Dryland Organic Farming Partially Offsets Negative Effects of Highly Simplified Agricultural Landscapes on Forbs, Bees, and Bee–Flower Networks

2019 ◽  
Vol 48 (4) ◽  
pp. 826-835 ◽  
Author(s):  
Subodh Adhikari ◽  
Laura A Burkle ◽  
Kevin M O’Neill ◽  
David K Weaver ◽  
Casey M Delphia ◽  
...  

AbstractIndustrialized farming practices result in simplified agricultural landscapes, reduced biodiversity, and degraded species-interaction networks. Thus far, most research assessing the combined effects of farming systems and landscape complexity on beneficial insects has been conducted in relatively diversified and mesic systems and may not represent the large-scale, monoculture-based dryland agriculture that dominates many regions worldwide. Specifically, the effects of farming systems on forbs, bees, and their interactions are poorly understood in highly simplified dryland landscapes such as those in the Northern Great Plains, United States, an area globally important for conventional and organic small grain, pulse, forage, and oilseed production. During a 3-yr (2013–2015) study, we assessed 1) the effects of dryland no-till conventional and tilled organic farming on forbs, bees, and bee–flower networks and 2) the relationship between natural habitat and bee abundance. Flower density and richness were greater in tilled organic fields than in no-till conventional fields, and forb community composition differed between farming systems. We observed high bee diversity (109 taxa) in this highly simplified landscape, and bee abundance, richness, and community composition were similar between systems. Compared with tilled organic fields, bee–flower interactions in no-till conventional fields were poorly connected, suggesting these systems maintain relatively impoverished plant-pollinator networks. Natural habitat (11% of the landscape) did not affect small-bodied bee abundance in either farming system but positively affected large-bodied bees within 2,000 m of crop-field centers. In highly simplified agricultural landscapes, dryland organic farming and no-till conventional farming together support relatively high bee diversity, presumably because dryland organic farming enhances floral resources and bee–flower networks, and no-till management in conventional farming provides undisturbed ground-nesting habitats for wild bees (Hymenoptera: Apoidea).

2012 ◽  
Vol 10 (1) ◽  
pp. 45-63
Author(s):  
Anna Augustyniuk-Kram

This review deals with the influence of organic farming, as well as with the effects the conversion of conventional to ecological farming systems have had on the quality of soil and biodiversity. Organic farming is defined as a system in which crop and animal production must be balanced, and all means of production needed for plant and animal breeding are produced within the farm. Organic farming prohibits the use of pesticides and artificial fertilizers, therefore is widely perceived as being more environmentally friendly than conventional farming. Organic farming is also identified with the production of high-quality food, with the improvement of animal welfare, as well as associated with rural development. This type of farming aims to sustain the quality and fertility of the soil and to maintain key ecological soil functions. The presented overview shows that organic farming leads to higher soil quality and more biological activity in soil than conventional farming. A growing number of studies also show that organic farming can have a positive effect on ecosystems by increasing biological diversity and by a diversification of the agricultural landscape. This is to prevent the loss of the natural habitat of many wild plant and animal species.


2019 ◽  
Author(s):  
Alexander James Austin ◽  
Lori Lawson-Handley ◽  
James Gilbert

Understanding the decline in bee populations and their plant mutualists is of paramount concern for ecosystem health, as well as our future food security. Intensive farming practices are one of the major drivers behind such declines. Organic farming is one of the principal alternatives to conventional practices yet the evidence for its effects are mixed, with some studies showing limited benefits. We conducted bee and floral surveys on 10 paired organic and conventional farms across Yorkshire, UK, to investigate how farming practice influenced the abundance, richness and community composition of bees and flowering plants. Firstly, we found that species richness for flowering plants and bees was similar across organic and conventional farms. Floral composition differed between organic and conventional farms with the greatest differences seen in May and June, whereas bee community composition was similar among farming practices. Secondly, both bee and floral abundance were higher in organic farms. Peaks in floral abundance, and corresponding bee abundance, occurred in particular months, most notably in July, with abundance during the rest of the season being similar across both farming practices. Synthesis and applications: Our results suggest that higher floral availability on organic farms corresponds with increased bee abundance. Of particular importance was the higher floral abundance during spring, in the pollinator 'hungry gap', where floral resources are traditionally scarce. However, conventional farms performed comparably to organic farms across the rest of the season, as well as showing similar levels of species richness, diversity and species composition for both flowering plants and bees. We suggest that targeted management on conventional farms, aimed at boosting floral abundance in the spring, when floral abundance is low, could allow conventional farms to make up the shortfall. Additionally, focusing on increasing the diversity of flowering plants, in terms of both phenology and nutritional composition, for both adult bees and their larvae, could improve bee community diversity across both farming systems.


2019 ◽  
Vol 270-271 ◽  
pp. 9-18 ◽  
Author(s):  
Subodh Adhikari ◽  
Laura A. Burkle ◽  
Kevin M. O’Neill ◽  
David K. Weaver ◽  
Fabian D. Menalled

2018 ◽  
Author(s):  
Samiran Banerjee ◽  
Florian Walder ◽  
Lucie Büchi ◽  
Marcel Meyer ◽  
Alain Y. Held ◽  
...  

AbstractRoot-associated microbes play a key role in plant performance and productivity, making them important players in agroecosystems. So far, very few studies have assessed the impact of different farming systems on the root microbiota and it is still unclear whether agricultural intensification influences network complexity of microbial communities. We investigated the impact of conventional, no-till and organic farming on wheat root fungal communities usingPacBio SMRT sequencingon samples collected from 60 farmlands in Switzerland. Organic farming harboured a much more complex fungal network than conventional and no-till farming systems. The abundance of keystone taxa was the highest under organic farming where agricultural intensification was the lowest. The occurrence of keystone taxa was best explained by soil phosphorus levels, bulk density, pH and mycorrhizal colonization. The majority of keystone taxa are known to form arbuscular mycorrhizal associations with plants and belong to the ordersGlomerales,Paraglomerales, andDiversisporales. Supporting this, the abundance of mycorrhizal fungi in roots and soils was also significantly higher under organic farming. To our knowledge, this is the first study to report mycorrhizal keystone taxa for agroecosystems, and we demonstrate that agricultural intensification reduces network complexity and the abundance of keystone taxa in the root microbiota.


Author(s):  
T.N. Melnichuk ◽  
◽  
A.A. Gongalo ◽  
A.Yu. Egovtseva ◽  
E.R. Abdurashytova ◽  
...  

Microbial preparations improve mineral nutrition of plants, protect against phytopathogens, and increase their resistance to stress factors. The aim of our research is to study the effect of microbial preparations on the biological activity of rhizosphere and the productivity of oil flax under no-till in the Crimean Steppe. Microbiological analysis of the rhizosphere of oil flax showed that there is a tendency to increase the number of microorganisms of various ecological and trophic groups both under the conditions of the conventional farming system (CFS) and no-till when seeds are inoculated with a complex of microbial preparations (CMP). Under CFS, the number of microorganisms using mineral forms of nitrogen as nutrition increased by 28 %; pedotrophs – by 37 %; ammonifiers and oligotrophs increased under both farming systems. The total number of nitrogen fixers increased by 29 % under CFS as a result of biological preparations use, while under no-till there was only a trend towards increasing the amount of azotobacter. The number of actinomycetes increased under the influence of CMP by 50% under direct sowing; micromycetes decreased under both farming systems. The number of cellulose-degrading microorganisms increased by 18 and 27 % under no- till and CFS, respectively. The yield of oilseed flax under no-till was 0.11 t/ha (12.9 %) higher than under conventional farming system. On average, over three years (2017-2019), an increase in yield amounted to 0.12 t/ha (19%) due to the use of microbial preparations.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9732
Author(s):  
Sigisfredo Garnica ◽  
Ronja Rosenstein ◽  
Max Emil Schön

Understanding the impacts of agricultural practices on belowground fungal communities is crucial in order to preserve biological diversity in agricultural soils and enhance their role in agroecosystem functioning. Although fungal communities are widely distributed, relatively few studies have correlated agricultural production practices. We investigated the diversity, composition and ecological functionality of fungal communities in roots of winter wheat (Triticum aestivum) growing in conventional and organic farming systems. Direct and nested polymerase chain reaction (PCR) amplifications spanning the internal transcribed spacer (ITS) region of the rDNA from pooled fine root samples were performed with two different sets of fungal specific primers. Fungal identification was carried out through similarity searches against validated reference sequences (RefSeq). The R package ‘picante’ and FUNGuild were used to analyse fungal community composition and trophic mode, respectively. Either by direct or cloning sequencing, 130 complete ITS sequences were clustered into 39 operational taxonomic units (OTUs) (25 singletons), belonging to the Ascomycota (24), the Basidiomycota (14) and to the Glomeromycota (1). Fungal communities from conventional farming sites are phylogenetically more related than expected by chance. Constrained ordination analysis identified total N, total S and Pcal that had a significant effect on the OTU’s abundance and distribution, and a further correlation with the diversity of the co-occurring vegetation could be hypothesised. The functional predictions based on FUNGuild suggested that conventional farming increased the presence of plant pathogenic fungi compared with organic farming. Based on diversity, OTU distribution, nutrition mode and the significant phylogenetic clustering of fungal communities, this study shows that fungal communities differ across sampling sites, depending on agricultural practices. Although it is not fully clear which factors determine the fungal communities, our findings suggest that organic farming systems have a positive effect on fungal communities in winter wheat crops.


2009 ◽  
Vol 19 (2) ◽  
pp. 418-422 ◽  
Author(s):  
Peter Juroszek ◽  
Hsing-Hua Tsai

Organic production is considered by many researchers to be a viable alternative to conventional farming systems. Equivalent yields already have been demonstrated in several studies. The major objective of our study was to collect data on total and marketable fruit yields of sweet pepper (Capsicum annuum) under organic farming conditions in the tropics. Experiments were conducted during the hot-wet season from 7 Mar. 2007 to 30 July 2007 and during the cool-dry season from 27 Nov. 2007 to 7 Apr. 2008. The six experimental entries included four commercial F1 hybrids and two genotypes bred at AVRDC–The World Vegetable Center (Shanhua, Taiwan). During the hot-wet season, high total (44.6–55.7 t·ha−1) and marketable yields (36.9–45.6 t·ha−1) were achieved under organic farming conditions in the open field similar to yields of conventionally produced sweet pepper in previous field experiments at AVRDC. The total yield of the commercial cultivars Queen Star and Hercules exceeded 50 t·ha−1; however, this was not significantly different compared with the other trial entries. During the cool-dry season, the total (25.4–45.7 t·ha−1) and marketable yields (21.1–37.8 t·ha−1) of all trial entries were reduced, probably because the relatively late planting date in November and relatively low air temperature resulted in reduced fruit set. The commercial cultivars Andalus and Green Bell Improved realized in both seasons a total fruit yield of more than 40.0 t·ha−1, suggesting that these can be grown successfully in hot-wet and cool-dry seasons. The relatively high yields of sweet pepper achieved on-station under tropical climatic conditions may encourage farmers and agricultural stakeholders to consider organic farming approaches as a viable alternative to conventional farming systems.


2020 ◽  
Vol 49 (3) ◽  
pp. 717-725
Author(s):  
D S Stein ◽  
D M Debinski ◽  
J M Pleasants ◽  
A L Toth

Abstract Native pollinators are important for providing vital services in agroecosystems; however, their numbers are declining globally. Bees are the most efficient and diverse members of the pollinator community; therefore, it is imperative that management strategies be implemented that positively affect bee community composition and health. Here, we test responses of the bee and flowering plant communities to land management treatments in the context of grasslands in the upper Midwestern United States, a critical area with respect to bee declines. Twelve sites were selected to examine floral resources and wild bee communities based on three different types of grasslands: tallgrass prairie remnants, ungrazed restorations, and grazed restorations. Total bee abundance was significantly higher in ungrazed restorations than remnants, but there were no significant differences among grasslands in community composition or Shannon diversity. Across the three grassland types we also examined mass and lipid stores as nutritional health indicators in three sweat bees (Halictidae), Augochlora pura, Agapostemon virescens, and Halictus ligatus. Although there were no differences in lipid content, total average bee mass was significantly higher in Ag. virescens collected from ungrazed restorations as compared to remnants. Floral abundance of native and non-native species combined was significantly higher in grazed restorations compared to remnants and ungrazed restorations. However, ungrazed restorations had higher abundance and richness of native flowering ramets. These data suggest that bee abundance and nutrition are driven by high abundance of native flowering plant species, rather than total flowering plants.


Author(s):  
R. Chethan ◽  
R.K. K. Patil ◽  
B. Halappa

A study was carried out to know the response of organic, integrated and conventional farming systems on the diversity of soil meso and macro arthropod populations in the cotton inter cropped with groundnut and pigeonpea at MARS, UAS, Dharwad during kharif -2015-16. The organic farming system has recorded highest meso and macro arthropod population of 21.35 per 100 g of soil and 42.00 per pitfall trap respectively. Cotton intercropped with groundnut has recorded higher population of meso and macro arthropods (15.50 /100 g of soil and 41.26/ pitfall trap, respectively). The seasonal abundance of soil arthropods was high in October (25.89/100g of soil) and least in December (5.78/ 100g of soil) months. The diversity of soil arthropod populations assessed on the Shannon’s index of below ground arthropod populations recorded was highest in organic farming (0.61) and least in conventional farming (0.51) system. Hence, the organic farming system increases abundance and diversity of soil organisms and soil fertility, and it adds large amounts of organic residue inputs, which in turn increases the biological activity in soil.


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