half in the second sampling. This was most likely due to increased copper fertilization promoted by the fertilizer industry. The same reason applies for the increase of zinc in 1987-1998. Of the harmful elements, the concentration of cadmium increased due the use of cadmium-containing raw phosphate to prepare fertilizers in some of the years in the first period. Later only low cadmium fertilizers have been used, and there is no marked change in the cadmium in soil. Table 2. Means of chemical characteristics of agricultural soils (n=705) in 1998 and the changes between 1974-1987 and 1987-1998 (Sippola and Yli- Halla 2004). Mean 1998 Change 1974-87 Change 1987-98 ph(h20) 5.8 +0.18 units -0.04 units % % Bulk Dens. 1.00 0.0 N.S. +4 Org. C. % 8.3 +4 N.S. -9 Ca mg dm-3 1436 0 N.S. +7 K mg dm-3 111 +10-2 Mg mgdm-3 202 +2 N.S. +7 P mg dm-3 13.1 +16 +22 S mg dm-3 25.0 - +28 Al mg dm-3 493 +4 N.S. -1 N.S. B mg dm-3 0.59 +62-5 N.S. Cd mg dm-3 0.08 +31 +4 N.S. Co mg dm-3 0.64 +19-4 Cr mg dm-3 0.36 +17 +7 Cu mgdm-3 4.5 +32 +15 Fe mg dm-3 742 +10 +3 Mn mg dm-3 58-2 N.S. 0 N.S. Mo mg dm-3 0.06 +27-12 Ni mg dm-3 0.98-2 N.S. +1 N.S. Zn mg dm-3 3.0-22 +22 48
Outlook Soil research in Europe is coordinated by European Soil Bureau with main tasks to collect, harmonise, organise and distribute soil information. In future there is an increasing demand for soil information, for addressing a number of environmental problems and questions. These include: leaching of agrochemicals, deposition, balances and monitoring of heavy metals, disposal of waste, degradation of soil structure, loss of organic matter, and risk of erosion (Montanarella and Jones 1999). References Hansen, S. H., Jensen, E., Nielsen, N. E. & Svendsen, H. 1990. Daisy soil plant atmosphere system model Technical Report A10, Miljøstyrelsen. Jansson, P.E., Eckersten, H. & Johnsson, H. 1991. SOILN model. User s manual. Swedish University of agricultural Sciences, Department of Soil Sciences, Communications 91:6. Montanarella, L. & Jones, R.J.A. 1999. The European Soil Bureau. European Soil Bureau. Res. Rep. 6: 3-14. Mäkelä-Kurtto, R. & Sippola, J. 2001. AROMIS. National report Finland. Mimeograph. 15 p. Sillanpää, M. 1982. Micronutrients and the nutrient status of soils: a global study. FAO Soils Bulletin 48. 444 p. Sillanpää, M. 1990. Micronutrient assessment at the country level: an intenational study. FAO Soils Bulletin 63. 208 p. Sillanpää, M. & Jansson; H. 1992. Status of cadmium, lead, cobalt and selenium in soils and plants of thirty countries. FAO Soils Bull. 65. 195 p. Sippola, J. & Yli-Halla, M. 2004. Status of soil mapping in Finland. European Soil Bureau. Res. Rep. 9: 105-110. 49