Organic Agriculture: Global Challenges and Environmental Impacts

Abstract

Agriculture has been intensified for years to provide food and nutrition security for the growing world population in emerging nations. Conventional methods, especially the widespread and ineffective use of N fertilizer, increase the cost of agricultural production and contribute to environmental degradation, including the production of greenhouse gases, ammonium volatilization, groundwater pollution, etc. In long term, intensive agricultural practices cause depletion of soil productivity by limiting its functions such as biomass production, carbon sequestration, etc. which may threaten our sustenance. In this crisis scenario, for sustainable intensification, organic agriculture has been proposed as a one-stop solution with enormous benefits. Many researchers have proved that organic fertilizer application in agriculture improves soil health by enhancing biogeochemical properties. Moreover, organic agriculture has been claimed as climate-smart agriculture. Contrarily, it is clear that organic fertilizer (as compost, manure, etc.) may cause heavy metal pollution and that organic particles may pollute the atmosphere. There is controversy on how OA affects biodiversity. Although just 1.5% of all land is organically grown (excluding organic non-agricultural land), the world has recently seen a surge in interest in OA. This chapter will concentrate on the present incarnation of organic agriculture worldwide, including advancements, benefits, and environmental consequences.

1. Introduction

In the twenty-first century, one of the biggest challenges that have been addressed globally is “food security”. The Food and Agricultural Organization has reported that food production will have to increase by 70% for a 2.1 billion additional global population by 2050 [1]. Between 1970 and 2010, the world’s grain production double to 2.5 billion tons, with an increase in the average yield of 1600 to 3030 kg per hectare [2]. However, this agricultural intensification is practiced worldwide mainly through the increase in global fertilizer usage from 32 to 106 Mt yr⁻¹ [3]. In addition, Synthetic N fertilizer widely used for high-yield production contributes 38.8% of N₂O emission, a GHG with 265 times more global warming potential than CO₂ over a 100 years period [4]. Traditional farming methods for increasing agricultural productivity increase environmental problems such biodiversity loss, rapid soil erosion and deterioration, eutrophication, groundwater pollution, adverse effects of pesticides on wildlife and humans, etc. It is already abundantly evident that current “non-organic” agricultural methods, which mainly rely on intensive synthetic fertilizer input and pesticide application, cannot meet the task of providing enough food while maintaining a sustainable ecology [5]. Hence, ecological methods to sustainable intensification are the all-in-one solution for the production of food in the future. Nowadays, “organic agriculture” is recognized as a method of ecological intensification on a global scale [6].

Contrary to traditional farming, organic agriculture (OA) produces food in quantities insufficient for mass consumption, but it is environmentally benign and produces as nutritious or more nutrient-dense foods with less (or no) pesticide residues. Generally, when a natural ecosystem converts to farming practices, the topsoil losses about 20–40% of SOC following cultivation in the first few years [7]. OA helps to sequestrate SOC in soil and improves soil health by enhancing soil biological activities, nutrient dynamics, and availability [8]. It has been scientifically demonstrated that organic soils have 44% more long-term carbon storage than conventionally managed soils by evaluating over a thousand soil samples from farms maintained organically and conventionally in 48 states of the USA [9]. According to a recent research, organic farming reduces soil erosion by delivering less mean sediment than conventional farming [10]. OA helps to mitigate GHG emissions by reducing nitrous oxide by 50% and methane emissions by 70% [11]. OA may be viewed as a climate-smart agricultural strategy for reducing the consequences of climate change and enhancing soil health and quality, including nutrient and water retention, as well as boosting agricultural output.

Organic farming is a fast-growing sector. Since people are becoming health-conscious day by day, the demand for organic food is skyrocketing in the local market. The fact is, OA currently occupies only 1.5% of the global total agricultural land [12]. There is a concern that it is difficult to predict the impacts of widespread OA adoption due to mounting evidence that organic fertilizers can include significant levels of trace metals including Cu, Ni, Cr, Zn, As, Pb, and Cd [13]. Application of organic manure above 6.25 t ha⁻¹ per season may contribute to greater CH₄ and N₂O emissions in the rice ecosystem [14]. Yet, the use of animal manures, the use of natural pesticides and fertilizers, the management of postharvest residues, irrigation, and tillage activities may all have a detrimental influence on the environment [15]. Further research is undergoing globally to understand the environmental impacts of long-term adaptation of OA on a large scale. This review will discuss the present scenario of OA worldwide and the current reports in the literature regarding its environmental impacts under the long-term adaptation in different management systems.

2. Organic agriculture (OA)

Considering ecological principles as the base for crop production, the concept of organic agriculture is analogous worldwide. The General Assembly of IFOAM defines “organic Agriculture as a production system that sustains the health of soils, ecosystems, and people. It relies on ecological processes, biodiversity and cycles adapted to local conditions, rather than the use of inputs with adverse effects. OA combines tradition, innovation, and science to benefit the shared environment and promote fair relationships and good quality of life for all involved”. Although there are many meanings and interpretations of OA, common techniques to maintain soil fertility and produce high-quality products in OA include: (1) implementing suitable rotation programs; (2) adding composts; (3) using physical, mechanical, and biological mechanisms to control diseases, pests, and weeds; and (4) implementing organic practices in the feed and livestock production [16]. Cover crops and green manures, however, are crucial to the success of OA because they perform a variety of vital tasks such as fixing nitrogen (N), contributing organic matter (OM), and offering home for beneficial species [17]. Efficiency, environmental impact, economic feasibility, and social well-being are the four main sustainability criteria that Reganold and Wachter [18] have used to analyze the success of organic farming. They came to the conclusion that, although having lower yields, OA provides more environmental services and societal benefits. In order to create sustainable farming systems, which probably would include a combination of organic and non-organic methods, organic farming techniques must be taken into account.

2.1 Global scenario of OA

According to a study on “The World of Organic Agriculture – Statistics and Emerging Trends 2021”, approximately 72.3 million hectares were under organic agricultural management worldwide in 2019. This is over 1.1 million hectares or 1.6% more than the previous year. 2019 saw a more than six-fold rise in the proportion of agricultural land that was organic compared to 1999. Half of the world’s organic farming acreage is in Oceania. Around 23% of the world’s organic agricultural land is in Europe, a region that has seen steady expansion in this area over the years, followed by South America with 12% (Figure 1). Organic farming is not growing as much in certain continents, including Asia and Africa, due to larger populations and more food demand, as organic farmers do not receive as much produce as conventional farmers do. In 2019 the agricultural land has significantly decreased in Asia (−7.1%) due to the drop in organic farmland in China. And Oceania (−0.3%) respectively.

Figure 1.

2019 global organic agricultural land distribution by region (Source: FiBL survey 2021).

At 35.69 million hectares, Australia has the most organic land worldwide. Argentina comes in second place with 3.67 million hectares, while Spain comes in at more over two million hectares. Yet, grazing land makes up 97% of Australia’s agriculture, according to estimates. Almost 80% of all agricultural area used for organic production is found in the top 10 nations (Figure 2). In terms of percentage, 1.5% of all organic land in the globe is organic. Liechtenstein has the greatest percentage of its agricultural land managed organically, at 41%. More than 10% of the organic share is held by the majority of European nations. Organic land expansion has accelerated in numerous nations, including India (18.6%) and Ukraine (54.6%) A total of 35 Mha of non-agricultural land—including land used for forestry, aquaculture, wild collecting, and grazing regions on non-agricultural land—is organic [12]. This data posits that there may be a good probability of increasing the popularity of organic farming among farmers in areas with lower population densities, strain on the land, overall food demand and shortfall.

Figure 2.

The 10 countries with the largest area of organic agricultural land in 2019 (Source: FiBL survey 2021).

Further, there are more than 3 million organic producers worldwide. Asia, Africa, and Europe together account for more than 91% of global producers. The country with the greatest number of organic producers is India (1.36 million), followed by Uganda and Ethiopia. 1–2% of all food sales globally are organic. According to the nation, future growth is anticipated to range from 10 to 50% yearly [19]. Almost 106 billion euros worth of organic food was sold at retail in total. The United States is the nation with the biggest market for organic food.

When compared to conventional agriculture, the adoption of OA is economically competitive. For instance, OA is more lucrative (22–35%) than conventional agriculture due to the higher cost of organic goods compared to their non-organic equivalents (20–24%). Though with lower organic yields of 10–18%, breakeven premiums for organic earnings must still be at least 5–7% to meet conventional profits. Reduced environmental costs (negative externalities) and improved ecosystem services brought about by the use of appropriate farming methods may also support OA financially [20].

In conclusion, while being modest globally, agricultural land is expected to grow. Organic agricultural practices have several advantages for sustainability and can help ensure global food security [20]. Moreover, it is becoming increasingly evident that OA can be crucial in tackling issues including land and soil erosion, climate variability, hunger relief, poverty reduction, health, and biodiversity management [21].

3. Environmental aspects of OA

3.1 Organic agriculture and soil health

One of the keystones of organic agriculture is to ameliorate and maintain soil health. Soil organic carbon (SOC) strongly affects soil health and functionality. From an agronomic and ecological perspective, proper SOC stock management is crucial for crop productivity in organic farming [22]. The main practices of OA including returning plant residues and manure application, and/or integrating cover crops into the system reduce SOC losses from topsoil, and either maintain SOC or increase SOC stocks [23]. For example, a meta-analysis contrasting conventional and organic farming methods under Mediterranean croplands revealed that the rate of SOC sequestration in topsoil (average soil depth 19.4 cm) rose by 0.97 Mg C ha⁻¹ yr⁻¹ under OA in comparison to those under conventional management [24]. According to a recent study, decreased tillage in organic farming raised cumulative SOC stocks by 1.7%, or 1.5 Mg ha⁻¹ (0–50 cm), and 3.6%, or 4.0 Mg ha⁻¹ (0–100 cm), compared to traditional tillage, with estimated mean C sequestration levels of 0.09 and 0.27 Mg ha⁻¹ yr⁻¹, respectively [25]. An optimized conventional system with some “organic” tactics, like cover crops, crop rotation, and mulches, but without using mineral fertilizers, demonstrated higher sequestration in one research [26]. Yet, in a different study, only the biodynamic system with a high livestock density showed a noticeable advantage [27]. Using basic default values for carbon sequestration in forests, Table 1 compares the sequestration rates in organic and conventional agriculture systems and demonstrates the efficiency of the organic system in the USA. These results show that in the studied locations, organic systems consistently retain more carbon than conventional systems. Yet, compared to organic farming, conventional farming paired with forests sequesters more carbon. Also, the relative production in organic farming is satisfactory, but more acreage is required for the profound respect.

Reference	C sequestration rate (kg ha^−1 yr^−1)			Relative productivity of organic system		Potential carbon sequestration by afforestation (in kg ha^−1 yr^−1)	Total sequestration C (kg ha^−1 yr^−1)
	Organic		Conventional	Relative yields	Additional area demand ha^−1		Conventional + forest	Advantage/disadvantage of organic system
Switzerland1	Min	−123	−207	84%	1.2	1700	98	−221
	Max	42	−207	83%	1.2	1700	117	−75
USA Pennsylvania2	Min	857	217	92%	1.1	3300	464	393
	Max	1218	217	97%	1.0	3300	309	909

Table 1.

A comparison of the sequestration potential of a “organic” and a “conventional + forest” system is carried out based on the measured sequestration rates of four comparable field studies in Europe and the USA.

¹

[27].

²

[28].

Higher SOM concentrations in the topsoil layer on arable land under organic farming can positively influence soil stability, according to a number of studies [9, 29]. According to the findings of William et al. [30], organic farming reduces bulk density by 3% more than the conventional farming system. Additionally, it enhances water infiltration capacity and increases aggregate stability by 50% under green manure application than conventional farming. Seitz et al. [10] demonstrated that organic agricultural practices decline soil erosion by decreasing mean sediment delivery by 30% more than modern agricultural practices. It is revealed that conservation tillage may decrease soil erosion and improve soil structure [31]. In contrast, organic farming with minimum tillage may increase soil compaction in long term and decreases the earthworm population in the soil [32].

The incorporation of manure or compost in organic agriculture helps to avoid exceeding soluble nutrients release such as nitrogen and phosphorus, at the same time, contributing an essential source of carbon for the growth and activity of soil organisms. Organic N fertilizers significantly increase the potential for nitrification, nitrite oxidation, and denitrification [33]. Moreover, with particular management practices, seasonal variation affects soil N mineralization and potentially synchronizes soil available N supply with demand for cash crops, productivity, nutrient (N and P) loading, risk of losses, and nutrient use efficiency from organic manufacturing systems can vary [34]. The best strategy to increase microbial biomass and its activity is by amending the soil with organic materials [35, 36]. Organic fertilizer increases the microbial exoenzymatic activities involved in the mineralization of C, N, and P [37]. Certain microbial communities engaged in symbiotic nitrogen fixation and microbial stimulation of nutrient absorption at root surfaces are made more effective by OA [38].

OA ensures soil sustainability by improving soil bio-physiochemical activities. Though, caution is required for soil health-related issues in organic agriculture, as the on-farm management efficiency differs. Nevertheless, for eco-friendly agricultural production organic agriculture in the standard way can be considered a large potent system.

3.2 Greenhouse gas fluxes under OA

It is assumed that agriculture is a major contributor to GHG emissions and is vulnerable to climate change. OA is suggested as a one-stop solution to mitigate emissions. Some past studies have produced controversial results regarding the potential of OA for mitigation [39]. For example, The amount of greenhouse gases (GHGs) emitted from agricultural output as a whole and the intensity of GHGs emitted per hectare of agricultural land are both rising in the USA, according to McGee [40]. According to Williams et al. [41] lower yields and higher rates of nitrate leaching counteract the reduced input consumption in most organic cropping systems in England, which create equivalent or higher GHG emissions per ton of crop than conventional processes.

By using meta-analysis, structural factors impacting GHG emissions for traditional and open architecture systems have been studied [42]. As compared to traditional farming, OA had fewer GHG emissions in nearly two-thirds of the 195 observations. In terms of GHG emissions for farms growing field crops, dairy products, and mixed crops, OA outperformed conventional farming. On farms that raised animals, grew vegetables, or produced fruit, OA was less likely to be more effective in terms of GHG emissions. Yet, the unit or foundation of measurement had a significant impact on how well OA reduced GHG emissions. Due to yield variations, output-based (ratio/Mg) metrics greatly lessened the superiority of GHG emissions impacts for OA compared to area-based (ratio/ha) measures. The fact that most studies were from Europe and did not take into account nutritional spillover effects in conventional-organic conversions was one of the drawbacks of this meta-analysis [42].

Using a life-cycle analysis, Smith et al. [39] evaluated the effects on net GHG emissions of a 100% switch to organic food production in England and Wales. He came to the conclusion that organic farming reduces direct GHG emissions, but when increased overseas land usage to make up for local supply shortages is taken into account, net emissions are higher (Figure 3).

Figure 3.

Total greenhouse gas emissions (GHG) from farming in conventional and organic systems in England and Wales (E & W). (a) For food crops for human consumption both from home and overseas production. (b) Additional net emissions due to soil C sequestration (CS) and overseas land use changes (LUC) to compensate for shortfalls in home production: high = all LUC by conversion from grassland, no CS; medium = 50% of LUC by conversion from grassland, moderate CS; low = 25% of LUC by conversion from grassland, high CS; COC = carbon opportunity cost of Searchinger et al. [43] (Methods).

3.2.1 CO₂ emission

Under irrigated conventional and irrigated OA management of common beans in the Mediterranean climate, Kontopoulou et al. [44] measured CO₂ emissions. In comparison to conventional management, OA had higher cumulative CO₂ emissions over the 84-day cropping period (2.5 and 2.8 Mg CO₂ ha⁻¹ for high and low salinity irrigation water, respectively) (2.1 and 2.3 Mg CO₂ ha⁻¹ for high and low-salinity irrigation water, respectively). Compost and other organic manures can improve soil C stocks [45] but may also result in higher CO₂ emissions [46]. Also, the use of compost may have improved the following factors: (1) soil structure and pore space continuity; (2) root penetration and gas and water movement; (3) root exudation and, therefore, a microbial activity that may have increased microbial respiration in the rhizosphere [44]. The global warming potential (GWP) per 1 m² of land in organic farming was determined to be 0.12 kg CO₂ eq., which was three times lower than in the conventional system, according to an environmental impact evaluation of organic and conventional leek production methods in Belgium (0.36 kg CO₂ eq.) [47]. The GWP in organic and conventional herbaceous farming systems was also studied in Spain. The organic system greatly reduced GHG emissions (between 35.9 and 64.7% and 16.3 and 41.9%, respectively) [24].

3.2.2 CH₄ emission

Based on the activity of certain CH₄⁻ and ammonium oxidizing bacteria and site-specific circumstances, well-aerated soils have the ability to behave as CH₄ sinks. A meta-study was carried out to compare area-scaled CH₄ emissions from organic and non-organic farming, however no appreciable differences between the two cultivation methods were discovered [2]. It has been shown that soils managed organically assimilate more CH₄ than soils managed conventionally (−0.61 versus −0.54 kg CH₄ ha⁻¹ yr⁻¹; mitigating 20.2 and 18.0 kg CO₂ eq. ha⁻¹, respectively) [5]. The cause is that consistent treatment of piled cow dung boosts methanogenic archaea biomass and enzymatic activity [23]. Contrarily, rice paddies are a significant source of CH₄ emissions under both types of management, contributing 6023 kg CO₂ eq. ha⁻¹ yr⁻¹ under organic management and 4857 CO₂ eq. ha⁻¹ yr⁻¹ under conventional management. In the rice environment, emissions of CH₄ are caused by anaerobic microbial degradation of OM and organic fertilizer [48].

3.2.3 N₂O emission

The anticipation of decreased soil N₂O emissions is supported by the usually lower N input level for soils under OA compared to those under conventional management approaches [48]. In addition, Skinner et al. [3] observed that organic systems reduced N₂O emissions per hectare by 40.2% when compared to non-organic systems. It is expected that a significant portion of the ensuing N₂O emissions may begin to be effective beyond the vegetative period under investigation because of the delayed release of mineral N from organic sources [3]. As opposed to unamended and conventionally managed plots (0.64 kg N₂O ha⁻¹), manure-amended organic plots had greater cumulative N₂O emissions over the winter in plots that were grown with soybeans (1.63 kg N₂O ha⁻¹) [49]. Yet, under OA, denitrification efficiency improves most likely as a result of the following factors: (1) higher C inputs from grassland and fertilizer; (2) higher SOC and N contents; (3) bigger, more active microbial communities; and (4) variations in how the denitrifier communities work [50].

3.3 Organic fertilizer and heavy metal contamination

While if other activities (such air deposition or mining) might potentially result in soil buildup, organic fertilizer, such as manure and compost, can be the main source releasing heavy metals into the ecosystem [51]. There is a lot of data to support the claim that organic fertilizers (such manure, compost, and sludge) may contain significant amounts of trace metals including Cr, Ni, Cu, Zn, As, Cd, and Pb as well as have a high bio transfer potential [13]. Various trace metals have lower thresholds for non-agricultural usage and higher threshold limits for conventional and organic agriculture. For instance, 212 samples of Chinese organic fertilizers including cattle dung had Cr, As, Cd, and Pb contents that were 4.2%, 13.7%, 2.4%, and 1.4% higher than the recommended range, respectively [52]. According to some authors, organic amendments increase the mobility of Cd in soil, and copper follows a similar pattern in the soil horizon [53].

3.4 Water quality

Water is essential for both human and ecological wellbeing, as well as the long-term ecological and socioeconomic resilience of our food and agricultural systems. Water use and pollution are mostly the responsibility of the agriculture sector. Water usage and outflow in both plant and animal farms are major contributors to water pollution. The pesticides, fertilizers, and feed put to the ponds cause a multitude of contaminants to be carried in the wastewater [54]. Synthetic fertilizers cause numerous contaminants to combine with freshwater, but because they are not allowed in organic agriculture, the water quality is finally improved.

Organic farming employs a variety of methods to prevent soil erosion, water runoff, and nutrient leakage. Organic farming practices maintain nitrogen in crop plants used in rotation and stop nitrate leaching [55]. N leaching per area appears to be lessened in organic agriculture on average [56, 57]. When organic matter is added to the soil, soil organisms develop and reproduce more quickly and hold onto soil nitrogen in a more stable form [58]. Lower N inputs are often linked to lower N losses from organic systems [59]. In addition to that, higher levels of organic matter in organically maintained soils can increase their ability to store nitrogen [60, 61]. Non-leguminous plants are frequently used in organic farming as cover crops. It was observed that in cover-cropped areas with high levels of biological activity, the soil’s capacity to retain nitrogen against leaching was also higher [62].

Effective remarks on phosphorus (P) leaching from organic versus conventional systems cannot be made due to the dearth of research [57, 63]. Because many organic inputs have poor N:P ratios, organic farmers frequently overfertilize for P while attempting to meet crop N requirements [64]. P surpluses in agricultural areas do not necessarily translate into P shortages since many soils depend on erosion rates and the absorption of P in organic inputs as well as having strong P buffering capacities (or P deficit in crop P restriction) [64].

Critics contend that some organic pesticides are more dangerous than synthetic pesticides [65], despite the common belief that organic management reduces pesticide burdens [18]. Despite having lower toxicity quotients, several organic pesticides, like sulfur and rotenone, can cause toxicity if they are used more often [66]. In contrast to that, organic farming generally uses integrated pest management [67] or less toxic pesticides [68]. It’s probable that organic agriculture has less pesticide leaching than conventional agriculture does.

Utilizing methods that recycle and store nutrients within the farming system, organic farmers may prevent water pollution. When these procedures are carried out as a component of an integrated, systems-based strategy, they are both most efficient and long-lasting. In places where pollution is a real problem, organic agriculture is highly anticipated as a positive solution [69].

3.5 Air quality

By discharging nutrients, pathogens, heavy metals (including Cu), particulate matter, and toxic gases into the air, OA may contribute to air pollution [15]. For instance, the common practice of OA farming with traditional tillage may degrade air quality by dispersing fine dust and debris in the atmosphere. However, compared to conventionally managed farms, organically managed farms may have lower airborne particle concentrations due to usually less soil erosion [35]. Moreover, the processing and surface application of animal manures, as well as emissions from feedlots, have all been linked to air pollutants such particulate matter, oxides of N, C, and S, as well as NH₃, CH₄, and H₂S, volatile organic compounds, and pathogens [15]. Moreover, OA may degrade the air quality as a result of N losses from organic compost or green manures due to the volatilization of excess N that does not meet crop needs [35].

3.6 Impacts of OA on biodiversity

Comparing organic agriculture practices to traditional systems, several species and organism groupings may be found in greater numbers. According to certain studies, organic farming practices often boost biodiversity [70]. Most research comparing biodiversity in organic and conventional farming showed that organic farming has less of an impact on the ecosystem [56]. Organic farming raises agricultural landscape diversity, for instance by attracting carabid beetles [71, 72] vascular vegetation [73], or birds [74]. By utilizing toxic herbicides and pesticides that build up in ground and surface waterways, conventional agriculture contributes to the loss of biodiversity. This contaminates fisheries, pollinator habitats, and wildlife’s natural habitats. Yet, organic farming preserves the health of ecosystems, soils, and people. Given that organic food is grown in accordance with nature, organic farmers are guardians of biodiversity on all scales, from seeds and worms to birds and bees. In research, it was found that predator abundances and predator-prey ratios were 20 times greater in organic fields than in conventional fields, the abundance of cereal aphids was five times lower in organic fields. This suggests that organic fields have a much better potential for biological pest management [75].

Organic agriculture ensures greater variety and abundance of floral species in the crop, crop perimeter, and uncultivated areas [76, 77]. In contrast with conventional farms, Shepherd et al. [78] discovered six times more species in the crop on organic agriculture. Hole et al. [79] found that rare agricultural species are more common on organic farms. Higher bee diversity [80], higher butterfly abundance [81], microbiological activity and biomass in soil [82] was found in organic farming compared to traditional one. Forfeiting the use of herbicides, using very little and fresher organic fertilizer, varying crop rotations with a higher proportion of clover grass, conservation tillage, and a more diverse farming structure are typical organic farming practices that most noticeably boost biodiversity. Nevertheless, organic farming seems to perform superior to traditional farming and offers significant environmental benefits like reducing water consumption, reducing carbon and ecological footprints, and stopping the use of dangerous chemicals and their spread across the environment and up the food system.

3.7 Controversial scientific debate on OA

In the scientific community, the effects of organic farming on the environment have been hotly debated for many years. Regarding how much organic farming can do to help with resource issues and if its promotion is a sensible course of action for addressing current socio-ecological issues, there are still divergent opinions. Two major objections have been made in the last 20 years or so that suggest organic agriculture is not superior to conventional agriculture in terms of its effects on the environment. As discussed further in detail below and illustrated schematically in Figure 4.

Figure 4.

There are two main discussion lines that can be traced back to two significant objections against the environmental advantages of organic farming (OA) [83].

The yield gap between organic and conventional systems is therefore an important topic in these discussions, and it is mostly examined in light of a few important meta-studies [84, 85, 86]. Moreover, it has been stated that the idea of yield stability, which refers to the temporal unpredictability and dependability of output, is crucial when contrasting organic and conventional agriculture in terms of food security [87]. In general, it is becoming more and more apparent that the sustainability evaluation of various agricultural systems must take into account a wide range of complicated monetary and environmental interrelationships in addition to output [88, 89].

On the other hand, tradeoff assessments predominate in the debates of OA’s environmental benefits. For instance, the common logic that local biodiversity benefits of OA are negated or even turn into disadvantages owing to larger land needs when extended dominates when it comes to the consequences on biodiversity. More comprehensive OA may result in other areas of land use intensification, which would have a net negative impact on the environment, such as increased greenhouse gas (GHG) emissions from LU change or biodiversity loss through habitat conversion [43, 90]. The assumption is that large-scale conversion would result in an increase in arable land to fulfill the unaltered (or rising) demand for agricultural goods because of yield gaps, which is why OA is condemned for increased nutrient leaching [91]. Several researchers also point out that a paucity of data, especially on water conservation, prevents drawing firm general conclusions. This is true even if studies have found decreased eutrophication potential in OA [92] and more efficient nutrient use on a specific region [93] owing to system boundaries [94]. Furthermore, it is claimed that evaluating the consequences of widespread OA adoption on biodiversity and GHG emissions is difficult since it is unclear how yield levels relate to land that is used for production or to convert natural habitat [18, 95, 96]. Besides which, there are arguments suggesting that comparison studies done to date may not account for OA’s as-yet-unmeasured and perhaps beneficial benefits [97], such as the advantages of OA’s broad continuous regions for biodiversity [98]. Hence, some writers contend that, in terms of integrated policy actions that concurrently address improvements in various environmental parameters, extending OA may be the most cost-effective method [99].

4. Conclusion

Presently global agriculture is at a new threshold. It has become the leading source of environmental pollution in many countries. Nonetheless, OA systems are thought to be less harmful than typical conventional agriculture methods. Nevertheless, there is conflicting scientific data supporting these environmental benefits, and there have long been debates over OA. There is some evidence that the soils under OA reduce GHG emissions, although direct data are few and subject to bias due to geography. It enhances SOC stock and improves soil biogeochemical activities. In contrary, it is evident that organic fertilizer (such as compost, manure etc) may lead heavy metal contamination and air can be polluted by organic particulates. The effects of OA on biodiversity are debatable. Though global organic agricultural land occupies only 1.5% organic share (except, organic nonagricultural land), switching to OA has gained new global momentum now a days. Since consumer demand for organic food continues to rise, more agricultural land will be used for organic farming in the future. Nevertheless, in order to more thoroughly evaluate the environmental effects of OA, long-term field studies in significant global agricultural regions using LCA are required.