Higher Energy-use Efficiency Research Articles

Optimisation of supplemental light systems in Norwegian tomato greenhouses - A simulation study

Tomato greenhouses at high latitudes (≥58°North) require supplemental light to enable high yields and year-round production. Supplemental light systems can differ in lamp type, high-pressure sodium (HPS) or light emitting diode (LED), and also vary in lamp capacity. Based on a combined greenhouse climate, tomato yield, and greenhouse economics model, a methodology was developed, for determining the optimal supplemental light system, dependent on local climate and economic conditions. Two optimisation objectives were considered separately, maximal energy use efficiency (EUE) and maximal net financial result (NFR). The developed methodology was applied to four different greenhouse locations in Norway. At each location, both optimisation objectives were reached with LEDs. The optimal lamp capacities range from 256 to 341 μmol m −2 s −1 (maximal EUE) and 302–323 μmol m −2 s −1 (maximal NFR). The economically optimal lamp capacity is little sensitive to climate conditions. At the lamp type respective NFR maxima, LEDs resulted, on average, in 10% higher tomato yield, 102.2 NOK m −2 year −1 higher NFR, and 35% higher EUE. Consequently, switching from HPS lamps to LEDs enables increasing productivity, energy efficiency and profitability of greenhouse tomato production. Furthermore, the difference between EUE and NFR optima was, on average, 24% lower in terms of EUE and 56% lower in terms of NFR, when using LEDs instead of HPS lamps. On farm-scale, the proposed methodology can be used as decision-support-tool for selecting an efficient and profitable supplemental light system for greenhouse tomato production, dependent on local climate and economic conditions. • A model-based methodology for optimising greenhouse lamp type and capacity is presented. • The methodology was applied to four greenhouse locations in Norway. • LEDs with capacities between 256 and 341 μmol m −2 s −1 reached maximal energy use efficiency. • LEDs with capacities between 302 and 323 μmol m −2 s −1 reached maximal net financial results. • Economically optimal lamp capacity is little sensitive to climate conditions.

Improvement of Water Productivity, Economics and Energetics of Potato through Straw Mulching and Irrigation Scheduling in Indian Punjab

A field experiment was conducted to assess the effect of straw mulching and irrigation scheduling on water balance, economics and energetics of potato during 2013–2014 and 2014–2015. The experiment was laid out in a split plot design with mulch levels (no mulch and mulch 6.25 t ha−1) in the main plots and four irrigation schedules {ridge planting furrow irrigation (RPFI), bed planting furrow irrigation (BPFI), ridge planting drip irrigation (RPDI) and bed planting drip irrigation (BPDI)} in the subplots. Straw mulching resulted in 19.0% higher potato tuber yield than no mulch as a result of 36.2 mm higher transpiration and 44.2 mm lower soil evaporation. Energy productivity (EP) and energy use efficiency (EUE) were also significantly higher with straw mulch than no mulch with US$498 ha−1 higher net returns in pooled data of both years. Drip irrigation of beds and ridges resulted in 34.9% and 26.4% higher tuber yields, respectively, than furrow irrigation along with savings of 23.3 and 53.3 mm irrigation water, respectively. Seasonal transpiration was 31.0 and 31.7% higher in ridge- and bed-planted drip-irrigated crops, respectively, than furrow-irrigated crops in pooled data. Apparent and real water productivities were significantly higher in drip irrigated crops compared to furrow irrigated crops. RPDI and BPDI crops gave US$612 and US$876 ha−1 higher net returns with 35.7 and 28.8% higher EUE than RPFI and BPFI, respectively.

Energy auditing of long-term conservation agriculture based irrigated intensive maize systems in semi-arid tropics of India

Abstract In a 7-year study, we assessed the conservation agriculture (CA) practices [permanent bed (PB) and zero tillage (ZT)] and conventional till (CT) in 4-diversified maize rotations [maize-wheat-mungbean (MWMb), maize-chickpea-Sesbania green manure (MCS), maize-mustard-mungbean (MMuMb) and maize-maize-Sesbania green manure (MMS)]. Results showed that ZT and PB plots consumed lower energy (7 yr average) in land preparation (49.7–51.5%) and irrigation (16.8–22.9%) compared to CT. Significantly higher system output (10.6–14.5%) and net energy (14.8–18.9%) returns, biomass productivity (9.9–14.1%), energy use-efficiency (13.4–17.1%), and bio-energetic based adult equivalent yield (17.3–19.8%) was recorded in ZT and PB than the CT. Among the crop rotation plots the net energy-output (35,3346 MJ ha−1), biomass yield (11.87 Mg ha−1), energy use efficiency (4.16), and bio-energetic based adult equivalent yield (46 adults ha−1 year−1) was recorded significantly (P ≤ 0.05) higher in MWMb plots. Interaction between tillage and crop rotations were significant (P ≤ 0.05) for mean system output and net energy returns, biomass productivity and bio-energetic based adult equivalent yield. Thus, our long-term study suggests that CA practices with diversified maize based rotation (MWMb) could be a feasible alternative to attain high energy-use efficiency, biomass productivity and bio-energetic based adult equivalent yield in north-western India and other similar agro-ecologies of South Asia.

Effects of changing farm management and farm structure on energy balance and energy-use efficiency—A case study of organic and conventional farming systems in southern Germany

Abstract Fossil energy input, energy output, and energy use- efficiency (EUE) are important indicators of the environmental effects, resource consumption and economic performance of farming systems. In this study, the energy balance (process analysis) and EUE of different organic and conventional farming systems – mixed farming, arable farming, and agroforestry (AGFS) systems – were analyzed due to their importance in Germany. The analysis was based on long-term experiments at the Scheyern Research Farm in southern Germany. The results showed that the conversion from multi-structured organic mixed farming to a specialized organic arable farming system reduced the fossil energy input in crop production only marginally (from 5.9 to 5.5 GJ ha −1 yr −1 ), but considerably decreased dry matter yield (from 5.4 to 2.5 Mg ha −1 yr −1 ), energy output (from 99 to 46 GJ ha −1 yr −1 ) and EUE (from 16.8 to 8.3). Improved management in the conventional arable farming system (with high-yielding varieties and better N management) reduced the energy input from 14.0 to 12.2 GJ ha −1 yr −1 , increased the energy output from 155 to 179 GJ ha −1 yr −1 , and elevated the EUE from 11.1 to 14.6. The establishment of AGFS with short rotation trees (without fertilization and pesticide use) led to the reduction of energy input. Based on the results, we concluded that mixed farming is one of the best ways of producing food with high EUE under the conditions of organic farming. Therefore the conversion from organic mixed farming to an organic arable farming system is not recommended. Our AGFS results were from the first stage of a long-term experiment; it showed no negative effects on DM yield and energy output and positive effects on energy-use efficiency at this stage. However, further research is needed to know the long-term influence of AGFS.

Productivity, profitability and energy dynamics of rice (Oryza sativa) under tillage and organic nitrogen management practices in rice–vegetable pea (Pisum sativum) cropping system of Sikkim Himalayas

Fixed plot field experimentation was carried out at Research Farm of ICAR Sikkim Centre during 2013 and 2014 to identify the efficient tillage and organic nitrogen management practices for achieving higher productivity, profitability and energy use efficiency (EUE) of rice (Oryza sativa L.) in rice–vegetable pea (Pisum sativum L.) cropping system of Sikkim Himalaya. The results revealed that higher productive tillers/hill, panicle length (cm), panicle weight (g), grains/panicle, 1000–grain weight (g) and grain yield (3.27 t/ha) were recorded with reduced tillage (RT) followed by conventional tillage (CT) and no–till (NT). Maximum gross returns (96×103 `/ha) was recorded with RT followed by NT (95.8×103 `/ha) and CT (95.5×103 `/ha). However, maximum net returns (67×103 `/ha) and B:C ratio (2.34) was recorded with NT over RT and CT. NT was most energy efficient practice and had 33% less energy requirement as compared to CT. Amongst the organic nitrogen sources, higher yield attributes and grain yield (3.7 tonnes/ha) were recorded with the application of 50% RDN (recommended dose of nitrogen) through FYM (Farmyard manure)+ 50% RDN through VC (vermicompost)+BF (biofertilizer) which was significantly superior over other organic nitrogen sources. The grain yield increased by 29.7% over the farmers’ practice. With respect to the economic and energy indicators, application of 50% RDN through FYM + 50% RDN through VC+BF proved its superiority over others and recorded 32.4% higher net returns and 9.2% higher EUE over the prevailing farmers’ practice (FYM @5 tonnes/ha) of the region.

Bio-energy, Productivity and Economics of rice (Oryza sativaL.)-based Cropping Systems in Coastal Flood Plain of West Bengal, India

A field experiment was carried out at farmers’ field in coastal saline zone of West Bengal, India during 2011–12 and 2012–13 with four cropping systems viz. rice-greengram, rice-sunflower, rice-sunflower+greengram and rice-lady's finger. Rice-lady's finger system recorded significantly higher rice equivalent yield, system productivity in both the years. Significantly higher net return ( 1, 05, 670 ha−1) was obtained in rice-lady's finger cropping system, followed by rice greengram, whereas B: C ratio was found at par. Among the management components fertilizer consumed maximum energy followed by operational labour and land preparation. Energy consumption was found significantly higher in rice-lady's finger system (44, 902 MJ ha−1) and lowest in rice-greengram system (29, 005 MJ ha−1). Total bioenergy output follows the order: rice-lady's finger>rice-sunflower>rice-sunflower+greengram>rice-greengram. But this order was reversed for energy-use efficiency (EUE). Significantly higher specific energy was recorded in rice-sunflower system (3415 MJ t−1) and it was the most energy-investment intensive among them. However, significantly higher energy productivity was observed in rice-lady's finger system (0.63 kg MJ−1) and lowest in rice-greengram (0.30 kg MJ−1). Regarding energy intensiveness the results were contrary to EUE. Rice-lady's finger system was emerged as most energy intensive system as compared to other three cropping systems and the rice-greengram system is the least. It can be concluded that though the yield and net return in rice-lady's finger system were higher than other system, the rice-greengram system is more suitable cropping system in constrains prone coastal saline zone with limited irrigation facilities due to low requirement of non-renewable energy, higher EUE and benefit-cost ratio.

Holographic Vector Wave Femtosecond Laser Processing

Parallel femtosecond laser processing using a computer-generated hologram (CGH) displayed on a spatial light modulator (SLM), called holographic femtosecond laser processing, provides the advantages of high throughput and high energy-use efficiency. Use of a light wave with spatially controlled polarization fields, called a vector wave, also offers novel properties in various applications. In this study, we demonstrated holographic femtosecond laser processing with a vector wave by using a pair of SLMs. In particular, we performed three-dimensional reconstruction with multifocal radial beams. We also realized simultaneous reconstruction with two different types of vector beams by using a novel design method of a CGH composed of multiple small CGHs. To our knowledge, this is the first demonstration of its kind. The polarization fields of the multifocal vector beams at the sample plane were analyzed from the orientations of periodic nanostructures fabricated with femtosecond laser light.

Polarization distribution control of parallel femtosecond pulses with spatial light modulators

A parallel femtosecond pulse irradiation method using a computer-generated hologram displayed on a spatial light modulator provides the advantages of high throughput and high energy-use efficiency. Polarization control of the femtosecond pulse enables some unique properties, for example, selective excitation of an anisotropic molecule, focusing at a size beyond the diffraction limit owing to the longitudinal vector component of a radially polarized beam focused by a high-numerical-aperture objective lens, and fabrication of periodic nanostructures with femtosecond laser light. In this study, we propose a parallel femtosecond laser irradiation system with arbitrary polarization distribution control using a pair of spatial light modulators. By using the system, the interval between the diffraction spots was the closest yet reported by avoiding mutual interference among their side lobes. The interval was improved to half compared with our previous work. We also demonstrated the parallel fabrication of periodic nanostructures with orientation control, which, to our knowledge, is the first reported demonstration of its kind.

Parallel femtosecond laser processing with vector-wave control

Parallel femtosecond laser processing with a computer-generated hologram displayed on a spatial light modulator, has the advantages of high throughput and high energy-use efficiency. For further increase of the processing efficiency, we demonstrated parallel femtosecond laser processing with vector-wave control that is based on polarization control using a pair of spatial light modulators. In this paper, we propose a novel laser processing method based on polarization control of parallel pulses. The laser processing system is composed of a pair of SLMs displaying a dynamic CGH, one for making parallel pulses from incoming pulse and the other for controlling the polarization of the diffraction pulse. We demonstrate parallel processing with the different polarization simultaneously. We call this method the vector-wave femtosecond laser processing because of a use of the vector control of polarization. 2. Principle of vector control of laser pulses When Jones matrices of two SLMs, a half-wave plate (HWP), and a quarter-wave plate (QWP) are given as Sα, Sβ, H, and Q, the electric field of the output beam Eout for electric field of an input beam Ein after passing through the optical devices is denoted as,

CO2 Capture System Using Lithium Silicate for Distributed Power Supply

Distributed power-supply systems have become more widespread recently. Recent distributed systems, such as fuel cells, offer high energy-use efficiency because they generate heat or hot water and electric power simultaneously. However, to avoid global warming, carbon dioxide (CO2) from the exhaust gas has to be collected and separated, without emitting it to the atmosphere. We are investigating lithium silicate (Li4SiO4) (LS) because it has superior characteristics as a CO2 absorber. Aiming at the construction of a CO2 capture and separation system using LS, we are studying ways to process (capture and separate) the exhaust gas from distributed power-supply systems. We thought that the CO2 capture and separate system we should design must process exhaust gases with 30% CO2 concentration and 35 L/min flow rate and that it must capture and separate more than 50% of the CO2 contained in the exhaust gases. However, as a result of a preliminary estimation, it became clear that the volume of the assumed CO2 capture and separate system would be considerable. Therefore, we built a reduction model experimental setup with three reaction containers with three different aspect ratios. The results regarding container shape suggest that a long container would be advantageous..

Input-output and economic analysis of soybean production in the main cultivation areas in Iran

Vegetable oil consumption in Iran is about 1.4 million tons per year of which more than 90% is obtained from imports. Therefore, development of oilseed crops especially soybean cultivation is particularly important to reach food security. Since the technical and economic justification are the first requirements in introducing new crops, the aim of this study was to evaluate different inputs, energy use efficiency (EUE), and economic aspects of soybean production in Iran. Necessary data were collected from 30 soybean farms in two main climatic locations of the country via face to face questionnaire method based on statistical information of the year 2011. The results revealed that soybean production consumed a total of 29895.49 MJ ha-1, of which the share of diesel fuel and chemical fertilizer energy consumption were 67.47 and 9.5%, respectively. About 68.4% of the total energy inputs used in soybean production was direct (human labor, diesel) and the rest (31.6%) was indirect (seeds, fertilizers, manure, chemicals, machinery). Nonrenewable energy sources have 93% share of total input energy. So it was concluded that soybean production needs to improve the efficiency of energy consumption and to employ renewable energy as much as possible. Mean grain yield which was rain-fed farming was about 1850 kg ha-1. In this current study, total output energy and net energy was estimated as 54131 and 24235.5 MJ ha-1, respectively. Also, energy productivity value and EUE was determined as 0.062 kg MJ-1 and 1.81, respectively. According to economic analysis of soybean production, total expenditure, gross income, net income, and benefit-cost ratio (BCR) were calculated as 920 $ ha-1, 1239 $ ha-1, 319 $ ha-1, and 1.35, respectively. Regarding to high EUE and BCR of soybean production in Iran, technical guidance should be considered. Early sowing date, proper plant rotation (wheat-soybean) and application of combine vehicle were severely recommended to minimize fossil fuels consumption and more sustainable soybean production. Key words: Energy use efficiency, soybean, benefit-cost ratio (BCR), energy sources.

Poly(ADP‐ribose) polymerase in plants affects energy homeostasis, cell death and stress tolerance

Plants contain two genes that code for poly(ADP-ribose) polymerase (PARP): parp1 and parp2. Both PARPs are activated by DNA damage caused by, example reactive oxygen species. Upon activation polymers of ADP-ribose are synthesized on a range of nuclear enzymes using NAD(+) as substrate. Here, we show that in plants stresses such as drought, high light and heat activate PARP causing NAD(+) breakdown and ATP consumption. When the PARP activity is reduced by means of chemical inhibitors or by gene silencing, cell death is inhibited and plants become tolerant to a broad range of abiotic stresses like high light, drought and heat. Plant lines with low poly(ADP-ribosyl)ation activity maintain under stress conditions their energy homeostasis by reducing NAD(+) breakdown and consequently energy consumption. The higher energy-use efficiency avoids the need for a too intense mitochondrial respiration and consequently reduces the formation of reactive oxygen species. From these results it can be concluded that breeding or engineering for a high energy-use efficiency under stress conditions is a valuable, but until today nearly unexploited, approach to enhance overall stress tolerance of crops.

Bioenergy and economic analysis of soybean-based crop production systems in central India

The study examines the energy requirement and energy input–output relationship of soybean-based crop production systems viz., soybean ( Glycine max (L.) Merr.)–wheat ( Triticum aestivum L.), soybean–mustard ( Brassica juncea (L.) Czern & Coss.) and soybean–chickpea ( Cicer arietinum L.) in central India. Using a pre-tested questionnaire, 135 farmers were selected through a multi-stage stratified random sampling technique. Results revealed that manures and chemical fertilizers (50.87%), seedbed preparation (18.30%) and sowing management (17.69%) consumed the bulk of the energy (operational and non-operational) for all crops, it was highest in soybean–wheat (23705±29.48 MJ ha −1) and the lowest in soybean–chickpea (15672±26.29 MJ ha −1) . Wheat, with the highest grain productivity, produced the most biomass energy (78541±28.75 MJ ha −1) and highest grain-energy productivity (0.150 kg MJ −1) . The total bioenergy output of the crop production systems followed the order: soybean–wheat (131277±29.26 MJ ha −1) > soybean–mustard (101661±28.91 MJ ha −1) > soybean–chickpea (92658±28.87 MJ ha −1) . But this order was reversed for energy-use efficiency (EUE): soybean–chickpea (5.91)> soybean–mustard (5.86)> soybean–wheat (5.54). Specific energy was highest in soybean (9173 MJ t −1 grain) followed by mustard (8912 MJ t −1 seed), chickpea (7190 MJ t −1 grain) and wheat (6646 MJ t −1 grain) indicating that soybean is the most energy-investment intensive crop. Regarding energy intensiveness the results were contrary to EUE. Energy intensiveness ( MJ Rs −1) was higher in wheat (1.40) followed by mustard (1.11), soybean (0.89) and chickpea (0.87) and the soybean–wheat system (1.13) emerged as the most energy-intensive system compared to soybean–mustard (0.97) and soybean–chickpea (0.88). Though the net return from soybean–wheat was marginally higher than other systems, the soybean–chickpea system is more suitable in the central ecological niche of India due to its low requirement for non-renewable resources, higher EUE and benefit–cost ratio.

Effect of land configuration and mulching on productivity and energy use in groundnut (Arachis hypogaea)

A field experiment was conducted during the rainy (kharif) seasons of 201315 on acid lateritic soils of Konkan, to study the effect of land configuration and mulching on resource use efficiency and productivity of groundnut (Arachis hypogaea L.). The experiment consisted of 4 land configuration and 3 mulching treatments. The pooled results revealed that, groundnut pod yield was significantly influenced by various land configuration and mulching treatments and it was significantly highest under broad bed and furrow method of land configuration (8020 cm) i.e. 2.48 t/ha over flat bed sowing, ridges and furrow method (50 cm) and raised bed and furrow (30 width with 30 cm furrow) method of sowing. However, use of transparent polythene (7 micron) film mulch resulted in significantly higher pod yield of 2.50 t/ha over paddy straw mulching (2.18 t/ha) and no mulching (control), i.e. 1.70 t/ha. The maximum field water-use efficiency was observed under broad bed and furrow method with transparent polythene mulch (1.77 kg/ha-mm) treatment. Economics of the treatments indicated that, groundnut sown on broad bed and furrow method topped in the rank for net returns ( 31,392/ha) with benefit: cost ratio of 1.41:1. However, trans- parent polythene mulch noticed higher net returns of 26,341/ha with benefit to cost ratio 1:1.32 followed by paddy straw mulching ( 17,597/ha with 1.23 : 1 benefit: cost ratio). Broad bed furrow method with polythene mulch treatment showed the highest field water-use efficiency of 1.77 kg/ha mm, highest energy balance (63629 MJ/ha) with higher energy-use efficiency (4.11) and energy productivity of 0.14 kg/MJ.

TILLAGE SYSTEMS AND STUBBLE MANAGEMENT IN A MEDITERRANEAN-TYPE ENVIRONMENT IN RELATION TO CROP YIELD AND SOIL MOISTURE

The effect of tillage and crop rotations can only be seen over many crop years. Crop yield and soil results are evaluated from two long-term trials, established in 1978–79 and 1985–86 to investigate various forms of tillage and the timing of such operations in various wheat (Triticum aestivum)-based rotations on a Calcixerollic Xerochrept in northern Syria. In a tillage systems trial involving two wheat–legume–watermelon (Citrullus lanatus) rotations, deep tillage showed no advantage over a shallow sweep-tillage system, either for soil moisture storage or yield increase of any crop. The zero-till system suited legume crops but gave lower productivity in wheat due to a build up of grassy weeds, and was not suitable for watermelon. Minimum tillage, with its higher energy-use efficiency and yield levels equal to or even slightly above those of deep-tillage systems, appears promising for the lowland areas of West Asia and North Africa. In a tillage timing trial, wheat in a wheat–lentil (Lens culinaris) rotation yielded best after conventional deep disc-plough tillage, but lentil yields were higher in a zero-till system.