Integrated evaluation of the capacity and main properties of gleyic luvisols with different fertilization systems ; Glėjiškųjų išplautžemių (gleyic luvisols) pagrindinių savybių ir našumo, taikant skirtingas tręšimo sistemas, integruotas vertinimas
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Integrated evaluation of the capacity and main properties of gleyic luvisols with different fertilization systems ; Glėjiškųjų išplautžemių (gleyic luvisols) pagrindinių savybių ir našumo, taikant skirtingas tręšimo sistemas, integruotas vertinimas

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LIETUVOS ŽEMöS ŪKIO UNIVERSITETAS Romut÷ Mikučionien÷ GLöJIŠKŲJŲ IŠPLAUTŽEMIŲ (GLEYIC LUVISOLS) PAGRINDINIŲ SAVYBIŲ IR NAŠUMO, TAIKANT SKIRTINGAS TRĘŠIMO SISTEMAS, INTEGRUOTAS VERTINIMAS Daktaro disertacijos santrauka Biomedicinos mokslai, Agronomija (06 B) Akademija, 2010 1 Disertacija rengta 2005 – 2009 metais Lietuvos žem÷s ūkio universitete. Mokslinis vadovas: prof. habil. dr. Zigmas Jonas Vaišvila (Lietuvos žem÷s ūkio universitetas, biomedicinos mokslai, agromomija 06 B). Konsultantas: doc. dr. Jonas Kučinskas (Lietuvos žem÷s ūkio universitetas, biomedicinos mokslai, agromomija 06 B). Disertacija ginama Lietuvos žem÷s ūkio universiteto Agronomijos mokslo krypties taryboje: Pirmininkas: prof. habil. dr. Algirdas Juozas Motuzas (Lietuvos žem÷s ūkio universitetas, biomedicinos mokslai, agromomija 06 B). Nariai: habil. dr. Nijol÷ Anisimovien÷ (Botanikos institutas, biomedicinos mokslai, botanika 04 B). doc. dr. Vytautas Liakas (Lietuvos žem÷s ūkio universitetas, biomedicinos mokslai, agromomija 06 B). dr. Audrius Sasnauskas (Lietuvos agrarinių ir miškų mokslų centro filialas, Sodininkyst÷s ir daržininikyst÷s institutas, biomedicinos mokslai, agromomija 06 B). dr. (HP) Alvyra Šlepetien÷ (Lietuvos agrarinių ir miškų mokslų centro filialas Lietuvos žemdirbyst÷s institutas, biomedicinos mokslai, agromomija 06 B). Oponentai: dr.

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 LIETUVOS EMöSŪKIO UNIVERSITETAS
Romut÷Mikučionien÷ 
   GLöJIŠKŲJŲIŠPLAUTEMIŲ(GLEYIC LUVISOLS) PAGRINDINIŲSAVYBIŲIR NAŠUMO, TAIKANT SKIRTINGAS TRʊIMO SISTEMAS, INTEGRUOTAS VERTINIMAS  
Daktaro disertacijos santrauka
Biomedicinos mokslai, Agronomija (06 B)        Akademija, 2010
 
 Disertacija rengta 2005 – 2009 metais Lietuvos e÷msūkio universitete.   Mokslinis vadovas: prof. habil. dr. Zigmas Jonas Vaišvila (Lietuvos me÷sūkio universitetas, biomedicinos mokslai, agromomija 06 B). Konsultantas: doc. dr. Jonas Kučinskas (Lietuvos em÷sūkio universitetas, biomedicinos mokslai, agromomija 06 B).   Disertacija ginama Lietuvos em÷sūkio universiteto Agronomijos mokslo krypties taryboje:   Pirmininkas: prof. habil. dr. Algirdas Juozas Motuzas (Lietuvos em÷sūkio universitetas, biomedicinos mokslai, agromomija 06 B).  Nariai: habil. dr. Nijol÷ Anisimovien÷ institutas, biomedicinos mokslai, botanika (Botanikos 04 B). doc. dr. Vytautas Liakas (Lietuvos em÷sūkio universitetas, biomedicinos mokslai, agromomija 06 B). dr. Audrius Sasnauskas (Lietuvos agrarinių mišk irų mokslų centro filialas, Sodininkyst÷s ir darininikys÷ institutas, biomedicinos mokslai, agromomija 06 B).t s dr. (HP) Alvyra Šlepetien÷(Lietuvos agrariniųir miškųmokslųcentro filialas Lietuvos emdirbys÷t s institutas, biomedicinos mokslai, agromomija 06 B).  Oponentai:  dr. Kęstutis Armolaitis (Lietuvos agrarinių ir miškų mokslų filialas, Mišk centroų institutas, biomedicinos mokslai, ekologija ir aplinkotyra 03 B). habil. dr. Gvidas Šidlauskas (Lietuvos e÷msūkio universitetas, biomedicinos mokslai, agromomija 06 B).   Disertacija bus ginama viešame Agronomijos mokslo krypties tarybos pos÷dyje 2010 m. gegu÷s m÷n. 13 d. 11 val. Lietuvos em÷sūkio universitete, c.r., 261 auditorijoje. Adresas: Studentųg. 11, LT – 53067, Akademija, Kauno r., Lietuva.   Disertacijos santrauka išsiuntin÷ta 2010 m. balandio m÷n. 13 d. Disertaciją galima periūr÷ti Lietuvos em÷sūkio universiteto ir emdirbyst÷s instituto bibliotekose.   
I N T R O D U C T I O N Relevance of the subject. Long time ago the soil was kept as holy and virgin intense, though now at the beginning of the 3-rd millennium it is investigated and used with intense for supply of human requirements with intense. The soil is not only a target to be used for agricultural purposes but it is also the component of the ecosystems. Nevertheless, the optimisation of soil resources is the main challenge for European countries implementing the agriculture (COM 232, 2006). Nowadays, the promising farming relies on the modern soil tillage and plant growing technologies, the increased risks of the resistance to use of the pesticides, the climate changes, though, the sustainability is either depended on the soil properties, the patterns of environmental and soil use. In Lithuania either the worldwide, due to the intensiveness in agriculture and anthropogenic activity, the soil degradation is existent. However, the soil capacity as well as the crop productivity will be directly influenced by the soil degradation and pollution, declining in soil organic matter and biological diversity. It is known, that the complex of factors determines the soil potential capacity, thus, due to sustainable environmental management it is important to maintain the relevant application of nutritional elements into the soil as well as the attaining the proper nutrient use by plants consumers. That not only the different species of crop plants but also the applied fertilization are the processors determining the soil quality as well as plant productivity. The fertilization system is an objective to allocate the organic and mineral fertilizers for agricultural plants within the crop rotation. Therewith, the evaluation of the fertilisation efficiency could be relevant along the long-term experiments (Nilson, 1993; Jaakkola, et al., 1997). While, choosing of the optimal fertilisation for the crop rotation it is also important to evaluate the factors influencing not only the crop productivity but also the soil potential fertility. Along the mineral fertilization system, and especially following only the nitrogen fertilisation, the plants are promoted to intensified growth and along that in soils, the mineralisation of organic material is increasing, the humus stock is declining and negatively influence on soil physical properties are noticed. Recent research studies indicate that the part of the nutrition elements supplied for crop plants along the intensive fertilisation is not used, while being not immobilised into the soil stable compounds is migrating into the deeper soil layer (Krikštapony÷t et al., 2006). While in only the mineral fertilisation system the plant residues became the source for soil humus formation. The content and chemical composition of the crop plant residues influences not only the accumulation properties but also the quality composition of soil humus. As for example, the unfavourable C:N ration influence the slowing into the mineralisation processes. In organic fertilization system, the organic fertilizers are the source of soil humus. Though, as the organic fertilisers are applied the moisture as well as the thermal regime of the soil is becoming stabilised, the soil structure is improved, the mobility of harmful elements (heavy metals, etc.) is decreasing. The combined organic-mineral fertilization system determines the beneficent use of mineral nutrition by the crop plants in the beginning of vegetation, whereas, slowly decomposed organic fertilisers compose the stocks of nutrients for crop plants on following growth and development stages (Krikštapony÷t, 2001, 2003). Combined use of mineral and organic fertilizers in crop rotation is enlarging the efficiency of fertilisers as well as providing the favourable conditions for the crop plants to use the nutrients (Bagdonien÷, 1997) There are many of the crop rotation fertilisation experiments carried out in Lithuania (Greimas, Janušien÷, 1994; Greimas, 2003; Tripolskaja, 1994; Plesevičien÷, Guys, 1997; Zakarauskait÷ ir kt., 2001; Krištaponyt÷2005). Though, the data on the correlative, 2002, evaluation of the organic, organic-mineral and mineral fertilization systems impact on soil 3
physical, chemical properties as well as on productivity of crops are still lack. It is even unknown how the implemented organic, organic-mineral and mineral fertilization systems are determining the potential capacity of the Gleyic Luvisols as well as the stability and the longevity of their parameters. Thus, there is a lack in data describing the reliance of the changes in properties of Gleyic Luvisols and the crop productivity through the performed fertilization system. Relevance of the study. There are many ways to promote the productivity of agricultural crop plants (fertilisation, soil moisture and pH control, weed control and soil tillage), – however, they influence irregularly the stability of ecosystem. One of the main tasks in today agricultural science – to preserve the fertile and clean soil as the main part of the ecosystem as well as the healthy environment for people. Lithuania along with other EU member countries is committed to implement the program of reduced pollution in agricultural environment. Therefore, the sustainable fertilisation depending on the crop plant is one of the tasks needs to be followed. It is the first time then following the research results obtained in the long-term experiment investigations, the evaluation of full-scale changes in main physical and chemical properties of the Gleyic Luvisols and the reliance of crop plants productivity with the implementation of the organic, organic-mineral and mineral fertilization systems was done. Thus, the estimations will be consistent while evaluating the agricultural practise in Luvisols with the aim of the sustainable agriculture as well as preserving the healthy environment for people. Aim and tasks of the investigation.It is presumptive, that the organic, organic-mineral and mineral fertilization systems would influence the changes in the physical and chemical properties of the Gleyic Luvisols, the turnover of the organic matter and the stability of organic carbon in soil, whereas the productivity of crop plants in crop rotation. The aim: To evaluate the impact of the performed fertilisation system on the physical and chemical properties of the Gleyic Luvisols as well as on the productivity of crop plants in 4-year crop rotation. Tasks:   To evaluate and to compare the impact of the performed organic, organic-mineral and mineral fertilisation systems in 4-year crop rotation on:  the bulk density, the porosity and the stability and composition of aggregates in · arable layer of the Gleyic Luvisols; · the agrochemical parameters (the potassium and phosphorus, the phosphorus fractions, the qualitative composition of humus, the soil nitrogen, the organic carbon and nitrogen pools) in arable layer of the Gleyic Luvisols; · the productivity of crop plants.  reliance of the productivity of spring barley, winter wheat and perennialTo estimate the grasses on the soil bulk density, the porosity and the stability and composition of aggregates, the content of nutrients in arable layer of the Gleyic Luvisols. Scientific novelty and practical importance.In the long-term fertilization experiment on the light sandy loam over moraine clay (Calc(ar)i-Epihypogleyic Luvisols) there were the integrated evaluation of the changes in arable layer done and the estimation of the tendencies and consistent patterns in the productivity of crop plants performed. The obtained research results of the organic, organic-mineral and mineral fertilization impact on the Gleyic Luvisols bulk density, porosity and composition of aggregates, the changes in qualitative composition of organic matter and humus, the phosphorus and it fractions, the
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soil nitrogen accumulation, the potassium and also the productivity of crop plants in 4-year crop rotation are novel. The performed research also gained the knowledge on the main properties and productivity of the Gleyic Luvisols and on the technology patterns within the soil-fertilisers-plant systems evaluation. The mentioned aspects are actual in the agriculture within the tendencies of decreasing in the extent of fertile soil sources. On the bases of the long-term researches in theCalc(ar)i-Epihypogleyic Luvisolsthere were either determined the proper fertilisation systems not only for the obtaining of the consistent crop plant productivity but also for the estimating the certain stabilisation and improving of soil use and productivity parameters. The estimated consistents could be further used in performing the fertilisation recommendations, thus, the fertilisation then could correspond the requirements of reduced pollution in agriculture and of sustained and improved fertility of the Gleyic Luvisols. Statements to be defended: 1. The long-term fertilization with organic, organic-mineral and mineral fertilizers is changing the soil bulk density, porosity and structure in arable layer of the Gleyic Luvisols. Thus, the soil bulk density and porosity are also influenced by the crop plants in the crop rotation. 2. The applied fertilisation systems in the crop rotation impact the changes in the subsistence of organic matter and the main nutrients. The long-term fertilization with organic, organic-mineral and mineral fertilizers and also the crop rotation are determining the stability of organic carbon pools in soil arable layer. 3. The long-term fertilization with low and average dosage of organic, organic-mineral and mineral fertilizers in applied fertilization system sustain the use of nutrients by crop plants and their average productivity within the diverse meteorological conditions. 4. The correlation of the productivity of spring barley, perennial grasses and winter wheat with the physical and chemical parameters in arable layer of the Gleyic Luvisols is different. Approval and publication of the dissertation work.The main results of the dissertation work were published in 2 peer-reviewed Lithuanianscientific journalsand in 3 proceedings ofscientificconferences. The main study results and statements were presented and discussed at 3 Lithuanian and internationalscientificconferences. Volume of the work. The dissertation is written in Lithuanian. It consists of an introduction, overview of the literature, experimental materials and methods, analysis and discussion of data, conclusions, list of articles and references. The dissertation comprises of 83 pages, including 19 tables, 21 figures and 198 references.  MATERIAL AND METHODS  Experimental materials.In the 4-year crop rotation winter wheat(Triticum aestivum), beetroot (Beta vulgaris), spring barely (Hordeum vulgare) with perennial grasses (Trifolium pratenseandPhleum pratense)were cultivated. Organic fertilizers (farming manure 50 and 100 t ha-1rotation while the beetroot growth. In the system per) were applied once per rotation the averages rates of the mineral fertilization (N31P38K75and N79P65K90) was used, though, in the organic-mineral fertilization the combined application of manure (50 t ha-1) with the mineral fertilizers (N31P38K75) was done. Study site.The long-term fertilization trials have been carried out since 1966 in the experimental station of the Lithuanian University of Agriculture on light sandy loam over moraine clayCalc(ar)i-Epihypogleyic Luvisols. 5
Expermantal methods. Soil sampling for evaluation of the chemical properties was carried out in spring in 2006, 2007 and 2008 before the fertilisation. Composite soil samples in three field replicates (n=3) were taken in each investigate treatment. The samples were collected in the arable Ap horizon of 0–20 cm deep layer to investigate the amount of varying form of organic carbon, phosphorus, potassium and nitrogen, soil pH and mobile humic substances. For the evaluation of the concentration of mineral nitrogen in soil, the former mineral horizon of 0–60 cm deep layer was sampled. Visible roots and plant residues were removed from soil samples by hand. Air-dried soil samples, beyond samples of mineral nitrogen, was crushed and passed through a 2–mm sieve. For the analyses of humus content and composition an aliquot of the dried soil was passed through a 0.25–mm sieve. The sieved soil was dried in an oven at 105°C temperature for 16 h. Since all samples were free of carbonates, the measured total carbon was equivalent to the organic carbon content. Composite soil samples (n=3) were prepared after the harvesting in the arable Ap horizon of 0–20 cm deep layer for the evaluation ofsoil physical (soil bulk density, total and air-filled porosity, moisture, structure and aggregate stability) properties. The yield was weighted during the harvesting. Analyses of physical properties of the soil.Analyses of physical properties of the soil were done in the Department of Soil Science and Agrochemistry Laboratory of the Lithuanian University of Agriculture. Soil bulk density, porosity was estimated by Katchinski cylinder method; the soil structure and aggregate stability – by Savinov method; the soil moisture – by weighing, before drying at 105°C. Analyses of chemical properties of the soil. The analyses of soil chemical properties were performed at the Chemical Research Laboratory of Lithuanian Institute of Agriculture. The analyses were done as followed: the soil pHKCl– ionometrically, KCl (ISO 10390, 2005); the humus content – by Tyurin method; the mobile humic substance – by Tyurin method, modified by Ponamariova and Plotnikova (1980) in 0,1 NaOH suspension; the available phosphorus (P2O5) and potassium (K2O) – by Egner-Riehm-Domingo (A–L )method (Egnér et al., 1960); the total phosphorus and potassium – byKjeldahl method; the organic carbon – by dry combustion at 900°a Heraeus apparatus (ISO 10694, 1995); the nitrate nitrogen –C with ionometrically; the ammonia nitrogen – photometrically (ISO 14256–2, 2005). Total carbon, total nitrogen, C/N ratio was measured by dry combustion method using a CNS elemental analyser Vario EL. Determination of carbon content by dry combustion method the prepared sample were pressed into a special tin foil container and burned in the oxygen-enriched atmosphere at +1150°C temperature. The combustion gas and helium carrier gas mixture was passed through absorption columns, which absorbed the individual compartments. The content of organic and mineral phosphorus and phosphates fraction were established at the Aagrochemical Research Centre of Lithuanian Institute of Agriculture by Chang and Jecson method, modified by Askinaz, Ginzburg and Lebedev (Chang, Jacson, 1957; Askinazi et al., 1963).  RESULTS AND DISCUSSION  Soil physical properties. The physical as well as the chemical properties of soil is effecting not only the yield of crop plants but also water, air and temperature regimes in soil, either is determining the ongoing soil processes, including biological activity and nutrient state. Soil bulk density and porosity. Soil bulk density is an informative indicator of soil physical condition, though, the mostly changing in the consequence of an anthropogenic factors. Analysis of data on long-term studies showed that, if to compare with the control (no fertilisation applied) plots the bulk density in soil arable layer of spring barley plots 6
along the organic (50 and 100 t ha-1of manure were applied for the spring barley preplant) and composite fertilisation system did not differed significantly, although, the bulk density along the mineral fertilization system have increased significantly (1 table).  Table 1. Long-term fertilisation impact on soil density and porosity along the different fertilization systems. Experimental Station of LUA, 2006–2008  Soil Fertilization system  %density porosity Mg m-3total air-filled 2006 m. spring barley Control (no fertilisation applied) 1.33 49.6 31.2 50 t ha-1 47.2manure* 1.32 28.4 100 t ha-1 47.2 1.32 25.6manure * N35P40K60 18.7 43.0 1.39 N80P60K60 21.6 1.37 44.3 50 t ha-1manure * + N35P40K60 1.34 20.5 44.2 LSD05 0.037 5.01 6.34 2007 m. perennial grasses Control (no fertilisation applied) 1.37 45.6 18.3 50 t ha-1 1.35manure ** 22.4 50.2 100 t ha-1 47.6 19.2manure ** 1.34 P40K60 47.5 1.35 17.8 P60K60 44.4 14.9 1.39 50 t ha-1 Pmanure **40K60 16.7 44.7 1.36 + LSD05 0.06 3.65 3.55 2008 m. winter wheat Control (no fertilisation applied) 1.50 45.0 13.4 50 t ha-1manure *** 43.6 1.46 11.9 100 t ha-1manure *** 42.8 1.48 10.4 N30P40K60 16.0 47.8 1.47 N100P60K60 9.3 1.50 40.5 50 t ha-1manure *** + N30P40K60 44.5 12.4 1.46 LSD05 0.063 7.12 7.31 Average Control (no fertilisation applied) 1.40 46.7 21.0 50 t ha-1 47.0manure 1.38 20.9 100 t ha-1manure 1.38 45.9 18.4 N31P38K75 46.1 1.40 17.5 N79P65K90 15.3 43.1 1.42 50 t ha-1manure + N31P38K75 1.39 44.5 16.5 LSD05 0.022 5.7 4.1 Note: *– 1-year, ** – 2-year, *** – 3-year manureffeect. Organic fertilization system –50 t ha-1, 100 t ha-1manure once per rotation); organic-mineral fertilization system –50 t ha-1manure once per rotation and N31P38K75; mineral fertilization system – N31P38K75, N79P65K90  Comparable soil bulk density changes were also estimated then the perennial grasses were cultivated after the spring barley along the organic and mineral fertilization. In comparison with the previous years, the highest increase in bulk density was estimated in the winter wheat plots over the rainy 2008 year. Thus, along the application of different fertilization systems the soil bulk density ranged from 1.46 to 1.50 Mg m-3, and was the lowest performing the organic, organic-mineral and mineral (with NPK fertilization at the lowest dose) fertilization systems. The mean data from 2006–2008 years represents, the bulk density in arable layer was optimal along the organic and organic-mineral fertilization systems (1.38–1.39 Mg m-3). While applying the mineral fertilisation system, the bulk 7
density was the highest (1.40–1.42 Mg m-3). Thus, the regression analysis showed that mean average bulk density (r = 0.67) is determined by the humus content. Then we have assumed that, the soil bulk density is depending on the fertilisation system, while the most positive influence on the bulk density was estimated along the application of organic fertilisers. Total soil porositythe converse value of soil bulk density. Thus, as. Total soil porosity is the bulk density the changes in total soil porosity were depending on the fertilization system. As the mean average data indicated, the differences in total porosity were narrow whenever the organic fertilisation system was applied, while, along the mineral and organic-mineral fertilisation systems the porosity was, respectively, by 0.6–3.6 and 2.2 percent lower compared with the total soil porosity in the control plots. Though, the correlation-regression analysis have showed that, the total soil porosity was not depending on the content of organic matter but was on an average influenced by the soil bulk density (r = 0.66) and have been strongly depended on the soil aeration porosity (r = 0.91, y = – 47.054 +1.434 x, t = 3.053). Aeration porosity.is an optimal when the air composesIt is known that, the aeration in soil in average 20–25 percent of the total soil porosity. Thus, our research has shown that, the aeration porosity was changing along the fertilization system: in the plots of spring barley the aeration porosity was 18.7–31.2 percent, in perennial grasses – 14.9–22.4 percent, and in the plots of winter wheat – 9.3–13.4 percent. While, teh highest aeration porosity was estimated in the plots of spring barley and perennial grasses then no fertilisation was applied (control) and along the organic fertilisation system. The tendencies in the decrease of aeration porosity were determined in all plots of winter wheat. Thus, the estimated aeration porosity there was the lowest. However, there were no consistent changes along the application of the organic and mineral fertilisers estimated. In summarise of the results it could be stated that, the organic fertilisers have had the highest effect on the both the total and the aeration porosity in soil. Soil structure and stability. From the agronomic point of view, the soil structural aggregates in size of 0.25–5.00 mm are the most valuable. As the obtained data shown, the soil structure in the plots of spring barley was in contrast along the application of the organic, organic-mineral and mineral fertilisers (Fig. 1). There were the tendencies of decrease in quantity of constructive aggregates along the application of only the mineral or the organic-mineral fertilisers, thus, it was not changing applying the organic fertilisers. The comparative analysis in the size of soil aggregates has shown that, in the plots of spring barley under the influence of the preplant soil tillage system there were reduction in the quantity of the larger soil aggregates (> 5 mm), while, increase in the quantity of the smaller soil aggregates (<5–0,25 mm) estimated. However, in the plots of perennial grasses and winter wheat the increase in the quantity of soil aggregates in larger than 5 mm in size was determined, concerning that, the quantity of the smaller soil aggregates was declining. Analysis of data on long-term studies showed that, 34.6–40.1 percent of soil aggregates were composed of the most valuable soil constructive aggregates in size of 0.25–5.00 mm. While comparing the influence of the applied fertilisation system on the quantity of valuable soil constructive aggregates it could be noticed that, it was higher along the organic fertilisation (39.6–40.1 percent) system, thus, to the lower extent – along the organic-mineral (35.8 percent) and the mineral (37.1–34.6 percent) fertilization systems. The correlation analysis have showed that, in the Gleyic Luvisols along the increase in the content of humus substances the increase in the quantity of soil constructive aggregates was low (r = 0.45), while, along the increase in the amount of mobile humic acids – the increase was in an average (r = 0.64). The obtained tendencies confirm that, the mobile humic acids in the organic matter are involved to connect the clay minerals. However, the significant strong coherence of the soil structure with the soil density (y = 190.643–
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109.565x; R2= 0.524; t = 1.221) as well as with the aeration porosity (y = 21.842+0.874x; R2= 0.776; t = 2.458) was estimated.  60,02006 2007 2008 Average80 2006 2007 2008 Average 50,0 70 60 40,0 50 30,040 20,0 30 20 10,0 10 0,00 K O-1 O-2 OM M-1 M-2 K O-1 O-2 M-1 M-2 OM Fertilization system Fertilization system Fig.1.Long-term fertilisation impact of soil aggregates (5–0.25 mm) quantity and stability (>0.25 mm) on Gleyic Luvisols. Experimental Station of LUA, 2006–2008 K – Control (no fertilisation applied); O – organic(1–50 t h-a1, 2–100 t ha-1manure once per rotation); OM – organic-mineral; M– mineral (1 – N31P38K75, 2 – N79P65K90) fertilization systems  The stability and the resistance to the destructive water activity of soil aggregates show the soil structural quality. Even though, the quantity of the stable aggregates in soil along the different fertilization system differed in lower extent a little, thus, there were the tendencies that the quantity has increased (by 2.1–3.4 percentunit) applying the organic fertilisers. In the combined application of the organic and the mineral fertilisers the quantity of the stable aggregates in soil was not changing noticeably, though, it was decreasing applying only the mineral fertilisers. The higher extent in the quantity of the stable aggregates was estimated in the plots of perennial grasses and winter wheat, though, the lower – in the plots of spring barley. The regression analysis have showed that, there was the linear reliance of water-stable soil aggregates on the content of organic carbon (r = 0.70), and the soil bulk density (r = 0.59), and the soil aeration porosity (r = 0.32). That, the quantity of the stable aggregates was increasing along the increase in the content of organic carbon and in the aeration porosity but along the decrease in the soil bulk density. However, the quantity of the stable aggregates was significantly depending on the C:N ratio in arable layer, that, the increase in the quantity of the stable aggregates was estimated along the decrease in the content of nitrogen (y = 194.158– 12.858x; R2= 0.78; t = 2.495). Thus, the reliance of the quantity of the stable aggregates on the amount of the mobile humic substances was on an average value (r = 0.52). In summarise of the above mentioned results it could be concluded that, along the long-term fertilisation, particularly applying the organic fertilisers, there were estimated the changes in soil physical properties, – the soil bulk density was decreasing, thus, the soil porosity as well as the quantity of the stable aggregates was increasing. The composite and the mineral fertilisation systems, though, the crop plants in the crop rotation had no negative influence on soil physical properties. That, the soil bulk density have remained optimal, thus, there were no consistent changes in the soil porosity. However, the soil porosity could be more relied on the crop plants (perennial grasses and winter wheat) in the rotation. Soil organic matter.Analyses of the long-term fertilisation impact on the changes in humus content in the light sandy loam over moraine clay Gleyic Luvisols have shown that, the higher extent in humus content have been estimated in the plots of perennial grasses, thus, significantly lower – in winter wheat plots and the lowest extent– in spring barley plots (Table 2). The average data indicated that, the soil humus content significantly differed along the different long-term 9
fertilisation. Evaluating the humus content along the combined application of organic and mineral fertilizers (organic-mineral fertilization system) for the crop plants in the crop rotation, it was not significantly extending if to compare with the organic fertilisation system, thus, was significantly increasing (p>0.05) if to compare with the mineral fertilization system. It was estimated that, the application 50 and 100 t ha-1of the manure (organic fertilization system) once per crop rotation have increased the humus content in soil by 0.2 and 0.43 percent units, thus, along the composite fertilisation (organic-mineral fertilization system) and the application of mineral fertilisers (mineral fertilization system), respectively, – by0.34 and 0.06–0.09 percent units. There through, the soil humus content significantly increased then applying only the organic fertilizers.  Table 2. Long-term fertilisation impact on humus content in arable layer of Gleyic Luvisols. Experimental Station of LUA, 2006–2008. Fertilization system Crop Control plant (no afeprptilliiesda)t ion OrganMica nure t ha-1 N rPKLeSsat  DgrOanic-mineral Minrela 05 50* 100* 50* N31P38K75 N79P65K90 Spring barley 2.37 2.58 2.83 2.72 2.39 2.51 0.137 Perennial grasses 2.87 3.06 3.31 3.21 2.89 2.89 0.1 32 Winter wheat 2.65 2.84 3.05 2.97 2.79 2.77 0.281 Average 2.63 2.83 3.06 2.97 2.69 2.72 0.076 Note: * – manure was applied once per rotation to beetroot.  Qualitative humic substance. Analysing the different fertilisation impact on the content of mobile humus substances (JHM) in arable layer of Gleyic Luvisols, it was significant increase estimated (LSD05= 0.58) in the plots of spring barley when the preplant there fertilised with 100 t ha-1of the manure or the organic-mineral fertilisation system was performed (Table 3). If to compare with the organic fertilisation system, the comparable content of the JHM was estimated also along the application of only the mineral fertilizers when there were lower (50 t ha-1) amount of manure applied for the preplant of the spring barley. The similar variation in the JHM was assessed in the plots of the perennial grasses. While, in the plots of winter wheat on the Gleyic Luvisols significant increase in the JHM was determined along only the organic fertilization system when the highest (100 t ha-1) amount of manure applied once per crop rotation. The mobile humic acids (JHR) in Gleyic Luvisols constituted about 45–55 percent from the total amount of all mobile humus substances. The tendencies in the changes of the content of JHR along the fertilisation system were comparable to the changes of the mobile humus substances. Thus, the higher extent in the content of the JHR was estimated in plots of perennial grasses, when in lower extent – in theplots of winter wheat and spring barley on Gleyic Luvisols (Table 3). The regression analysis have showed that, the accumulation of the mobile humic acids in arable layer of Gleyic Luvisols along the different fertilisation system is depended in average extent (r10.51) on soil pH value and in low (r10.31) – on soil structural aggregates. The concentration of organic carbon indicates the soil productivity, thus, humus as the “store” of soil nutrients contains about 58 percent of the organic carbon. On behalf of the obtained results, the strong correlation on the content of soil humus and on total nitrogen in soil were obtained (y = 0.093+0.414xr = 0.952, t = 6.237). Thus, the data have shown that the arable layer of the Gleyic; Luvisols is rich in nitrogen (Table 4). It was also estimated that, the fertilisation systems had no significant (p < 0.05) influence on C:N ratio in soil. However, the C:N ratio (11.1-10.6) was in higher extent while the composite organic-mineral fertilisation was performed. 10
Table 3. Long-term fertilisation impact on content mobile humus substances and humic acids in arable layer of Gleyic Luvisols. Experimental Station of LUA, 2006–2008. Fertilization system rganic-M Crop plant fCerotniltirsoalt io(nn o Organic Omineral ineral LSD05   applied) Manure t ha-1 rates NPK 50* 100* 50* N31P38K75 N79P65K90 Mobile humus substances gC kg-1 Spring barley 3.26 3.60 3.91 3.92 3.51 3.63 0.58 Perennial grass 3.65 4.00 4.27 4.24 3.94 3.80 0.54 Winter wheat 3.67 3.86 4.08 3.94 3.71 3.67 0.35 Average 3.53 3.82 4.09 4.03 3.72 3.70 0.15 Mobile humic acids gC kg-1   Spring barley 1.60 1.80 1.98 1.96 1.76 1.83 0.27 Perennial grass 1.70 2.02 2.15 2.00 1.94 1.82 0.28 Winter wheat 1.68 1.76 1.90 1.88 1.71 1.67 0.26 Average 1.66 1.86 2.01 1.95 1.80 1.77 0.15 Note: *– manure was applied once per rotation to betroot.  Table 4.Long-term fertilisation impact on carbon and nitrogen content and C:N ratio in arable layer of Gleyic Luvisols. Experimental Station of LUA, 2006–2008. Fertilization system Control Organi Crop plant fertil(insoa tion OrganMica nure t ha-1K NPs DS lL nerac-mineral Mi05 applied) rate 50* 100* 50* N31P38K75 N79P65K90 Carbon gC kg-1 Spring barley 14.19 15.32 16.69 16.13 15.79 15.5 2 1.83 Perennial grass 14.14 15.11 16.61 15.61 13.80 14.09 0.998 Winter wheat 13.63 14.28 15.32 14.89 13.47 13.41 1.124 Nitrogen gN kg-1   Spring barley 1.34 1.05 1.53 1.46 1.44 1.44 0.63 Perennial grass 1.37 1.46 1.57 1.46 1.32 1.38 0.10 Winter wheat 1.32 1.38 1.47 1.41 1.3 1.32 0.11 C: N ratio Spring barley 10.6 10.8 10.9 11.1 10.99 10.8 0.72 Perennial grass 10.3 10.3 10.6 10.7 10.4 10.2 0.13 Winter wheat 10.3 10.3 10.4 10.6 10.4 10.2 0.32 Note: *– manure was applied once per rotation to betroot.  Soil organic C pools.fertilisation impact on the changes in the C poolsThe long-term were estimated in our study. The C pools in arable layer were the highest in winter wheat plots, while, it was lower – in perennial grasses and thelowest – in sprig barley plots (Fig. 3). Even though the organic fertilisers were applied once per crop rotation, the impact on the C pools was estimated several years after the organic fertilisation. If to compare with the control plots, the significantly higher C pools were determined when the preplant was fertilised by 100 t ha-1 manure or half of manure was applied in combination with mineral fertilisers. Thus, the analogous data was estimated in the plots of perennial grasses and winter wheat. Average data on the carbon pools in arable layer significantly differed (p<0.05) in the organic, organic-mineral and mineral fertilization systems. The C pools were in higher extent in arable layer when the crop plants were fertilised by the larger amount of manure or fertilisation with manure was combined with the mineral fertilisers once per crop rotation. However, the C pools in soil were differed not significantly in plots there the fertilisation by the lowest rate of mineral fertilisers once per crop rotation was performed. 11