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Societal Impact Statement: Intercropping techniques like the Three Sisters, where maize, beans, and squash are grown in an intermixed arrangement, have sustained communities in the Americas for thousands of years and continue to be practiced around the world. In collaboration with the Catawba Indian Nation, we assessed the yield and labor demands required when farming with Three Sisters versus monoculture arrangements. Our results illustrate how farmers could use different planting strategies depending on their priorities (e.g., maximizing yield) and available resources (e.g., conserving land, seeds, or labor). Studies like these can help inform food sovereignty programs and support cultural initiatives in Native communities. Summary: Many Native American communities have historically grown maize, beans, and squash in polyculture as the Three Sisters because of the reciprocal ecological benefits the species provide each other and the surrounding environment. For instance, archaeological remains indicate that the Catawba Indian Nation had grown the Three Sisters for hundreds of years before experiencing the expansion of the colonial market economy, a smallpox epidemic, and the drastic loss of land.To support the Catawba Indian Nation's food sovereignty and traditional ecological knowledge initiatives, we assess the yield and labor demands of growing their traditional variety of maize, beans, and squash plants in the Three Sisters planting design versus in monoculture conditions.While total maize yield was equivalent in monoculture and the Three Sisters, plants grew larger, had higher survival, and produced greater yield per plant and per unit area of land in the Three Sisters. [Correction added on 21 November 2024, after first online publication: The preceding sentence has been corrected.] Squash yield was highest in monoculture. Trellising bean plants in monoculture required the most labor, and altogether, yield per hour of labor was higher in monoculture than in the Three Sisters.Ultimately, the most appropriate farming strategy for the Catawba Indian Nation to use will depend on their priorities (e.g., maximizing the production of one species versus all species). We discuss the challenges managers of small farms face when considering traditional versus modern agricultural methods and describe how a respectful partnership between the Catawba Nation and Davidson College expanded and enhanced the outcomes of this study. [ABSTRACT FROM AUTHOR]

Abstract Companion planting of white clover (Trifolium repens L.) with orchard grass (Dactylis glomerata L.), a famous hay grass, improves the forage quality of orchard grass. Microbiome profiling techniques can reveal the specific role of white clover companion planting with orchard grass. This study aimed to explore the microbiome distribution and gene functions of rhizosphere and non-rhizosphere soil via companion planting systems of white clover and orchard grass. From metagenomics sequencing analysis, we confirmed the significant role of white clover on soil environment modeling during companion planting with orchard grass. Twenty-eight biomarkers of rhizosphere soil organisms were identified during companion planting, including Proteobacteria, Betaproteobacteria, Flavobacteriia, and Caulobacterales. The number of gene functions of nitrogen and carbon fixation in companion planting was higher than that in single plants, indicating new functional flora for companion planting. We characterized specific rhizosphere effects, typical biomarker flora, and potential regulatory mechanisms for white clover-related companion planting by metagenomics analyses.

Companion planting of white clover (Trifolium repens L.) with orchard grass (Dactylis glomerata L.), a famous hay grass, improves the forage quality of orchard grass. Microbiome profiling techniques can reveal the specific role of white clover companion planting with orchard grass. This study aimed to explore the microbiome distribution and gene functions of rhizosphere and non-rhizosphere soil via companion planting systems of white clover and orchard grass. From metagenomics sequencing analysis, we confirmed the significant role of white clover on soil environment modeling during companion planting with orchard grass. Twenty-eight biomarkers of rhizosphere soil organisms were identified during companion planting, including Proteobacteria, Betaproteobacteria, Flavobacteriia, and Caulobacterales. The number of gene functions of nitrogen and carbon fixation in companion planting was higher than that in single plants, indicating new functional flora for companion planting. We characterized specific rhizosphere effects, typical biomarker flora, and potential regulatory mechanisms for white clover-related companion planting by metagenomics analyses. [ABSTRACT FROM AUTHOR]

To promote sustainable cultivation and soil health in agriculture, urgent strategies are needed to address the challenges posed by continuous cropping for high-quality pepper production. This study investigated the impact of oats incorporation and biochar amendment in a 12-year continuous pepper cropping system. Compared with the pepper monoculture system (CK), the combination treatment of intercropping with oats and biochar amendment (T1) significantly increased the soluble solids content by 3.13% and the β-carotene content by 8.83-fold in pepper fruits (P < 0.05). The soil pH under intercropping with oats or biochar modification was comparable to that of the CK. Notably, lower soil bacterial operational taxonomic units were observed under this treatment, and soil bacterial diversity decreased consistently with pepper development, regardless of the cultivation system. In contrast, fungal diversity exhibited fluctuations under the companion oat/biochar condition, with fungal community patterns modulated throughout the pepper development process (P < 0.05). Dominant microbes such as Sphingomonas, Pseudomonas, Chrysosporium, Mortierella, and Cladosporium were identified in continuous cropping pepper soils. Kyoto Encyclopedia of Genes and Genomes metabolic profiling revealed significant effects of the cultivation type on the metabolic pathways of functional genes in soil microbial communities. Overall, the practice of planting oats and using biochar in the soils of continuously cropped pepper fields is feasible and sustains the pepper industry as an agroecosystem. [ABSTRACT FROM AUTHOR]

The effects of companion planting on soil antibiotic resistance genes (ARGs) and associated microbial composition have remained largely unclear until now. In this study, we assessed the changes in the soil microbiome and ARGs frequencies for tomato growing soils that were companion planted with basil (TB) or cilantro (TC) using a metagenome approach. The abundance of the phytopathogen Ralstonia solanacearum was significantly lower in the TC or TB treatments compared to the tomato monoculture soils (TT). A significant enrichment of Pseudomonas and Aquabacterium and a depletion of Nocardioides and Streptomyces were observed in the TC treatment. Interestingly, both TC and TB companion planting reduced the absolute abundance and the number of subtypes of ARGs. The TC soil showed the lowest numbers of unique ARG subtypes, especially the ARGs resistant to vancomycin and rifamycin, as well as those associated with multidrug resistance. Furthermore, network analysis further revealed that Nocardioides and Streptomyces were potential hosts of ARGs, whereas Flavobacterium negatively correlated with mdtG, suggesting a suppressive effect in reducing ARGs. Together, our results suggest that the companion planting of tomatoes with basil or cilantro can reduce the risk of ARG accumulation, making it a feasible farming management tool to promote soil and plant health in sustainable agriculture. [ABSTRACT FROM AUTHOR]

Combining Donna Haraway’s call to acknowledge non-human significant others in her Companion Species Manifesto with the ‘biocentric form of literary criticism’11 Gagliano, Ryan and Vieira, ‘Introduction’, p. xi. advocated by critical plant studies, this essay uses the agricultural practice of companion planting as a Framework for reading beyond the canon of anglicised world literature. I analyse three short stories – Sofie Isager Ahl’s ‘Naboplanter’ (‘Companion Plants’, 2018), Can Xue’s ‘鸡仔的心愿’ (‘Chick’s Heart’s Desire’, 2020) and Audrey R. Hollis’ ‘Seedlings’ (2018) – that translate between the botanical and the human realms and use vegetal voices to challenge gendered social conventions, linguistic preconceptions and lingering anthropocentrism. By planting together texts in Chinese, Danish and English intermingled with the idiom of plants, I propose messy, multimodal and multilingual translation as a fundamental figuration in our pursuit of a planetary approach to comparative literature.

IntroductionUntil recently, much of the Elwha River was inaccessible to anadromous fish species due to the Elwha and Glines Canyon dams. Dam deconstruction resulted in approximately 325 ha of formerly inundated lake beds devoid of natural riparian corridors or adjacent forests. Efforts to restore the vegetation have had varying success. Areas where fine sediments settled along the valley walls quickly regenerated, while coarse terraces were slower to revegetate from plantings and directed seeding. One seeded species, riverbank lupine (Lupinus rivularis), quickly established on the coarse-textured terraces. Riverbank lupine is a pioneering species that assimilates nitrogen (N) through N-fixing bacteria; thus, it enriches the soil with bioavailable N and organic matter upon decomposition.MethodsThe goal of this study was to investigate lupine’s influence on conifer establishment in the coarse sediments of the former Lake Mills basin along the Elwha River. Conifers planted 3 years prior to the study in plots with different levels of lupine cover (sparse, medium, or dense) were measured for growth, foliar total nitrogen, and ectomycorrhizal (ECM) root colonization. Soil N, organic matter (OM), and surrounding plant community composition were also evaluated at this time.ResultsAfter 3 years, conifers did not statistically differ in height or basal diameter among differing levels of lupine cover. However, conifers in the medium- and dense-cover plots had significantly greater foliar N concentrations (β = 0.25, SE = 0.08, p < 0.001). The roots of conifers in the dense- and medium-cover plots had significantly less ECM colonization than those in the sparse-cover plots (β = 0.14, SE = 0.03, p = 0.03). No differences existed regarding soil total N or OM. Plant community composition differed among lupine cover classes (permutational multivariate analysis of variance (PERMANOVA), (F(2,21) = 2.02, p = 0.01). Higher lupine cover resulted in lower species richness (β = 25.9, SE = 0.61, p = 0.04).DiscussionBased on our findings, the inclusion of native lupine in coarse, N-limiting soils contributes to the N pools without reducing the growth of planted conifers, which may accelerate forest succession leading to closed canopies much faster than passive recovery.

Social connections are crucial for today's middle and high school students. We address this social need through a 3-H Social and Emotional Learning (SEL) Cycle. Through the Three Sisters Garden activity presented here, we teach secondary school students about biodiversity and sustainability as we integrate the arts into STEM (STEAM). Students investigate the growth and development of organisms from a crosscutting lens of systems. Students initiate the sensemaking process by paralleling their own need for companionship to plants. Students end the lesson by initiating a scientific argumentation for a Three (or Four) Brothers/Others Garden. The 3-H learning cycle begins and returns to social and emotional connections, giving equal weight of importance to the heart (social and emotional), hands (problem-solving), and heads (sensemaking). The lesson presented here exemplifies school garden-based learning and students' ability to initiate sensemaking of the indigenous Three Sisters Garden intercropping method. Analyzing gardens from a systems lens allows students to make emotional and cognitive connections between their own need for social connections and plants increased growth and productivity in a polyculture. When students emotionally, socially, and cognitively participate in the process of science, they begin to see themselves as a part of the scientific process. [ABSTRACT FROM AUTHOR]

Summary: Production of cereal crops in sub-Saharan Africa is threatened by parasitic striga weeds and attack by stemborers and the invasive fall armyworm (FAW), compounded by increasing hot and dry conditions. A climate-smart push-pull technology (PPT) significantly reduces effects of these biotic challenges. To improve further resilience of the system to climate change, more adapted and suitable companion plants were identified and integrated in a new version of PPT, termed 'third generation PPT'. Our study evaluates field performance and farmer opinions of this new version in comparison with the earlier version, climate-smart PPT, and farmers' own practices of growing maize in controlling stemborers, FAW, and striga weeds. Trials were conducted across five locations in western Kenya for two cropping seasons in the year 2019 following a one-farm one-replicate completely randomized design. We assessed infestation on striga, stemborers, and FAW, and yield performance of the three cropping systems. We also sought the opinions of the hosting farmers through semi-structured questionnaires that were administered through individual interviews. Both PPT plots recorded significantly (P < 0.05) lower striga count, FAW, and stemborer damage, and higher grain yield than in plots that followed farmers' own practices. There was no statistically significant difference between the two PPT plots except for stemborer damage for which the third generation PPT recorded higher damage than the climate-smart PPT. However, farmers preferred the third generation PPT for important traits possessed by its companion plants which their counterparts in climate-smart PPT are deficient. The cultivar Xaraes was rated as 'very good' for resistance to spider mites, biomass yield, and drought tolerance while Desmodium incanum was rated 'very good' for seed production and drought tolerance. The third generation PPT is based on companion crops that are more resilient to hot and dry conditions which are increasing rapidly in prevalence with climate change. This version therefore presents a better option to upscale the technology and meet different needs of farmers especially in arid and semi-arid conditions. [ABSTRACT FROM AUTHOR]

We benchmark the 5000+ qubit system Advantage coupled with the Hybrid Solver Service 2 released by D-Wave Systems Inc. in September 2020 by using a new class of optimization problems called garden optimization problems known in companion planting. These problems are scalable to an arbitrarily large number of variables and intuitively find application in real-world scenarios. We derive their QUBO formulation and illustrate their relation to the quadratic assignment problem. We demonstrate that the Advantage system and the new hybrid solver can solve larger problems in less time than their predecessors. However, we also show that the solvers based on the 2000+ qubit system DW2000Q sometimes produce more favourable results if they can solve the problems. [ABSTRACT FROM AUTHOR]

Strawberry is a salt-sensitive plant adversely affected by slightly or moderately saline conditions. The growth, fruit, and biochemical parameters of strawberry plants grown under NaCl (0, 30, 60, and 90 mmol L−1 ) conditions with or without a halophytic companion plant (Portulaca oleracea L.) were elucidated in a pot experiment. Salt stress negatively affected the growth, physiological (stomatal conductance and electrolyte leakage), and biochemical parameters such as chlorophyll contents (chl-a and chl-b); proline, hydrogen peroxide, malondialdehyde, catalase, and peroxidase enzyme activities; total soluble solids; and lycopene and vitamin C contents, as well as the mineral uptake, of strawberry plants. The companionship of P. oleracea increased fresh weight, dry weight, and fruit average weight, as well as the total fruit yield of strawberry plants along with improvements of physiological and biochemical parameters. This study showed that the cultivation of P. oleracea with strawberry plants under salt stress conditions effectively increased strawberry fruit yield and quality. Therefore, we suggest that approaches towards the use of P. oleracea could be an environmentally friendly method that should be commonly practiced where salinity is of great concern. [ABSTRACT FROM AUTHOR]

Companion planting is one of the most common and effective planting methods in modern agriculture. White clover (Trifolium repens L.) and orchard grass (Dactylis glomerata L.) are two typical pastures planted together to promote each other’s growth. However, the detailed biological foundations of companion planting remain unclear. In this study, we screened typical microbiome profiles under separate and combination planting conditions using 16s RNA gene sequencing techniques. We identified the typical distinctive microorganism subtypes based on the microbiome profiles and recognized the enriched functions of top abundant microorganisms in soil using different planting strategies with the help of Kyoto Encyclopedia of Genes and Genomes and Clusters of Orthologous Groups annotation. This analysis confirmed that the optimal microorganisms and screened functional annotations are correlated with nitrogen fixation; thus, companion planting may improve the yield and efficacy of plants by improving the efficiency of nitrogen fixation.

Combining a non-host plant (companion plant or CP) with a target cultivated plant is considered as a promising strategy to reduce pest pressure. Among the companion plants (CP) commonly used in integrated systems, those belonging to the Amaryllidaceae family (chives, garlic, onion, leek) exhibit characteristics related to certain volatile organic compounds (VOCs) with promising repellent potentialities. The aim of this work was to investigate the potential disruption of sweet pepper (host plant) colonization by the green peach aphid (Myzus persicae) when exposed to leek (Allium porrum) as a CP. Retention/dispersion, EPG and clip-cage/Petri dish laboratory experiments were thus performed to study the effect of leek VOCs on aphid settlement/migration, feeding behavior and life history traits parameters, respectively. This work revealed that leek as a CP had a negative effect on aphid feeding behavior, by disturbing the balance between phloem and xylem sap ingestion, but had no influence concerning aphid settlement. Surprisingly, leek as a CP triggered some unexpected probiotic effects on certain life history traits such as aphid survival, biomass, and fecundity, suggesting a possible hormetic effect of leek VOCs on aphid physiology. The possibility of experience-induced preference of aphids for leek VOCs was also discussed. [ABSTRACT FROM AUTHOR]

Companion planting is one of the most common and effective planting methods in modern agriculture. White clover (Trifolium repens L.) and orchard grass (Dactylis glomerata L.) are two typical pastures planted together to promote each other's growth. However, the detailed biological foundations of companion planting remain unclear. In this study, we screened typical microbiome profiles under separate and combination planting conditions using 16s RNA gene sequencing techniques. We identified the typical distinctive microorganism subtypes based on the microbiome profiles and recognized the enriched functions of top abundant microorganisms in soil using different planting strategies with the help of Kyoto Encyclopedia of Genes and Genomes and Clusters of Orthologous Groups annotation. This analysis confirmed that the optimal microorganisms and screened functional annotations are correlated with nitrogen fixation; thus, companion planting may improve the yield and efficacy of plants by improving the efficiency of nitrogen fixation. [ABSTRACT FROM AUTHOR]

Biomass production and metal accumulation in plant tissue (bioconcentration) are two critical factors limiting the phytoextraction rate. Metal translocation to aboveground organs should be accounted for as the third most important factor, as harvesting of the plant roots is usually economically disadvantageous. These three parameters could be potentially increased with the use of companion planting, a well-known agricultural technique, and inoculation with plant growth–promoting bacteria (PGPB). The aim of the study was to determine whether intercropping and inoculation with endophytic PGPB (Burkholderia phytofirmans PsJNT) can increase the efficiency of phytoextraction of Zn, Pb, and Cd. The study was conducted on Brassica juncea (L.) Czern. "Małopolska" grown in a monoculture or co-planted with Zea mays L. "Codimon" and Medicago sativa L. "Sanditi." Results show that companion planting and inoculation with rhizobacteria can increase the efficiency of metal phytoextraction, mainly by increasing the yield of dry biomass and the survival rate of plants grown on contaminated soil. We have shown that the simultaneous planting of B. juncea with M. sativa and inoculation with PGPB were the most efficient variants of assisted phytoextraction reaching a recovery of 95% Zn, 90% Cd, and on average about 160% Pb compared with control B. juncea plants grown in monoculture. [ABSTRACT FROM AUTHOR]

Abstract. The twospotted spider mite (TSSM), Tetranychus urticae Koch is one of the most important pests on greenhouses/high tunnels worldwide. We evaluated effects of Chinese chive grown under the wooden structure which supports the bags used of strawberry grown, in two high tunnels from November 2016 to January 2017. TSSM mobile forms and number of eggs were counted on strawberry leaves. Five plants were randomly chosen on each plot. TSSM populations on strawberry leaves were assessed with magnifying glass (10 ×). Reductions were observed on three of eight assessments on TSSM mobile forms. On one date was observed reductions on mean number of TSSM eggs. Cumulate mite days overall data of TSSM mobile forms from two high tunnels reveals a reduction with intercrop. On the other hand, number of eggs was not altered. Results suggest that Chinese chive intercropped can reduce TSSM populations on strawberry high tunnels. Efeito do cultivo consorciado de Allium tuberosum Rottlerex Sprengel(Amaryllidaceae) em populações de Tetranychus urticae Koch (Acari: Tetranychidae) em morangueiro Resumo. O ácaro-rajado, Tetranychus urticae Koch, é uma das mais importantes pragas em casas de vegetação no mundo. Foi avaliado o efeito do consórcio de cebolinha chinesa, cultivada sob as estruturas de madeira que suportam as sacolas para o cultivo de morangueiro (sistema suspenso), em duas casas de vegetação, entre novembro de 2016 e janeiro de 2017. Formas móveis e ovos de ácaros foram contabilizados em folhas de morangueiro. Para as avaliações, cinco plantas foram aleatoriamente selecionadas em cada parcela. Populações de ácaro-rajado em folhas de morangueiro foram avaliadas com lupa de bolso, com 10 x de aumento. Reduções foram observadas em três de oito avaliações de formas móveis de ácaro-rajado. Foram observadas reduções no número de ovos em uma avaliação. Tomando em consideração os dados de ácaros acumulados por dia, foi observado que o consórcio reduziu em 54% a população de ácaros. Por outro lado, o número de ovos não foi alterado.

ABSTRACT: Studies showed that intercropping garlic reduced pests in strawberry field crops. However, influence of intercropping on yield was not tested. The objective of the study was to evaluate the strawberry pseudofruit and garlic bulb productions in monocropping and intercropping systems. Assessments of the yields and calculation of the land equivalent ratio, competition ratio and gross income were performed. The experiments were conducted in three areas (two open field and one greenhouse) in Londrina municipality. Treatments in the field experiments were garlic or strawberry in monocrops (controls), strawberry (S) + one garlic row (GR), S + 2GR or S + 3GR per plot. In the greenhouse experiment, plants were grown in pots with following treatments: garlic or strawberry in monocrops, 2S + 2 garlic plants per plot (GPP), 2S + 4GPP or 2S + 5GPP. Similar yields (garlic bulbs and strawberry pseudofruits) were observed among the treatments. Intercropping garlic among strawberry plants increased the land equivalent ratio. The intercrop land equivalent ratio index ranged from 1.34 to 2.55. An increasing in gross income were observed when increasing garlic plant densities in intercropping with strawberry. Results showed that intercropping garlic with strawberry increases land equivalent ratio and gross income. Production of strawberry pseudofruits and garlic bulbs were not influenced by intercropping systems compared to monocropping.

The entire process of agricultural and horticultural food production is unsustainable as practiced by current highly intensive industrial systems. Energy consumption is particularly intensive for cultivation, and for fertilizer production and its incorporation into soil. Provision of nitrogen contributes a major source of the greenhouse gas, N2O. All losses due to pests, diseases and weeds are of food for which the carbon footprint has already been committed and so crop protection becomes an even greater concern. The rapidly increasing global need for food and the aggravation of associated problems by the effects of climate change create a need for new and sustainable crop protection. The overall requirement for sustainability is to remove seasonal inputs, and consequently all crop protection will need to be delivered via the seed or other planting material. Although genetic modification (GM) has transformed the prospects of sustainable crop protection, considerably more development is essential for the realisation of the full potential of GM and thereby consumer acceptability. Secondary plant metabolism offers wider and perhaps more robust new crop protection via GM and can be accomplished without associated yield loss because of the low level of photosynthate diverted for plant defence by secondary metabolism. Toxic mechanisms can continue to be targeted but exploiting non‐toxic regulatory and signalling mechanisms should be the ultimate objective. There are many problems facing these proposals, both technical and social, and these are discussed but it is certainly not possible to stay where we are in terms of sustainability. The evidence for success is mounting and the technical opportunities from secondary plant metabolism are discussed here. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Strawberry is affected by several pests and diseases. Neopamera bilobata is an emerging pest that has been reported by several strawberry growers, usually associated with catfacing symptoms in fruits. We evaluated intercropping garlic or Chinese chives on N. bilobata populations on strawberry crops grown in high tunnels in two experiments. In the first experiment, we evaluated N. bilobata populations on strawberry intercropping with garlic plants (three densities: 8, 16, 24 GP – garlic plant per plot) on the bags by taking 12 samples from December 2015 to April 2017. N. bilobata populations on strawberry were also assessed when Chinese chives were grown under the suspended wooden structures in which strawberry plants are grown ('undercropping') (14 samples), in two high tunnels, from November 2016 to March 2017. The number of nymphs and adults on 14 randomly selected fruits per plot were assessed. During the garlic intercropping experiment, the treatments of three densities of garlic reduced N. bilobata populations; however, the 24 GP treatment caused a greater reduction than the 8 GP treatment. Garlic densities reduced N. bilobata populations by 35, 50, and 64% for the 8, 16, and 24 GP treatments, respectively. Chinese chives cultivated under the structures reduced N. bilobata populations by 47%. The results suggest that intercropping garlic or undercropping Chinese chives are suitable tools to be tested in integrated pest management in strawberry crops. [ABSTRACT FROM AUTHOR]

Highlights • Heavy machinery operations or repetitive tillage causes soil compaction. • Reduced bulk density and improved infiltration rate favors better root growth. • Consequently better yield attributes lead to higher crop productivity. • Monetary benefits confirmed sub-soiling to be economically remunerative. • Sub-soiling once in 3 years can improve productivity in 1.2 m ha in N-W India. Abstract Soil compaction in Indian Punjab is an emerging problem affecting crop productivity. Heavy machinery operations or repetitive tillage in fields are main reasons behind this problem. To investigate the direct and residual effect of sub-soiling on soil physical properties and productivity of cotton-wheat cropping system, we conducted a field experiment for three cropping cycles (2014-2017) at two different sites and evaluated a total of five treatments (Control, Sub-soiling at 1.0 m, Sub-soiling at 1.5 m, Cross Sub-soiling at 1.0 m and Cross Sub-soiling at 1.5 m) in complete randomized block design. Results elucidated that any level of sub-soiling if applied once, improved the infiltration rate besides reduction in the bulk density for two years. Consequently, higher root length and increased root mass of cotton under sub-soiled treatments revealed advantages by improvement in yield attributes and seed cotton. Cotton sown after sub-soiling recorded significantly higher seed cotton yield while control exhibited statistically least for two years. Sub-soiling applied prior to cotton sowing in initial year also had beneficial residual effect on succeeding wheat for subsequent two crop cycles. However, during third year, at par yield levels among studied treatments for both the crops indicated that residual effect of sub-soiling persisted no longer beyond two years. Better economic returns and consequently improved benefit: cost ratio clearly revealed that sub-soiling has economic benefits. Our studies concluded that sub-soiling exerted beneficial effect on soil physical properties by reduction in bulk density and improved infiltration rate and any sub-soiling either at 1.0 or 1.5 m once in three years has potential for improving productivity of cotton-wheat cropping system occupying 1.2 million ha in North-Western India. [ABSTRACT FROM AUTHOR]

Abstract The supply of nitrogen (N) from legumes is a key in maintaining soil N fertility in plant production with low fertilizer N inputs. Leaf-feeding of isotope tracers is a commonly used methodology to study the flow of carbon (C) and N from legumes into soil and companion plants. Here we investigated the temporal fate of 15N and 14C fed as a single-pulse via leaves to red and white clover in pure stands and in mixtures with grass in order to investigate the suitability of leaf-labeling for estimation of rhizodeposition and N transfer. The 15N was present in all sampled plant parts of the legumes, soil and companion ryegrass already at the first day after the end of the labeling period. Thereafter, tracer levels remained surprisingly constant especially in the legume root parts. The rapid appearance of 15N in soil was most likely dominated by tracer in unrecovered root parts, whereas 15N in companion ryegrass was most likely caused by root exudation. After the rapid phase of tracer translocation, a second slower phase was best described by tracer loss from shoot tissue (phyllodeposition), rather than turnover of root and nodules with time. We conclude that labeling studies with multiple pulses need intensive labeling schemes and greater temporal sampling resolution in order to avoid bias and determine dominating sources of tracer moving from legumes to companion species for N transfer estimation. The study also underlined the importance of identifying the dominating sources of legume C and N losses to soil in order to select the correct approach to estimate rhizo- and phyllodeposition. Highlights • Leaf-feeding of C and N tracers were studied in two field experiments. • Temporal 14C and 15N enrichment indicate minimal root and nodule turnover within months. • N deposition occurred as rapid root exudation and subsequently from leaves. • Implications for estimation of rhizodeposition and N transfer are discussed. [ABSTRACT FROM AUTHOR]

BACKGROUND Intercropping companion plants (CPs) with horticultural crops could be an eco‐friendly strategy to optimize pest management. In this research, volatile organic compounds (VOCs) emitted by some CPs were investigated for their repellent properties towards the green peach aphid (Myzus persicae Sulzer). The aim of this study was to understand the modes of action involved: direct effects on the aphid and/or indirect effects via the host plant (pepper, Capsicum annuum L.). RESULTS: We identified two promising repellent CP species: the volatile blend from basil (Ocimum basilicum, direct repellent effect) and the mixture of (or previously intercropped) C. annuum plants with Tagetes patula cv. Nana (indirect effect). This effect was cultivar‐dependent and linked to the volatile bouquet. For the 16 compounds present in the O. basilicum or T. patula bouquets tested individually, (E)‐β‐farnesene, and eugenol reported good repellent properties against M. persicae. Other compounds were repellent at medium and/or highest concentrations. Thus, the presence of repellent VOCs in a mixture does not mean that it has a repellent propriety. CONCLUSION: We identified two promising repellent CP species towards M. persicae, with a likely effect of one CP's VOCs on the host plant repellency and highlighted the specific effectiveness of VOC blends. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Highlights • Health condition of nectar plants depends on Sedum species as companion plants. • Substrate moisture influence on nectar plants growth, planted together with Sedums. • Effects of companion planting depend on growth forms and leaf traits of plants. • High nectar plant density affects shoot biomass and health condition negatively. • Companion planting with appropriate Sedums can improve green roof performance. Abstract Introducing nectar-producing plants to green roofs and other urban green infrastructure has been attempted to support pollinator activities. Green roofs can be drought-prone, placing limitations on the success of plant growth and nectar production in the absence of irrigation. Plant species differ greatly in water usage patterns, so companion planting with low and high water users has been proposed to increase performance of high water use species, including species important for urban pollinators. Additionally, crassulacean acid metabolism (CAM) plants such as Sedum tend to have low water usage and are reported to improve health condition of neighbors. However, Sedum species differ in morphological and physiological traits such as leaf shapes and the speed at which they switch to CAM, resulting in water usage differences during drought that could affect neighboring plants. This study quantifies the effects of companion planting with CAM plants (Sedum album , Sedum kamtschaticum) on nectar-producing plants (Fagopyrum esculentum , Trifolium repens), focusing on target plant growth form and leaf traits of neighboring Sedum. The health condition of F. esuculentum and soil water contents were improved significantly when they were planted together with S. album , which has small leaves and rapid CAM induction. Therefore, suppression of evapotranspiration of neighboring CAM plants could have positive effects on erect growth form nectar species. In contrast, the health condition of T. repens , which shows prostrate growth, was not affected by neighboring CAM plant species. Judging from these results, growth characteristics including leaf traits of neighboring Sedum and growth forms of the target plants could be important factors determining the effects of companion planting in urban green infrastructure. [ABSTRACT FROM AUTHOR]

Farmers may not want certain natural enemies of insect pests to be present in their fields all year round, due to the detrimental effects they might have on themselves or on their crop. We explored the potential for manipulating the behavior of the African weaver ant, Oecophylla longinoda, which may bite humans while being a major natural enemy against the invasive fruit fly, Bactrocera dorsalis, in Africa. Our aim was to find repellents that might help to protect farmers when working in the fields, while also coming up with ways of increasing weaver ant populations, by finding carbohydrate sources from local cultivated plants (attractant). To that end, we carried out behavioral experiments in the laboratory which revealed (i) that oily repellents were the most efficient of all those tested, (ii) that the extra floral nectar of a legume crop, such as cowpea, was consumed by weaver ants, but in quite small amounts and also differently depending on the varieties. This approach, tackling these two aspects at the same time, was based on and shaped by the reality faced by farmers. The results are key to breaking down obstacles to using weaver ants in Africa and are discussed in this respect. [ABSTRACT FROM AUTHOR]

Even though potato (Solanum tuberosum L.)-based intercropping systems are widely practised in developing countries, only a few studies have focused on legumes as the companion intercrops. This study was conducted to assess the effect of incorporating legumes into the potato production system on ground cover, soil moisture content (SMC), tuber and legume yield, potato equivalent yield (PEY), gross and net income and benefit: cost ratio (BCR). The treatments comprised of pure potato stand (PS), potato-dolichos (Lablab purpureus L.) (PD), potato-garden pea (Pisum sativum L.) (PG) and potato-bean (Phaseolus vulgaris L.) (PB). Results indicated a significantly higher (69%) ground cover at tuber initiation stage in PD compared to 66% in PG and PB and 56% in PS. Similarly, the highest SMC values were recorded at tuber initiation stage: 230, 207, 201 and 188 mm m−1 in PD, PG, PB and PS, respectively. Fresh tuber yield was highest in PS (36 t ha−1) and PD (35 t ha−1) and lowest in PG (29 t ha−1). PEY was higher under intercropping than monocropping systems. Potato-dolichos was the most profitable intercropping system with a net income of US$ 9174 ha−1 and a BCR of 5.7 compared to PS (US$ 7436 ha−1) with a BCR of 5.1. The study showed that dolichos is a promising legume crop that could be integrated into potato cropping systems to improve CWP without compromising the tuber yield. [ABSTRACT FROM AUTHOR]

A potential strategy for controlling pests is through the use of "companion plants" within a crop system. This strategy has been used in several trials to fight against a major crop insect pest: the aphid. We reviewed the literature to highlight the major mechanisms by which a companion plant may act. Trials carried out under laboratory or field conditions revealed that companion plants operate through several mechanisms. A companion plant may be associated with a target crop for various reasons. Firstly, it can attract aphids and draw them away from their host plants. Secondly, it can alter the recognition of the host plant. This effect is mostly attributed to companion plant volatiles since they disturb the aphid host plant location, and additionally they may react chemically and physiologically with the host plant, making it an unsuitable host for aphids. Thirdly, it can attract natural enemies by providing shelter and food resources. In this review, the feasibility of using companion plants is discussed. We conclude that many factors need to be taken into account for a successful companion plant strategy. For the best long-term results, companion plant strategies have to be combined with other alternative approaches against aphids. [ABSTRACT FROM AUTHOR]

Companion plants ( CPs) may affect the performance of pests on their hosts because of their potential to emit volatile organic compounds ( VOCs) and their effectiveness depends not only on the species, but also on their arrangement in the crop system., The present study aimed to evaluate the effect of intercropping rosemary, lavender or basil on the performance of Myzus persicae populations on sweet pepper plants ( Capsicum annum) under greenhouse conditions., In a first set of experiments, sweet pepper plants were neighboured by either one or two CPs. In another set of experiments, rosemary was tested at three distances (0.5, 1.5 and 2.5 m) from the host plant., The first set of experiments showed similar patterns of aphid performance (i.e. number of females and nymphs) when a sweet pepper plant was surrounded by one or two companion plants. However, aphid performance was affected more when sweet pepper plants were intercropped with rosemary compared with lavender or basil., The effect of the companion plant decreased significantly with distance. Rosemary was most effective at 0.5 m, although its effectiveness decreased at 1.5 m, becoming insignificant at 2.5 m., The results suggest that a CP may be effective under greenhouse conditions provided that it is located near the target plant. [ABSTRACT FROM AUTHOR]