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Influence of Soil Cultivation Technologies and Fertilisation on Productivity and Energy Production of Arable Crops

Influence of Soil Cultivation Technologies and Fertilisation on Productivity and Energy... DOI: 10.2478/v10207-012-0004-9 STEFAN ZÁK 1, MILAN MACÁK 2, ROMAN HASANA 1 Plant Production Research Center Piesany 2 Slovak University of Agriculture in Nitra ZÁK, S. ­ MACÁK, M. ­ HASANA, R.: Influence of soil cultivation technologies and fertilisation on productivity and energy production of arable crops. Agriculture (Ponohospodárstvo), vol. 58, 2012, no. 1, pp. 25­33. The influence of three soil tillage technologies and two fertilisation levels on a productivity of crops and biomass for energy use, expressed in yield, cereal units (CU), energy acquired and indicative price of energy per hectare was evaluated at the experimental fields of Research Institute of Plant Production in Piesany during 2007­2009. The highest yield of dry matter has been identified for maize for silage 19.41 t/ha, followed by winter oilseed rape 15.77 t/ha, triticale 15.39 t/ha and winter wheat 14.08 t/ha. Conventional tillage created soil condition for higher yield of dry matter in an average 17.92 t/ha, followed by minimum soil tillage 16.27 t/ha and no-till-age technology 14.3 t/ha. Nitrogen-based fertilisation (N 120 ) has ensured a significantly higher yield of dry matter and a higher price of acquired energy 491.1 compared with 462.1 of zeronitrogen fertilisation. The highest yield of cereal units has been identified for maize for silage 9.01 CU, followed by winter wheat 5.21 CU, triticale 4.70 CU and winter oilseed rape 4.55 CU. Energy of maize for silage has been calculated from biogas, winter oilseed rape from rape methyl ester, straw and crop residues, and for winter wheat and triticale from ethanol and straw. Average energy storage in plant biomass of crop rotation was 222.93 GJ/ha. The highest amount of energy acquired has been identified for winter oilseed rape 342.80 GJ/ha, followed by maize for silage with 236.99 GJ/ha, winter triticale 159.39 GJ/ha and winter wheat 152.52 GJ/ha. Key words: crop rotation, productivity, arable crops, energy crops, soil cultivation, fertilisation Development of environmentally sound technologies is focused on effective use of fertilisers and suitable tillage technologies. These two factors are also important for optimising energy production from biomass on arable land. Biomass has always been a major source of energy for mankind and is presently estimated to contribute about 10­14% of the world's energy supply (McKendry 2002). Beyond its agricultural and food-processing use, biomass is also used as an excellent fuel. Biochemical and thermo chemical conversion technologies can convert CO2 neutral biomass feedstock into carbon containing biofuels such as biodiesel, dimethyl esters to hydrogen (Cannell 2003; Prasertsana & Sajjakulnukit 2006). Energy crops currently contribute a relatively small proportion to the total energy produced from biomass each year, but the proportion is set to grow over the next few decades (Sims et al. 2006). Today, the biggest amounts of fuel ethanol (bio ethanol) are produced from sugar-beet (Brazil) or maize (USA). However, it is also possible to use other amylaceous crop-plants (barley, oat, rice, wheat, rye, potato, sorghum) and agricultural residues as straw from wheat, rye, oat, barley and rice (Kim & Dale 2004). Some of the more common energy crops related to this research are listed below. For example, oil crops are as follows: oilseed rape, linseed, field mustard, hemp, sunflower, safflower, castor oil, olive, palm, coconut and groundnut. Vegetable oils can be used directly as heating fuels or refined to transport biofuels Ing. Stefan Zák, PhD., Ing. Roman Hasana, PhD., Plant Production Research Center Piesany ­ Research Institute of Plant Production Piesany, 921 68 Piesany, Bratislavská cesta 122, Slovak Republic. E-mail: zak@vurv.sk Doc. Dr. Ing. Milan Macák, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovak Republic. E-mail: milan.macak@uniag.sk such as biodiesel esters. The grain of cereals (e.g. barley, wheat, oats, maize and rye) can be used to produce ethanol and the straw can be used as a solid fuel. They can also be grown and harvested as a whole crop (grain plus straw) before the grain has ripened and used as a solid fuel or for biogas production feedstock. Solid energy crops (e.g. whole crop maize, cardoon, sorghum, kenaf, reed canary grass and short rotation coppice willow). These crops can be utilised whole to produce heat and electricity directly through combustion or indirectly through conversion for use as biofuels like methanol and ethanol (Vilcek 2003; Otepka & Haban 2006; Sims et al. 2006; Otepka et al. 2011). Cereals like rye, triticale, barley, maize and alfalfa show relatively low values of greenhouse gas emissions, and cumulated energy demand whereas hemp and Jerusalem artichoke have a considerable worse balance (Plöchl et al. 2009). Cultivation of wheat, triticale and rye for energy purposes had been earlier investigated also by Mikulíková et al. (2008). Slovak agriculture can devote a certain amount of secondary agricultural soil to a special-purpose cultivation of green biomass for energy production either in the form of green plants for biogas (maize, cereals, pulses, etc.) or for a subsequent combined energy and heat production. From a total area of 370 thousands hectares of agricultural soil, 100,000 hectares has been thought over as a feasible area under cultivation for energy plantation of phytomass and dendromass. The aim of the present research was to assess the influence of the field crops, soil cultivation and nitrogen fertilisation on productivity of crops and level of alternative energy use. medium humus content of 1.8%­2.0%, 187­234 mg/kg available P (according to Egner), 173­219 mg/kg available K (according to Schachtschabel) and 255­307 mg/kg available Mg (Mehlich II). Evaluated factors of the field experiment: · Factor A (crop-plant): a1 ­ winter triticale, a2 ­ maize for silage, a3 ­ winter wheat, a4 ­ winter oilseed rape; · Factor B (soil cultivation): b1 ­ direct sowing (no-tillage), b2 ­ minimum-tillage (disk tillage), b3 ­ conventional tillage (mouldboard ploughing); · Factor C (nitrogen fertilisation): c1 = N0 = unfertilised; c2 = N120 = 120 kg/ha of nitrogen; · Factor D (years): d1 = 2006/2007; d2 = 2007/2008; d3 = 2008/2009. There are 48 treatment combinations and 96 plots sized 19.0 m × 1.5 m = 28.5 m2 included in the experiment. The experimental design was a randomised complete block in a split-plot arrangement with two replicates of four-course crop rotation. Crops were the main plots, the soil tillage technologies were the subplots, with two levels of fertilisation (Table 1). Common management practices for crop protection, processing and harvesting were used. We evaluated the productivity of crops using two indicators. Crop of dry matter according to plant analysis; cereal units (CU) according Cvancara (1967) using coefficients as follows: for winter wheat and triticale 1.0, winter oilseed rape 2.0, maize for silage 0.15. Term cereal units is used to express the contribution that crops make to the nutrition of monogastric beings. Energy production from evaluated crops was calculated according to the amount of acquired energy: energy of maize for silage has been calculated from methane (1 m3 = 35.8 GJ), amount of methane was calculated from biogas production (from one kg of dry matter of maize biomass 680 dm3 biogas is obtained), of winter oilseed rape from biodiesel ­ rape methyl ester, 1t rape methyle ester = 33.997 GJ and straw 1t = 17.5 GJ, and for winter wheat and triticale from ethanol 1t = 25.121 GJ and straw 1t = 15.5 GJ (Opath & Horbaj 2004; Sims et al. 2006). Gain of energy was expressed in indicative price in Euro (). Indicative price of 1 GJ of energy from biomass has been balanced at the level of 2.15 (own calculation for 2009 year). The data were statistically evaluated MATERIAL AND METHODS The field experiment was carried out in 2007­2009 on Luvi-Haplic Chernozem in Plant Production Research Center Piesany ­ Research Station in Borovce. The experimental site is located in the maize-barley growing region in Western Slovakia (E 17°75', N 48°58') with an altitude of 167 m above MSL (Mean Sea Level). The location has continental climate with an average annual temperature of 9.09°C an average annual precipitation of 544.9 mm. The main soil type is a Luvi-Haplic Chernozem on carbonate loess with loamy to clay-loamy texture with a pH of 5.6­7.2 and 26 by an analysis of variance using the Statgraphics plus procedure and for comparing treatment group means Fisher's LSD (Least Significance Difference) method was used. 2006 was standard, in years 2007 and 2008 exceptionally warm and in 2009 warm. Long-term average temperature in a period 1971­2000 was 15.6°C for a vegetation period and 2.5°C for a winter period. Average annual precipitation ranged from 532.1 mm (year 2008) to 599.1 mm (year 2007). Average annual precipitation amount of a long-term average was 544.9 mm, and all the years were standard humid conditions. Precipitation during a vegetation period (April­September) ranged from 254.2 mm (year 2009) to 351.6 mm (year 2007), for all the years a precipitation during a vegetation period was standard. Precipitation during a winter period (October­March) ranged from 187.5 mm (year 2008) to 329.7 mm (year 2009), a precipitation amount of winter period was standard in years 2006, 2007 and 2008, but very humid in 2009. Because of a different yield potential of individual crops, the evaluation based on a crop of dry matter (t/ ha), cereal units, energy acquired (GJ/ha) and indicative price of energy () has been applied in order to inte- RESULTS AND DISCUSSION The weather was diverse during 2006­2009. As a long-term average annual temperature for a period of 1971­2000 was 9.1°C, the year 2006 was considered warm, but years 2007, 2008 and 2009 was considered exceptionally warm (Figure 1). The temperature during a vegetation period (April ­ September) ranged from 17.05°C (year 2007) to 18.6°C (year 2009), while in 2007 the vegetation period was warm, in years 2006 and 2008 very warm and in 2009 exceptionally warm. During a winter half year (October­March), the temperature varied between 2.9°C (year 2006) and 4.7°C (year 2008). The temperature in a winter half year mm Figure 1. Weather condition of experimental site during 2006­2009 in Borovce °C grate productivity of crops and other factors compared. Statistical evaluation is presented in Tables 2 and 3. Yield of dry matter, cereals units and energy acquired were influenced by the year, crops, tillage technology and different fertilisation (Table 2). Significant interaction between year and crop, and between year and tillage technology indicates that the year conditions significantly affected all evaluated sources of variation except fertilisation. Yield of "crop dry matter" as an indicator of crops productivity is documented in Table 3. During 2007­ 2009, a crop of dry matter reached a yield of 16.16 t/ha as an average of the experiment. Significant differences were observed between the years. While in 2008 yield of dry matter was 17.40 t/ha. In 2007 and 2009 yield of dry matter was only 15.88 t/ha or 15.21, respectively. Concerning crops, the significantly highest yield of dry matter has been identified for maize for silage 19.41 t/ha with comparison to winter oilseed rape (15.77 t/ha) and triticale (15.39 t/ha). Winter wheat has statistically the lowest yield at the average level of 14.08 t/ha. There is an alternative technology of traditional agricultural soil processing, so called minimising cultivation, which is based on reduction of some operating processes used in common. It is possible to perform this technology only in particular soil conditions (Vilcek & Kovác 2011). In our experiment, the highest yield of dry matter has been identified for use of conventional till- T a b l e 1 Fertilisation treatments of field crops during 2007­2009 Crop Winter triticale Maize for silage Winter wheat Winter oilseed rape N0 (lower level) N0 PK N0 PK N0 PK N0 PK N120 (higher level) N120 P30 K90 N120 P45 K110 N120 P30 K80 N120 P40 K150 T a b l e 2 F statistics from ANOVA for yield of dry matter, unit grain equivalent and energy acquired of crop rotation for the years 2007­2009 Yield of dry matter [t/ha] Sum of squares 241.11 1,123.46 629.88 92.93 2,959.30 245.05 25.03 708.25 1,411.62 7,847.51 F 20.37 63.27 53.21 15.70 9.69 Source of variability Year (Y) Crop (C) Tillage (T) Fertilization (F) Y×C Y×T Y×F C×T Residual Total d.f. 2 3 2 1 6 4 2 6 196 287 Cereal units Sum of squares 179.57 964.28 59.00 42.33 503.76 2.69 2.84 32.95 231.85 2,054.90 F 98.25 351.73 32.28 46.33 Energy acquired [GJ/ha] Sum of squares 190,086.4 1,696,389.1 134,666.4 23,241.5 1,180,472.8 26,201.7 113.3 131,216.0 205,764.1 3,643,232.6 F 119.56 711.33 84.70 29.23 218.00 725.00 0.07 24.23 ­ ­ 78.00 82.56 0.66 1.55 5.40 ­ ­ 2.12 18.67 ­ ­ Significant at P < 0.01 probability level age (CT) technology of soil cultivation 17.92 t/ha, followed by minimum tillage technology (MTT) 16.27 t/ha and the lowest yield of dry matter has been identified for a non-tillage technology (NTT) ­ 14.30 t/ha. Therefore, use of CT has significantly higher yield of dry matter than use of MTT and NTT, while use of MTT has significantly higher yield of dry matter than use of NTT. Concerning evaluated crops and soil cultivation technology (Table 4), the higher yield of dry matter of winter oilseed rape was under CT ­ 18.31 t/ha with comparisons to 13.85 t/ha and 15.14 t/ha in NTT and MTT. Similarly, maize for silage under CT reached 22.86 t/ha with comparison to 14.13 t/ha in NTT. Evaluated cereals have smaller differences between technology than maize and winter oilseed rape. These results are supported also by research of Hnát (2009) on eastern Slovakia with the evaluation of the same tillage treatments on yield of maize. CT supports the significantly higher yield of grain followed by the MTT and the lowest yield for NTT system was determined. Similarly Candráková et al. (2008) found out the highest maize yield in CT and shallow tillage (up to 150 mm) compared with disking. In winter wheat, they have not found significant differences between tillage treatments. Kotorová et al. (2010) also found that the tillage systems decreased the yield of grain maize in order CT>MTT>NTT. T a b l e 3 Average value of indicators of evaluated crops under different soil cultivation technology and fertilization level during 2007­2009 Indicator Total average of the experiment 2007 2008 2009 LSD0.01 Winter oilseed rape Winter triticale Maize for silage Winter wheat LSD0.01 No-tillage technology (NTT) Minimum-tillage technology (MTT) Conventional technology (CT) LSD0.01 Lower level (N0) Higher level (N120) LSD0.01 Dry matter [t/ha] 16.16 Year 15.88b 17.40c 15.20 0.66 Crops 15.77b 15.39 14.08 1.05 14.30a 16.27b 17.92 c b a Cereal units 5.87 5.27a 6.98b 5.35 Energy acquired [GJ/ha] 222.93 243.98b 338.04c 186.76 Indicative price of energy per ha [] 479.30 524.50b 509.90b 395.90a 18.75 737.00c 342.70a 509.50b 327.90a 21.95 422.50a 478.90b 536.40c 19.01 462.10a 491.10b 15.52 0.27 4.55a 4.70 5.21 8.06 342.80c 159.39 152.52 12.22 196.53a 222.75b 249.50 10.58 214.94a 228.40 b c a 19.41c 9.01c 236.99b 0.41 5.33a 5.84b 6.43 Fertilisation Soil cultivation technology 0.91 15.59a 16.73 0.35 5.48a 6.25 The means followed by the same letter are not significantly different at P0.01 < probability level 29 Nitrogen-based fertilisation (N120) has guaranteed a significantly higher yield of dry matter with comparison to N0. Evaluated crops response differently to the conditions of years or soil cultivation technologies as indicates highly significant interactions: crop × year and crop × soil cultivation technology (Table 2). Comparison of crop productivity (Table 3) has been performed by means of cereal units. The average of the experiment was 5.87 CU in a period 2007­2009. A highly significant difference has been identified between the most favourable year 2008 (9.01 CU) and 2007 (4.70 CU) or 2009 (CU 5.21 CU). The highest yield of cereal units has been identified for maize for silage 9.01 CU, followed by winter wheat ­ 5.21 CU, triticale ­ 4.70 CU, winter oilseed rape ­ 4.55 CU. Maize for silage has been proved to be significantly more productive than winter wheat, triticale and winter oilseed rape, while the yield of cereal units of winter oilseed rape and triticale has been significantly lower than winter wheat. The significantly highest yield of cereal units has been identified for a use of CT of soil cultivation 6.43 CU, followed by MTT ­ 5.84 CU and the lowest yield of cereal units was under NTT ­ 5.33 CU. In all evaluated crops (Table 4) the highest yield expressed in CU was under CT. For maize for silage MTT (disk cultivation) is comparable with conventional mouldboard ploughing. Nitrogen-based fertilisation (N120) has guaranteed a highly significant increase in yield of cereal units (6.25 CU) with comparison to zero nitrogen (5.48 CU). From an environmental point of view we have to take into consideration also energy inputs (Pospisil & Rzonca 2010) and environmental load from nitrogen fertilisation (Fazekasová et al. 2011). Uzík and Zofajová (2009) also found that effect of N on grain yield of different cultivars of winter wheat was significant, but little effective on the fertile soil environment. The highest average grain yield (8.76 t/ha) was higher only by 4.6% in the treatment N120 compared with zero treatment N0 in the favourable year 2005. In the less favourable year 2006, increase of grain yield at N120 rate compared with N0 was higher (116.3%). Interactions year × crop and crop × technology of soil cultivation has highly significant effect on the variability of cereal units production. T a b l e 4 Indicators value for evaluated crops under different cultivation technologies 2007­2009 in Borovce Interactions Crops × soil cultivation technology Oilseed rape ­ no-tillage technology Oilseed rape ­ minimum-tillage tech. Oilseed rape ­ conventional tillage Triticale ­ no-tillage technology Triticale ­ minimum-tillage technology Triticale ­ conventional tillage Maize ­ no-tillage technology Maize ­ minimum-tillage technology Maize ­ conventional tillage Wheat ­ no-tillage technology Wheat ­ minimum-tillage technology Wheat ­ conventional tillage Dry matter [t/ha] Cereal units Energy acquired [GJ/ha] Indicative price of energy per ha [] 646.9 715.9 848.2 336.8 324.6 366.7 373.0 551.9 603.7 333.4 323.3 327.0 Indicative price of 1 GJ of energy from biomass 2.15 (own calculation according 2009 year level) . Growing crops for energy production have been compared on the basis of energy acquired (in GJ/ha). During 2007­2009, average energy of the experiment at the level of 222.93 GJ/ha was acquired. In the most favourable year condition (in 2008), the significant energy acquired in plant biomass has been noted (Table 3). The highest amount of energy acquired (in GJ/ha) has been identified for winter oilseed rape ­ 342.80 GJ/ha, followed by maize for silage with 236.99 GJ/ ha. Triticale with 159.39 GJ/ha and winter wheat with 152.52 GJ/ha acquired significantly less amount of energy with comparison to winter oilseed rape and maize for silage. Composition of energy has been as follow: winter triticale ­ 35% composed of ethanol and 65% of straw, maize for silage 100% of biogas, winter wheat ­ 40% of ethanol and 60% of straw, winter oilseed rape ­ 10% of biodiesel and 90% of straw and crop residues. Values of the indicators are found in Table 5. These results are higher than energy value of the crop obtained by energy balance evaluation due to full accounting of storage energy of biomass. Pospisil and Rzonca (2010) stated the energy value of winter wheat yields in interval 96.4­107.6 GJ/ha and for maize in interval 149.4­ 177.6 GJ/ha by using coefficient of 17.64 GJ/mg of dry matter of main product. Shäfer (2005) mentioned that the process energy for crop production may be attributed to seed, straw and roots. The highest amount of energy acquired (in GJ/ha) has been identified for use of conventional technology of soil cultivation (CT) ­ 252.59 GJ/ha, followed by MTT ­ 222.28 GJ/ha and the lowest amount of energy acquired has been identified for NTT ­ 196.53 GJ/ha. Use of CT has therefore guaranteed a highly significant increment in the amount of energy acquired (in GJ/ha) compared with use of MTT or NTT. Use of MTT has guaranteed a highly significant increment in the amount of energy acquired compared with use of NTT. Nitrogen-based fertilisation (N120) has supported a highly significant increase in the amount of energy acquired (in GJ/ha), but net gain of energy was only 13.46 GJ/ha. Only interactions: year × crop, and crop × tillage technology have been highly significant. As an economic indicator, indicative price of acquired energy in plant biomass was calculated. During 2007­2009, indicative price of storage energy of whole crop rotation was balanced at 479.3. The highest indicative price of energy has been identified for winter oilseed rape (737.0) followed by maize for silage (509.5), winter triticale (342.7) and winter wheat (327.9). The highest indicative price of energy acquired was reached at CT ­ 536.4 followed by MTT T a b l e 5 The energy composition, calculated from different sources of energy crops [GJ/ha] growing in crop rotation pattern during 2007­2009 in Borovce Energy of crop rotation Total 342.8 300.9 333.0 394.5 337.7 347.9 Total 891.7 786.1 891.0 998.0 855.8 927.6 Winter triticale Experiment Ethanol Average NTT MTT CTT N0 N120 56.0 51.3 52.8 63.9 51.9 60.0 Straw 103.4 105.3 98.2 106.8 96.8 110.1 Total 159.4 156.6 151.0 170.6 148.7 170.1 Maize for silage Winter wheat Winter oilseed rape Bio diesel 30.8 31.1 28.1 33.2 29.3 32.3 Straw and crop residues 312.3 270.2 305.3 361.3 308.6 315.9 Ethanol 62.6 57.8 63.2 66.7 55.6 69.5 Straw 90.0 97.3 87.2 85.4 89.6 90.3 Total 152.5 155.1 150.4 152.1 145.3 159.8 Where: average ­ average of the experiment, NTT ­ no-tillage technology, MTT ­ minimum tillage technology, CTT ­conventional tillage technology, N 0 ­ lower fertilization level, N 120 ­ higher fertilization level ­ 478.9 and for NTT only 422.5. Nitrogen-based fertilisation (N120) has guaranteed a highly significant increase in indicative price of energy acquired (498.6) compared with 460.0 of zero-nitrogen fertilisation. All forms of bioenergy when substituted for fossil fuels will directly reduce CO2 emissions. Therefore, a combination of energy crop production with carbon sink and offset credits can result in maximum benefits from carbon mitigation strategies. This can be achieved by planting energy crops into previously arable or pasture land, which will lead to an increase in the average carbon stock on that land, while also yielding a source of biomass. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Agriculture de Gruyter

Influence of Soil Cultivation Technologies and Fertilisation on Productivity and Energy Production of Arable Crops

Agriculture , Volume 58 (1) – Apr 1, 2012

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Abstract

DOI: 10.2478/v10207-012-0004-9 STEFAN ZÁK 1, MILAN MACÁK 2, ROMAN HASANA 1 Plant Production Research Center Piesany 2 Slovak University of Agriculture in Nitra ZÁK, S. ­ MACÁK, M. ­ HASANA, R.: Influence of soil cultivation technologies and fertilisation on productivity and energy production of arable crops. Agriculture (Ponohospodárstvo), vol. 58, 2012, no. 1, pp. 25­33. The influence of three soil tillage technologies and two fertilisation levels on a productivity of crops and biomass for energy use, expressed in yield, cereal units (CU), energy acquired and indicative price of energy per hectare was evaluated at the experimental fields of Research Institute of Plant Production in Piesany during 2007­2009. The highest yield of dry matter has been identified for maize for silage 19.41 t/ha, followed by winter oilseed rape 15.77 t/ha, triticale 15.39 t/ha and winter wheat 14.08 t/ha. Conventional tillage created soil condition for higher yield of dry matter in an average 17.92 t/ha, followed by minimum soil tillage 16.27 t/ha and no-till-age technology 14.3 t/ha. Nitrogen-based fertilisation (N 120 ) has ensured a significantly higher yield of dry matter and a higher price of acquired energy 491.1 compared with 462.1 of zeronitrogen fertilisation. The highest yield of cereal units has been identified for maize for silage 9.01 CU, followed by winter wheat 5.21 CU, triticale 4.70 CU and winter oilseed rape 4.55 CU. Energy of maize for silage has been calculated from biogas, winter oilseed rape from rape methyl ester, straw and crop residues, and for winter wheat and triticale from ethanol and straw. Average energy storage in plant biomass of crop rotation was 222.93 GJ/ha. The highest amount of energy acquired has been identified for winter oilseed rape 342.80 GJ/ha, followed by maize for silage with 236.99 GJ/ha, winter triticale 159.39 GJ/ha and winter wheat 152.52 GJ/ha. Key words: crop rotation, productivity, arable crops, energy crops, soil cultivation, fertilisation Development of environmentally sound technologies is focused on effective use of fertilisers and suitable tillage technologies. These two factors are also important for optimising energy production from biomass on arable land. Biomass has always been a major source of energy for mankind and is presently estimated to contribute about 10­14% of the world's energy supply (McKendry 2002). Beyond its agricultural and food-processing use, biomass is also used as an excellent fuel. Biochemical and thermo chemical conversion technologies can convert CO2 neutral biomass feedstock into carbon containing biofuels such as biodiesel, dimethyl esters to hydrogen (Cannell 2003; Prasertsana & Sajjakulnukit 2006). Energy crops currently contribute a relatively small proportion to the total energy produced from biomass each year, but the proportion is set to grow over the next few decades (Sims et al. 2006). Today, the biggest amounts of fuel ethanol (bio ethanol) are produced from sugar-beet (Brazil) or maize (USA). However, it is also possible to use other amylaceous crop-plants (barley, oat, rice, wheat, rye, potato, sorghum) and agricultural residues as straw from wheat, rye, oat, barley and rice (Kim & Dale 2004). Some of the more common energy crops related to this research are listed below. For example, oil crops are as follows: oilseed rape, linseed, field mustard, hemp, sunflower, safflower, castor oil, olive, palm, coconut and groundnut. Vegetable oils can be used directly as heating fuels or refined to transport biofuels Ing. Stefan Zák, PhD., Ing. Roman Hasana, PhD., Plant Production Research Center Piesany ­ Research Institute of Plant Production Piesany, 921 68 Piesany, Bratislavská cesta 122, Slovak Republic. E-mail: zak@vurv.sk Doc. Dr. Ing. Milan Macák, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovak Republic. E-mail: milan.macak@uniag.sk such as biodiesel esters. The grain of cereals (e.g. barley, wheat, oats, maize and rye) can be used to produce ethanol and the straw can be used as a solid fuel. They can also be grown and harvested as a whole crop (grain plus straw) before the grain has ripened and used as a solid fuel or for biogas production feedstock. Solid energy crops (e.g. whole crop maize, cardoon, sorghum, kenaf, reed canary grass and short rotation coppice willow). These crops can be utilised whole to produce heat and electricity directly through combustion or indirectly through conversion for use as biofuels like methanol and ethanol (Vilcek 2003; Otepka & Haban 2006; Sims et al. 2006; Otepka et al. 2011). Cereals like rye, triticale, barley, maize and alfalfa show relatively low values of greenhouse gas emissions, and cumulated energy demand whereas hemp and Jerusalem artichoke have a considerable worse balance (Plöchl et al. 2009). Cultivation of wheat, triticale and rye for energy purposes had been earlier investigated also by Mikulíková et al. (2008). Slovak agriculture can devote a certain amount of secondary agricultural soil to a special-purpose cultivation of green biomass for energy production either in the form of green plants for biogas (maize, cereals, pulses, etc.) or for a subsequent combined energy and heat production. From a total area of 370 thousands hectares of agricultural soil, 100,000 hectares has been thought over as a feasible area under cultivation for energy plantation of phytomass and dendromass. The aim of the present research was to assess the influence of the field crops, soil cultivation and nitrogen fertilisation on productivity of crops and level of alternative energy use. medium humus content of 1.8%­2.0%, 187­234 mg/kg available P (according to Egner), 173­219 mg/kg available K (according to Schachtschabel) and 255­307 mg/kg available Mg (Mehlich II). Evaluated factors of the field experiment: · Factor A (crop-plant): a1 ­ winter triticale, a2 ­ maize for silage, a3 ­ winter wheat, a4 ­ winter oilseed rape; · Factor B (soil cultivation): b1 ­ direct sowing (no-tillage), b2 ­ minimum-tillage (disk tillage), b3 ­ conventional tillage (mouldboard ploughing); · Factor C (nitrogen fertilisation): c1 = N0 = unfertilised; c2 = N120 = 120 kg/ha of nitrogen; · Factor D (years): d1 = 2006/2007; d2 = 2007/2008; d3 = 2008/2009. There are 48 treatment combinations and 96 plots sized 19.0 m × 1.5 m = 28.5 m2 included in the experiment. The experimental design was a randomised complete block in a split-plot arrangement with two replicates of four-course crop rotation. Crops were the main plots, the soil tillage technologies were the subplots, with two levels of fertilisation (Table 1). Common management practices for crop protection, processing and harvesting were used. We evaluated the productivity of crops using two indicators. Crop of dry matter according to plant analysis; cereal units (CU) according Cvancara (1967) using coefficients as follows: for winter wheat and triticale 1.0, winter oilseed rape 2.0, maize for silage 0.15. Term cereal units is used to express the contribution that crops make to the nutrition of monogastric beings. Energy production from evaluated crops was calculated according to the amount of acquired energy: energy of maize for silage has been calculated from methane (1 m3 = 35.8 GJ), amount of methane was calculated from biogas production (from one kg of dry matter of maize biomass 680 dm3 biogas is obtained), of winter oilseed rape from biodiesel ­ rape methyl ester, 1t rape methyle ester = 33.997 GJ and straw 1t = 17.5 GJ, and for winter wheat and triticale from ethanol 1t = 25.121 GJ and straw 1t = 15.5 GJ (Opath & Horbaj 2004; Sims et al. 2006). Gain of energy was expressed in indicative price in Euro (). Indicative price of 1 GJ of energy from biomass has been balanced at the level of 2.15 (own calculation for 2009 year). The data were statistically evaluated MATERIAL AND METHODS The field experiment was carried out in 2007­2009 on Luvi-Haplic Chernozem in Plant Production Research Center Piesany ­ Research Station in Borovce. The experimental site is located in the maize-barley growing region in Western Slovakia (E 17°75', N 48°58') with an altitude of 167 m above MSL (Mean Sea Level). The location has continental climate with an average annual temperature of 9.09°C an average annual precipitation of 544.9 mm. The main soil type is a Luvi-Haplic Chernozem on carbonate loess with loamy to clay-loamy texture with a pH of 5.6­7.2 and 26 by an analysis of variance using the Statgraphics plus procedure and for comparing treatment group means Fisher's LSD (Least Significance Difference) method was used. 2006 was standard, in years 2007 and 2008 exceptionally warm and in 2009 warm. Long-term average temperature in a period 1971­2000 was 15.6°C for a vegetation period and 2.5°C for a winter period. Average annual precipitation ranged from 532.1 mm (year 2008) to 599.1 mm (year 2007). Average annual precipitation amount of a long-term average was 544.9 mm, and all the years were standard humid conditions. Precipitation during a vegetation period (April­September) ranged from 254.2 mm (year 2009) to 351.6 mm (year 2007), for all the years a precipitation during a vegetation period was standard. Precipitation during a winter period (October­March) ranged from 187.5 mm (year 2008) to 329.7 mm (year 2009), a precipitation amount of winter period was standard in years 2006, 2007 and 2008, but very humid in 2009. Because of a different yield potential of individual crops, the evaluation based on a crop of dry matter (t/ ha), cereal units, energy acquired (GJ/ha) and indicative price of energy () has been applied in order to inte- RESULTS AND DISCUSSION The weather was diverse during 2006­2009. As a long-term average annual temperature for a period of 1971­2000 was 9.1°C, the year 2006 was considered warm, but years 2007, 2008 and 2009 was considered exceptionally warm (Figure 1). The temperature during a vegetation period (April ­ September) ranged from 17.05°C (year 2007) to 18.6°C (year 2009), while in 2007 the vegetation period was warm, in years 2006 and 2008 very warm and in 2009 exceptionally warm. During a winter half year (October­March), the temperature varied between 2.9°C (year 2006) and 4.7°C (year 2008). The temperature in a winter half year mm Figure 1. Weather condition of experimental site during 2006­2009 in Borovce °C grate productivity of crops and other factors compared. Statistical evaluation is presented in Tables 2 and 3. Yield of dry matter, cereals units and energy acquired were influenced by the year, crops, tillage technology and different fertilisation (Table 2). Significant interaction between year and crop, and between year and tillage technology indicates that the year conditions significantly affected all evaluated sources of variation except fertilisation. Yield of "crop dry matter" as an indicator of crops productivity is documented in Table 3. During 2007­ 2009, a crop of dry matter reached a yield of 16.16 t/ha as an average of the experiment. Significant differences were observed between the years. While in 2008 yield of dry matter was 17.40 t/ha. In 2007 and 2009 yield of dry matter was only 15.88 t/ha or 15.21, respectively. Concerning crops, the significantly highest yield of dry matter has been identified for maize for silage 19.41 t/ha with comparison to winter oilseed rape (15.77 t/ha) and triticale (15.39 t/ha). Winter wheat has statistically the lowest yield at the average level of 14.08 t/ha. There is an alternative technology of traditional agricultural soil processing, so called minimising cultivation, which is based on reduction of some operating processes used in common. It is possible to perform this technology only in particular soil conditions (Vilcek & Kovác 2011). In our experiment, the highest yield of dry matter has been identified for use of conventional till- T a b l e 1 Fertilisation treatments of field crops during 2007­2009 Crop Winter triticale Maize for silage Winter wheat Winter oilseed rape N0 (lower level) N0 PK N0 PK N0 PK N0 PK N120 (higher level) N120 P30 K90 N120 P45 K110 N120 P30 K80 N120 P40 K150 T a b l e 2 F statistics from ANOVA for yield of dry matter, unit grain equivalent and energy acquired of crop rotation for the years 2007­2009 Yield of dry matter [t/ha] Sum of squares 241.11 1,123.46 629.88 92.93 2,959.30 245.05 25.03 708.25 1,411.62 7,847.51 F 20.37 63.27 53.21 15.70 9.69 Source of variability Year (Y) Crop (C) Tillage (T) Fertilization (F) Y×C Y×T Y×F C×T Residual Total d.f. 2 3 2 1 6 4 2 6 196 287 Cereal units Sum of squares 179.57 964.28 59.00 42.33 503.76 2.69 2.84 32.95 231.85 2,054.90 F 98.25 351.73 32.28 46.33 Energy acquired [GJ/ha] Sum of squares 190,086.4 1,696,389.1 134,666.4 23,241.5 1,180,472.8 26,201.7 113.3 131,216.0 205,764.1 3,643,232.6 F 119.56 711.33 84.70 29.23 218.00 725.00 0.07 24.23 ­ ­ 78.00 82.56 0.66 1.55 5.40 ­ ­ 2.12 18.67 ­ ­ Significant at P < 0.01 probability level age (CT) technology of soil cultivation 17.92 t/ha, followed by minimum tillage technology (MTT) 16.27 t/ha and the lowest yield of dry matter has been identified for a non-tillage technology (NTT) ­ 14.30 t/ha. Therefore, use of CT has significantly higher yield of dry matter than use of MTT and NTT, while use of MTT has significantly higher yield of dry matter than use of NTT. Concerning evaluated crops and soil cultivation technology (Table 4), the higher yield of dry matter of winter oilseed rape was under CT ­ 18.31 t/ha with comparisons to 13.85 t/ha and 15.14 t/ha in NTT and MTT. Similarly, maize for silage under CT reached 22.86 t/ha with comparison to 14.13 t/ha in NTT. Evaluated cereals have smaller differences between technology than maize and winter oilseed rape. These results are supported also by research of Hnát (2009) on eastern Slovakia with the evaluation of the same tillage treatments on yield of maize. CT supports the significantly higher yield of grain followed by the MTT and the lowest yield for NTT system was determined. Similarly Candráková et al. (2008) found out the highest maize yield in CT and shallow tillage (up to 150 mm) compared with disking. In winter wheat, they have not found significant differences between tillage treatments. Kotorová et al. (2010) also found that the tillage systems decreased the yield of grain maize in order CT>MTT>NTT. T a b l e 3 Average value of indicators of evaluated crops under different soil cultivation technology and fertilization level during 2007­2009 Indicator Total average of the experiment 2007 2008 2009 LSD0.01 Winter oilseed rape Winter triticale Maize for silage Winter wheat LSD0.01 No-tillage technology (NTT) Minimum-tillage technology (MTT) Conventional technology (CT) LSD0.01 Lower level (N0) Higher level (N120) LSD0.01 Dry matter [t/ha] 16.16 Year 15.88b 17.40c 15.20 0.66 Crops 15.77b 15.39 14.08 1.05 14.30a 16.27b 17.92 c b a Cereal units 5.87 5.27a 6.98b 5.35 Energy acquired [GJ/ha] 222.93 243.98b 338.04c 186.76 Indicative price of energy per ha [] 479.30 524.50b 509.90b 395.90a 18.75 737.00c 342.70a 509.50b 327.90a 21.95 422.50a 478.90b 536.40c 19.01 462.10a 491.10b 15.52 0.27 4.55a 4.70 5.21 8.06 342.80c 159.39 152.52 12.22 196.53a 222.75b 249.50 10.58 214.94a 228.40 b c a 19.41c 9.01c 236.99b 0.41 5.33a 5.84b 6.43 Fertilisation Soil cultivation technology 0.91 15.59a 16.73 0.35 5.48a 6.25 The means followed by the same letter are not significantly different at P0.01 < probability level 29 Nitrogen-based fertilisation (N120) has guaranteed a significantly higher yield of dry matter with comparison to N0. Evaluated crops response differently to the conditions of years or soil cultivation technologies as indicates highly significant interactions: crop × year and crop × soil cultivation technology (Table 2). Comparison of crop productivity (Table 3) has been performed by means of cereal units. The average of the experiment was 5.87 CU in a period 2007­2009. A highly significant difference has been identified between the most favourable year 2008 (9.01 CU) and 2007 (4.70 CU) or 2009 (CU 5.21 CU). The highest yield of cereal units has been identified for maize for silage 9.01 CU, followed by winter wheat ­ 5.21 CU, triticale ­ 4.70 CU, winter oilseed rape ­ 4.55 CU. Maize for silage has been proved to be significantly more productive than winter wheat, triticale and winter oilseed rape, while the yield of cereal units of winter oilseed rape and triticale has been significantly lower than winter wheat. The significantly highest yield of cereal units has been identified for a use of CT of soil cultivation 6.43 CU, followed by MTT ­ 5.84 CU and the lowest yield of cereal units was under NTT ­ 5.33 CU. In all evaluated crops (Table 4) the highest yield expressed in CU was under CT. For maize for silage MTT (disk cultivation) is comparable with conventional mouldboard ploughing. Nitrogen-based fertilisation (N120) has guaranteed a highly significant increase in yield of cereal units (6.25 CU) with comparison to zero nitrogen (5.48 CU). From an environmental point of view we have to take into consideration also energy inputs (Pospisil & Rzonca 2010) and environmental load from nitrogen fertilisation (Fazekasová et al. 2011). Uzík and Zofajová (2009) also found that effect of N on grain yield of different cultivars of winter wheat was significant, but little effective on the fertile soil environment. The highest average grain yield (8.76 t/ha) was higher only by 4.6% in the treatment N120 compared with zero treatment N0 in the favourable year 2005. In the less favourable year 2006, increase of grain yield at N120 rate compared with N0 was higher (116.3%). Interactions year × crop and crop × technology of soil cultivation has highly significant effect on the variability of cereal units production. T a b l e 4 Indicators value for evaluated crops under different cultivation technologies 2007­2009 in Borovce Interactions Crops × soil cultivation technology Oilseed rape ­ no-tillage technology Oilseed rape ­ minimum-tillage tech. Oilseed rape ­ conventional tillage Triticale ­ no-tillage technology Triticale ­ minimum-tillage technology Triticale ­ conventional tillage Maize ­ no-tillage technology Maize ­ minimum-tillage technology Maize ­ conventional tillage Wheat ­ no-tillage technology Wheat ­ minimum-tillage technology Wheat ­ conventional tillage Dry matter [t/ha] Cereal units Energy acquired [GJ/ha] Indicative price of energy per ha [] 646.9 715.9 848.2 336.8 324.6 366.7 373.0 551.9 603.7 333.4 323.3 327.0 Indicative price of 1 GJ of energy from biomass 2.15 (own calculation according 2009 year level) . Growing crops for energy production have been compared on the basis of energy acquired (in GJ/ha). During 2007­2009, average energy of the experiment at the level of 222.93 GJ/ha was acquired. In the most favourable year condition (in 2008), the significant energy acquired in plant biomass has been noted (Table 3). The highest amount of energy acquired (in GJ/ha) has been identified for winter oilseed rape ­ 342.80 GJ/ha, followed by maize for silage with 236.99 GJ/ ha. Triticale with 159.39 GJ/ha and winter wheat with 152.52 GJ/ha acquired significantly less amount of energy with comparison to winter oilseed rape and maize for silage. Composition of energy has been as follow: winter triticale ­ 35% composed of ethanol and 65% of straw, maize for silage 100% of biogas, winter wheat ­ 40% of ethanol and 60% of straw, winter oilseed rape ­ 10% of biodiesel and 90% of straw and crop residues. Values of the indicators are found in Table 5. These results are higher than energy value of the crop obtained by energy balance evaluation due to full accounting of storage energy of biomass. Pospisil and Rzonca (2010) stated the energy value of winter wheat yields in interval 96.4­107.6 GJ/ha and for maize in interval 149.4­ 177.6 GJ/ha by using coefficient of 17.64 GJ/mg of dry matter of main product. Shäfer (2005) mentioned that the process energy for crop production may be attributed to seed, straw and roots. The highest amount of energy acquired (in GJ/ha) has been identified for use of conventional technology of soil cultivation (CT) ­ 252.59 GJ/ha, followed by MTT ­ 222.28 GJ/ha and the lowest amount of energy acquired has been identified for NTT ­ 196.53 GJ/ha. Use of CT has therefore guaranteed a highly significant increment in the amount of energy acquired (in GJ/ha) compared with use of MTT or NTT. Use of MTT has guaranteed a highly significant increment in the amount of energy acquired compared with use of NTT. Nitrogen-based fertilisation (N120) has supported a highly significant increase in the amount of energy acquired (in GJ/ha), but net gain of energy was only 13.46 GJ/ha. Only interactions: year × crop, and crop × tillage technology have been highly significant. As an economic indicator, indicative price of acquired energy in plant biomass was calculated. During 2007­2009, indicative price of storage energy of whole crop rotation was balanced at 479.3. The highest indicative price of energy has been identified for winter oilseed rape (737.0) followed by maize for silage (509.5), winter triticale (342.7) and winter wheat (327.9). The highest indicative price of energy acquired was reached at CT ­ 536.4 followed by MTT T a b l e 5 The energy composition, calculated from different sources of energy crops [GJ/ha] growing in crop rotation pattern during 2007­2009 in Borovce Energy of crop rotation Total 342.8 300.9 333.0 394.5 337.7 347.9 Total 891.7 786.1 891.0 998.0 855.8 927.6 Winter triticale Experiment Ethanol Average NTT MTT CTT N0 N120 56.0 51.3 52.8 63.9 51.9 60.0 Straw 103.4 105.3 98.2 106.8 96.8 110.1 Total 159.4 156.6 151.0 170.6 148.7 170.1 Maize for silage Winter wheat Winter oilseed rape Bio diesel 30.8 31.1 28.1 33.2 29.3 32.3 Straw and crop residues 312.3 270.2 305.3 361.3 308.6 315.9 Ethanol 62.6 57.8 63.2 66.7 55.6 69.5 Straw 90.0 97.3 87.2 85.4 89.6 90.3 Total 152.5 155.1 150.4 152.1 145.3 159.8 Where: average ­ average of the experiment, NTT ­ no-tillage technology, MTT ­ minimum tillage technology, CTT ­conventional tillage technology, N 0 ­ lower fertilization level, N 120 ­ higher fertilization level ­ 478.9 and for NTT only 422.5. Nitrogen-based fertilisation (N120) has guaranteed a highly significant increase in indicative price of energy acquired (498.6) compared with 460.0 of zero-nitrogen fertilisation. All forms of bioenergy when substituted for fossil fuels will directly reduce CO2 emissions. Therefore, a combination of energy crop production with carbon sink and offset credits can result in maximum benefits from carbon mitigation strategies. This can be achieved by planting energy crops into previously arable or pasture land, which will lead to an increase in the average carbon stock on that land, while also yielding a source of biomass.

Journal

Agriculturede Gruyter

Published: Apr 1, 2012

References