SciCombinator

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Concept: Agroecology

429

Organic agriculture is proposed as a promising approach to achieving sustainable food systems, but its feasibility is also contested. We use a food systems model that addresses agronomic characteristics of organic agriculture to analyze the role that organic agriculture could play in sustainable food systems. Here we show that a 100% conversion to organic agriculture needs more land than conventional agriculture but reduces N-surplus and pesticide use. However, in combination with reductions of food wastage and food-competing feed from arable land, with correspondingly reduced production and consumption of animal products, land use under organic agriculture remains below the reference scenario. Other indicators such as greenhouse gas emissions also improve, but adequate nitrogen supply is challenging. Besides focusing on production, sustainable food systems need to address waste, crop-grass-livestock interdependencies and human consumption. None of the corresponding strategies needs full implementation and their combined partial implementation delivers a more sustainable food future.

Concepts: Carbon dioxide, Agriculture, Organic farming, Natural gas, Sustainable agriculture, Greenhouse gas, Agroecology, Permaculture

73

Numerous reports have emphasized the need for major changes in the global food system: agriculture must meet the twin challenge of feeding a growing population, with rising demand for meat and high-calorie diets, while simultaneously minimizing its global environmental impacts. Organic farming—a system aimed at producing food with minimal harm to ecosystems, animals or humans—is often proposed as a solution. However, critics argue that organic agriculture may have lower yields and would therefore need more land to produce the same amount of food as conventional farms, resulting in more widespread deforestation and biodiversity loss, and thus undermining the environmental benefits of organic practices. Here we use a comprehensive meta-analysis to examine the relative yield performance of organic and conventional farming systems globally. Our analysis of available data shows that, overall, organic yields are typically lower than conventional yields. But these yield differences are highly contextual, depending on system and site characteristics, and range from 5% lower organic yields (rain-fed legumes and perennials on weak-acidic to weak-alkaline soils), 13% lower yields (when best organic practices are used), to 34% lower yields (when the conventional and organic systems are most comparable). Under certain conditions—that is, with good management practices, particular crop types and growing conditions—organic systems can thus nearly match conventional yields, whereas under others it at present cannot. To establish organic agriculture as an important tool in sustainable food production, the factors limiting organic yields need to be more fully understood, alongside assessments of the many social, environmental and economic benefits of organic farming systems.

Concepts: Biodiversity, Agriculture, Organic farming, Sustainable agriculture, Green Revolution, Crop rotation, Agroecology, Industrial agriculture

63

Land area devoted to organic agriculture has increased steadily over the last 20 years in the United States, and elsewhere around the world. A primary criticism of organic agriculture is lower yield compared to non-organic systems. Previous analyses documenting the yield deficiency in organic production have relied mostly on data generated under experimental conditions, but these studies do not necessarily reflect the full range of innovation or practical limitations that are part of commercial agriculture. The analysis we present here offers a new perspective, based on organic yield data collected from over 10,000 organic farmers representing nearly 800,000 hectares of organic farmland. We used publicly available data from the United States Department of Agriculture to estimate yield differences between organic and conventional production methods for the 2014 production year. Similar to previous work, organic crop yields in our analysis were lower than conventional crop yields for most crops. Averaged across all crops, organic yield averaged 80% of conventional yield. However, several crops had no significant difference in yields between organic and conventional production, and organic yields surpassed conventional yields for some hay crops. The organic to conventional yield ratio varied widely among crops, and in some cases, among locations within a crop. For soybean (Glycine max) and potato (Solanum tuberosum), organic yield was more similar to conventional yield in states where conventional yield was greatest. The opposite trend was observed for barley (Hordeum vulgare), wheat (Triticum aestevum), and hay crops, however, suggesting the geographical yield potential has an inconsistent effect on the organic yield gap.

Concepts: Agriculture, United States, Wheat, Soybean, Organic farming, Crops, Crop rotation, Agroecology

25

The beneficial use of silver nanoparticles (AgNPs) in agroecosystems is not fully explored with partial information available, of which most of the studies are limited to laboratory conditions and only few involve natural ecosystems. AgNPs, being the most popular metallic nanoparticles exhibiting antimicrobial property, are predominantly used for plant disease management. Owing to the ill hazards of chemically synthesized AgNPs, their biosynthesis using environment-friendly biomolecules is gaining noteworthy attention. In addition, considering the advantages of nanoformulations over biopesticides, there is no doubt that biosynthesized AgNP-based biopesticides could revolutionize the agricultural sector in the future. Though enhanced commercial use of AgNPs has generated biosafety issues in modern scenario but expecting their significant contribution towards agricultural sector, it is too early to predict the risk factor associated with their usage. To unveil the toxicity factor of AgNPs, we need to focus and understand the major interactions of AgNPs in agroecosytems. Hence, the present review highlights (i) the potential application of AgNPs in the agricultural sector particularly for plant disease management, (ii) significance of biosynthesized AgNPs using microbes and plants over their chemical synthesis, (iii) major interactions of AgNPs in agroecosystems (with soil, soil biota, and plants) with emphasis to deal with toxicity-determining factors, and (iv) identifying future research work holding promising applications of biosynthesized AgNPs in agroecosystems.

Concepts: Present, Biodiversity, Agriculture, Future, Chemistry, Ecosystem, Chemical synthesis, Agroecology

11

To promote global food and ecosystem security, several innovative farming systems have been identified that better balance multiple sustainability goals. The most rapidly growing and contentious of these systems is organic agriculture. Whether organic agriculture can continue to expand will likely be determined by whether it is economically competitive with conventional agriculture. Here, we examined the financial performance of organic and conventional agriculture by conducting a meta-analysis of a global dataset spanning 55 crops grown on five continents. When organic premiums were not applied, benefit/cost ratios (-8 to -7%) and net present values (-27 to -23%) of organic agriculture were significantly lower than conventional agriculture. However, when actual premiums were applied, organic agriculture was significantly more profitable (22-35%) and had higher benefit/cost ratios (20-24%) than conventional agriculture. Although premiums were 29-32%, breakeven premiums necessary for organic profits to match conventional profits were only 5-7%, even with organic yields being 10-18% lower. Total costs were not significantly different, but labor costs were significantly higher (7-13%) with organic farming practices. Studies in our meta-analysis accounted for neither environmental costs (negative externalities) nor ecosystem services from good farming practices, which likely favor organic agriculture. With only 1% of the global agricultural land in organic production, our findings suggest that organic agriculture can continue to expand even if premiums decline. Furthermore, with their multiple sustainability benefits, organic farming systems can contribute a larger share in feeding the world.

Concepts: Agriculture, Organic farming, Sustainable agriculture, Crop rotation, Agroecology, Industrial agriculture, Permaculture, Wildculture

6

Organic farming (OF) has been believed to be capable of curtailing some hazardous effects associated with chemical farming (CF). However, debates also exist on whether OF can feed a world with increasing human population. We hypothesized that some improvements on OF may produce adequate crops and reduce environmental pollutions from CF. This paper makes comparative analysis of crop yield, soil organic matter and economic benefits within the practice on Biodiversity Management of Organic Farming (BMOF) at Hongyi Organic Farm (HOF) over eight years and between BMOF and CF. Linking crop production with livestock to maximal uses of by-products from each production and avoid xenobiotic chemicals, we have achieved beneficial improvement in soil properties, effective pest and weed control, and increased crop yields. After eight years experiment, we have obtained a gradual but stable increase in crop yields with a 9.6-fold increase of net income. The net income of HOF was 258,827 dollars and 24,423 dollars in 2014 and 2007 respectively. Thus, BMOF can not only feed more population, but also increase adaptive capacity of agriculture ecosystems and gain much higher economic benefits.

Concepts: Biodiversity, Agriculture, Soil, Organic farming, Sustainability, Yield, Crop rotation, Agroecology

5

There has been growing policy interest in social justice issues related to both health and food. We sought to understand the state of knowledge on relationships between health equity-i.e. health inequalities that are socially produced-and food systems, where the concepts of ‘food security’ and ‘food sovereignty’ are prominent. We undertook exploratory scoping and mapping stages of a ‘meta-narrative synthesis’ on pathways from global food systems to health equity outcomes. The review was oriented by a conceptual framework delineating eight pathways to health (in)equity through the food system: 1-Multi-Scalar Environmental, Social Context; 2-Occupational Exposures; 3-Environmental Change; 4-Traditional Livelihoods, Cultural Continuity; 5-Intake of Contaminants; 6-Nutrition; 7-Social Determinants of Health and 8-Political, Economic and Regulatory context. The terms ‘food security’ and ‘food sovereignty’ were, respectively, paired with a series of health equity-related terms. Combinations of health equity and food security (1414 citations) greatly outnumbered pairings with food sovereignty (18 citations). Prominent crosscutting themes that were observed included climate change, biotechnology, gender, racialization, indigeneity, poverty, citizenship and HIV as well as institutional barriers to reducing health inequities in the food system. The literature indicates that food sovereignty-based approaches to health in specific contexts, such as advancing healthy school food systems, promoting soil fertility, gender equity and nutrition, and addressing structural racism, can complement the longer-term socio-political restructuring processes that health equity requires. Our conceptual model offers a useful starting point for identifying interventions with strong potential to promote health equity. A research agenda to explore project-based interventions in the food system along these pathways can support the identification of ways to strengthen both food sovereignty and health equity.

Concepts: Agriculture, Health disparities, Nutrition, Economics, Concept, Population health, Food security, Agroecology

4

Globally soil quality and food security continue to decrease indicating that agriculture and the food system need to adapt. Improving connection to the soil by knowledge exchange can help achieve this. We propose a framework of three types of connections that allow the targeting of appropriate messages to different groups of people. Direct connection by, for example, handling soil develops soil awareness for management that can be fostered by farmers joining groups on soil-focused farming such as organic farming or no-till. Indirect connections between soil, food and ecosystem services can inform food choices and environmental awareness in the public and can be promoted by, for example, gardening, education and art. Temporal connection revealed from past usage of soil helps to bring awareness to policy workers of the need for the long-term preservation of soil quality for environmental conservation. The understanding of indirect and temporal connections can be helped by comparing them with the operations of the networks of soil organisms and porosity that sustain soil fertility and soil functions.

Concepts: Biodiversity, Agriculture, Soil, Sustainability, Food security, Sustainable agriculture, Agroecology, Permaculture

3

Humans adapted over a period of 2.3 million years to a diet high in quality and diversity. Genome-nutrition divergence describes the misalignment between modern global diets and the genome formed through evolution. A survey of hominin diets over time shows that humans have thrived on a broad range of foods. Earlier diets were highly diverse and nutrient dense, in contrast to modern food systems in which monotonous diets of staple cereals and ultraprocessed foods play a more prominent role. Applying the lens of genome-nutrition divergence to malnutrition reveals shared risk factors for undernutrition and overnutrition at nutrient, food, and environmental levels. Mechanisms for food system shifts, such as crop-neutral agricultural policy, agroecology, and social policy, are explored as a means to realign modern diets with the nutritional patterns to which humans may be better adapted to thrive.

Concepts: Agriculture, Nutrition, Ecology, Obesity, Food, Malnutrition, Agroecology, Food systems

3

Cropland use activities are major drivers of global environmental changes and of farming system resilience. Rotating crops is a critical land-use driver, and a farmers' key strategy to control environmental stresses and crop performances. Evidence has accumulated that crop rotations have been dramatically simplified over the last 50 years. In contrast, organic farming stands as an alternative production way that promotes crop diversification. However, our understanding of crop rotations is surprisingly limited. In order to understand if organic farming would result in more diversified and multifunctional landscapes, we provide here a novel, systematic comparison of organic-to-conventional crop rotations at the global scale based on a meta-analysis of the scientific literature, paired with an independent analysis of organic-to-conventional land-use. We show that organic farming leads to differences in land-use compared to conventional: overall, crop rotations are 15% longer and result in higher diversity and evener crop species distribution. These changes are driven by a higher abundance of temporary fodders, catch and cover-crops, mostly to the detriment of cereals. We also highlighted differences in organic rotations between Europe and North-America, two leading regions for organic production. This increased complexity of organic crop rotations is likely to enhance ecosystem service provisioning to agroecosystems.

Concepts: Agriculture, Organic farming, Sustainable agriculture, Crop rotation, Agroecology, Industrial agriculture, Green manure, Wildculture