Agricultural Chemical Inputs Research Articles

Enhancing the Growth of Chili Plants and Soil Health: Synergistic Effects of Coconut Shell Biochar and Bacillus Sp. Strain Ya-1 on Rhizosphere Microecology and Plant Metabolism

To mitigate soil degradation and decrease dependency on chemical inputs in agriculture, this study examined the joint effects of coconut shell biochar and Bacillus strain Ya-1 on soil fertility, rhizosphere bacterial communities, and the growth of chili (Capsicum annuum L.). A controlled pot experiment with four treatments was conducted: control (CK), biochar only (C), Bacillus strain Ya-1 only (B), and a combination of both (BC). The BC treatment significantly enhanced the soil carbon and available phosphorus contents by approximately 20% and the soil nitrogen content and pH by 18% and 0.3 units, respectively, compared to the control. It also increased microbial biomass carbon and nitrogen by 25% and 30%, respectively, indicating improved soil microbial diversity as shown by the highest Pielou evenness index and Shannon index values. The combined application of biochar and the Ya-1 strain resulted in a 15% increase in chili plant height and a 40% improvement in root dehydrogenase activity, suggesting enhanced nutrient uptake and metabolism. Metabolic profiling showed shifts in stress response and nutrient assimilation under different treatments. Collectively, these results indicate the potential of biochar and microbial inoculants to significantly promote soil and plant health, providing a sustainable strategy to improve agricultural productivity and reduce reliance on chemical inputs.

Climate Change and Ecosystem Services: A Participatory Approach in a Brazilian Mountainous Region

Climate change is present in all sectors of global societies, causing various damages, including to agriculture. In this process, understanding the perception of the most affected population and including them in decision-making is a matter of social justice and a more assertive path. Aiming to obtain subsidies for better adaptation to climate change in family farming, this study established a methodology for evaluating the risks of climate change impacts on ecosystem services, related to water and food security, under the perception of rural actors in the mountainous region of the Rio de Janeiro state, Brazil. The methodology consisted of five steps, including the application of the questionnaire to 29 rural actors and ending with validation of the results in a focus group. The main results obtained were that the interviewees perceive the risks of the impacts of climate change in ES, both related to water and food security. Additionally, 24.14% of interviewees mentioned that their family has a monthly income below the Brazilian minimum wage, which exposes their food insecurity. In relation to water security, the risks classified as Very High were mainly in relation to low per capita investments in adaptation policies and infrastructure for environmental protection, between others. The use of many chemical inputs in agriculture also highlighted as a risk to water and food security. Regarding the methodology, it concluded that it was effective in obtaining the perception of the rural actors interviewed regarding the impacts of climate change on ecosystem services at a local scale.

Ozone Treatment as a Sustainable Alternative for Suppressing Blue Mold in Mandarins and Extending Shelf Life

Citrus fruits, particularly mandarins, are highly valued globally for their nutritional benefits and versatile culinary uses. However, the challenge of post-harvest decay, primarily due to blue mold (Penicillium italicum) infections, results in significant food losses and necessitates effective preservation strategies. Traditional methods often rely on fungicides, raising concerns about chemical residues and environmental impact. This study investigates the efficacy of ozone as an alternative approach to controlling blue mold in mandarins. Various gaseous ozone treatments were tested, including single, double, and triple treatments, with durations ranging from 10 to 60 min and concentrations from 3.3 to 20 ppm. Additionally, ozonated water treatments were evaluated with concentrations of 2, 4, and 6 ppm. To simulate a realistic infestation scenario, mandarins were artificially infected with P. italicum spores before undergoing both gaseous ozone and ozonated water treatments. The storage conditions for the mandarins were meticulously controlled, maintaining a humidity level of 50–60% and a temperature range of 10–12 °C. Each fruit was analyzed, and the presence of P. italicum infection was determined two and three weeks after the ozonation. Results indicated that ozone treatments significantly reduced mold growth, with gaseous ozone demonstrating efficacy rates up to 97.5% and ozonated water treatments achieving preservation rates between 95% and 97%. These results underscore ozone’s potential as a safe, efficient, and sustainable alternative to conventional fungicides, offering promising solutions for extending the shelf life of mandarins. Further research is recommended to optimize ozone treatment parameters, assess long-term effects on fruit quality and nutritional content, and refine application techniques to harness ozone’s potential in citrus fruit preservation fully. This approach not only addresses food security challenges but also aligns with global efforts to reduce chemical inputs in agriculture and promote environmentally sustainable practices.

Does fiscal expenditure matter for agricultural development? Examining the impact of technological progress on food production

AbstractRice is a staple food for vast population of China and it remarkably contributes toward China's food security. Several fiscal programs have been implemented by Chinese central government for sustainable agriculture production. In this study, we examine the long‐run influence of agricultural public investment (API) and (agro)chemical inputs use (i.e., fertilizer and pesticide) on rice yield in main rice‐producing provinces of China. Second‐generation panel unit root tests, Westerlund error correction model cointegration test, Augmented‐Mean Group (AMG) and Common Correlated Effect Mean Group (CCEMG) estimation techniques have been used in this article. The co‐integration test results reveal strong evidence of the existence of the long‐run co‐integrating link between the considered series. The results of the AMG and CCEMG methods show that (i) API, (ii) fertilizer use, and (iii) power consumption for agricultural machinery positively and significantly impact rice productivity, whereas pesticide usage affects it negatively. Panel quantile regression showed that API, fertilizer use, power consumption, and sown area are significant and positive at 0.10–0.90 quantiles. The results also indicate that pesticide usage increases rice production at 0.10–0.30 quantiles but decreases rice production at 0.40–0.90 quantile levels. Based on these findings, we derive pertinent implications for China's food security.

Breeding for Resistance against Pest and Diseases in Tomatoes: A Review

Diseases and pests have a substantial effect on tomato production, greatly affecting both the quantity and quality of this crucial vegetable crop. Although fungicides and insecticides have been important in controlling plant diseases and pests, their excessive usage raises significant environmental issues. Vegetable breeders are increasingly concentrating on developing cultivars with natural tolerance to biotic stresses to promote sustainability and environmental friendliness. The change in focus is intended to cultivate tomato cultivars with inherent resistance to diseases and pests, hence decreasing the need for chemical treatments. Advancements in creating high-yielding genetically resistant tomato cultivars are a result of detailed study on the genetic basis of pest and disease resistance in tomato crops, as well as the complex interactions between the host plant and pathogens. For effective breeding programs and pre-breeding activities, scientists and breeders must have access to sources of resistance and a thorough grasp of the genetic complexities involved. This requires examining the genetic composition of both the tomato plants and the different infections that are impacting them. Breeders may generate tomato cultivars with strong resistance to common diseases and pests by using the inherent defensive mechanisms found in certain tomato types via selective crossing. Continuing to study how hosts and pathogens interact and the molecular processes involved in resistance is crucial. This information offers vital insights on how to improve and expand resistance, leading to the creation of cultivars with long-lasting and wide-ranging resistance. Currently, the emphasis on breeding is a proactive and sustainable strategy for transfer of resistances in high yielding tomato cultivars. Researchers aim to develop tomato cultivars that provide high yield and demonstrate tolerance to changing disease and pest stresses by integrating genetic knowledge with sophisticated breeding methods. This comprehensive method protects tomato crops and encourages environmental sustainability by decreasing the need on chemical inputs in agriculture.

Policy strategies for managing food safety risks associated with climate change and agriculture

Managing food safety risks associated with climate change and agriculture necessitates comprehensive policy strategies to safeguard public health, ensure food security, and sustain agricultural productivity. This review delves into the multifaceted challenges posed by climate change on food safety and explores policy approaches aimed at mitigating these risks. Climate change presents a myriad of challenges to food safety, including altered patterns of precipitation, temperature extremes, and increased occurrences of extreme weather events. These changes impact various stages of the food supply chain, from production to consumption, exacerbating existing food safety risks and introducing new ones. Addressing these challenges requires proactive policy strategies that integrate climate adaptation and food safety management. Policy strategies for managing food safety risks associated with climate change encompass a range of measures aimed at enhancing resilience, promoting sustainable agricultural practices, and strengthening food safety systems. One key approach involves the implementation of climate-smart agriculture (CSA) practices, which aim to improve agricultural productivity while minimizing environmental impacts and enhancing resilience to climate change. CSA practices such as crop diversification, soil conservation, and water management can help mitigate the impacts of climate change on food safety by reducing the risk of contamination and enhancing the quality of agricultural products. Furthermore, policies aimed at promoting sustainable food production systems can contribute to mitigating food safety risks associated with climate change. These policies may include incentives for farmers to adopt sustainable farming practices, support for organic farming, and regulations to reduce the use of chemical inputs in agriculture. By promoting environmentally friendly farming practices, such policies can help minimize the occurrence of foodborne pathogens and chemical contaminants in food products, thereby enhancing food safety. In addition to promoting sustainable agricultural practices, policy strategies for managing food safety risks associated with climate change also focus on strengthening food safety systems and enhancing surveillance and monitoring mechanisms. This includes investing in infrastructure and capacity building to improve food safety testing and inspection capabilities, as well as enhancing early warning systems for foodborne disease outbreaks. By strengthening food safety systems, policymakers can better detect and respond to emerging food safety risks exacerbated by climate change, thereby reducing the likelihood of foodborne illness and protecting public health. Furthermore, international collaboration and knowledge sharing are essential components of effective policy strategies for managing food safety risks associated with climate change. Given the global nature of both climate change and the food supply chain, coordinated action at the international level is crucial for addressing shared challenges and exchanging best practices. International organizations such as the World Health Organization (WHO), the Food and Agriculture Organization (FAO), and the World Organization for Animal Health (OIE) play a critical role in facilitating collaboration and providing technical assistance to countries in developing and implementing effective food safety policies in the context of climate change. Managing food safety risks associated with climate change and agriculture requires a multifaceted approach that integrates climate adaptation, sustainable agriculture, and robust food safety systems. By implementing proactive policy strategies that promote sustainable practices, strengthen food safety systems, and foster international collaboration, policymakers can mitigate the impacts of climate change on food safety and ensure the availability of safe and nutritious food for all.

Harnessing fungal endophytes for natural management: a biocontrol perspective.

In the ever-evolving realm of agriculture, the convoluted interaction between plants and microorganisms have assumed paramount significance. Fungal endophytes, once perceived as mere bystanders within plant tissues, have now emerged as dynamic defenders of plant health. This comprehensive review delves into the captivating world of fungal endophytes and their multifaceted biocontrol mechanisms. Exploring their unique ability to coexist with their plant hosts, fungal endophytes have unlocked a treasure trove of biological weaponry to fend off pathogens and enhance plant resilience. From the synthesis of bioactive secondary metabolites to intricate signaling pathways these silent allies are masters of biological warfare. The world of fungal endophytes is quite fascinating as they engage in a delicate dance with the plant immune system, orchestrating a symphony of defense that challenges traditional notions of plant-pathogen interactions. The journey through the various mechanisms employed by these enigmatic endophytes to combat diseases, will lead to revelational understanding of sustainable agriculture. The review delves into cutting-edge research and promising prospects, shedding light on how fungal endophytes hold the key to biocontrol and the reduction of chemical inputs in agriculture. Their ecological significance, potential for bioprospecting and avenues for future research are also explored. This exploration of the biocontrol mechanisms of fungal endophytes promise not only to enrich our comprehension of plant-microbe relationships but also, to shape the future of sustainable and ecofriendly agricultural practices. In this intricate web of life, fungal endophytes are indeed the unsung heroes, silently guarding our crops and illuminating a path towards a greener, healthier tomorrow.

Intercropping on French farms: Reducing pesticide and N fertiliser use while maintaining gross margins

Experimental studies to date have demonstrated the agronomic and environmental benefits of intercropping, making it a key diversification method for reducing chemical inputs in agriculture. However, intercropping is still a niche practice in European cropping systems, particularly for arable crops. Few studies have focused on farmers’ perspectives or used farm data to assess the on-farm performances of intercropping. Here, we present an analysis of data collected from farms of the DEPHY network, a demonstration farm network that aims to show that pesticide use can be reduced through changes in farming practices. We focused our study on four main species in France: winter wheat (Triticum aestivum L.), winter barley (Hordeum vulgare L.), pea (Pisum sativum L.) and rapeseed (Brassica napus L.). We carried out paired comparison tests between sole crops and intercrops for each species (16 pairs for winter wheat, 12 for winter barley, 15 for peas and 31 for rapeseed) to compare the use of pesticides (herbicides, fungicides, insecticides and all pesticides combined), mineral nitrogen fertiliser and the gross margin. We showed that pesticide use was reduced on average by 40–50% in the case of wheat- and barley-based intercrops compared with sole wheat and barley crops, respectively. Pesticide use for peas was reduced by 72% on average. Nitrogen fertiliser use was also reduced by up to 38% for wheat. On the other hand, in the case of rapeseed, which is mainly intercropped with unharvested companion plants, we found no significant differences in pesticide or fertiliser use between the sole crops and intercrops. This suggests that farmers must choose companion plants carefully depending on their objectives and desired services. Finally, our findings show that intercropping negatively affects gross margins for wheat, but gross margins are maintained for barley-, pea- and rapeseed-based intercrops compared to sole crops.

The European Green Deal improves the sustainability of food systems but has uneven economic impacts on consumers and farmers

The European Green Deal aims notably to achieve a fair, healthy, and environmentally friendly food system in the European Union. We develop a partial equilibrium economic model to assess the market and non-market impacts of the three main levers of the Green Deal targeting the food chain: reducing the use of chemical inputs in agriculture, decreasing post-harvest losses, and shifting toward healthier average diets containing lower quantities of animal-based products. Substantially improving the climate, biodiversity, and nutrition performance of the European food system requires jointly using the three levers. This allows a 20% reduction in greenhouse gas emissions of food consumption and a 40–50% decrease in biodiversity damage. Consumers win economically thanks to lower food expenditures. Livestock producers lose through quantity and price declines. Impacts on revenues of food/feed field crop producers are positive only when the increase in food consumption products outweighs the decrease in feed consumption.

Special Issue on Precision Technologies and Novel Farming Practices to Reduce Chemical Inputs in Agriculture

The sustainability of agriculture is a key point to feed human population in the future [...]

Identification of the phytohormones indole‐3‐acetic acid and trans‐zeatin in microalgae

AbstractBACKGROUNDMicroalgae can biosynthesize phytohormones that promote plant growth and development. These compounds can potentially replace synthetic agricultural inputs that are harmful to the environment. The main plant growth‐promoting phytohormones present in microalgae are auxins and cytokinins. The objective of this study was to evaluate the influence of culture conditions (autotrophic and heterotrophic) on the concentrations of the endogenous phytohormones indole‐3‐acetic acid (IAA) and trans‐zeatin (tZ) in the microalgae Chlorella fusca LEB 111, Chlorella vulgaris LEB 112, Scenedesmus obliquus LEB 117, Synechococcus nidulans LEB 115 and Spirulina sp. LEB 18.RESULTSAll microalgae produced IAA and tZ under the three evaluated conditions (autotrophic light/dark (12/12 h), autotrophic continuous light (24 h) and heterotrophic). The IAA concentrations ranged from 1.94 to 56.45 nmol g−1, whereas those of tZ ranged from 0.06 to 35.52 pmol g−1. The cultivation conditions increased the carbohydrate and protein concentrations. Continuous light favored the production of carbohydrates in the studied cyanobacteria (Synechococcus nidulans LEB 115 and Spirulina sp. LEB 18). However, the light/dark condition (12/12 h) afforded the highest protein concentrations for green algae and cyanobacteria. There were no statistically significant differences in the lipid content of the strains studied.CONCLUSIONSThe results of this study are valuable and indicate that the cultivation conditions and species used in this study may be applied in sustainable agriculture, providing alternatives that may contribute to minimizing the environmental impact of synthetic chemical inputs in agriculture. © 2023 Society of Chemical Industry.

Phylogenetic affiliation of endophytic actinobacteria associated with selected orchid species and their role in growth promotion and suppression of phytopathogens.

Endophytic actinobacteria aid in plant development and disease resistance by boosting nutrient uptake or producing secondary metabolites. For the first time, we investigated the culturable endophytic actinobacteria associated with ten epiphytic orchid species of Assam, India. 51 morphologically distinct actinobacteria were recovered from surface sterilized roots and leaves of orchids and characterized based on different PGP and antifungal traits. According to the 16S rRNA gene sequence, these isolates were divided into six families and eight genera, where Streptomyces was most abundant (n=29, 56.86%), followed by Actinomadura, Nocardia, Nocardiopsis, Nocardioides, Pseudonocardia, Microbacterium, and Mycolicibacterium. Regarding PGP characteristics, 25 (49.01%) isolates demonstrated phosphate solubilization in the range of 61.1±4.4 - 289.7±11.9 µg/ml, whereas 27 (52.94%) isolates biosynthesized IAA in the range of 4.0 ± 0.08 - 43.8 ± 0.2 µg/ml, and 35 (68.62%) isolates generated ammonia in the range of 0.9 ± 0.1 - 5.9 ± 0.2 µmol/ml. These isolates also produced extracellular enzymes, viz. protease (43.13%), cellulase (23.52%), pectinase (21.56%), ACC deaminase (27.45%), and chitinase (37.25%). Out of 51 isolates, 27 (52.94%) showed antagonism against at least one test phytopathogen. In molecular screening, most isolates with antifungal and chitinase producing traits revealed the presence of 18 family chitinase genes. Two actinobacterial endophytes, Streptomyces sp. VCLA3 and Streptomyces sp. RVRA7 were ranked as the best strains based on PGP and antifungal activity on bonitur scale. GC-MS examination of ethyl acetate extract of these potent strains displayed antimicrobial compound phenol, 2,4-bis-(1,1-dimethylethyl) as the major metabolite along with other antifungal and plant growth beneficial bioactive chemicals. SEM analysis of fungal pathogen F. oxysporum (MTCC 4633) affected by Streptomyces sp. VCLA3 revealed significant destruction in the spore structure. An in vivo plant growth promotion experiment with VCLA3 and RVRA7 on chili plants exhibited statistically significant (p<0.05) improvements in all of the evaluated vegetative parameters compared to the control. Our research thus gives insight into the diversity, composition, and functional significance of endophytic actinobacteria associated with orchids. This research demonstrates that isolates with multiple plant development and broad-spectrum antifungal properties are beneficial for plant growth. They may provide a viable alternative to chemical fertilizers and pesticides and a sustainable solution for chemical inputs in agriculture.

Calliterpenone, a natural plant growth promoter from a medicinal plant Callicarpa macrophylla, sustainably enhances the yield and productivity of crops.

The global population is rising at an alarming rate, which is threatening food and nutritional security. Although chemical fertilizers and pesticides are important for achieving food security, their excessive usage critically affects soil health and adds up residues in the food chain. There is an increasing interest in identifying eco-friendly farm inputs that can improve crop productivity through sustainable agricultural practices. One of the most common approaches to reducing chemical inputs in agriculture is the use of plant growth regulators (PGRs). Here, we demonstrate the benefits of a natural and novel plant growth enhancer “calliterpenone,” isolated from Callicarpa macrophylla, a medicinal plant, for increasing crop productivity in six crops, viz., rice, wheat, potato, tomato, chickpea, and onion. Results revealed that the application of calliterpenone (foliar spraying or seed soaking) enhanced the yield of rice (28.89%), onion (20.63%), potato (37.17%), tomato (28.36%), and chickpea (26.08%) at 0.001 mM and of wheat (27.23%) at 0.01 mM concentrations in comparison to control. This enhancement in yield was reflected through improvements in its growth attributes, viz., spike length, tillers plant−1, seeds spike−1, plant height, and biomass. Furthermore, the exogenous application of calliterpenone could increase the endogenous level of indole-3-acetic acid (IAA) in all tested crops and decrease the content of abscisic acid (ABA) in a few. Trials conducted at farmers' fields showed an overall ~12% increase in rice yield (mean of 11 farmers' fields ranging from 3.48 to 19.63%) and ~10% increase in wheat yield (ranging from 3.91 to 17.51%). The 0.001 mM of calliterpenone was the best effective dose for most crops except wheat, where a concentration of 0.01 mM was found to be the most optimal. This study indicates that calliterpenone is a natural plant growth promoter that can be used in boosting the yields of multiple crops and would be an important input component of organic farming.

Organochlorine pesticides residue affinity in fish muscle and their public health risks in North West Ethiopia.

Pesticides are the parent compounds, their metabolites, and associated impurities of agricultural and health chemical inputs. If they are found at concentration levels higher than the standard limits, they have potential negative impacts on the ecosystem in general and on fish and humans in particular. This study investigates organochlorine pesticides (OCPs) residue occurrences in fish muscle and assesses their public health potential risks, in North West Ethiopia. The concentration of OCPs residue under gas chromatography with electron capture detector (GC-ECD) was detected in 37.84% of fish muscle samples. The mean amounts detected were Endosalfan I, 341.50 ± 32.19 μg/kg; Endosalfan II, 36.01 ± 2.3μg/kg; Endosalfan sulfate, 5.43 ± 4.06 μg/kg; 4, 4, DDE (4,4-dichlorodiphenyldichloroethylene), 64.01 ± 9.08 μg /kg; 4,4, DDD (4,4-dichlorodiphenyldichloroethane), 5.65 ± 3.12 μg/kg; and 4, 4, DDT (4,4-dichlorodiphenyltrichloroethane), 1.58 ± 0.30 μg/kg. The mean concentration of Endosalfan I tested in fish muscle samples was higher than that of the permissible limit of different international standards. However, due to the low per capita consumption rate of fish origin food in Ethiopia, the health risk index (HRI) ranges from 0.002 to 0.1275, which shows there is no public health risk. This study highlights the possibility of chemical residue occurrence in fish food products, and hence pesticide use regulations and monitoring concentration levels should be implemented regularly to avoid human and environmental health risks.

An Understanding of Education in Supporting Cotton Production: An Empirical Study in Benin, West Africa

Benin is an underdeveloped country whose economy is dependent on agriculture, principally cotton production. Kandi is a community in the country’s northeast region, and is regarded as one of Benin’s top four cotton-producing communities. This community has a deficient level of education. The present paper aimed to investigate whether education could contribute to increasing cotton production in Kandi. A questionnaire was distributed to educated, uneducated, and organic farmers in the research area to achieve this goal. A linear regression strategy was applied, with the key components of the research areas being the usage of agricultural chemical inputs (pesticides and fertilizers), miscellaneous factors, and the level of education of farmers. The data collected were utilized to compare the different groups polled (educated and uneducated farmers). Organic farmers are used in this paper as a model of suitable agriculture development in the study area. The key finding is that primary education affects agricultural production. Solutions are presented with a focus on organic farmers.

Effect of the seed coating with biomass of Dunaliella salina on early plant growth and in the secondary metabolites content of Coriandrum sativum.

The environmental and health risks associated with the application of synthetic chemical inputs in agriculture increased the demand for technologies that allow higher performance and quality of vegetable crops by implementing synergistic materials with the principles of sustainability. In this work, the seed coating with the biomass of Dunaliella salina incorporated in a bioplastic film of Manihot esculenta (cassava) was evaluated as an initial growth and secondary compounds stimulator of Coriandrum sativum (coriander) plants. The obtained results demonstrated that the coating stimulated an increase in the germination percentage (28.75%) and also in concentration of bioactive compounds, such as the six-fold increment of caffeic acid (13.33 mg 100 g-1). The carbohydrates, lipids, and proteins present in the microalgae biomass seem to be responsible for these increments once they are known for providing energy to the seedling development and coordinating the secondary metabolites synthesis. As conclusion, we consider the coating with biomass of D. salina an alternative for crop improvement that contributes to the development of sustainable agricultural practices.

Rhizosphere Bacterial Networks, but Not Diversity, Are Impacted by Pea-Wheat Intercropping.

Plant-plant associations, notably cereal-legume intercropping, have been proposed in agroecology to better value resources and thus reduce the use of chemical inputs in agriculture. Wheat-pea intercropping allows to decreasing the use of nitrogen fertilization through ecological processes such as niche complementarity and facilitation. Rhizosphere microbial communities may account for these processes, since they play a major role in biogeochemical cycles and impact plant nutrition. Still, knowledge on the effect of intecropping on the rhizosphere microbiota remains scarce. Especially, it is an open question whether rhizosphere microbial communities in cereal-legume intercropping are the sum or not of the microbiota of each plant species cultivated in sole cropping. In the present study, we assessed the impact of wheat and pea in IC on the diversity and structure of their respective rhizosphere microbiota. For this purpose, several cultivars of wheat and pea were cultivated in sole and intercropping. Roots of wheat and pea were collected separately in intercropping for microbiota analyses to allow deciphering the effect of IC on the bacterial community of each plant species/cultivar tested. Our data confirmed the well-known specificity of the rhizosphere effect and further stress the differentiation of bacterial communities between pea genotypes (Hr and hr). As regards the intercropping effect, diversity and structure of the rhizosphere microbiota were comparable to sole cropping. However, a specific co-occurrence pattern in each crop rhizosphere due to intercropping was revealed through network analysis. Bacterial co-occurrence network of wheat rhizosphere in IC was dominated by OTUs belonging to Alphaproteobacteria, Bacteroidetes and Gammaproteobacteria. We also evidenced a common network found in both rhizosphere under IC, indicating the interaction between the plant species; this common network was dominated by Acidobacteria, Alphaproteobacteria, and Bacteroidetes, with three OTUs belonging to Acidobacteria, Betaproteobacteria and Chloroflexi that were identified as keystone taxa. These findings indicate more complex rhizosphere bacterial networks in intercropping. Possible implications of these conclusions are discussed in relation with the functioning of rhizosphere microbiota in intercropping accounting for its beneficial effects.

Macrophytes as a potential tool for crop production by providing nutrient as well as protection against common phyto pathogen

Applications of synthetic chemical fertilizers and pesticides lead to several environmental hazards, causing damages to entire ecosystem. To reduce damage caused by such chemical inputs in agriculture and environment required a serious attention for replacement of chemicals input with eco-friendly options. In this study decaying macrophytes were selected as an option for organic agriculture, by analyzing its ability to provide important mineral nutrient to the maize crop grown in low nutrient soil as well as for providing resistant towards many common phyto-pathogens to enhance yield. The results of the study showed that decaying macrophytes have high concentration of stored important mineral nutrient in their body mass, which get released in the soil during its decay and to be used by the maize plant. The decaying macrophytes leaf extract have considerable amount of phenolic and flavonoids also having antimicrobial activity. The antimicrobial activity of the leaf extract has been analyzed against the common phyto-pathogen Pseudomonas aeruginosa , and S. aureus by agar disc method and the formation of clear zone indicate its potential as bio-control agent. So under intensive agricultural practices, application of such biological waste is of particular importance for enhancing soil fertility without chemical input, to ensure sustainable agriculture.

Biological inputs and agricultural policies in South America: between disruptive innovation and continuity

In South America, public policies take a strong interest in alternative technologies to agricultural chemical inputs (pesticides and fertilisers). Some South American countries support biological inputs, also known as bioinputs, through national incentive programmes and regulatory changes. Argentina, Brazil and Colombia are playing a leading role. However, the intention behind this promotion of bioinputs is not to break with industrial agricultural production models, from which States derive a large part of their tax income through exports. Rather, the goal is to foster coexistence between chemical and biological inputs in the context of a transition towards the bioeconomy. In this sense, the promotion of bioinputs meets the expectations of many South American farmers, as well as those of the agricultural inputs industry, which over the last few decades has diversified into these technologies. But these industrial dynamics are counter to certain farmers’ movements that defend on-farm production of biological inputs.

Effects of anthropogenic pollution and hydrological variation on macroinvertebrates in Mediterranean rivers: A case-study in the upper Tagus river basin (Spain)

Seasonal hydrological variation and chemical pollution represent two main drivers of freshwater biodiversity change in Mediterranean rivers. We investigated to what extent low flow conditions can modify the effects of chemical pollution on macroinvertebrate communities. To that purpose, we selected twelve sampling sites in the upper Tagus river basin (central Spain) having different sources of chemical pollution and levels of seasonal hydrological variation. The sites were classified as natural (high flow variation, low chemical impact), agricultural (high flow variation, high agricultural chemical inputs) and urban (limited flow variation, high urban chemical inputs). In these sites, we measured daily water discharge, nutrients, and contaminant concentrations, and we sampled benthic macroinvertebrates, in spring, summer and autumn. Significant differences related to toxic pressure and nutrient concentrations were observed between the three groups of sites. Seasonal patterns were found for some water quality parameters (e.g. nitrites, ammonia, suspended solids, metal toxicity), particularly in agricultural sites. Taxonomic and functional richness were slightly lower in the polluted sites (agricultural and urban), particularly during low flow periods (summer and early autumn). Functional diversity was significantly lower in sites with seasonal flow variation (agricultural sites) as compared to the more constant ones (urban sites). The frequency of traits such as large size, asexual reproduction, aquatic passive dispersion and the production of cocoons increased in response to pollution during low flow periods. This study shows that the impacts of anthropogenic chemical pollution on taxonomic and functional characteristics of macroinvertebrate communities seem to be larger during low flow periods. Therefore, further studies and monitoring campaigns assessing the effects of chemical pollution within these periods are recommended.