AGROCHEMISTRY for BSc students

Átírás

1 UNIVERSITY OF SZEGED FACULTY OF AGRICULTURE PLANT SCIENCES AND ENVIROMENTAL PROTECTION INSTITUTE AGROCHEMISTRY for BSc students edited by Dr. Ferenc Lantos 2015.

2 A köny kereskedelmi forgalomba nem hozható! Historians don t know the date of start of fertilization in the history of mankind, but the fertility of the soil and its effective using has been interest by the ancient empires farmers. Over thousands of years had been proven that the soil has a renewable capacity that humans can turn their own benefit as well. Age-old experience that the correct nutrients supply can insure good quality and optimal amount crops. The production factors largely determined the structure of societies. The development and structural changes of societies were determined by agriculture based on strong foundations in every historical period. Therefore, the prevailing power developed and updated the agriculture and horticulture. The strengthening of chemistry as a science was significant not only in industry, but also in agriculture meant a change. Agro-chemistry is chemistry applied in agriculture, which we can use to save nutrient content, fertility and evolved structure of soil, and if necessary we can grade it up. After the II. Word War the production competition between the Eastern and the Western powers increased. Reaching maximum yield was the most important factor in agriculture. In this aspect agro-chemistry - as the new method of nutrient supply of soil - started an outstanding development. Our country is an agricultural country due to a specific natural environment, where field-grown and also greenhouse-grown vegetables have a a very important part today, the production competition was replaced by a market economy, so in addition to the high yield the good quality is also a criteria. Because of the high number of operators marketing requires the application of more and more professionals with high-level agrochemical expertise in agriculture. In today s the soil less technology and large amounts of fertilizer is used by intensive vegetable forcing, because the agrochemical expertise is necessary in horticulture. Nem ismeretes a történészek előtt, hogy a trágyázás művelete mikor kezdődött el az emberiség történelmében, de a talaj termékenysége s annak hatékony kihasználása már az ókori birodalmak földműveseit is foglalkoztatták. Az évezredek során bebizonyosodott, hogy a talaj megújuló képességgel is rendelkezik, melyet az emberiség a saját hasznára is fordíthat. Ősrégi tapasztalat, hogy a helyes tápanyag- gazdálkodás jobb minőségű, és nagyobb mennyiségű terméshozamot biztosít. A termelési tényezők nagyban meghatározták a társadalmak felépítését. A társadalom fejlődését, strukturális változását minden történelmi korszakban az erős alapokon nyugvó mezőgazdaság jelentette. Ezért célszerű volt a mindenkori hatalomnak a földművelés és a növénytermesztés fejlesztése, illetve modernizálása. A kémia mint tudomány erősödése, nemcsak az iparban jelentett fellendülést, de óriási mérföldkövet jelentett a mezőgazdaságban is. Az agrokémia a növénytermesztésben alkalmazott kémia, mely segítségével a talaj tápanyagtartalmát, termőképességét, kialakult szerkezetét meg tudjuk őrizni, s ha szükséges fel tudjuk azt javítani. A II. világháborút követően egyre fokozódott a termelési verseny a keleti és a nyugati hatalmak között. A növénytermesztésben ezért egyre nagyobb hangsúlyt fektettek a nagyobb terméshozam elérésére. Ebben az agrokémia, mint a talajerőgazdálkodás új módszere kiemelkedő fejlődésnek indult. Hazánk sajátságos természeti adottságainál fogva mezőgazdasági ország, melyben igen jelentős szerepet játszik a szabadföldi,- illetve a termesztő-berendezésekben történő zöldségtermesztés is. Napjainkban a termelési versenyt felváltotta a piacgazdaság, tehát a nagy terméshozam mellett a jó minőség is kritérium. A piaci szereplők igen nagyszámú részaránya miatt mind jobban szükségessé válik a magas szintű agrokémiai ismeretekkel rendelkező agrárszakemberek alkalmazása. Napjaink talaj nélküli, intenzív zöldséghajtatása például kizárólag műtrágyák alkalmazásával történik, ezért a kertészeti ismeretek mellett nélkülözhetetlen az agrokémia.

3 AGROCHEMISTRY AGROKÉMIA szerkesztette: Dr. Lantos Ferenc ISBN A kiadást támogatta a Nemzeti Kulturális Alap Igazgatósága 3437/02083 pályázat alapján. Kiadó: Szegedi Tudományegyetem Készült 100 példányban.

4 UNIVERSITY OF SZEGED FACULTY OF AGRICULTURE PLANT SCIENCES AND ENVIROMENTAL PROTECTION INSTITUTE HUNGARY AGROCHEMISTRY for BSc students edited by Ferenc Lantos PhD lectored by Attila Mészáros PhD chemist Antalné Regős agro-chemistry expert 2015.

5 CONTENTS INTRODUCTION The Role of agro-chemistry Subject and importancef of agro-chemistry Concept of soil fertility The chemical composition of plants Dry materials of plants Role of water (H2O) The water requirement of plants Arsenic (As) contamination of irrigation water The botanical classification of nutrients Classification of elements: Nutrient content Nutrients in plant and soil Nitrogen Phosphorus Potassium Calcium Magnesium Sulfur Iron

6 Copper Manganese Zinc Boron Molybdenum Dynamics of nutrient uptake Nutrient uptake in respect of energy Influencing factors of nutrient uptake Nutrient requirements Fertilizer needs Contexts of nutrient requirements and fertilizer needs Levels of nutrient supply of plants Levels of nutrient supply of soil Properties of the fields Medium hard soil (chernozem) Medium hard forest soils (brown forest soils) Hard meadow soil Loose and sandy soils Saline soils Shallow layer, sloping soils The relationship between nutrient supply and yield Effect of nutrients on quality of crops Nutritional characteristics

7 8. Yield-increasing nutrients in plant production, in ornamental plant production and vegetable growing Fertilizers Fertilization guidelines Obligation to comply with environmental regulations Solid fertilizers Nitrogen fertilizers Phosphorus fertilizers Potassium fertilizers Compound fertilizers Mixed fertilizers Acidifying effect of fertilizers: Lime fertilizers, liming materials Magnesium fertilizers Full value (complex) fertilizers Macro- micro elements content fertilizers Retarded fertilizers Liquid fertilizers Most important properties of liquid fertilizers: Benefits: Drawbacks: N- solutions NP-solutions NPK- solutions

8 Suspension solutions Drawbacks: Organic fertilizers Farmyard manure Handling of manure Why is 170 kg nitrogen/ha/year the allowed amount of organic manure? How much organic manure equalss to 170 kg of nitrogen? Liquid manure Other organic manures Green manure The nutrient balance Levels of nutrient balance: Soil improvement Control works before soil improvement Necessary tests of saline soils: Necessary tests of sour soils: Necessary tests of sandy soils: Materials of soil improvement: Natural, mineral materials: Industrial by-products or waste materials Effect of nutrient supply Effect of nutrient supply on the quality of the wheat yield Effect of nutrient supply on the quality of the barley yield Effect of nutrient supply on the quality of the maize yield

9 Effect of nutrient supply on the quality of sugar beet Effect of nutrient supply on the quality of sunflower Effect of nutrient supply on the quality of rape Effect of nutrient supply on the quality of potato Effect of nutrient supply on the quality of legumes Effect of nutrient supply on the quality of vegetables Effect of nutrient supply on the quality of grape Soilless growing Benefits of soilless technology Drawbacks of soilless technology Organic cultivation Regulations of organic farming To maintain and increase soil fertility and biological activity according to legislation Permitted nutrients in organic plant cultivation Toxic elements in soil Exercises Determination of necessary nutrient Effect of crop grown previously Effect of manure Effect of irrigation Determination of necessary phosphorus LABORATORY EXERCISES Detection of ammonium

10 Detection of nitrate: Detection of carbamide: Detection of calcium: Detection of chloride: Visual plant diagnosis practices Attachments Bibliography BEVEZETÉS Az agrokémia feladata Az agrokémia tárgya, jelentősége A talajtermékenység fogalma A növények kémiai összetétele A növények szárazanyag alkotói Szénhidrátok Zsírok, olajok Vitaminok Aromás vegyületek, alkaloidok Enzimek Növényi hormonok Szervetlen alkotórészek A víz (H2O) szerepe a növény életében A növények vízigénye A tápelemek növénytani osztályozása

11 A tápelemek osztályozása Makroelemek: C, H, O, N, P, K Tápelem-tartalom Tápelemek a növényekben és a talajban Nitrogén Foszfor Kálium Kalcium Magnézium Kén Vas Réz Mangán Cink Bór Molibdén A tápanyagfelvétel dinamikája A tápanyagfelvétel energetikai szempontból A tápanyagfelvételre ható tényezők Tápanyagigény Fajlagos tápanyagigény (kg/t) = Trágyaigény A tápanyagigény és a trágyaigény összefüggései

12 A növény tápanyag-ellátottságának szintjei A talaj tápanyag-ellátottságának szintjei Szántóföldi termőhelyek tulajdonságai II. Középkötött erdőtalajok (barna erdőtalajok) IV. Laza- és homoktalajok VI. Sekély termőrétegű, erodált, lejtős talajok A tápanyagellátás és a termés kapcsolata A tápanyagok hatása a termés minőségére Termésnövelő anyagok a szabadföldi növénytermesztésben, a dísznövénytermesztésben, valamint a kertészeti hajtatásban Műtrágya 49% A műtrágyák Halmazállapot szerint Összetétel szerint Kijuttatás módja szerint A műtrágyázás irányelvei A környezetvédelmi előírások kötelező betartása! Szilárd műtrágyák Nitrogén műtrágyák Foszfor műtrágyák Foszforműtrágya-gyártás eljárásai: Szuperfoszfát (kalcium-dihidrogénfoszfát+kalcium-szulfát) Ca 5 (PO 4 ) 3 F +10 H 2 SO 4 = 6 H 3 PO CaSO HF. P 2 O 5 tartalma %. A legelterjedtebb foszfor műtrágya. Elősegíti a növények

13 gyökeresedését, majd szerepet játszik a növények virágzásában is. Gyengén savanyító hatású, gipsztartalma miatt szikes talajon is alkalmazható. Higroszkópos, ezen kívül savkárokat is okozhat. Hazánkban leginkább az őszi gabona és cukorrépa alá alkalmazzák Kálium műtrágyák Összetett műtrágyák Ammónium-foszfátok, Magnézium-ammónium-foszfát MgNH 4 PO A keverés kémiai feltételei: A keverés fizikai előfeltételei: Műtrágyák savanyító hatása: Mésztrágyák, meszező anyagok Magnézium tartalmú műtrágyák Teljes értékű (komplex) műtrágyák Mikro- és mezoelem tartalmú műtrágyák Retardált műtrágyák Folyékony műtrágyák A folyékony műtrágyák legfontosabb fizikomechanikai tulajdonságai:. 182 Alkalmazás előnyei: Alkalmazás hátrányai: N-oldatok NP-oldatok NPK- oldatok Szuszpenziós oldatok

14 11. Szerves trágyák Istállótrágya vagy almos trágya Alkotórészei: Trágyakezelési eljárások Miért éppen 170 kg nitrogén/ha/év a szerves trágyával kiadható mennyiség? Mennyi szerves trágyának felel meg a 170 kg nitrogén? Hígtrágya alkotórészei: Egyéb szerves trágyák Tőzegfekáltrágya Komposzt A tápanyagmérleg A tápanyagmérleg szintjei: Talajjavítás A talajjavítást megelőző vizsgálatok Csoportosításuk: I. Természetes, ásványi eredetű anyagok: Mészkő és dolomit őrlemények Lápi mésziszap (tavi mész) és meszes lápföld: Gipsz- CaSO II. Ipari melléktermékek, hulladékok: Cukorgyári mésziszap: Papírgyári mésziszap

15 Acetiléngyári mésziszap A tápanyagellátás hatása A tápanyagellátás hatása a búza termésminőségére A búza trágyázásának irányelvei: A tápanyagellátás hatása az árpa termésminőségére Az árpa fejlődési szakaszai: Az árpa trágyázásának irányelvei: A tápanyagellátás hatása a kukorica termésminőségére A kukorica fejlődési szakaszai: A kukorica trágyázásának irányelvei: A tápanyagellátás hatása a cukorrépa termésminőségére A cukorrépa fejlődési szakaszai: A cukorrépa trágyázásának irányelvei: A tápanyagellátás hatása a napraforgó termésminőségére A napraforgó fejlődési szakaszai: A napraforgó trágyázásának irányelvei: A tápanyagellátás hatása az őszi káposztarepce termésminőségére Az őszi káposztarepce fejlődési szakaszai: Az őszi káposztarepce trágyázásának irányelvei: A tápanyagellátás hatása a burgonya termésminőségére A burgonya fejlődési szakaszai: A tápanyagellátás hatása a pillangósok termésminőségére A pillangósok trágyázásának irányelvei: A pillangósok trágyázásának irányelvei: A tápanyagellátás hatása a kertészeti növények termésminőségére

16 A zöldségnövények trágyázásának irányelvei: I. Szántóföldi zöldségtermesztés II. Intenzív zöldséghajtatás A tápanyagellátás hatása a szőlő termésminőségére A szőlő éves fejlődési szakaszai: A szőlő trágyázásának irányelvei: Alaptrágyázás: A szőlő növekedéséhez szükséges nitrogén biztosítása. Időpontja telepítést megelőző évben t/ha istállótrágya. Később a nyugalmi időszakban Talaj nélküli termesztések A talaj nélküli termesztés előnyei: A talaj nélküli termesztés hátrányai: Az ökológiai termesztés A tápanyag-gazdálkodás előírásai az ökológiagazdálkodásban Cél: A talaj termőképesség és biológiai aktivitás fenntartása, növelése a jogszabály előírása szerint: Toxikus elemek a talajban I. A szükséges tápanyagmennyiség meghatározása X= (T F1 sz ) ± K Elővetemény-hatás Az istállótrágya hatása Az öntözés hatása II. A nitrogén-utánpótlás meghatározása

17 Példa: Megoldás: III. A foszfor-utánpótlás meghatározása Példa: Megoldás: III. A tápanyag-utánpótlás megvalósításának gyakorlati munkafázisai 222 LABORATÓRIUMI GYAKORLATOK Vizuális növénydiagnózis gyakorlat

18 INTRODUCTION Historians don t know the date of start of fertilization in the history of mankind, but the fertility of the soil and its effective using has been interest by the ancient empires farmers. Over thousands of years had been proven that the soil has a renewable capacity that humans can turn their own benefit as well. Age-old experience that the correct nutrients supply can insure good quality and optimal amount crops. The production factors largely determined the structure of societies. The development and structural changes of societies were determined by agriculture based on strong foundations in every historical period. Therefore, the prevailing power developed and updated the agriculture and horticulture. The strengthening of chemistry as a science was significant not only in industry, but also in agriculture meant a change. Agro-chemistry is chemistry applied in agriculture, which we can use to save nutrient content, fertility and evolved structure of soil, and if necessary we can grade it up. After the II. Word War the production competition between the Eastern and the Western powers increased. Reaching maximum yield was the most important factor in agriculture. In this aspect agro-chemistry - as the new method of nutrient supply of soil - started an outstanding development. Our country is an agricultural country due to a specific natural environment, where field-grown and also greenhouse-grown vegetables have a a very important part today, the production competition was replaced by a market economy, so in addition to the high yield the good quality is also a criteria. Because of the high number of operators marketing requires the application of more and more professionals with high-level agrochemical expertise in agriculture. In today s the soil less technology and large amounts of fertilizer is used by intensive vegetable forcing, because the agrochemical expertise is necessary in horticulture. 18

19 Agriculture is not only a manufacturer sector. In addition provides beside its basic function environment and society-shaping tasks. In more countries of European Union and in the overseas countries (USA, Japan, Australia) increase the number of organic farms. This special cultivation system is suitable for most plants. Therefore, in the field of agro-chemistry more new sciences and discoveries are necessaryin the future for safe foods. This textbook provides help to study about the production of human foodstuff and the cultivation of forage plants. It reveals the relationship between soil and plant, which the farmers can use for management of farm. Agro-chemistry is a relatively new discipline, which involves laws of many different disciplines such as soil science, chemistry, physics, biology, botany and mathematics. The preparation of this textbook was suppported by TÁMOP C-12/1/KONV " Dr. Ferenc Lantos 19

20 1. THE ROLE OF AGRO-CHEMISTRY Agro-chemistry essentially summarizes the chemical basics of the nutrient supply applied during plant production. It studies the interaction between the soil, fertilizers, other organic materials and plants by nutrient uptake of plants. So, the plant is in constant interaction with the soil, the fertilizers and organic materials. This means that agro-chemistry must investigate the interaction between the nutrients and plant. This skill allows the nutrient supply for reach the maximum yield, considering the structure of soil and nutrient demand of the plant. Subject and importancef of agro-chemistry By scientific experiments, test growing and other methods investigate the chemical changes in soil and plant. Over and above every factors which can increase the yield and quality. Investigate the methods with which we can save the nutrient content of soil and we can upgrade the nutrient supply of soil. Further task the upgrade of mildly fertile soils. Saving the good fertile soils. Analysis of cycle of biological nutrients. Nutrient balance calculations. Concept of soil fertility The ability of the soil to supply the plant with nutrients, water, air, and be able to provide great physical, chemical and biological conditions for the plant. 20

21 Physical condition: structure and compendious of soil. Chemical condition: up taken nutrient content and water supply of soil. Biological condition: the effect of useful fungi, bacteria and other saprophytic organisms living in the soilon yield growth 21

22 2. THE CHEMICAL COMPOSITION OF PLANTS The constituent components of plants can be divided into organic and inorganic substances. The organic and inorganic constituents of dry matter are considered. Some parts of plants of dry material of 85-95% are organic materials. Together with we can found some degree of water in every plants (for example the water content of maize crop is 15-18%, and tomato s 75-85% ). Dry materials of plants Organic ingredients: Protein Proteins are made up of amino acids organic macromolecules. For its construction especially the uptake of nitrogen is necessary. It can be found in all parts of plants. There is difference between the protein content of seeds and leaves. The protein concentration in crops of legumes is high, in crops of sunflower is extremely high, however in vegetables is low-down. Chlorophyll in the leaves also contains protein. Carbohydrates Carbohydrates are carbon, oxygen and hydrogen-containing organic compounds produced during photosynthesis. For its construction especially the uptake of potassium is necessary. Mst part of carbohydrates is present in plants as starch. Sugar beet, sugarcane, table grapes and most fruits have extremely high carbohydrate content. Potato has extremely high starch content. Carbohydrates can be found in roost, tubers, stems, crops and leaves. 22

23 Fats and oils After the most important energy supplier compounds are carbohydrates. Natural fats are usually made up of triglycerides in 99%, which are consisting of glycerol esters with fatty acids. It is insoluble in water, but highly soluble in nonpolar solvents. In room temperature most plant fats are liquid, so they are called plant oils in agricultural terminology. For its construction especially the uptake of phosphorus and nitrogen is necessary. Fats are present in every part of the plant, of course in different concentration. In start the seeds and crops have little fat, increase of accumulation occurs during the growth of plant. Fats are stored in cotyledons, the endosperm of the seeds, leaves, stem, roots, but we find it in the embryo sac and in pollen too. Sunflower, rap, oil flax and other oil plants have extremely high oil content. Vitamins Vitamins are biologically active, from different chemical combination, small molecules organic compounds. They are in extremely high concentration in vegetables and fruits. Thirteen vitamins are known, some of them are soluble in water, while othesr are oil-soluble. The water-soluble vitamins are vitamin B1, vitamin B2, vitamin B12, niacin, pyridoxine, pantothenic acid, biotin, folic acid and vitamin C (ascorbic acid). Fat-soluble vitamins are vitamin A, vitamin D, vitamin E, and vitamin K. All plants contain some vitamins. The vitamin concentration is different in each plant and part of plant. In their development sunlight has capital role. Aromatic compounds, alkaloids The benzene and all of its derivatives, which have a benzene ring in their molecules consisting of 6 carbon- and 6 hydrogen atoms. The aromatic name derives from the first tested from plants extracted compounds, which had 23

24 characteristic smell (benzyl alcohol, benzaldehyde, toluene). These are mostly in medicinal herbs, which are called volatile oils. The alkaloids can be recovered from plants nitrogen-containing, organic compounds with multiple ring structure. Thery are used mostly by drug industry. They might also have toxic effect. Enzymes Enzymes increase the reaction speed of materials, so-called. biocatalysts. Each enzym is a protein therefore their operation depends on temperature effect on plants, ph of soil or solution. Each enzymhas typical temperature and ph optimum. For its construction especially the uptake of nitrogen is necessary. Plant hormones The hormone is a Greek word, which means stimulation. The plant hormones (phytohormones) are compounds regulating the life processes of plants. The plant hormones can function in more regulatory system: - growth, - development of root, stem, leaf, bloom and crop. plant hormones are: - auxin: stimulates growth, - gibberellin: s increases the opening of stem part, - cytokinin: stimulates cell proliferation, - abscisic acid: inhibits the growth - ethylene: inhibits the growth of the crop; promotes maturation. 24

25 Inorganic constituents: Ash It is determined in laboratory by burning at 550 C. Its amount is differentin each plant and plant part, but it also depends on the age and mineral content of the plant. They are partly necessary nutrientsfor the plant, on the other hand they are physiological elements. dispensable from respect of the nutrient uptake of plant, or have not been elucidated yet The plant cannot cannotselect the toxic and dispensable elements at the uptake of necessary elements. Ash content is a little pert of green plant, therefore it is expressed in dry material % (Table 1.). Components of ash: (K, Ca, Mg, Na, P, Fe, Cu, Mo, B). The composition dry matter of the plant is characterized by the following average values: C: 40-45%; H: 5-6%, O: 40-42%; other elements: 2-10%. Table 1. Ash content of some cultivated plants ((Loch,-Nosticzius, 1992) PLANTS PART OF PLANT ASH (DRY MATERIAL %) wheat seed 1,2 wheat straw 7,0 corn seed 0,6 barley seed 1,7 barley straw 6,4 sugar beet root 2,0 lucerne hay 9,7 potato tuber 2,2 25

26 Role of water (H2O) Metabolism-processes are chemical reactions occurring mostly in aqueous media. Consequently, the water: - is absorbed in organism of the plant during the photosynthesis, - is a solvent, which makes the nutrients in available condition, - is transport and storage medium, - in case of high temperature it has cooling effect on the plant, - 95% is vaporized by the plant. The precondition of water uptake is the salt concentration of soil solution be less than the salt concentration of root cells. Therefore the basic of water uptake is the osmosis. If the cell is not full saturated with water, it exerts a suction force, which is greater the smaller of cell saturation. Plants can only absorb water from soil, when the force is smaller than the suction force. Consequently the capillary water and part of loosely bound water can be available for plants. They cannot utilize hygroscopic watercannot, because its outer streak absorbs with 50 bar suction force to soil. However, the suction force of our cultivated plants are only 5-15 bar. The water amount absorbed with large power is called dead water content. Therefore, the available water (AW) for plant is the difference between the soil capacity (SC) and dead water (DW). (Table. 2.) Available water can be modeled by the following formula: AW= SC DW Table 2. Available water content of some soil types (Loch,-Nosticius, 1992) SOIL SC DW AW rough sand sandy loam alluvial soil loam

27 The water uptake and transpiration of plants are in dynamic poise with the water content of the soil and air humidity. However, a number of climatic factors also have influence on plants. The vaporization of plant is called transpiration. During the cultivation the air humidity, the temperature, the air movement, the intensity of solar radiation and the precipitation have influence on the transpiration of plants. The transpiration occurs through the stomata of the leaves. Consequently, the intensity of transpiration is determined by the size, distribution and openness of stomata. The content of water is different per plant and parts of plant (Table 3.). Table 3. Water content of major crops (Gazdagné, 2007). PLANTS Water content (%) wheat 12 corn 15 alfalfa hay 15 cucumber, water melon 85 fruits, grapes 80 The water requirement of plants During the growing season the water requirement is different by species and varieties. The extent of water consumption is varied too. In this, the actual water needs of plant, the meteorological, the ecological and technological factors have role. The water needs of plant are characterized by transpiration coefficient. It determines the necessary water amount to produce a unit of dry matter. The water requirement of C3 and C4-type plants are different (Table 4). This also means, that the precipitation cannotnot cover the necessary water requirement of the plant. Therefore the plant must use winter precipitation stored in sthe oil, and they also need irrigation. 27

28 Figure 1. Local water quality (internet) Table 4. Transpiration coefficient of cultivated plants (by Frank & Hank). PLANTS Transpiration coeffitient C3-type plants flax 820 soy 810 clover 775 early potato 407 potato 849 oat 433 spring barley 476 spring wheat 577 C4-type plants corn 314 millet 222 silage corn 205 silage sorghum

29 Arsenic (As) contamination of irrigation water Arsenic (As, atomic number 33) is a chemical element that occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. Arsenic was also used in various agricultural insecticides and poisons. For example, lead hydrogen arsenate (PbHAsO4) was a common insecticide previously used on fruit trees, but contact with the compound sometimes resulted in brain damage among those working as sprayers. In the second half of the 20th century, monosodium methyl arsenate (MSMA, CH4AsNaO3) and disodium methyl arsenate (DSMA, CH4AsNa2O3) less toxic organic forms of arsenic have replaced lead arsenate in agriculture. Arsenic is easily absorbed by vegetables from irrigation water. The accumulation of arsenic in vegetables could pose a serious risk on the quality of vegetables and human health. The two forms of inorganic arsenic, arsenate (AsV) and arsenite (AsIII), are easily taken up by plant root cells (e.g. carrot, parsley, kohlrabi). 29

30 3. THE BOTANICAL CLASSIFICATION OF NUTRIENTS According to Mangel (1976) the nutrients are the elements, which are necessary for the plants to grow. and no other elements can perform their biological function cannot. Necessary elements are: C,H,O,N,P,S,K,Ca,Mg,Fe,Mn,Cu,Zn,Mo,B. The attributes of nutrients: Element deficiency causes trouble in the development of the plant. Deficiency symptoms can be prevented or eliminated by the supplement of element. Biological effect of element is proven. The element cannot be replaced by other elements. Classification of elements: The nutrients are grouped based on their quantitative or plant physiological function role (Table 5). Based on their quantity in the dry matter of plants there are macro, micro and secondary nutrients. The quantity of macro-elements in plants is higher than 0,1%, while that of the microelements is s much lower than that. The quantity of secondary elements is between the two values. Macro-elements: C, H, O, N, P, K Micro-elements: Fe, Mn, Cu, Zn, Mo, B Secondary elements: Ca, Mg 30

31 The non-metallic elements are important building blocks of the organic compounds. The alkali metals and alkaline earth-metals are present mostly in ionic form in the plant. Plants absorb and transport them as cations. When bound to enzymes they change their structure. The heavy metals bind strongly to organic matter, and built in the form of chelates. The heavy metals mostly act their effect as enzyme activators in the plants. Table 5. Grouping of elements Elements Uptake and transport non-metallic elements C carbon CO2 H hidrogen HCO3 O oxigen H2O-ből N nitrogen NO3 -, NH4 + - ion S sulfur SO 2 4- ion P phosphorus P2O5 B boron H3BO3 Si silicon Si(OH)4 alkali metals and alkaline earth-metals K potassium K2O Na natrium Na + Mg magnesium Mg 2+ Ca calcium Ca 2+ heavy metals Fe iron Mn manganese Fe 2+ MnO 2 4- ion Cu coppper Zn zinc Cu 2+ Zn 2+ 31

32 Nutrient content Nutrients are in various concentrations in dry matter of plants. Even, within the same plant, the nutrient composition of some parts may be different (Table 6). The age and the nutrient needs of the plant, the nutrient content and the water supply of the soil can influence the amount of nutrients. The young plant parts have higher levels of nutrients than older plants. Table 6. Macro, micro and secondary element content of some plants (Loch,-Nosticzius, 1992). PLANT NUTRIENTS N P S K Ca Mg Fe Mn Zn Cu B Mo wheat 2,0 0,4 0,02 0,5 0,05 0, ,5 straw 0,5 0,1 0,07 1 0,3 0, ,2 potato 1,5 0,2 0,1 2 0,05 0, ,3 sugar beet 0,8 0,2 0,06 1,5 0,2 0, ,6 32

33 4. NUTRIENTS IN PLANT AND SOIL Nitrogen The nitrogen is in the plant as amino acids or proteins or nucleotides or nucleic acids, additionally it is the most important components of chlorophyll. Elder plants cannot absorb the nitrogen in elementary form, it is absorbed as NO 3 - and NH4 + -ion. Plants absorb more nitrogen to grow their vegetative parts. On sandy soils cultivated plants (root vegetables, potatoes, fruits, grapes) develop better by ammonium NH 4 + -, other plants (cereals) prefer the nitrate NO 3 -. There are plants that grow equally well uptaking both ions. Having the proper nitrogen supply the vegetative plant parts begin to grow and fruit ripening also will be start.. Shoots and leaves will be growing in deep green color, healthily. In case of nitrogen deficiency the vegetative growing period will be short, while the reproductive period will be quicker. Growing of stem will be short and thin. The lower leaves will be dull green, sometimes reddish or yellowish. The roots get elongated, with poor branches only. Product quality and quantity are below the expected results. The element nitrogen can be recycled element. In case of nitrogen overdose the cereals bend, their resistance will be reduced e.g. against (Fusarium graminearum). Plants cast off their flowers before fertilization, beforefruit set. The tissue of grape comma is soft and spongy. Nitrogen is present in the soil mostly in the form of compounds. The change, of the organic and inorganic nitrogen compounds constituting all the all nitrogen content of the soil and their transformation is a dynamic process determined by complex microbiological, soil and climatic factors (Figure 1.). 33

34 Figure Nitrogen cycling 34

35 The total nitrogen content of mineral soils is between 0,02-0,4%. Over 95% of the nitrogen in the cultivated soils is in organic binding. Its amount is in proportion with humus content. In nitrogen supplying of plants the atmosphere is a reserve source. Plants cannot utilize the nitrogen content of the air. It will be utilized by micro-organism (Rhizobium sp.). Consequently, the nitrogen is in a constant cycle in nature. In nitrogen cycling there are enriching phases and phases casing loss. Nitrogen enriching phases are: the microbial nitrogen bonding, the humification, organic manure and fertilizer application. The nitrogen loss phases are: the denitrification, the nutrient uptake of plants and the leaching of nitrogen (Figure 2.). Nitrogen is a reusable element. The nitrification is a process necessary for the nutrient supply of plants, in which the organic nitrogen changes to inorganic bound nitrogen. The nitrification happens in the presence of oxygen. So, the better the soil is ventilated, the more favorable the conditions for nitrification are. Nitrogen will be available for plants. The nitrogen cycling is opposite to process of mineralization. If the C-N ratio of the organic material is greater than that of the micro-organisms in soil, than energy is necessary for nitrogen dissociation. In this case the microorganisms cover their needs from soil nitrogen. The nitrogen content of the soil is increased by the so-called nitrogen fixing plants. For example, nitrogen fixing bacteria live in symbiosis with the plant in the root of legumes and Facelia. Ammonification: the amino-n transforms into ammonia by effect of bacteria + (R-NH 2 NH 4 ). During nitrification the ammonia with oxygen uptake transforms into nitrite and then converts into nitrate (by nitrate bacteria). 2NH O2 2HNO 2 + 2H 2 O + 2H + 2HNO 2 + O 2 2HNO 3 35

36 Phosphorus The phosphorus has a major role in the development of the reproductive processes of plants. Primarily, it provides energy for the germination of seed, in ATP form. Later the seeds of fruits will absorb a significant amount of phosphorus. During vegetable forcing it can accelerate the process of rooting. This will increase the drought tolerance of young plants. The phosphorus is present in plant both in organic and inorganic forms. Its inorganic form is the orthophosphoric acid H3PO4, or salts of calcium, magnesium and potassium. Plants absorb it in form of H 2 PO 4 -. The uptake is influenced by soil or nutrient solution ph. The low ph hinders the uptake of monovalent orthophosphate ions. The organic form is present in the nucleic acids (DNA). The nucleic acids take part in in protein synthesis, cell division, in transport of genetic material and in growth. The phosphorus can be recycled. The phosphorus cycle has two phases. In the first, the phosphorus absorbs into organic compounds then it disintegrates again inorganic compounds in the environment. The plant material is partially returned into the soil then it will be again an available element for plants. The plough of stubble-field, the green manure and the till of root remains have minimal role in phosphorus cycle. The organic fertilizer has direct role. It is as phosphorusperoxide P 2 O 5 form in soil. Its concentration depends on soil type (Table 7.). Phosphorus is readily mobilized in plant. In case of phosphorus deficiency the element migrates from older tissues to meristem. We can observe the retarded growth of the plant. The stem and sprouts will be flimsy, the nervation and leaves have deep red coloring. Recalculation: P 2 O 5 x 0,436 = P ; P x 2,29 = P 2 O 5. 36

37 Table 7. Determination of P 2 O 5 value of soils (Buzás, 2006) P 2 O 5 value Definition mg/kg low soil mg/kg medium soil over 150 mg/kg optimal soil mg/kg excessive Potassium Out of cations it is the K + - ion that plants contain in largest amount. It does not bind strongly to the cell, so the water can easily wash it out of the plant. They have plant physiological role in the synthesis of carbohydrates and starch. During vegetable forcing it promotes the coloring of tomato or sweet pepper. Biological cycle starts with the uptake by the roots of plants, then the smaller part will be absorbed into the plant, the greater part into the fruits. The plough of stubble-field, the green manure and the till of root remains have minimal role in potassium cycle. The greater part of potassium remains in the fruits, therefore the amount of potassium extracted by fruits can be supplemented by organic and chemical fertilizers. Potassium can be found mostly in clay minerals in soil. We know potassium providers and potassium binding clay minerals. The potassium needs of plants cultivated on potassium binding clay minerals cannot be satisfied until the potassium binding clay minerals are not saturated by potassium. It is means a year-long, intensive fertilization with potassium. The potassium-providing ability of soils is different, it is determined by the formula K 2 O. Although, the soil does not countain any potassium-oxide, it is a tradition to give the value of potassium providing ability of soil by potassium-oxide (AL= ammonium lactate method). 37

38 In case of potassium deficiency the carbohydrate content of fruits, grape and vegetables will be low. The fruits color poorly. The tip and edges of leaf are yellowing, then browning and eventually wither. The lamina is curled. The resistance of the cereals against the powdery mildew (Erisyphe graminis) will decrease. Recalculation: K 2 O x 0,83= K; K x 1,204 = K 2 O. Table 8. Determination of K 2 O value of soils (Buzás, 2006) K2O value Definition mg/kg low soil mg/kg medium soil over 170 mg/kg optimal soil mg/kg excessive Calcium Calcium occurs in plants in form of salt of organic and inorganic acids and binding to ions of plasma colloids as well. The Ca 2+- ion with interaction the ß-indoleacetic acid have significant role in cell elongation and cell differentiation. It is a central component of the primary cell walls of medium plate, in which it has a stabilizer role. The plant physiological role of Ca 2 + is direct in the development of the plasma membrane. The negative charge sites of pectin (polygalacturonic acid) connected like a bridge by calcium, thereby it significantly determines the stabilized of cell walls. Calcium has a role in hindering the changes casued by environmental effects, because the hormones transmitting the environmental effects provide the uninterrupted metabolic process withcalcium. The hormone cannot get into the cell to induce metabolic changes ast it bounds to receptors of cell membrane. The desired effect is mediated by using a calcium binding protein, calmodulin. The Ca 2+ - ions can be relatively easily transported with transpiration to 38

39 xilem. Generally they cannot be transported to floem. Since the transport of calcium is poor, its return from leaves to stem and roots or from older parts to young plant parts is minor. Calcium is presents in the soil in form of CaCO 3. In case of calcium deficiency the meristem tissue and the root hairs cannot grow. In apple fruit brown spots start up. On red pepper bells and tomato blossom-end rot develops. The buds of fruit trees cannot unsnap, the leaves curl up spoon shaped. Magnesium The most important role of magnesium is in photosynthesis. Chlorophyll contains 27% magnesium. It can be found in protoplasm as a free ion. It participates in the development of the water balance of plants. Plants absorb it in form of Mg 2+. Magnesium has a direct role in the structure of enzymes and metabolism of phosphorus. Most part of magnesium is present in soil as silicates and carbonates. Major silicates are biotin, serpentine and olivine, while carbonates are magnesite and dolomite. In case of calcium deficiency tissues of older leaves will be yellow between the veins (chlorosis), while the central vein remains green. Fan-shaped yellowing will start from the inside, which develops near the petiole between the central veins. The symptoms develop in every case on older leaves. But unlike nitrogen or potassium deficiency, it develops on the middle part or lower two-thirds of the stem. On the symptoms is typical of bright yellow, often purplish, reddish-orange color. The overdose of nitrogen, potassium or calcium and the low level of soil ph can increase the development of disturbance. 39

40 Sulfur Cultivated plants contain a significantly smaller amount of sulfur than the above-mentioned macro-elements, and yet it has an important role in the life of the. Among others it isa component of the sulfur-containing amino acids (cystine, cysteine, methionine), the koenzin-a, the vitamin H and it presents in oil content of hemp, flax, soy and mustard as well. Plants absorb it in form of SO ion. The sulfate ion is built into the structure of protein, but it has a direct role in binding of bacteria Rizobium living on the root of legumes. The sulfur occurs in inorganic and organic form in soil. The organic sulfur content is in proportion with soil humus content. The inorganic sulfur is present as gypsum CaSO 4 2H 2 O, in saline soil as NaSO 4 and MgSO 4. In the sulfur cycling of soils the mineralization of organic matter has a central role. During mineralization released hydrogen-sulfide will be oxidized to elemental sulfur and to sulphate. 2H2S + O2 2H2O + 2S 510 kj 2S + 3O2 + 2H2O 2H2SO kj In unventilated, pan soil the sulphate can be reduced to hydrogen sulfide, which is toxic to plants. It is possible that it forms iron sulfide with iron, which is insoluble. It inhibits the iron uptake. In case of sulfur deficiency the older leaves will be yellow or red. It is an anthocyanin pigmentation. In corn and cereal poor tillering, delayed ripening, and the short stem show the deficiency of element. The growing of cruciferous plants (rape, mustard, and radish) is weak, its kids are stunted due to sulfur deficiency. 40

41 Iron The amount of iron in plants is an intermediate between macro and micro elements. Its physiological importance manifests during chlorophyll synthesis. The plant physiology effect of iron is primary in the process of respiration and photosynthesis. It is a central component of iron-containing plant enzymes. Plants absorb it in the form of chelate. It can be found in the crystal lattice of iron in soil, in relatively high amount. In sour soils the Fe 3+ ions are in greater concentration. In neutral soil ph the Fe 2+ ions precipitate as iron-hydroxide. In alkaline soil both forms precipitate. In case of iron deficiency the plants perish by carbohydrate hunger due to inhibition of photosynthesis. The soil, under natural conditions, always contains enough iron therefore the symptom of chlorosis is of secondary origin, not iron deficiency. The cause of iron chlorosis is thought to be the disturbance in the balance of Fe 2+ and Fe 3+. In calcareous soils the iron continuously removes from the soil solution due to the calcium carbonate, on sour soils it binds the phosphate. It is not the absolute iron content of plantsthat is important, it is the active form of available iron content. The top sof the stem and the leaves of apple start yellowing, black spots appear on the leaves of pear, while the leaves of cherry are yellow, but the finest veins remain green. The symptom of chlorosiscan also be caused by over irrigation. 41

42 Copper The copper has a primary role in photosynthesis, carbohydrate and protein metabolism, respiratory processes andin formingenzymes. Plants absorb it in form of Cu 2+ ion. The iron, manganese and zinc are copper antagonists; these elements inhibit the uptake of copper. The copper concentration is very low in soil, 0.01 ppm. Its mobility is also small. In ionic form copper can quickly be absorbed by humic substances in soil. Copper deficiency can be observed in soils that are rich in organic matter. Copper deficiency causes damage in the blooming fruit trees. Leaves of young seedlings fall. It inhibits the growth of internode of cereals and the crops remain frivolous in spike. The edge of older leaves die. Manganese Many enzymes are activated by manganese. The oxidation of α-keto-glutaric acid, the decarboxylation of oxaloacetic and oxalic acid are realized by Mn 2+ ions. The manganese has a primary role in photosynthesis and in the process of hydrolysis. Manganese has a favourable effect on the metabolism of carbohydrates, and it increases the Vitamin C content of vegetables. Plants absorb it in form of Mn 2+ ion. The calcium is manganese antagonist. The plants contain very different concentrations of manganese. The amount of manganese of soil is highly dependent on the soil ph. In sour soils the manganese can accumulate in toxic amount. The manganese accumulates to the humus layer, therefore manganese deficiency occurs mostly - chernozem and brown forest soils rich in organic matter. 42

43 Manganese deficiency the oats, peas and spinach are sensitive. On dicotyledonouss plants mosaic chlorisis will appear and later brown spots on leaves. Zinc Zinc stimulates the growth of plants by auxin production. It participates in protein metabolism processes. Many enzymes are activated by zinc. Plants absorb it in form of Zn 2+ ion, but in small amount. Phosphorus is zinc antagonist. Zinc occurs in soil as biotite, augite and in crystal lattice of several micas. Cereals are not sensitive to Zinc deficiency. However, the corn, beans, flax and hops respond sensitively to the deficiency of the element. In case of grape vine the leaves might remain small, stem shoots and the berries remain tiny. The deficiency inhibits the budding of fruit trees, stems of apple remain bald. Boron The physiological role of boron is complex, it has a primary role in the fertilisation of flowers and in crop production. It has important role in nutrients uptake and carbohydrates transport as well. It participates in the production of auxin. The boron is present as H3BO3 in the soil mica and other minerals. Plants absorb it as borate ion. The boron demand of monocots is less than that of the dicotyledonous plants. However, an overdose can be toxic to the plant. Soil liming can reduce the boron content of soil. Most plants are sensitive to boron deficiency. Fertilization of grape cluster is defective. Boron deficiency can cause a wash-out symptom (heart rot) in 43

44 sugar beet and cruciferous plants organization as well. In apple a fruit flesh rot symptom can develop due to boron deficiency. Molybdenum The molybdenum is present in plants as metal component of several enzymes. Its plant physiological role in the N-metabolism is prominent. It participates in nitrate reduction, because it is the metallic creator of nitrate reductase enzyme. Plants absorb it in form of molybdate ion from soil. Sulphate ions are molybdenum antagonists. The molybdenum content of soils is very low, 0.5 to 10 ppm. The molybdenum concentration of sandy soils is very poor, however meadow soils are extremely rich. The molybdenum concentration of soil is in direct proportion with the reduction of soil ph, although the element binds to the soil strongly. Its transportability can be repared by soil liming. The molybdenum demand of plants is different. The brassicas and legumes need more, however the grasses need less molybdenum. In case of molybdenum deficiency the content of sugar, chlorophyll and Vitamin C will be reduced. The petioles will extend (whip handle symptom). 44

45 5. DYNAMICS OF NUTRIENT UPTAKE The plants can uptake the nutrients through their root system or leaves. They use both ways for perfect nutrient utilization. Through the root system the plant can cover the necessary nutrient needs by natural nutrients content of soil and manure. The plant absorbs only additional nutrients, mostly micro elements through the leaves. This process happens by spray fertilization during plant growing. Nutrient uptake in respect of energy - Passive processes: the ions reach the endodermis on basis of physical properties by diffusion or ion exchange processes (without energy!). - Active processes: the ions can penetrate into the cell only through specific transporters (carrier), despite the concentration difference in the root zone. The activation of transporters is realized by ATP, which derives from oxidative or photosynthetic phosphorus. Consequently the respiration of roots has an influence 0, on active ion uptake through the roots. Influencing factors of nutrient uptake The uptake of nutrients through the root system depends on: - character of soils - water content of soils, - structure of soils, 45