Energy Optimization in Different Production Technologies of Winter Triticale Grain

: This article presents the results of a ﬁeld experiment investigating the energy efﬁciency of grain produced by a semi-dwarf genotype of winter triticale at different levels of agricultural inputs. The energy efﬁciency of winter triticale grain production was evaluated in two low-input and two high-input cultivation practices that differed in the rate of nitrogen fertilizer (split application) and disease control. The energy inputs associated with the production of winter triticale grain at low levels of agricultural inputs were determined to be 14.5 to 14.7 GJ ha − 1 . Higher levels of agricultural inputs increased the demand for energy in grain production by 25% on average. The energy output of grain peaked (163.3 GJ ha − 1 ) in response to a fertilizer rate of 120 kg ha − 1 applied in a split ratio of 50:50 (BBCH 27/32) and two fungicide treatments (BBCH 31 and 39). The energy output of grain from the remaining cultivation regimes was 3–13% lower. The energy efﬁciency ratio was highest in the low-input cultivation regime with a nitrogen rate of 90 kg ha − 1 split into two applications (60 and 30 kg ha − 1 for BBCH 27 and 32, respectively), seed dressing with fungicide (thiram and tebuconazole) and one fungicide treatment (azoxystrobin) (BBCH 39).

Triticale has lower agronomic needs, in particular lower nitrogen requirements, than other cereals, and its biomass is particularly suitable for energy generation because relatively low nitrogen fertilizer rates (i) decrease protein content and increase bioethanol yields per unit area [46], and (ii) improve the energy efficiency of biomass production [56].The energy efficiency of agricultural production has to be increased to combat climate change and the energy crisis.Effective energy use is one of the key priorities of sustainable agriculture [57,58].Patterson [59] defines energy efficiency as the ratio of energy outputs to energy inputs.The demand for energy in the production process and the volume of energy accumulated in biomass are two important components of the energy balance, which determine not only energy efficiency, but also the eco-efficiency of agricultural production [60].Agricultural production systems characterized by higher energy efficiency are more environmentally friendly [61][62][63][64].Agrotechnologies with lower energy efficiency increase the consumption of non-renewable energy resources [65] and contribute to greenhouse gas emissions [66][67][68][69].
Energy efficiency is determined by the intensity of agricultural inputs [48,49,70,71].The demand for energy can be reduced by optimizing agricultural operations and deploying production technologies that are best suited to the cultivated crops and local conditions [72].Nitrogen fertilization and disease control are very important agronomic factors in the production of winter triticale grain [4,[73][74][75][76][77]. Nitrogen fertilizers have a large share of energy inputs due to the high value of energy stored in chemical bonds [49,58,62].For this reason, efficient nitrogen use not only increases agricultural profits, but also reduces local pollutant emissions and greenhouse gas emissions, and improves global food security [51,78,79].High nitrogen use efficiency is a key prerequisite for high energy efficiency in agriculture.In cereal production, nitrogen use efficiency can be improved by introducing high-yielding and nitrogen-efficient cultivars (hybrid, dwarf, semi-dwarf), adapting nitrogen fertilizer rates to the nutritional requirements of the produced crops, or applying nitrogen in split rates in different stages of plant development [48,49,80].Similarly to fertilizers, plant protection products are also highly energy-intensive inputs in agricultural production [69], but they considerably boost the yield potential of crops [74,76].Plant protection products do not induce significant changes in energy inputs [49,81], but they considerably improve energy outputs by increasing biomass yields [82][83][84].
The aim of this study was to evaluate the energy efficiency (energy inputs, energy output, energy gain and energy efficiency ratio) of grain production in a semi-dwarf genotype of winter triticale at four levels of agricultural inputs.Triticale was grown in a field experiment in a large farm in north-eastern Poland.

Materials and Methods
A field experiment was conducted in 2008-2011 in the Agricultural Experiment Station in Bałcyny in north-eastern Poland (53°35′46.4′′N, 19°51′19.5′′E, elevation 137 m).The experimental treatments were four levels of agricultural inputs in the production of a semi-dwarf genotype of winter triticale ((× Triticosecale Wittm.)cv.Alekto, which differed in the spring nitrogen rate (split application) and fungal disease control (Table 1).The experiment had a randomized block design (RBD) with three replications.Plot size was 15 m 2 (10 by 1.5 m).In each year of the study, the preceding crop was winter rapeseed (Brassica napus L.).Each year, the experiment was established on Haplic Luvisol (LV-ha) originating from boulder clay [85].Soil was disc harrowed and deep plowed after the harvest of the preceding crop.Sowing was preceded by tillage and harrowing.Fertilizers were applied before sowing at 70 kg ha −1 P2O5 (enriched superphosphate-40% P2O5) and 100 kg ha −1 K2O (potash salt-60% K2O).Each year, the seeds of semi-dwarf winter triticale cv.Alekto were dressed with thiram and tebuconazole and sown with a row seeder in late September at 400 germinating kernels per 1 m2, to a depth of 3.0 cm.During the autumn growing seasons, in stage Biologische Bundesanstalt, Bundessortenamt and Chemical Industry (BBCH) 14-15 [86], weeds were controlled with 1600 g ha −1 prosulfocarb, 50 g ha −1 diflufenican, 250 g ha −1 isoproturon and 3.75 g ha −1 chlorosulfuron.In the stage BBCH 31, ethephon (growth regulator) was applied at 480 g ha −1 .Winter triticale was harvested at physiological maturity (BBCH 89) using a small-plot harvester (7-10 August).Energy inputs were divided into categories based on the respective agricultural operations and energy fluxes (Equation ( 1)).
The energy inputs for labor, tractor and machine operation, fuel consumption and materials were determined based on energy consumption and energy indicators per unit area in crop production (Table 2).
The higher heating value (HHV) of winter triticale grain was estimated by adiabatic combustion in a calorimeter (IKA C 2000, USA) with the use of a dynamic method.The lower heating value (LHV) was calculated based on the moisture content of freshly harvested grain [87] (Equation ( 2 where: LHV-lower heating value of grain fresh matter (MJ kg −1 ), HHV-higher heating value of grain dry matter (MJ kg −1 ), MC-moisture content of freshly harvested grain (%), 0.0244-correction coefficient for water vaporization enthalpy (MJ kg −1 per 1% moisture content).
The energy output of triticale grain was calculated as the product of fresh matter yield (FMY) and LHV (Equation (3)) of grain.

Energy output (GJ ha
The energy efficiency of winter triticale grain was determined based on energy gain (Equation ( 4)) and the energy efficiency ratio (Equation ( 5)): Energy gain (GJ ha −1 ) = Energy output (GJ ha −1 ) − Energy inputs (GJ ha −1 ) ( Energy efficiency ratio = The energy inputs in the production of winter triticale were determined in a process analysis by measuring diesel oil consumption, labor and the field performance of tractors and agricultural machines during standard agronomic operations in a large farm (own measurements, Table 3).Energy inputs were divided into two categories: (i) based on energy fluxes (labor, energy carriers, machines, agricultural tools, materials-seeds, fertilizers and pesticides) and (ii) agronomic operations (tillage, sowing, mineral fertilization, weed control, growth regulation, disease control, grain harvest).

Results and Discussion
The majority of conventional farming systems rely on high-input production technologies involving energy-intensive materials (fertilizers, pesticides) [89].In crop production, energy inputs are determined mainly by crop species and the number of agronomic operations, i.e., by the intensity of the applied production technology [48,49,58,90,91].In the present study, the average energy inputs associated with the 3-year production cycle of a semi-dwarf genotype of winter triticale ranged from 14.5-14.7 GJ ha −1 (low inputs A and B) to 17.1-19.3GJ ha −1 (high inputs C and D) (Table 4).Similar energy inputs in the production of triticale grain were reported by Bielski et al. [49] (16.7-21.9GJ ha −1 ) and Raczkowski [92] (12.1-22.2GJ ha −1 ).In the work of Vigovskis et al. [93], the energy inputs associated with winter triticale production were much higher at 35 GJ ha −1 .In a study by Czarnocki et al. [94], the analyzed parameter ranged from 12.6 to 13.6 GJ ha −1 , depending on the applied tillage method.Technology D was the most energy-intensive due to the highest nitrogen fertilizer rates (90 and 60 kg ha −1 applied in stages BBCH 27 and 32, respectively) and a single fungicide treatment in stage BBCH 31.Energy consumption in the remaining production variants was lower by 11% (C), 24% (B) and 25% (A) (Table 4).
In the current study, the use of chemical control agents made only a minor contribution to total energy inputs (±6%) in the production of winter triticale grain (Table 4).According to Bielski [81] and Bielski et al. [49], fungicides account for 1.2-1.9% of total energy inputs in the production of winter triticale, subject to the intensity of the production technology.In a study by Deike et al. [84], fungicides were also responsible for a low percentage of energy inputs in the production of various crops, which could be attributed to the low fungicide dose per unit area [82].Nonetheless, the use of pesticides should be minimized in agricultural production to prevent the contamination of soil, water and food, and to protect beneficial microorganisms.However, the application of pesticides can be reduced only when the pressure from weeds, pests and pathogens is low, but in the longterm perspective, this strategy can have adverse effects by considerably decreasing crop yields [101].
The analysis of energy fluxes (Table 5) revealed that agricultural materials (seeds, fertilizers, pesticides, growth regulator) accounted for 78.0-83.3% of total energy inputs associated with the evaluated levels of agricultural inputs.The above can be attributed mainly to considerable amounts of energy accumulated in mineral fertilizers (61.2-70.4% of total energy inputs) and seeds (8.7-11.5%).Other studies of winter triticale [49] and spring triticale [92] also demonstrated that agricultural materials had the largest share of total energy inputs in crop production (74-84%).In the work of Bielski [81], fertilizers and pesticides were responsible for 66% of total energy inputs (61% and 5%, respectively) in various winter triticale production systems.Agricultural materials also accumulated significant amounts of energy (77-89% of total energy inputs) in a study analyzing energy consumption in various production technologies of winter barley [90].In other studies, agricultural materials had a somewhat smaller share of total energy inputs in the production of winter triticale (64%) [91] and spring triticale (58%) [55].The relative proportions of mineral nitrogen fertilizers and pesticides in total energy inputs were determined to be 28% and 5%, respectively, by Deike et al. [84].The relatively small share of fertilizers in the structure of energy inputs resulted from low rates of nitrogen application (98 kg ha −1 on average).In the present study, energy carriers, the operation of machines and tractors and labor accounted for 11.0-14.5%,4.5-6.0%and 1.1-1.5% of total energy inputs, respectively (Table 5).Higher levels of agricultural inputs in winter triticale cultivation led to an absolute increase in all energy fluxes without inducing significant changes in their structure (Table 5).Raczkowski [92], Bielski et al. [49] and Gozubuyuk et al. [91] estimated the percentage of energy carriers in total energy inputs to be 8.8-14.5%,17.2-21.5% and 27.9%, respectively, in winter triticale production.The cited authors also found that labor accounted for only 0.3-3.5% of total energy inputs.Similar results were reported by Szempliński [96], Dubis [97] and Gozubuyuk et al. [91] in studies investigating the main energy fluxes in the production of other cereal species (spring barley, spring wheat, winter wheat).
Research shows that intensive crop farming increases GHG emissions per unit yield, and N fertilizers and energy carriers are the main contributors [102,103].The effect of plant protection products on GHG emissions remains relatively small because the applied doses are nearly 10-fold lower than the rates of N fertilizers [102].In a study by Wójcik-Gront and Bloch-Michalik [102], GHG emissions in winter triticale production were higher (0.304 kg CO2 eq.kg −1 ) at higher levels of agricultural inputs and a mean N fertilizer rate of 124.65 kg ha −1 , and lower (0.277 kg CO2 eq.kg −1 ) at lower levels of agricultural inputs and a mean N fertilizer rate of 88.62 kg N ha −1 .Higher GHG emissions at a higher intensity of agricultural inputs and higher N fertilizer rates were also noted in wheat, rye, spring triticale, barley, oat and maize [102].Hughes et al. [104] demonstrated that GHG emissions were higher in winter barley production (0.335 kg CO2 eq.kg −1 ) than in spring barley production (0.300 kg CO2 eq.kg −1 ), mostly due to higher N fertilizer rates.Van Stappen et al. [105] reported GHG emissions of 0.349 kg CO2 eq.kg −1 in wheat grain production in Belgium, whereas Charles et al. [106] noted an increase in GHG emissions to 0.381 kg CO2 eq.kg −1 when winter wheat was fertilized with 140 kg N ha −1 in Switzerland.Other authors [107,108] found that GHG emissions can be reduced through agricultural intensification by increasing crop yield per unit area.
The energy potential of crop production technologies is determined based on energy gain and the energy efficiency ratio [49,70,71].In the current experiment, semi-dwarf winter triticale cv.Alekto had a positive energy balance regardless of the levels of agricultural inputs, i.e., the energy output in terms of grain yield exceeded the energy inputs associated with grain production (Table 6).The energy output of grain was highest (163.3GJ ha −1 ) in treatment C with a nitrogen fertilization rate of 120 kg ha −1 and two fungicide treatments.The energy output of grain produced in the remaining treatments was lower by 3% (high inputs D), 6% (low inputs B) and 13% (low inputs A).Energy gain was also highest in treatment C (high inputs) at 146.2 GJ ha −1 .In the remaining treatments (A, B and D), the energy gain of winter triticale grain was lower by 7.0 to 18.9 GJ ha −1 relative to treatment C. Energy output (141.8GJ ha −1 ) and energy gain (127.3GJ ha −1 ) were lowest in the low-input treatment A where nitrogen was applied at 90 kg ha −1 and disease control was limited to seed dressing only.Other authors also found that the energy potential of winter and spring triticale is determined mainly by agricultural intensification, mostly the nitrogen rate [48,49,55,81].In a study by Bielski et al. [49], the energy output of winter triticale grain supplied with nitrogen at 150 kg ha −1 increased by 19% and 39% relative to treatments where nitrogen was applied at 120 and 30 kg ha −1 , respectively.Agricultural intensification also enhances energy gain by increasing biomass yields [49,51,109].The net energy output of crops can be improved through the application of cultivation and protective treatments which minimize yield losses caused by pests, weeds and pathogens [110] and increase nitrogen use efficiency [84].An analysis of energy indicators (Table 6) revealed that the energy efficiency ratio was highest (9.8-10.5) in low-input treatments A and B. Higher energy inputs associated with an increase in agricultural inputs decreased the energy efficiency of the production process by 3-10% (C) and 16-22% (D).
Bielski [81] and Gozubuyuk et al. [91] reported equally high energy efficiency ratios in the production of winter triticale grain of 7.4-9.9and 10.5, respectively.In the work of Klikocka et al. [55], the energy efficiency ratio of spring triticale reached 6.8.In contrast, the energy efficiency ratios calculated by Vigovskis et al. [93] in other cereal species (spring barley, spring wheat, triticale) were significantly lower, in the range of 1.5-1.8.The energy efficiency ratio is a useful metric for determining the optimal allocation of agricultural inputs in crop production [62].In a study by Bielski et al. [49], the energy efficiency ratio of semi-dwarf winter triticale cv.Twingo peaked at 8.2 with low-input production technology.The analyzed parameter decreased by 24-27% when agricultural inputs were intensified.Lewandowski and Schmidt [51], Bielski [81], Bielski et al. [48] and Bielski et al. [49] also reported a considerable decrease in the energy efficiency ratio of winter triticale production in response to a high nitrogen rate that was not compensated by a corresponding increase in the energy output in terms of grain yield.Agricultural intensification also decreased the energy efficiency ratio in the production of winter wheat and sugar beet [109], maize and sorghum [111], sweet sorghum [71], winter rapeseed [98] and fodder galega [112].

Conclusions
Energy inputs should be reduced in modern crop production technologies to optimize energy use and minimize the adverse environmental impacts of agriculture.For this reason, the importance of energy-efficient solutions is increasingly emphasized in the farming sector.In the present study, the energy inputs in the production of semi-dwarf genotype winter triticale cv.Alekto ranged from 14.5 to 19.3 GJ ha −1 , subject to the levels of agricultural inputs.Fertilizers had the largest share of total energy inputs (61.2-70.4%),and mineral fertilization was the most energy-intensive farming operation (62.7-71.5%).Energy output and energy gain peaked in response to two fungicide treatments, seed dressing and a fertilizer rate of 120 kg ha −1 applied in a split ratio of 50:50 (BBCH 27/32).The energy efficiency ratio was highest when winter triticale was fertilized with 90 kg ha −1 (60 and 30 kg ha −1 in BBCH stages 27 and 32, respectively), seeds were dressed and a single fungicide treatment was applied (BBCH 39).Regardless of the obtained results, the energy efficiency ratio of winter triticale grain was very high (8.2-10.5)at all levels of agricultural inputs.However, in order to minimize greenhouse gas emissions from agriculture, the energy efficiency of grain production should be improved by reducing agricultural inputs.

Table 3 .
Technical parameters, performance and fuel consumption of agricultural machines in the production of winter triticale (2008-2011).

Table 4 .
Structure of energy inputs in the production of a semi-dwarf genotype of winter triticale per farming operation (2008-2011).

Table 5 .
Structure of energy inputs in the production of a semi-dwarf genotype of winter triticale by energy fluxes (2008-2011).

Table 6 .
Energy indicators in the production of a semi-dwarf genotype of winter triticale (2008-2011).