Energy balance and greenhouse gas emissions of dryland camelina as influenced by tillage and nitrogen

این تحقیق به منظور بررسی و مقایسه شاخص‌های انرژی در تولید گندم آبی تحت تأثیر روش‌های مختلف خاک‌ورزی و کاشت اجرا گردید. تحقیق در قالب طرح بلوک‌های کامل تصادفی با پنج تیمار و سه تکرار در شهرستان اقلید انجام شد. تیمارهای تحقیق عبارت بودند از: خاک‌ورزی مرسوم و کاشت به‌صورت بذرپاشی، خاک‌ورزی مرسوم و کاشت با خطی‌کار همدانی، کم خاک‌ورزی و کاشت با کمبینات، کشت مستقیم با خطی‌کار جیران صنعت و کشت مستقیم با خطی کار اسفوجیا. اطلاعات مربوط به عملکرد محصول و انرژی‌های ورودی و خروجی در هر تیمار برداشت گردید و شاخص‌های انرژی شامل راندمان انرژی، افزوده خالص انرژی و بهره‌وری انرژی در هر تیمار محاسبه و با هم مقایسه شدند. برای تجزیه و تحلیل داده‌های تحقیق از نرم افزار آماری SAS استفاده شد و مقایسه میانگین تیمارها با استفاده از آزمون چند دامنه‌ای دانکن صورت گرفت. نتایج نشان داد که تیمار کم خاک‌ورزی و کاشت با کمبینات بیشترین مقدار نسبت انرژی (1/46) را در بین تیمارهای تحقیق داشت و کمترین میزان نسبت انرژی (1/40) متعلق به تیمارهای خاک‌ورزی مرسوم بود. بیشترین انرژی خالص (47653 مگاژول) مربوط به تیمار کم‌خاک‌ورزی و کاشت با کمبینات بود و کمترین انرژی خالص (41388 مگاژول) به تیمار خاک‌ورزی مرسوم و کاشت با خطی‌کار همدانی تعلق گرفت. مقایسه تیمارها از نظر بهره‌وری انرژی نیز نشان داد که تیمار کم‌خاک‌ورزی و کاشت با کمبینات بیشترین بهره‌وری انرژی (0/115 کیلوگرم بر مگاژول) را به خود اختصاص داده است و دو تیمار خاک‌ورزی مرسوم دارای کمترین بهره‌وری انرژی (0/110 کیلوگرم بر مگاژول) بودند. بنابراین، استفاده از روش‌های خاک‌ورزی حفاظتی در تولید گندم آبی می‌تواند با کاهش انرژی مصرفی باعث افزایش بهره‌وری انرژی گردد.

Crop production process utilizes input energy and produces some biomass energy as output. During this process, greenhouse gases (GHGs) are also emitted which can make environmental risks. In this study, input and output energies, energy indices, and GHG emissions arising from inputs were estimated for wheat-cotton rotation under different tillage practices in Fars province. The study was conducted as a randomized complete plot experimental design with three tillage treatments and four replicates. Tillage methods included conventional tillage (CT), reduced tillage (RT), and no tillage (NT). Results showed that NT and RT decreased energy consumption in wheat and cotton production by 1.53 and 1.19%, respectively as compared to the CT due to less fuel and machinery utilization. More than 72% of energy requirement for wheat and cotton production was consumed by irrigation water and electricity for pumping irrigation water in all tillage methods. Conventional tillage resulted in the highest output energy, energy ratio, and energy productivity in wheat-cotton rotation compared to RT and NT. Total GHG emissions for wheat and cotton production were estimated to be 51829, 51608, and 51529 kg CO2e ha-1 in CT, RT, and NT, respectively indicating that NT and RT slightly reduced GHG emission compared to CT (0.6 and 0.4%, respectively). Results of this study indicated that irrigation showed the highest share in total energy requirement and GHG emission of wheat and cotton production in semi-arid climate condition of Fars province; therefore, total input energy and GHG emissions could be markedly reduced by using more efficient irrigation systems.

ABSTRACTThis study was carried out to evaluate the energy flow, GHG emissions, and global warming potential (GWP) in corn production in western Iran. The Data was collected by split plot Design based on randomized complete block design with four replications. The treatments consisted of a combination of three levels of the main tillage factor including conventional tillage (CT), minimum tillage (MT), no-tillage (NT), and three levels of chemical fertilizer including no fertilizer or N0P0K0 (NPK)0, N50P50K50 (NPK)50 and N100P100K100 (NPK)100. The results of this study showed that the total input energy in CT systems, MT, and NT was 56113.24, 51403.70, and 49144.45 MJ ha−1, respectively. The output energy in this tillage systems was 111989.11, 113312.80 and 109516.68 MJ ha−1 respectively. By reducing the rate of fertilizer, the amount of input and output energy was decreased. The NT and MT systems had higher energy efficiency than the CT one. Energy efficiency in (NPK)0, (NPK)50 and (NPK)100 was calculated to be 2.62, 2.53, and 1.88, respectively. The highest amounts of CO2, N2O, and CH4 were observed in corn production with CT systems. In no-fertilization treatments, GHG emissions were also lower. Moreover, the results showed that by decreasing tillage and increasing amount of fertilizer, GWP decreased. According to the results of this study, changing the practice of tillage from CT to MT and reducing fertilizer amount could increase energy efficiency in the region and reduce GHG emissions.

An on-farm research study was carried out during the winter (rabi) season of 201315 at Morena, Madhya Pradesh to study the impact of irrigation timing and sowing methods on yield, energy indices, water productivity and soil properties in wheat (Triticum aestivum L.) when grown after harvesting of toria (Brassica rapa). Different sowing times included sowing of crop after pre-irrigation (CS) and dry sowing and irrigation for germination (DS), while sowing methods included conventional tillage (CT), zero tillage (ZT) and happy seeder (HS). Results of wheat seeding with DS methods significantly influenced the growth parameters, grain, stover and protein yield, net profit, benefit: cost (B : C) ratio, energy outcomes as compared to the CS. Similarly, the maximum growth charac- ters, grain, stover and protein yield, economic benefits, energy outcomes and water productivity (WP) were re- corded with HS, followed by ZT and minimum with CT. The increase in grain yield- (12.5%) was observed with DS as compared to CS. Monetary savings of `3,990/ha was saved with ZT, followed by HS (`3,260/ha) as compared with a total cost of production under CT. Results also revealed that, savings of energy inputs were 12.8% with ZT, followed by 12.3% with HS compared with total energy inputs with CT. Total water use (TWU) with CS method was significantly higher than DS, whereas the reverse trend was observed in WP. Similarly, the TWU of wheat was sig- nificantly higher in CT than with ZT and HS, whereas maximum WP was recorded with HS, followed by ZT and the minimum with CT. After harvesting of wheat, physico-chemical properties also improved with HS, followed by ZT and CT.

Camelina (Camelina sativa L. Crantz), as a bioenergy and bio-product feedstock, may be grown as a rotation crop in the wheat-based cropping system to increase land use efficiency in the Northern Great Plains (NGP). In this study, which was conducted from 2008 to 2011 in central Montana, we evaluated the energy balance of three 2-year cop rotational sequences that included camelina-winter wheat (Triticum aestivum L.) (CAM-WW) and barley (Hordeum vulgare L.)-winter wheat (BAR-WW) compared with a traditional fallow-winter wheat (FAL-WW) rotation. Results indicated that 52 and 57 % more energy input was invested in CAM-WW and BAR-WW compared to FAL-WW system (9182 MJ ha−1), respectively. In all rotations, nitrogen fertilizer was the most energy-consuming input and accounted for 76, 68, and 69 % of the total energy used in wheat, barley, and camelina production, respectively. Averaged over 3 years, CAM-WW and BAR-WW systems yielded 34 and 29 % greater gross energy output compared with FAL-WW. The CAM-WW and BAR-WW also outperformed FAL-WW by 30 and 6 % in terms of net energy output. No significant differences in energy efficiency were found between the FAL-WW and CAM-WW systems. Taking into account of the greater net energy as well as similar values of energy use efficiency, the CAM-WW system performed better than the traditional FAL-WW system under rainfed conditions in central Montana. There is a good potential to improve the energy efficiency of the CAM-WW cropping system (by more than 26 %) through refinement of agronomic practices, mainly nitrogen fertilization and herbicide application, which can further enhance the sustainability of camelina feedstock production.

The study was conducted on input energy consumption for wheat production in irrigated condition at Punjab Agricultural University, Ludhiana. The results revealed that the highest input energy requirement of 15682.9 MJha-1was recorded for conventional tillage (CT) compared 13189.4, 12467.6 and 12467.6 MJha-1 for rotavator (RT), happy seeder (HS) and zero tillage (ZT), respectively. Nitrogen (N) application showed a positive relationship with input energy consumption and highest of 18297.0 MJha-1 was recorded with 150 kg Nha-1 compared 15164.5, 13651.3, 6694.7 MJha-1 for 0, 100 and 125 kg Nha-1, respectively. The main source of input energy use was fertilizer and irrigation. The higher share of direct and non-renewable input energy consumption was recorded in CT and indirect and renewable input energy consumption was higher in HS, ZT and RT. Direct & renewable and indirect & non-renewable input energy showed a negative and positive relationship with N rates. CT wheat with 150 kg Nha-1 produced the highest total output energy. The results showed that the highest 10.48, 0.38 kgMJ-1 and 3.96 MJkg-1 of output: input ratio, energy productivity and energy specific under ZT, ZT and CT, respectively. However, the maximum NPK energy equivalent in biomass was recorded in CT. Input: output ratio, energy productivity and NPK energy equivalent showed negative relationship and energy specific showed a positive relation with N rates. CT showed the higher net gain of energy compared to direct drilling methods as ZT, HS and RT.

Field experiments were conducted to evaluate conventional tillage (CT), permanent raised bed (PRB), and zero tillage (ZT) with residue retention and removal at three nitrogen levels (0, 100, and 120 kg N ha-1) on wheat productivity, energy input and energy output, energy use efficiency, specific energy, and CO2 emission from 2010 to 2012 under rice-wheat system at Pheta V.D.C, Bara, Nepal. The experiments were carried out in strip split plot designs with three replications. Zero tillage wheat produced significantly higher grain yield (2616.5 kg ha-1), saved 10.4 % energy input, increased energy output (12.4 %), enhancing energy use efficiency by 25.2 % and reducing specific energy by 23.6 %, as compared to conventional tillage. Diesel consumption on crop establishment and irrigations were the lowest for ZT (48.6 liter ha-1) and the highest for CT (86.3 liter ha-1). PRB consumed the lowest quantity of diesel on two irrigations (34.6 liter ha-1) with higher energy use efficiency (3.4 %) and lower specific energy (8.76 MJ kg-1) over CT. The CO2 emission from CT was the highest (224.32 kg ha-1) over ZT (126.4 kg ha-1) and PRB (146.11 kg ha-1). Residue retention increased 4 % grain yield over residue removal. Without nitrogen application, energy output was the lowest (34192 MJ ha-1) with the highest specific energy (12.6 MJ kg-1). Thus, zero-till wheat with 40-cm residue retention and 100 kg N ha-1 application was suggested for mass scale adoption in the Tarai region of Nepal.DOI: http://dx.doi.org/njst.v15i2.12104 Nepal Journal of Science and Technology Vol. 15, No.2 (2014) 1-10

Change of tillage system affects the soil carbon pools characters, reduces carbon emissions and improves maize yield in the Loess Plateau

ABSTRACTLentils and garlic are primarily grown under conventional tillage (CT) practice; however, both crops have been fetching lower profits due to the high cost of both cultivation as well as the required inputs. For securing more benefits and using residual soil-moisture, farmers have started the zero-tillage (ZT) practice in a rice-based cropping system. In general, it is imperative to compare these two systems (ZT and CT) to assess their energy consumption, and their broader environmental and financial performance. In this study, we found that the total energy input was reduced by 38% with ZT as compared to CT (3.96 GJ ha–1) for lentil cultivation; in contrast, for garlic, CT’s energy consumption was 11% of that of ZT (113.55 GJ ha–1). Energy output increased by 13% and 4% with ZT, in comparison to CT, for lentil and garlic, respectively. Similarly, ZT reduced CO2e (carbon dioxide-equivalent) emissions by 50% and 98%, as compared to CT, for lentil and garlic cultivation, respectively. The maximum financial benefit was seen to be obtained with ZT: the production cost was reduced by 28% and 33%, as compared to CT practices, for lentil and garlic, respectively. The return-cost ratios from ZT and CT were 3.39 and 2.18 for lentil, and 7.64 and 3.52 for garlic, respectively. We can, therefore, conclude that ZT is an energy-efficient, environment-friendly, and cost-effective practice of lentil and garlic production.

The effects of climate change such as dry spells, floods and erosion heavily impact agriculture especially smallholder systems on the Northwestern Loess Plateau of China. Nonetheless agriculture also contributes to global warming through the emission of greenhouse gases such as CO2, CH4 and N2O. Yet this complex conundrum can be alleviated and mitigated through sound soil and water management practices. Despite considerable literature on Conservation Agriculture (CA) as a strategy to improve the resilience and mitigation capacity of agroecosystems, there is still paucity of information on the impacts of CA on crop production and environmental quality on the Plateau. In order to fill this gap this study examined the effects of no-till and straw mulch on crop productivity and greenhouse gas fluxes in agroecosystems on the Plateau where farmers’ common practice of conventional tillage (CT) was tested against three CA practices: conventional tillage with straw mulch (CTS), no-till (NT) and no-till with straw mulch (NTS). The results indicated that all three CA practices (CTS, NT and NTS) markedly increased soil water content (SWC), soil organic carbon (SOC) and soil total nitrogen (STN) but reduced soil temperature (ST). Average grain yields were 854.46 ± 76.51, 699.30 ± 133.52 and 908.18±38.64 kg ha-1 respectively under CTS, NT and NTS indicating an increase by approximately 33%, 9% and 41% respectively compared with CT (644.61 ± 76.98 kg ha−1). There were significant (p < 0.05) reductions of Net CO2 emissions under NT (7.37 ± 0.89 tCO2e ha−1y−1) and NTS (6.65 ± 0.73 tCO2e ha-1y-1) compared with CTS (10.65 ± 0.18 tCO2e ha−1y−1) and CT (11.14 ± 0.58 tCO2e ha−1y−1). All the treatments served as sinks of CH4but NTS had the highest absorption capacity (−0.27 ± 0.024 tCO2e ha−1y−1) and increased absorption significantly (p < 0.05) compared with CT (−0.21 ± 0.017 tCO2e ha−1y−1); however, CA did not reduce emissions of N2O. These had an influence on Global warming potential (GWP) as NT and NTS resulted in significant reduction in net GWP. Grain yield was significantly correlated positively with SOC and STN (p < 0.05); ecosystem respiration was also significantly correlated with SWC and ST while CH4 flux was highly correlated with ST (p < 0.001). Crop yield and GHG responses to CA were controlled by soil hydrothermal and nutrient changes, thus improving these conditions through adoption of sustainable soil moisture improvement practices such as no-till, straw mulch, green manuring, contour ploughing and terracing can improve crop resilience to climate change and reduce GHG emissions in arid and semi-arid regions.

With skyrocketing petroleum prices and war in the oil-producing nations of the Middle East, biofuels are increasingly touted as desirable alternatives to petroleum. But can they really help free us from a petroleum economy? How do they compete with conventional fuels and each other on a cost basis? What are the environmental impacts? Researchers at the University of Minnesota have published a wide-ranging study that offers some answers. Currently, corn grain ethanol and soybean biodiesel are the two predominant alternative transportation fuels in the United States. Both can be used in conventional car and truck engines in blended form, and biodiesel can also be used in pure form (“B100”). Both are available at an increasing number of wholesale and retail locations across the nation. However, both require significant energy to produce, have their own environmental impacts, and could divert corn and soybeans from the nation’s food supply. Exactly what the energy balance and environmental impacts are and whether these fuels should be subsidized has been the subject of heated debate among scientists, policy makers, and the public. Researchers from the University of Minnesota and St. Olaf College led by ecology professor G. David Tilman hoped to inform this debate by conducting a comprehensive analysis of the full life cycles of these biofuels. According to the study, published in the 25 July 2006 issue of the Proceedings of the National Academy of Sciences, a viable alternative fuel must meet four criteria: show superior environmental benefits over the fossil fuel it displaces, be economically competitive with that fossil fuel, be producible in sufficient quantities to make a meaningful impact on energy demands, and provide a net energy gain over the energy sources used to produce it.

An energy balance under a conventional crop rotation system in northern Japan: Perspectives on fuel ethanol production from sugar beet

Enhanced efficiency nitrogen fertilizer effect on camelina production under conventional and conservation tillage practices

Determinants of annual fluxes of CO 2 and N 2O in long-term no-tillage and conventional tillage systems in northern France

SUMMARYConducting farmers participatory field trials at 40 sites for 3 consecutive years in four rice-wheat system dominated districts of Haryana state of India, this paper tested the hypothesis that zero tillage (ZT) based crop production emits less greenhouse gases and yet provide adequate economic benefits to farmers compared to the conventional tillage (CT). In each farmer's field, ZT and CT based wheat production were compared side by side for three consecutive years from 2009–10 to 2011–12. In assessing the mitigation potential of ZT, we examined the differences in input use and crop management, especially those contributing to GHGs emissions, between ZT wheat and CT wheat. We employed Cool Farm Tool (CFT) to estimate emission of GHGs from various wheat production activities. In order to assess economic benefits, we examined the difference in input costs, net returns and cost-benefit analysis of wheat production under CT and ZT. Results show that farmers can save approximately USD 79 ha−1 in terms of total production costs and increase net revenue of about USD 97.5 ha−1 under ZT compared to CT. Similarly, benefit-cost ratio under ZT is 1.43 against 1.31 under CT. Our estimate shows that shifting from CT to ZT based wheat production reduces GHG emission by 1.5 Mg CO2-eq ha−1 season−1. Overall, ZT has both climate change mitigation and economic benefits, implying the win-win outcome of better agricultural practices.