Organic farming (OF) principles include the idea of reducing dependence of fossil fuels, but little has been achieved on this objective so far in Danish OF. Energy use and greenhouse gas (GHG) emissions from an average 39 ha cash crop farm were calculated and alternative crop rotations for bio-energy production were modeled. Growing rapeseed on 10% of the land could produce bio-diesel to replace 50–60% of the tractor diesel used on the farm. Increasing grass-clover area to 20% of the land and using half of this yield for biogas production could change the cash crop farm to a net energy producer, and reduce GHG emissions while reducing the overall output of products only marginally. Increasing grass-clover area would improve the nutrient management on the farm and eliminate dependence on conventional pig slurry if the biogas residues were returned to cash crop fields.

Agriculture is one of the high input energy using sectors which ultimately produces the output energy for the survival of human beings. Wheat is an important cereal in the agriculture production system. It is a major food crop and staple food for many countries in the world. Higher population growth has increased demand for wheat, and this demand has been met through the adoption of modern agricultural practices which are heavily dependent on energy. The current study was planned to examine the input energy use efficiency of rainfed wheat growers in Pakistan and Turkey (countries among the top 10 global wheat producers). A total of 119 wheat growers from the rainfed areas of both countries were randomly selected. The data envelopment analysis was executed to estimate the input energy use efficiency score of the growers. The results of the study revealed that almost a similar source of input energy is used in both countries in wheat cultivation. The largest input energy consumption in Turkey was nitrogen fertilizer (10,531.50 MJ ha−1), while in Pakistan was farmyard manure (12,837.32 MJ ha−1). The Turkish growers have higher energy use efficiency 2.42 as compared to Pakistani growers, whose energy use efficiency was 1.09. Results further revealed that there is a substantial potential for energy savings in both countries by optimizing energy use. The study concluded that the exchange of energy-efficient practices between both countries can significantly reduce energy use and improve the yield of wheat.

Industrial principles of specialization, simplification and concentration began to be applied to agriculture after the Second World War with positive production results. But it is now widely recognized that this agriculture and food system faces daunting challenges in the decades ahead, including increased human population growth, natural resource depletion, ecological degradation, climate change and escalating energy costs. These challenges have refocused the attention of agriculturalists and food scientists on the question of how we can continue to feed the human species. But these challenges also provide opportunities to rethink and redesign our food system. Agriculturalists are recognizing that resilience is at least as important to food security as maximum production, and consumer concerns provide us with unprecedented opportunities for farmers and consumers to come together as ‘food citizens’ to determine appropriate changes in our food system. To that end it is important to examine the various production systems and infrastructures in an effort to select the most viable options for long-term sustainability.

Improving energy and resource use in US agriculture begins with the soil. Healthy soils improve air and water quality, increase land productivity, help resist the effects of drought and floods, improve energy efficiency and enhance the ability to mitigate climate change. In 1993, the US Board on Agriculture concluded that national policy should seek to: conserve and enhance soil quality as a fundamental first step to improve the environment; increase the efficiency of nutrient, pesticide and irrigation use in farming systems; increase the resistance of farming systems to erosion and runoff; and make greater use of field and landscape buffer zones, all delivered through farm system management plans. Despite their detailed analysis and thoughtful approach, only a few of their recommendations were implemented. But now, calls from the scientific community to improve resource and energy use in agriculture are becoming more urgent in tone and could help drive policy reform. We review the reasons behind this rising sense of urgency, highlight some of the potential policy drivers along with policy ‘game changers’ and offer policy options. We argue to expand our view of agriculture as a source not only of food, fiber, biofuels and renewable energy but also of other critical ecosystem services, like cleaner water, carbon sequestration and wildlife habitat, and to adjust policies to realize this potential on all agricultural lands. We recommend undertaking a second National Agricultural Land Study as a basis to develop a clear national strategy to help US agriculture meet the challenges it will face in the coming decades. For the short term, we offer incremental policies to improve energy and resource use and, for the long term, we offer a vision of what that national strategy might include once the necessary analyses are completed and consensus is reached.

Growing populations and a constrained fossil-manufactured energy supply present a major challenge for society and there is a real need to develop forms of agriculture that are less dependent on finite energy sources. It has been suggested that organic agriculture can provide a more energy efficient approach due to its focus on sustainable production methods. This review has investigated the extent to which this is true for a range of farming systems. Data from about 50 studies were reviewed with results suggesting that organic farming performs better than conventional for nearly all crop types when energy use is expressed on a unit of area basis. Results are more variable per unit of product due to the lower yield for most organic crops. For livestock, ruminant production systems tend to be more energy efficient under organic management due to the production of forage in grass–clover leys. Conversely, organic poultry tend to perform worse in terms of energy use as a result of higher feed conversion ratios and mortality rates compared to conventional fully housed or free-range systems. With regard to energy sources, there is some evidence that organic farms use more renewable energy and have less of an impact on natural ecosystems. Human energy requirements on organic farms are also higher as a result of greater system diversity and manual weed control. Overall this review has found that most organic farming systems are more energy efficient than their conventional counterparts, although there are some notable exceptions.

This paper focuses on systems producing short rotation coppice willows (SRCW) in chickens’ free-range areas. We aim to map chicken farmers’ motivation to implement SRCW, and to assess the economic viability of these systems. Semi-structured interviews were conducted with 18 free-range chicken farmers. Farmers agreed that chickens would prefer SRCW over grassland, which could benefit chicken welfare. They expected establishing an SRCW system would be labor intensive, and doubted if it would be a profitable investment. Some concerns of farmers might be taken away by exchanging information with farmers with SRCW experience. A partial budget analysis was performed to calculate the net present value (NPV) of six different scenarios, differing in the type of chickens, in whether the produced biomass was sold or valorized on-farm and in harvest pattern, all over a 23-yr period. The NPV was positive but low for all scenarios. A sensitivity analysis showed that changes in biomass yield, wood chip price, a price premium for poultry products and current fuel price were most likely to influence the NPV. A risk analysis revealed that NPVs were positive in the majority of the modeled cases. Scenarios in which biomass was used for on-farm heat production showed the highest risk of a negative NPV. A price premium for poultry products may be most effective at increasing profitability, but may only be feasible for farms selling directly to consumers. Establishing a solid market for biomass energy, including guaranteed demand and availability of appropriate machinery for cultivation, may mitigate farmers’ concerns.

Agriculture is a large source of greenhouse gas (GHG) emissions but changing management practices to those more beneficial to the environment could help mitigate climate change as long as they are economically and environmentally viable. This study examines the environmental (public) and economic (private) effects of adopting ten different beneficial management practices on a representative corn farm in Ontario, Canada. The study integrates changes in GHG emissions in carbon equivalents (CO2e) and changes in profit from changes in costs and revenues in two dimensions to reveal the scope and scale of different kinds of practices. 4R nitrogen management practices are smaller in scale compared to cropping practices and, therefore, have smaller potential costs and benefits. Land use changes, from practices including biomass, afforestation, crop rotation and cover cropping, have larger impacts on soil sequestration and carbon-equivalent GHG reduction, but with significantly greater costs. Seven practices were found to, at least partially, be economically and environmentally beneficial. The adoption of no-till and N-rate reduction is firmly positive, whereas the production of biomass has the largest potential economic and environmental gains. Crop rotation and diversification and cover cropping can be mutually beneficial, as can changing N-application practices. The use of inhibitors may be economically beneficial if yield gains outweigh purchase costs.

The effects of transgenic corn use and federal biofuel policies on state-level cropping patterns in the US Corn Belt region are investigated using state-level data from 2000 to 2019. During this time, producers moved away from diverse cropping patterns and toward simpler rotational practices. Empirical evidence indicates that the intensification of corn acres planted was positively impacted by the spread of genetically modified (GM) soybeans—used as a proxy for GM corn for biofuel usage—but the effects of biotech advancements on producer planting decisions vary across states. This suggests that future policy changes affecting corn production decisions at the farm level will also be heterogeneous across states.

Double-cropping winter rye cover crops (CC) with soybean in the North Central US could help with the global effort to sustainably intensify agriculture. Studies addressing the management of these systems are limited. Therefore, a field study was conducted from 2017 to 2019 in Central Iowa, US to evaluate winter rye CC biomass production, aboveground N accumulation, estimated economics, estimated within-field energy balance and estimated greenhouse gas (GHG) emissions under three N application rates (0, 60, 120 kg N ha−1) and three planting methods (pre- and post-harvest broadcast and post-harvest drilling). Averaged over N rates, all planting methods resulted in >5.0 Mg ha−1 year−1 rye aboveground biomass dry matter. Averaged over the 2-year study and compared with unfertilized treatments, applying 60 kg N ha−1 produced 1.1 Mg ha−1 more aboveground biomass (6.1 vs 5.0 Mg ha−1), accumulated 30 kg ha−1 more N in aboveground biomass (88 vs 58 kg N ha−1), and led to 20 GJ ha−1 more net energy. Biomass production was not significantly higher with 120 kg N ha−1 compared with the 60 kg N ha−1 rate. Even when accounting for an estimated 0.75 Mg ha−1 of above ground rye biomass left in the field after harvesting, more N was removed than applied at the 60 kg N ha−1 rate. The minimum rye prices over the 2-year study needed for double-cropping winter rye CC to be profitable (breakeven prices) averaged $117 and $104 Mg−1 for the 0 and 60 kg N ha−1 rates, which factors in estimated soybean yield reductions in 2019 compared with local averages but not off-site transportation. GHG emissions were estimated to increase approximately threefold between the unfertilized and 60 kg N ha−1 rates without considering bioenergy offsets. While environmental tradeoffs need further study, results suggest harvesting fertilized rye CC biomass before planting soybean is a promising practice for the North Central US to maximize total crop and net energy production.

For most economic goods market participants are ‘not forced to make a deal.’ They can walk away, perhaps permanently, or revisit a transaction later if the terms of trade are more to their liking. That is not the case for food. It is a biological necessity to participate in the food market. This coercive property of food demand and other unique market characteristics make the agricultural sector very unresponsive to changes in price and hence—in contrast to textbook expectations—its ability to quickly self-correct. In recent decades agricultural policy legislation has not taken into account the root causes of agriculture's chronic price and income problems. As a result, it has been largely ineffective and unnecessarily expensive. We argue in this paper that a well-designed supply management program can take agriculture's unique characteristics into account in a way that benefits farmers, consumers and the public as a whole.

Two solid state anaerobic digesters (SSADs), 15 L each, were set up for co-digestion of switchgrass with primary digestate of a liquid anaerobic digester (LAD) and the recirculating leachate. Both the LAD and two SSADs were operated at 50°C. The results showed that the bioreactors were not started up stably until day 16 and day 47 for reactors A and B, respectively. The supplement of LAD digestate or injection of sodium hydroxide (NaOH) into the recirculating leachate readily reinitiated the biogas production to normal daily high rates of the two individual SSADs, one on day 16 and the other on day 47. In contrast to reactor A, there was a longer lag phase for bioreactor B, however, it showed 46.2% [77.9 vs 53.3 L kg−1 volatile solid (VS)] more cumulative biogas yields, and higher reduction rate of total solid, VS, cellulose and hemicellulose of 29.5, 31, 40.6 and 15%, respectively, which was likely due to optimized pH and NaOH pretreated switchgrass during start-up period. Methane contents of biogas increased gradually and stabilized at 50% for both reactors, indicating a normal operation of anaerobic digestion lasted for at least 100 days. The determined parameters of digested residues met China organic fertilizer standard (NY 525-2012) except for high moisture and low total nutrient contents. Therefore, the product of SSAD has the potential value of organic fertilizer. It is concluded that the LAD digestate can be reused as inoculums by co-digestion with agricultural residues for biogas and organic fertilizer production in SSAD.

This paper presents a novel approach to multi-criteria sustainability performance assessment of horticultural crops. The crops are ranked by the decision-making method ELECTRE IV with environmental, energy and technological criteria. In total eight indicators are taken into consideration and calculated based on primary data collected from over 260 farms in northern Iran. Additionally, Data Envelopment Analysis is used to calculate the technical efficiency and potential for energy saving by different management of the production units. The novel contribution of this study is the comparison of several horticultural products (oranges, kiwis, persimmons and tangerines), when most of the previous studies have focused on one product. Moreover, novel calculations of the carbon footprint are presented for oranges, tangerines and persimmons. This paper also includes the first study on the environmental impact of persimmon fruit's production. The obtained results show that energy efficiency for orange, tangerine, kiwi and persimmon products: 1.1, 0.84, 0.53 and 1.22, respectively. In each hectare of kiwi orchards, the amount of CO2 emissions of 1219 kg and the ecological footprint of 3.21 hectares have been calculated, which is statistically significant compared to orange, tangerine and persimmon. The chemical and fuel inputs have the greatest potential for reducing energy consumption in the studied products. Results of ELECTRE IV showed that kiwi is the most sustainable selection for the studied region followed by orange, persimmon and tangerine, respectively. Kiwi has also relatively low technical efficiency. This means that this product has the greatest potential for a reduction of energy consumption, while maintaining the same amount of crop. It is recommended to include the development of kiwi orchards in the policies of Guilan, but with more careful management of the production inputs.