Mainstreaming of organic agriculture in the public, pushed by green policies and NGO activities, continues to play an important role in its success, promoting empathy for and trust in organic certification schemes. Lastly, organic products are more profitable for farmers, while consumers, not governments, pay for most of the premium prices. However, there are also important limitations to the biodiversity benefits of organic farming, resulting from reduced yields, misconceptions about pesticide use, taxon-specific benefits, and commercial intensification of production. While reducing food waste and meat consumption are important for global food security, lower crop yields and the additional land needed for similar yields are major obstacles for organic farming to benefit biodiversity conservation. When biodiversity benefits are measured per unit of land necessary for a defined agricultural output or yield and not simply per unit of agricultural land , the biodiversity benefits of organic farming can disappear. Globally and across all major crops, organic farming yields are lower by 19–25%. Vegetables and cereals show the highest yield gaps, with up to 50% yield decrease in wheat; however, yields of fruits and oil seed crops are not lower. Moreover, it is a myth that organic farms principally waive pesticides. Pesticides are allowed under organic labels as long as they are derived from natural substances rather than synthetic ones. Widespread insecticides used in organic farming include natural pyrethrin, derived from chrysanthemum, and azadirachtin from the Asian neem tree.
Copper sulfate is often applied to cope with fungal and bacterial diseases, for example, in vineyards, aeroponic tower garden system orchards, and vegetables, but is persistent and accumulates in soils.While the vast majority of organic arable crops are rarely treated with pesticides, potatoes, vegetables, hops, grapes, and other fruits are regularly and heavily treated with natural pesticides. For instance, spraying in organic grapes or apples has been shown to be just 20% less but can also be more than in conventional fields. Overall, this suggests that smart application strategies for pesticide use are needed regardless of organic or conventional agricultural systems. Similarly, harmful overfertilisation occurs not only with mineral fertilizers, but also with manure. Importantly, organic farming enhances only a limited spectrum of species. In particular, noncrop plants benefit due to missing herbicides, whereas more mobile, landscape-dependent insect populations benefit less. Furthermore, reduced applications of agrochemicals enhance common insect species associated with agriculture, but not the less common species associated with a great diversity of semi-natural habitats. These semi-natural habitats include hedges, herbaceous field boundaries, and traditional, uneconomic agroecosystems such as calcareous grasslands and orchard meadows. In fact, a meta-analysis of agrienvironment schemes found that off-field measures, such as field margins and hedgerows, are more than twice as effective in promoting biodiversity as in-field measures such as organic management . For example, higher farmland habitat diversity, but not conversion to organic farming, increases butterfly diversity on farms by ~50%. Increasing hedge length per field by 250 m raises bird diversity from one to 12 species, whereas conversion from conventional to organic farming increased species richness by only 50%. Lastly, current organic production is increasingly intensified, specialised, and often far away from the idealism and enthusiasm of the original organic movement .
In contrast to the small and diversified family farms that characterised the beginning of the organic movement, modern organic arable fields can be huge monocultures, resembling conventional fields. Organic vegetables often come from sterile greenhouse blocks or large-scale cultures under plastic sheets, covering entire landscapes. The Almeria Province is the heart of Europe’s intensive agriculture, where >50% of fruits and vegetables are grown under plastic sheets, with the proportion of organic farming increasing over the last decade from 1.4% to 10.3%. Further examples of landscape-damaging practices of organic production include vegetables that are produced in greenhouse blocks, favourably doubling yields by intensification and extending growing seasons, but at high cost for biodiversity. Overall, pesticide use, limited species benefits, and the above intensification suggest that certified organic production is not the silver bullet for current biodiversity conservation and agricultural production.Diversifying agricultural systems is key for the restoration of biodiversity and associated ecosystem services, such as pollination, and biological pest and weed control.Agricultural land, in particular in Europe and North America, is increasingly shaped by large mono-cultures and short crop rotations to simplify production techniques and to specialise on the best-selling products. Diverse crop rotations are increasingly missing or dominated by just one crop , or only up to three crop species . These simplified crop rotations deplete soils, and promote pest infestations, resistance through repeated pesticide applications, and the risk of resource bottlenecks for pollinators and biocontrol agents; all of which also increase the risk of yield declines. In contrast, resource continuity provided by a mixed pattern of crops, alone or combined with land-sharing practices, such as wildflower strips, effectively increases the stability of ecosystem services, such as pollination and biological pest control.
Globally, crop rotations are only 15% longer in organic than conventional farming . Still, organic farms have on average 48% higher crop species richness . Diversification of organic farming by multi-cropping and diversified crop rotations may reduce the yield gap to just 8–9%. However, crop rotations could be longer, for example, over at least a 7-year period , but there is little uptake in both organic and conventional agriculture. Instead, the current trend in organic farming is, similar to conventional agriculture, to specialise and intensify. Hence, measures to enhance biodiversity include temporal and spatial crop diversification, as reported from both temperate and tropical regions, but also cover crops or green manure, agroforestry, that is, combining trees and crops, or crop–livestock systems and other biodiversity-friendly measures. semi-natural habitats adjacent to croplands may include linear or patchy landscape elements, such as hedges and woody or herbaceous patches, facilitate spillover to small fields and enhance on-farm biodiversity. However, targeted on-farm measures to restore biodiversity are not mandatory in any organic certification scheme.We emphasise the key role of landscape-level species pools and suggest two major biodiversity friendly measures at the landscape scale that are missing in organic certification and agri-environmental EU policies. Landscape changes often provide much larger biodiversity benefits than the incentivised changes of local management. First, we provide evidence for the need to restore semi-natural habitats in simplified landscapes. Second, we focus on augmenting landscape heterogeneity through small and diversified crop fields.Local field or farm biodiversity is determined by the available pool of populations and species in the surrounding landscapes. In structurally poor, simplified landscapes, biodiversity is reduced so that only few species can be locally expected – independent of the type of local management . For example, current dramatic insect declines in German grasslands were mainly observed in simplified landscapes dominated by annual crops, irrespective of the local intensification level. This spatial scale mismatch, that is, the usual focus on local management instead of managing landscapes and their species pools, needs to be addressed for successfully redesigning organic certification schemes and policy instruments for biodiversity conservation.
Landscape complexity, that is, the amount of semi-natural habitats in the agricultural landscape, is well known to increase species pools, linking resources and populations of cropland and natural area, although effects are variable and taxon specific. For example, wild bee richness in standardised field margin strips doubles when landscape-wide habitat increases from 10% to 40%. Complex landscapes also enhance local availability of key predators and parasitoids for pest control,including a tenfold increase in parasitism of the pollen beetle, halving oil seed rape damage. Interestingly, 29% of the local species richness in protected calcareous grasslands, which are among the most species rich habitats in Central Europe, is lost when the percentage of arable land in the surrounding landscape increases from 10% to 80%. Complex landscapes support a broader range of resources and microclimates, thereby counteracting biotic homogenisation and promoting stability of population dynamics. There is evidence that a 20% threshold level of semi-natural habitat in agricultural landscapes is key to biodiversity maintenance. According to percolation theory, habitat loss below 20% causes disproportionally high losses in patch connectivity. This can disrupt exchange of organisms across the landscape, and therefore, their survival probability. Connectivity loss may be also counterbalanced by reduced field sizes per landscape as well as crop diversification, but quantification of these effects needs further research. In Europe, maintaining landscape complexity with semi-natural habitats needs to consider the traditional, uneconomic agroeco-systems that are threatened from agricultural intensification or abandonment, such as orchard meadows and dry grasslands.Although increasing the amount of semi-natural habitat in the landscape can mitigate biodiversity loss,dutch buckets for sale rising land prices make semi-natural habitat an expensive good that is difficult to maintain, yet alone to increase. Consequently, the idea has gained momentum that raising landscape wide heterogeneity of the crop mosaic may also exhibit major positive effects on biodiversity, without compromising the availability of agricultural land. A recent study, based on 435 landscapes across eight regions, showed that increasing configurational cropland heterogeneity by decreasing field size can be even as beneficial for multi-trophic diversity as increasing semi-natural habitat.
Reducing size of crop fields from 5 to 2.8 ha enhanced as many species as increasing semi-natural habitat from 0.5 to 11% . This was not just due to the increase in common grassy field margin strips along crop fields, as there was also a positive effect of increasing crop edges per se. Higher field edge densities can result in up to five times the number of wild bees and higher fruit set in an agricultural landscape and also reduces pest infestation. These patterns have been quantified in the mosaic landscapes of Europe, but the situation may be different in largescale regions with large fields and farms, for example, found in North America or Brazil. Batáry et al. found also high biodiversity benefits of small-scale over large-scale agriculture, which are on par or even higher than the biodiversity benefits from converting conventional to organic agriculture . Independent of field size, organic farming increased biodiversity, but also halved cereal yield levels, compared to conventional farms. However, profit per farmland area was 50% higher on 20-ha than 3-ha fields, due to the lower costs for managing large fields. The higher costs for managing small fields include also higher risks for compacted soil, higher crop damage, and growth heterogeneity due to the increase of edges and headland. However, conversion to long, narrow fields can minimise headland, while biodiversity enhancement is optimised through long margins, promoting ecosystem services through spillover of crop pollinators as well as predators and parasitoids in temperate and tropical regions. Furthermore, small fields allow better adaptation of crop diversification to local heterogeneity, for example in soil quality, and may reduce the risk of pest outbreaks, typical for large areas of monocultures . Increasing the number of crop types had also a positive effect on landscape-level biodiversity, but only in landscapes with >11% of semi-natural habitat. Pest densities are typically lower in landscapes with higher crop diversity, while monocultural, maize-dominated landscape are of little value for pollinators.According to the United Nations, the population of the world is expected to grow in the next century, which in turn encourages the development of innovative techniques to ensure agricultural sustainability. Agriculture on productive land is threatened not only by high levels of urbanization, uneven water distribution, and inclement weather, but also is threats to biodiversity that have unfavorable environmental impacts. Due to the anticipated drastic population growth and constraints on resources in the upcoming decades, only 10% of the demand for food is estimated to be met by expansion of productive lands, with the remainder relying on new techniques that can achieve higher yields. Therefore, developing novel methods to augment the ratio of crop production over used land is a vital issue. In recent years, the indoor vertical farming systems with artificial light are found to be a viable solution to resolve the in-creasing demands of future agricultural products. The IVFS are promising alternatives to open field or greenhouse agriculture because they have precisely monitoring environmental parameters and are insensitive to outdoor climates, which can boost annual sales volume per unit area up to 100 times compared to that of open lands. Furthermore, employment of light emitting diodes as light sources can initiate and sustain photosynthesis reactions and the optical wavelength, light intensity, and radiation intervals can further enhance growth quality.