Short Communication A perspective for setting the research priorities for the productivity of future crop production in Finland Jari Peltonen Peltonen, J. 1992.A perspective for setting the research priorities for the produc- tivity of future crop production in Finland. Agric. Sci. Finl. 1: 361-366. (Univ. Hel- sinki, Dept. Plant Production, SF-00710 Helsinki, Finland.) The author proposes that future research work on crop production should concentrate on alleviating the problems associated with overwintering and frost, early summer drought and rainy autumn in order to enhance the competitiveness of field crop pro- duction in Finland. Further, more detailed knowledge on the crops is required to under- stand the genotypic differences in potential yield formation in order to optimize ma- nagement practices. Increasing the nitrogen (N) fixation efficiency of leguminous spe- cies should be considered as an important target. Naked oats, sunflower, and legumi- nous plants might be advantageous species for future crop production in Finland. The bioenergetic implications of increasingcrop productivity are discussed. Key words: crop productivity, biochemical composition, bioenergetic cost, crop species Crop production forms the basis ofagriculture, i.e., there would be no agriculture without crop production. Therefore, when discussing the future ofFinnish agriculture, crop production research has a significant role in maintaining the competitive position ofFinnish agriculture. The competitive position could be achieved through sustaining environmentally sound agricul- ture featuring economic productivity while main- taining high yield and good quality. Furthermore, production should involve limited risks, taking into account the biological factors in addition to the environmental ones. Thus, an understanding of management practices as well as crop physiology has a key role in sustainable agriculture as defined above. Crop research should primarily be carried out in field experiments because the interactions between the phenomena studied and the environ- ment are emphasized in northern latitudes. Intensified productivity - a future prospect When adjusting to European integration, Finnish agricultural productivity must be considerably increased in order to improve competitiveness (Kola et al. 1992). Regarding crop production this can be attained either by breeding or more precise use of management practises. The improved pro- ductivity should result from optimization of inputs rather than increasing inputs (Kurppa 1992). The intensification of management practices by econo- mical, technological and biological methods is effi- cient only if the genotype-dependent yield potential of a plant from sprouting to harvesting is known (Peltonen and Peltonen-Sainio 1991). Thus, more precise information is needed on the critical plant growth stages in which the management practices are most favourable (Peltonen 1992 b). 361 Agric. Sci. Finl. 1 (1992) https://www.c-info.fi/en/info/?token=RnyIaM_IRQa07Rrq.WXoIQiual3sfDlIY6ixEjw._hd1080RmaLpzcXGLKzQVwq_D6KKZSNtypTiCYcdnPL1QM_wJJErOK6xiGXhjeRqtm2vNvEI-EAbVyD6DMXsrFJe0SfMSiIbLFaGAw6u966ahdlhCrRWhodzpxsmvghhNYAsXbMdI1rLUgMNl4f4hgISnnqOutpNSTL4q2120Jrk2TXswUQu00b-pk71ScCbnJg7k0lrQArjdiM0zxT3q6wMtdIBszoA6nTpHDa5EylY43EDhmf4oH2LFvGqgHZ1GDa25w The ecological cropping systems probably have no future in Finland, because the use of inputs (no industrial inorganic fertilizers and pesticides allo- wed) in these cropping systems cannot be as con- trolled biologically as in the intensive cropping sys- tems. Moreover, the quality ofFinnish agricultural products is very high and they are free from pesti- cide residues according to international standards (Kumpulainen 1992). This is because only a limit- ed number of pests and diseases are of importance in the marginal growing conditions prevailing in Finland (Karjalainen 1985). It is often claimed that yields cannot be sustained in monocultures based on repeated applications of inorganic fertili- zers and pesticides. The Rothamsted long-term experiments in the U.K. during the period 1852 - 1986 showed, however, that they can (Jenkinson 1991), although these experiments also indicated the importance ofcrop rotation. Within this context, resistance breeding in Fin- land has hardly ever resulted in significant yield improvements as has been the case in other Euro- pean countries (Karjalainen 1985, Doodson 1981). The geographical location ofFinland offers, however, special challenges for crop production research, alleviating the problems associated with overwintering and frost, early summer drought, and rainy autumn (Mukula and Rantanen 1989 a,b,c). Further, more precise information is needed on the physiological traits underlying a good crop ideo- type (Hovinen 1988 a, Peltonen-Sainio 1991)and its adaptation to long day and low light intensity (Pulli 1988). The yield potential of cultivated crops In the present situation it is extremely important to identify which crop species can be economically produced in Finland in the future. The chemical composition of crop species varies greatly in their utility for either livestock, feedstock or “non-food” production. The amount of photosynthates needed by a crop is partly dependent on the chemical com- position of the economic yield. In northern condi- tions, the ability of crops to convert light energy into biomass is, however, limited (Åkerberg and Haider 1976). Therefore, raising both quantity and quality simultaneously is increasingly difficult (Peltonen 1992 a). In the following, the productivity of crop species is analyzed and drawn on the basis of their pro- duction related to the use of photosynthates. The results from the examination of the biochemical pathways (Penning de Vries et al. 1974) for the production of carbohydrates, proteins, and lipids from glucose were used as the basis. From 1 unit of glucose about 0.83 unit of carbohydrates, 0.40 unit of protein (assuming N0 3-N to be the N source), or 0.33 unit of lipid could be produced. Based on these values it has been calculated how much energy pro- duced in photosynthesis is consumed in the forma- tion of the economic yield of certain crop species (Table 1). The nitrogen requirement of the crop was estimated by calculating the protein produced from available photosynthate (Sinclair and de Wit 1975), in addition to N required for 1 % increase in the protein concentration (Bhatia and Rabson 1976). To visualize more easily the differences between the crops, N requirements per gram of photosyntha- tes were plotted against economic yield per gram of photosynthate (Fig. 1). In the lower right-hand part of Fig. 1 there are the carbohydrate rich crops (cereals, potato, sugarbeet). Of all the plant species examied, the productivity, definedas conversion of photoassimilates into economic yield, is the highest in sugar beet and potato. In addition to their impor- tance as food crops they have become increasingly important in "non-food" uses; starch is used for glue and as a binder in the paper industry. The alternative use of starch as a raw material in produc- ing decomposed plastics is also increasing, espe- cially as plastic mulch for agricultural purposes (Doane 1981, Galliard 1986). The portion of domestic starch used as raw material for decompo- sed plastics is, however, only about 50% (Erikois- kasvitoimikunta 1987). The fate of cereals in future Finnish crop pro- duction has received most attention because cereals are “bulk” products and over-produced in the world 362 Short CommunicationAgric. Sei. Fin!. 1 (1992) market. In addition, it has been indicated that cereal production in particular suffers from the high pro- duction costs characteristic to of Finnish agricul- ture (Kola et al. 1992). Milk production has a bet- ter chance to adjust to European integration, but not withoutproblems, either. As an alternative, the pro- duction of naked cereals such as wheat, rye and naked oats for feed (Rekunen 1990) is suggested, because their feeding value is higher than that of ordinary hulled oats or barley. Naked oats is culti- vated relatively little in the world. The probable reason for this is its poor yielding ability as compar- ed with other cereals. The yield advantage ofhulled oats without husks over the yield of naked oats is still approximately 600 kg ha 1 (Peltonen-Sainio et al. 1992, manuscript). The limiting factor for the yield formation ofnaked oats is evidently the lower number of spikelets per panicle as compared with hulled oats (Peltonen-Sainio 1992, personal communication). Naked oats has, however, a clear advantage in industrial processing by saving the cost ofhulling. Due to the "nakedness" of the grain the risk of harvesting damage increases (Rekunen 1990). Lipid and protein contents are also high in naked oats (Table 1). Therefore, its yield formation requires more N fertilization than that of other cereals. The biological value of the protein in oats is not reduced by N fertilization as is the case in other cereals (Lasztity 1984). Naked oats may be an alternative for cereal production in Finland fol- lowing the advances in breeding for better yields. In the lower left-hand part ofFig. 1 there are the oil crops (turnip rape, rape, flax, sun flower). Sun- flower has the most effective yield formation of all of the oil crops. The reason for this may be its high potential maximum rate of leaf photosynthesis as compared to the other crops (Penning de Vries et al. 1989). Moreover, it requires less N for yield form- ation than turnip rape, rape or flax (Table 1). The high amount (57%) of polyunsaturated fatty acids Fig. 1. The requirement ofnitrogen (mg) for yield per gram ofavailable photosynthate (g) for 19 crop species. Regression functions for protein crops Y = 80.85 -82.38 X (R2 =0.95"'), and for carbohydrate crops Y = 54.49 -55.26 X (R2 =0.96"). There is no significant relationship between oil crop species. 363 Aghc. Sei. Fin!. 1 (1992)Short Communication Table 1. Chemical composition, yield productivity (grams ofbiomass per gram ofphotosynthate), and nitrogen requirements (milligrams ofN per gram ofphotosynthate) for crop yield of 19 crop species. Nitrogen requirement is calculated by assum- ing that protein is 16 % nitrogen by weight. The last column gives the percentage increase in nitrogen requirement for a 1 % increase in protein. Composition*) (% of dry weight) Nitrogen requirement Increase (mg/g) in nitrogen requirement Carbo- Protein Lipid Ash Yield With With 1% (%) hydrate productivity standard increase (g/g) protein in protein Barley (Hordeum vulgäre) 83 12 2 3 0.73 14.1 15.3 8.5 Hulled oats (Avena sativa) 80 12 5 3 0.71 13.6 14.7 8.1 Naked oats (Avena sativa) 76 16 6 2 0.67 17.1 18.2 6.4 Potato (Solatium tuberosum) 84 10 0 6 0.79 12.7 13.9 9.4 Rye (Secale cereale) 83 13 2 2 0.72 15.0 16.2 8.0 Sugar-beet (Beta vulgaris) 88 5 0 7 0.84 6.7 8.1 1.2 Wheat (Triticum aestivum) 82 14 2 2 0.72 16.0 17.2 7.5 Alfalfa (Medicago sativa) 61 24 4 11 0.69 26.4 27.5 4.2 Field bean f Viciafaba) 70 24 2 4 0.66 25.5 26.6 4.3 Lupine (Lupinus sp.) 58 34 5 3 0.59 32.0 32.9 2.9 Pea (Pisum sativum) 68 27 2 3 0.64 27.8 28.8 3.6 Red c\o\er(Trifoliumpratense) 60 24 4 12 0.69 26.6 27.7 4.1 Cocksfoot (Dactylis glomerata) 70 19 3 8 0.71 21.4 22.6 5.6 Meadow fescue (Festucapratensis) 68 19 3 10 0.71 21.7 22.9 5.5 Timothy (Phleumpratense) 71 18 3 8 0.71 20.5 21.6 5.4 Flax (Linum usitatissimum) 33 25 38 4 0.46 18.4 19.1 3.8 Rape (Brassica napus) 26 24 45 5 0.44 16.9 17.6 4.1 Sunflower (Helianthus annuus) 48 20 29 3 0.51 16.4 17.2 4.9 Turnip rape (Brassica rapa) 30 23 42 5 0.45 16.7 17.4 4.2 *) Information taken from Salo et al. (1990), naked oats from Peltonen-Sainio et al. (1992), manuscript. in sunflower seed oil is an indicator of its good qual- ity for human consumption. In contrast, rape seed oil contains some 25% of polyunsaturated fatty acids (Weiss, 1983). The rhizosphere pattern of sunflower is strong and deep. It can efficiently take up nutrients which may enable production even without application of chemical fertilizers. Harvest- ing of sunflower may be difficultbecause the mois- ture content of the seed seldom falls below 20% (FAO 1985). The inclusion of hybrids in crossing programs has been shown to lead to positive results with early maturity, good oil content, disease resistance and lodging resistance in breeding sunflower cultivars for northern latitudes (Dedio 1988). In the upper right-hand part ofFig. 1 there are the protein rich crops (lupine, pea, field bean, red clo- ver, alfalfa, and grasses). The productivity of lupine is lower than that of pea and field bean. Furth- ermore, the high content of alkaloids in lupine lessens its use as feed (Alaviuhkola 1986). Due to the high lysine content of pea and field bean (Salo et al. 1990), they have a high value in feeding. In breeding, more stable yield formation is obtained with the help of the af- and def-gene in pea and the //-gene in field bean (Hovinen 1988 a,b). The 364 Short CommunicationAgric. Sei. Finl. 1 (1992) increase of pea and field bean cultivation is thus recommended to substitute the imported soyabean for industry. Owing to their capacity for biological N fixation, leguminous plants such as pea, field bean, red clover and alfalfa are independent ofinor- ganic N fertilizer. For this reason red clover and alfalfa have higher productivity than meadow fescue, cocksfoot, and timothy (Fig. 1). Many efforts have been made to improve the N fixation ability of Rhizobium bacteria (Uomala 1986), but more detailed studies from this research area are still needed. Aresearch priority could be to attempt to increase the resistance of N fixation bacteria to soil acidity and early summer drought. References Alaviuhkola, T. 1986. Onko lupiinilla käyttöä sikatalou- dessa. Käytännön Maamies 35: 55-57. Bhatia, C.R. & Rabson, R. 1976. Bioenergetic considera- tions in cereal breeding for protein improvement. Science 194: 1418-1421. Dedio, W. 1988. Breeding sunflower cultivars for the north- ern latitudes. J. Agric. Sci. Finl. 60; 255-259. Doane, W.D. 1981. Starch: Industrial raw material. In; Pomeranz & Munck (eds.). Cereals; A Renewable Resource. St Paul. p. 265-290. Doodson, J.K. 1981. The economic contribution ofresistant winterwheat varieties. J. Natn. Inst. Agric. Bot. 15:413- 420. Erikoiskasvitoimikunta 1987. Erikoiskasvitoimikunnan mietintö. Komiteamietintö 33. Helsinki. 240 p. FAO 1985. Equipment and methods for sunflower pro- duction. FAO Economic Comission for Europe. Agri/Mech Repr. 108. New York. 10p. Galliard, T. 1986. Bulk chemicals from plants: starch and starch derived products. In: Fuller & Gallon (eds.). Plant Products and the New Technology. New York. p. 103- 105. Hovinen, S. 1988 a. Breeding of a protein pea ideotype for Finnish conditions, J. Agric, Sci. Finl. 60: 7-71. 1988 b. Breeding of field bean (Vida faba L.) with early maturity. J. Agric. Sci. Finl. 60: 261-267. Jenkinson, D.S. 1991. The Rothamsted long-term experi- ments: are they still of use. Agron. J. 83: 2-10. Karjalainen, R. 1985. Kasvin resistenssi ja taudinkestävyysjalostus. Helsingin yliopiston kasvipato- logian laitoksen monisteita n:o 8. 88 p. Kola, J.,Marttila, J. & Niemi, J. 1992.Finnish agriculture in European integration: A firm level approach. Agric. Sci. Finl. 1: 5-14. Kumpulainen, J. 1992. Kotimaisten ja ulkomaisten elintar- vikkeiden puhtaus ja laatu. Maatal.tiet. päivät, Helsinki. Mimeogr, [Available at Agric. Res. Centre of Finland, Food Res. Inst.] Kurppa, S. 1992. Tuhoeläintorjunnan kustannusvaikutukset. Suom. Maatal.tiet. Seur. Tied. No 16. p. 68-76. Lasztity, R. 1984. The chemistry of cereal proteins. CRC Press, Inc. Boca Raton, Florida. 203 p. Mukula, J. & Rantanen, O. 1989 a. Climatic risks to the yield and quality of field crops in Finland. 111. Rye. Ann. Agric. Fenn. 28: 3-11. & Rantanen, O, 1989 b. Climatic risks to the yield and quality of field crops in Finland. V. Spring wheat. Ann. Agric. Fenn. 28; 21-28. & Rantanen, O. 1989 c. Climatic risks to the yield and quality of field crops in Finland. VI, Barley. Ann. Agric. Fenn. 28: 29-36. Peltonen, J. 1992 a. Influence of environment and genotype on spring wheat yield and bread-making quality under Finnish conditions. Acta Agric. Scand. 42: 111-117. 1992b. Ear developmental stage used for timing supple- mental nitrogen application to spring wheat. Crop Sci, 32: (in press) & Peltonen-Sainio, P. 1991. Formation and abortion of florets ofwheat and oat cultivars differing in duration of pre-anthesis and post-anthesis phases. 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Uomala, P. 1986. Biologinen typensidonta ja sen tehostus. SITRA Biologisen typensidonnan ja ravinnetypen hyväksikäytön projekti. Sitra ja Maatalouskeskusten 365 Agric. Soi. Finl. 1 (1992)Short Communication Liitto. Tietolehtinen 1. 8 p. Manuscript received May 1992 Weiss, E.A. 1983, Sunflower. Oilseed crops, p. 402-462. Åkerberg, E. & Haider, T.O. 1976. Climatic influence on Jari Peltonen yield for summer cereals grown under northern climatic University ofHelsinki conditions. J. Agron. & Crop Sci. 143: 275-286. Department ofPlant Production SF-00710 Helsinki, Finland SELOSTUS Suomen kasvinviijelytutkimuksen painopisteitä tuotannon tehostamiseksi peltoviljelyssä Jari Peltonen Helsingin yliopisto Kasvinviljelytutkimuksella on merkittävä osuus Suomen maatalouden kilpailuaseman kehittämisessä. Meidän kas- vinviljelymme keskeisiä tutkimusongelmia ovat talvenkes- tävyys, alkukesän poutaisuuteen ja korjuukauden sateisiin oloihin sopeutuvien lajikkeiden ja viljelymenetelmien kehit- täminen. Viljelytoimenpiteiden tehostaminen niin taloudel- lis-teknologisen kuin biologisen tuotannonkannalta on kui- tenkin tehokkaimmillaan vasta, kun tunnemme viljelykas- vien lajikekohtaisen sadonmuodostuspotentiaalin. Tämä tieto antaa selkeän käsityksen siitä, missä kasvien kehitys- vaiheessa eri viljelytoimenpiteet ovat välttämättömiä. Kuo- rettoman kauran, auringonkukan ja palkokasvien tutkimi- seen tulisi kiinnittää entistä enemmän huomiota. Tutkimuk- sessa on pohdittu eri kasvilajien sadontuottokykyä ja typpi- taloutta yhteyttämisessä tuotetun energian hyväksikäyttöte- hon perusteella. 366 Short CommunicationAgric. Sei. Finl. 1 (1992)