Crotalaria Juncea Research Articles

Effect of Added Phosphorous and Organic Matter on the Availability of Phosphorous Fractions in Normal Soil under Field Capacity Moisture Tension

An Incubation study was conducted from January 2020 – May 2020 under "Laboratory conditions" at the Department of Soil Science and Agricultural Chemistry, Chandra Shekhar Azad Kanpur University of Agriculture and Technology, (U.P.) to study the “Effect of added phosphorous and organic matter on the availability of phosphorous fractions in normal soil under field capacity moisture tension”. To obtain a different fraction of phosphorus under the field capacity regime all three experiments were conducted under kankar soil conditions to determine Ca-P, Al-P and Fe-P as influenced by six different treatments. The results showed that with advancement in time of incubation, the availability of Ca-P (308.2 ppm and 235.3 ppm at 0 days and 90 days of incubation period, respectively), Al-P (89.5 ppm and 44.9 ppm at 0 days and 90 days of incubation period, respectively), while Fe-P (13.8 ppm and 13.1 ppm at 0 days and 90 days of incubation period, respectively) increased marginally at field capacity in kankar soil condition. Sunhemp (T2) proved more beneficial than FYM (T3) in increasing Fe-P, Al-P, and Ca-P as also Olsen’s P content in the soil. Therefore, the application of organic matter either in the form of sun hemp with phosphorus proved very useful in improving the avoidable content of the soil.

Crotalaria juncea L. enhances the bioremediation of sulfentrazone-contaminated soil and promotes changes in the soil bacterial community.

Sulfentrazone (STZ) is an efficient tool for the pre- and post-emergence control of monocotyledonous and dicotyledonous weeds in fields of crops such as pineapple, coffee, sugarcane, citrus, eucalyptus, tobacco, and soybean. However, this herbicide persists in the soil, causing phytotoxicity in the subsequent crop. Therefore, it is important to use efficient strategies for the remediation of STZ-contaminated areas. The aim of this study was to evaluate the effects of Crotalaria juncea L. on the remediation of STZ-contaminated soil and on the microbial activity and bacterial community structure therein. The study was conducted in three stages: (i) cultivation of C. juncea in soil contaminated with 200, 400, and 800 g ha-1 STZ; (ii) determination of the soil microbial activity (basal respiration, microbial biomass carbon, and bacterial community structure); and (iii) cultivation of a bioindicator species and determination of the residual fraction of STZ. The soil microbial activity was impacted by the soil type and STZ dose. Soil previously cultivated with C. juncea (rhizospheric soil) displayed higher CO2 and lower qCO2 values than non-rhizospheric soil (no previous C. juncea cultivation). Increasing doses of STZ reduced the activity and lowered the diversity indices of the soil microorganisms. The bacterial community structure was segregated between the rhizospheric and non-rhizospheric soils. Regardless of soil type, the bioindicator of remediation (Pennisetum glaucum R.Br.) grew only at the STZ dose of 200 g ha-1, and the plant intoxication level was also lower in rhizospheric soil treated with this herbicide dose. All P. glaucum plants died in the soils treated with 400 and 800 g ha-1 STZ. Previous cultivation of C. juncea in soils contaminated with 200, 400, and 800 g ha-1 STZ reduced the residual fraction of the herbicide by 4.8%, 12.5%, and 17.4%, respectively, compared with that in the non-rhizospheric soils. In conclusion, previous cultivation with C. juncea promoted increases in the soil bacterial activity and diversity indices, mitigated the deleterious effects of STZ on the bioindicator crop, and reduced the residual fraction of the herbicide in the soil.

Biogenic and physicogenic aggregates as indicators of quality in soils with sandy texture in areas of organic agriculture

ABSTRACT Sandy texture soils have a great expression in agricultural areas worldwide. In the Baixada Fluminense, soils with a sandy texture on the surface horizons are striking, and a good part of these areas is destined for producing vegetables using conventional cultivation methods. The sandy texture is one of the great challenges for agriculture due to the low water retention capacity provided to the soil, the rapid decomposition of organic matter, and the intense loss of nutrients by leaching. In these areas, the action of erosive processes is sometimes observed, whether water or wind erosion. The practices carried out in conventional agriculture can accentuate these processes. This study aimed to evaluate the influence of different soil management systems, with different vegetation covers, on the pathways of aggregate formation, the nutrient contents contained therein, and the organic matter fractions, with the objective of using these properties as indicators of soil quality. The study was carried out in an organic production unit, with no-till system (NT) and conventional system (CT), three vegetal covers were evaluated, namely; seed cocktail 1 (C1) (Crotalaria (Crotalaria juncea) (20 kg ha -1 ), Jack Bean (Canavalia ensiformis) (150 kg ha -1 ) and millet (Pennisetum glaucum) (60 kg ha -1 )), and seed cocktail 2 (C2) (with 50 % of the amount of seeds used in C1), and spontaneous plants (S. P). Undisturbed samples were collected at the layers of 0.00-0.05 and 0.05-0.10 m, and, from these samples, aggregates with a diameter between 9.7 and 8.0 mm were classified according to the formation route (Biogenic or Physicogenic). From these, the chemical properties were quantified (pH, Ca 2+ , Mg 2+ , Al 3+ , P, Na + , K + ), and also the carbon fractions (total organic carbon – TOC, mineral-associated organic carbon – MAOC), particulate organic carbon – POC, and free light fraction carbon – LFC). Based on the results, it was verified that the percentage of biogenic aggregates was higher than the physicogenic one in the layer of 0.00-0.05 m, not being verified influences of the vegetal coverage or the management system. Chemical properties did not differ significantly between training pathways. The CT, for the most part, was the system in which the highest values of chemical properties were observed, and in general, the C2 and S.P coatings were the ones that provided the greatest improvements for chemical properties and carbon content.

Effects of Fabaceae and Poaceae Pollen Accessibility and Traits on the Pollinivory of Adult Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae).

Pollen is a food source for adult Chrysoperla externa(Hagen), whose larvae are biocontrol agents against pests. However, adults may face challenges in foraging for pollen due to differences in pollen accessibility and variability in pollen morphology and chemistry. In the laboratory, we investigated the ability of adult C. externa to consume pollen from flowers of Cajanus cajan, Canavalia ensiformis, Crotalaria juncea, Flemingia macrophylla, Avena strigosa, Pennisetum glaucum, Sorghum bicolor, and Zea mays, and we explored whether adults chose any of these pollens based on their quantitative and qualitative features. Cajanus cajan and F. macrophylla pollen were the only ones not consumed by adults when confined to flowers. Pollen removed from the preanthesis buds was offered simultaneously for 24 and 48h. In both periods, adults consumed more of the medium-sized P. glaucum (with the second largest exine thickness) and large-sized Z. mays (with the thinnest exine) pollen, even though they had significantly less crude protein than Fabaceae pollen, whose sizes varied from medium (C. juncea, with the thickest exine) to large (C. ensiformis, whose exine thickness was equal to that of P. glaucum). Overall, adults consumed more Poaceae pollen than Fabaceae pollen, but the palynological features and the protein contents did not affect this choice. Our results highlighted that C. juncea, P. glaucum, S. bicolor and Z. mays are good pollen sources for adult C. externa and should be considered promising candidates in the selection of insectary plants to deploy in biocontrol programs aimed at the conservation of this lacewing.

Standardization of Nipping Technique for Enhancement of Seed Yield and Quality in Sunn Hemp

A field experiment entitled “standardization of nipping technique for enhancement of seed yield and quality in sunn hemp” was conducted during Kharif 2019-20 and 2020-21 at Seed Production Block, NSP, Seed Unit, UAS, Raichur. The experiment was laid out in a randomized complete block design with fifteen treatments including nipping and foliar spray of cycocel and their combinations in three replications. The results emanated from the experiment recorded maximum plant height (cm), early 50 per cent flowering and maturity in T1 (no nipping). Whereas, nipping at 30 and 40 DAS and foliar spray of cycocel at 50 DAS (T15) recorded maximum number of branches per plant, chlorophyll content (SPAD Values), leaf area (cm2), number of pods per plant, seed yield per plant, seed yield (q ha-1), seed germination (%), total seedling length (cm), seedling dry weight (mg) and seedling vigour index I and II. While the nipping at 30 DAS and foliar spray of cycocel @ 1000 ppm at 40 DAS (T12) is a better option in terms of obtaining higher net returns and B:C ratio in sunn hemp. Whereas, maximum cost of cultivation was found in nipping at 30, 40 DAS and 50 DAS (T8).

Different cover crops have a limited impact on marketable yields and biogeochemical cycling but secondary effects on pollinators and plant-parasitic nematodes in Florida organic vegetable systems

Cover crops are typically grown during the summer in Florida’s organic vegetable systems, where they can affect nutrient cycling, soil health, and pests/pollinators. We compared the effects of five summer cover crops and a weedy fallow on marketable yields and the cycling of phosphorus, potassium, and carbon. Weed, nematode, and insect pollinator abundance were also monitored to measure any secondary impacts of cover cropping. Cover crops included monocultures of sunn hemp or sorghum sudangrass, a sunn hemp and sorghum sudangrass biculture, a three species mixture (biculture plus buckwheat), and a five species mixture (three species mixture plus cowpea and sunflower). In both 2018 and 2019, cover crops were planted in June and terminated in August, and bell peppers were grown from August until December. Marketable yields were greater with the tree and five species mixtures relative to the biculture in 2018, with no effects of cover crops on yields in 2019. Phosphorus and potassium accumulation was typically greater with cover crops than in the weedy fallow, but cover crops did not affect pepper nutrient accumulation or soil concentrations. Similarly, differences in carbon accumulation (lowest in sorghum sudangrass monoculture and weedy fallow) did not affect soil organic matter, soil total carbon or permanganate-oxidizable carbon. When analyzed as part of a radar plot analysis, cover crops helped manage summer weeds and root-knot nematodes in 2019, but the sorghum sudangrass monoculture increased sting nematodes; only the three and five species mixtures benefitted pollinators as buckwheat was the only cover crop that flowered in this study. Overall, cover crops had a limited effect on marketable yields and biogeochemical cycling but had more important secondary effects on pests and pollinators.

Soil macrofauna correlations with soil chemical and physical properties and crop sequences under no-tillage

ABSTRACTSoil macrofauna is an important indicator of soil quality, as it is sensitive to changes in the environment as a result of soil management, which includes soil chemical and physical properties and the diversity of cultivated species. This study aimed to evaluate the composition and structure of soil macrofauna under a no-tillage system in different crop sequences, with and without crop rotation, over two growing seasons: a rainy summer and a dry winter. The crop sequences were soybean/corn rotation in the summer and corn in the winter; soybean/corn rotation in the summer and sunn hemp in the winter; soybean monoculture in the summer and sunn hemp in the winter; and corn monoculture in the summer and corn monoculture in the winter growing season. The nutrient content of the crop residues left on the soil surface, soil chemical and physical properties, and soil macrofauna were determined. Functional plant groups (grasses or legumes) individually influenced the composition of soil macrofauna more significantly than the effect of crop sequence, with or without rotation, and growing season. Grasses favored an increased density of groups such as Oligochaeta, Isoptera, and Formicidae. In contrast, legumes contributed to the variation in the total density of individuals and Diplura and Coleoptera groups. Furthermore, the influence of functional plant groups (grasses or legumes) on the composition and density of soil macrofauna were related to soil chemical (P and N content) and physical properties (particulate organic carbon and soil moisture), which determined the composition of soil macrofauna groups.

Integrated nutrient-management practices effect on productivity of rice (Oryza sativa) and soil properties under rainfed lowland rice situation – A long-term study

An experiment was conducted on a fixed site at Agricultural Research Station (Paddy), Sirsi, University of Agricultural Sciences, Dharwad, Karnataka, India, during the rainy (kharif) season of 2000 to 2017 (18 years), to study the long-term effect of integrated nutrient-management (INM) practices on productivity of rice (Oryza sativa L.) and its soil health. The experiment was laid out in a split-plot design with 7 main plot treatments, viz. no manure, farmyard manure (FYM) @ 10 t/ha, vermicompost @ 5 t/ha, eupatorium @ 10 t/ha, gliricidia [Gliricidia sepium (Jacq.) Steud.] or quick stich @ 10 t/ha, sunhemp (Crotalaria juncea L.) grown in-situ @ 8.96 t/ha and paddy straw @ 5 t/ ha) and 3 subplot treatments [no fertilizer, 50% recommended dose of fertilizer (RDF) and 100% RDF]. The average of 18 years pooled data showed that, the grain yield, straw yield and net returns of rice were significantly higher with the application of gliricidia and eupatorium @ 10 t/ha compared to all other manures. Among the interactions of different organic manures and inorganic fertilizers, combinations of application of gliricidia @ 10 t/ha + 100% RDF resulted in significantly higher grain yield (6.2 t/ha), straw yield (7.8 t/ha) and net returns (`30,569/ha) followed by eupatorium + 100% RDF. The grain yield, straw yield and net returns obtained with application of green-leaf manures, viz. gliricidia alone (5.29, 6.01 t/ha and `25,443/ha, respectively) or eupatorium @ 10 t/ha alone were found to be at par with that of 100% RDF alone.

Meteorological variables, water balance, biomass and nutrients accumulation by cassava intercropped with Crotalaria juncea

Increasing cassava yield in response to growing consumer market demand requires good management practices to avoid degradation caused by soil nutrient depletion. The objective of this work was to evaluate components of macronutrient production and extraction of cassava in consortium with the legume Crotalaria juncea. A statistical design was used in randomized blocks, with four replications, in plots subdivided in time. In the plots were the treatments presence and absence of cassava consortium with C. juncea, the subplots were formed by 11 evaluation periods every 30 days for the production components and 6 evaluation periods every 60 days for the extraction of nutrients. The following were evaluated: production components (partitioned yields and total wet and dry mass - t ha-1) and extraction of macronutrients (nitrogen, phosphorus, potassium, calcium, magnesium and sulfur - kg ha-1). The water balance of the crop was determined on a monthly scale. The annual evapotranspiration of cassava was 1,273 mm in the 12-month cycle. The agricultural productivity of roots, stakes, stem, leaves, shoot and total biomass of cassava was 18.4, 1.8, 7.2, 2.7, 9.9 and 30.1 t ha-1, respectively. The dry mass yield of roots, stakes, stem, leaves, shoot and total was 5.1, 0.8, 2.1, 0.9, 3.0 and 8.9 t ha-1, respectively. There was a higher extraction of nitrogen by cassava, 119 kg ha-1, followed by calcium, potassium, magnesium, phosphorus and sulfur. The cassava consortium with C. juncea did not interfere in the variables studied.

De novo transcriptome of a bast fibre crop Crotalaria juncea reveals T2 ribonuclease genes to investigate late-acting self-rejection of pollens

The biology of gametophytic late-acting self-rejection of pollen in pre-zygotic ovules is relatively unknown in the Fabaceae family of plants. Our understanding of the genetic basis of late-acting self-incompatibility (LSI) is limited due to a lack of sequence data and candidate genes. Crotalaria juncea, a Fabaceae family member that produces commercially important phloem fiber, possesses LSI. Due to a lack of selfed seeds, it is difficult to maintain genetic purity in germplasm and develop breeding lines for improved fiber quality and yield. To investigate candidate genes for LSI in C. juncea, a high-quality de novo transcriptome was generated. It facilitated the identification of genes from the self-incompatibility-related ribonuclease (RNase) family, specifically a Class III T2/RNase gene with sequence properties similar to S-RNase proteins. Based on conserved amino acid motifs, histidine residues, and a high isoelectric point (pI ≥9.0), Cjun_RNS3.1 was identified as an S-RNase homologue (non-S-RNase) or relic S-RNase gene. Unlike typical S-RNases found in known SI plant systems, evolutionary analysis of the Cjun_RNS3.1 protein revealed its ancestral origin. The expression of Cjun_RNS3.1 and other T2/RNase genes revealed differential expression patterns in the pistils of LSI and self-compatible Crotalaria species. The upregulation of the Cjun_RNS3.1 gene during the different stages of pollen tube development indicates that it may be involved in the LSI. In summary, the sunn hemp transcriptome is the first genomic resource reported from a Fabaceae family plant with the LSI trait. A non-S-RNase gene with an ancestral evolutionary origin and a diverse function was found, which could be related to gametophytic LSI. This could be used as a model system to investigate the molecular basis of LSI in the Fabaceae family and help develop C. juncea breeding lines for fibre improvement.

Upholding Sunflower (Helianthus annuus) Yield and Profitability while Maintaining Soil Fertility Under Intercropping with Sunn Hemp and Mineral Fertilizer Application

Upholding Sunflower (Helianthus annuus) Yield and Profitability while Maintaining Soil Fertility Under Intercropping with Sunn Hemp and Mineral Fertilizer Application

Gas Exchanges and Agricultural Performance of Cover Plants in Compacted Soil After Soybean Cultivation

ABSTRACT The present study sought to evaluate gas exchange and biomass production in cover crops grown in soils with different levels of compaction, after soybean cultivation. Experimental design was completely randomized in 4 × 4 factorial scheme, with the factors being composed of four levels of soil density (1.0 ± 0.013; 1.15 ± 0.022; 1.30 ± 0.035 and 1.45 ± 0.040 Mg.m−3) and four cover crops (Avena strigosa Schreb.; Crotalaria juncea L.; Urochloa brizantha cv. Piatã and Crotalaria spectabilis Roth), with three repetitions. Net photosynthesis rate and the transpiration of cover plants were not influenced by soil compaction, unlike the SPAD index of U. brizantha, which improved performance in the photosynthetic process with increasing soil density. All cover plant species show a reduction in shoot dry biomass starting at a density of 1.00 Mg.m−3, as well as the dry biomass and root volume in the compacted layer and below the compacted layer for A. strigosa Schreb and U. brizantha and, with lower root volumes for C. juncea L. and C. spectabilis Roth in the layer below the compacted. U. brizantha showed the best root development in density of 1.45 Mg.m−3, and a greater number of roots per shoot dry biomass, being good alternatives for the preventive management of compaction in compacted soils. Root growth was higher above and below the compacted layer.

Cajanus cajan: a promissory high-nitrogen fixing cover crop for Uruguay

Cover crops can increase agricultural sustainability by protecting soil from erosion, increasing biodiversity, and symbiotically incorporating fixed nitrogen (N) into the soil. Nowadays, however, in Uruguay mostly grasses are planted in autumn to protect the soil from erosion. Another option is to study tropical legumes’ performance as cover crops, which can fix substantial amounts of nitrogen in short growing periods, thereby bridging the knowledge gap in Uruguayan agriculture. The main objective was to evaluate and compare the performance of six tropical legumes (Crotalaria juncea, Crotalaria spectabilis, Crotalaria ochroleuca, Cajanus cajan, Dolichos lablab, Mucuna pruriens) and the temperate legume Glycine max. The evaluation focused on aboveground biomass and the N mass derived from fixation (NmdFix), as well as other attributes; three field experiments were conducted on a southern Uruguay farm during the summers of 2017, 2018, and 2019. The growing cycle lengths for the cover crops in 2017, 2018, and 2019 were 117, 130, and 90 days, respectively. The results showed that when planting was done at late December (2017 and 2018 growing cycles), the species with the highest mean biomass yield were Crotalaria juncea (two year average 12.0 Mg ha-1) and Cajanus cajan (11.0 Mg ha-1), but Cajanus cajan (149 kg ha-1) more than doubled the NmdFix mass of Crotalaria juncea (57 kg ha-1). In 2018 biomass yields were much higher than in 2017, with Glycine max (20.0 Mg ha-1) yielding at a similar level to Crotalaria juncea and Cajanus cajan (20.5 and 18.7 Mg ha-1, respectively). Amounts of NmdFix, however, were much higher in Glycine max and Cajanus cajan (263 and 253 kg N ha-1, respectively), than in Crotalaria juncea (91 kg N ha-1). In 2019 planting had to be delayed until early February and only Glycine max maintained acceptable biomass and NmdFix levels. In conclusion, based on its fixing N potential, for late December sowings Cajanus cajan and Glycine max would be the most promising species for cover crop use, while for late January or early February sowings, only Glycine max would an option because the tropical species seriously impaired their productivity when grew longer into the cooler autumn temperatures.

Intercropping Cover Crops for a Vital Ecosystem Service: A Review of the Biocontrol of Insect Pests in Tea Agroecosystems.

The intercropping of cover crops has been adopted in several agroecosystems, including tea agroecosystems, which promotes ecological intensification. Prior studies have shown that growing cover crops in tea plantations provided different ecological services, including the biocontrol of pests. Cover crops enrich soil nutrients, reduce soil erosion, suppress weeds and insect pests, and increase the abundance of natural enemies (predators and parasitoids). We have reviewed the potential cover crops that can be incorporated into the tea agroecosystem, particularly emphasizing the ecological services of cover crops in pest control. Cover crops were categorized into cereals (buckwheat, sorghum), legumes (guar, cowpea, tephrosia, hairy indigo, and sunn hemp), aromatic plants (lavender, marigold, basil, and semen cassiae), and others (maize, mountain pepper, white clover, round-leaf cassia, and creeping indigo). Legumes and aromatic plants are the most potent cover crop species that can be intercropped in monoculture tea plantations due to their exceptional benefits. These cover crop species improve crop diversity and help with atmospheric nitrogen fixation, including with the emission of functional plant volatiles, which enhances the diversity and abundance of natural enemies, thereby assisting in the biocontrol of tea insect pests. The vital ecological services rendered by cover crops to monoculture tea plantations, including regarding the prevalent natural enemies and their pivotal role in the biocontrol of insect pests in the tea plantation, have also been reviewed. Climate-resilient crops (sorghum, cowpea) and volatile blends emitting aromatic plants (semen cassiae, marigold, flemingia) are recommended as cover crops that can be intercropped in tea plantations. These recommended cover crop species attract diverse natural enemies and suppress major tea pests (tea green leaf hopper, white flies, tea aphids, and mirid bugs). It is presumed that the incorporation of cover crops within the rows of tea plantations will be a promising strategy for mitigating pest attacks via the conservation biological control, thereby increasing tea yield and conserving agrobiodiversity. Furthermore, a cropping system with intercropped cover crop species would be environmentally benign and offer the opportunity to increase natural enemy abundance, delaying pest colonization and/or preventing pest outbreaks for pest management sustainability.

Assessment of Toxicological Effects of Triclosan on Microbes, Plants, and Genetic Material in Cells

Triclosan is an antiseptic ingredient that is commonly found in numerous personal care items that may end up in the environment. Their ecotoxicological profile, however, is still unknown. The current research aims to determine the toxicity of triclosan on E. coli, Vigna radiata and Crotalaria juncea seeds, and Allium cepa roots. The analyses include toxicity assays for microbes, phytotoxicity, and cytogenotoxicity. The results proposed if the triclosan tested (60-150 µM) became exceedingly harmful to the test bacterium, as seen by the decrease in E. coli CFU, indicated that triclosan had antibacterial properties and inhibited the test microbe, depending on the concentration of triclosan used. Triclosan at concentrations of 40 and 80 µM, respectively, decreased the sprouting length of Vigna radiata and Crotalaria juncea by 45-50% and 70-72%, respectively. Thus, the cytogenotoxicity assay using Allium cepa revealed that triclosan damages the meristematic cells. Triclosan at 40 µM concentration resulted in a 1.2% aberration index and a 10.4% mitotic index, and 80 µM caused a 1.4% aberration index and an 8.8% mitotic index. All of the findings point to triclosan being potentially hazardous to the biota.

Índice de qualidade do solo de um argissolo sob parcelas de longa duração no tabuleiro costeiro nordestino, Brasil

ABSTRACT Soil quality, measured through its chemical, physical and microbiological attributes, changes as a result of anthropic sensations and becomes an important tool to assess environmental quality. The objective of this study was to determine and evaluate the Quality Index of an Ultisol in a long-term (17-yr) plots under different management systems in the Coastal Tablelands of Sergipe State, in Northeastern, Brazil. Main effects were conventional tillage (CT), no-tillage (NT), and minimum tillage (MT) distributed cultivated strips with corn as the main crop. Split-range treatments were randomly distributed and cultivated with cowpea beans (Vigna unguiculata), sunn hemp (Crotalaria juncea), pigeon pea (Cajanus cajan), and millet (Pennisetum glaucum). A forest soil was used as reference, compared to the soil samples of the cultivated area. The Soil Quality Index (SQI) for the 0-0.10 m layer was calculated by the additive method. There were changes in soil properties between the different management systems, and between the experimental soil and the reference area. The highest SQI was obtained from the forest area (67.1) followed by the NT treatment (65.5), MT (65.1) and CT treatment (61.0). The lowest SQI was observed in the CT treatment previously cultivated with pigeon pea (56.5). Among the evaluated soil functions, maintenance of homeostasis had the greatest influence on the SQI. The higher acidity of the forest soil helps to explain the origin of the limitations of the soil in the cultivated area that occupies the same type of soil, tolerated by the adoption of conservationist managements.

Mudanças na microbiota do solo causada pelo uso de produtos comerciais e incorporação de materiais vegetais

ABSTRACT Growers have adopted monoculture to maintain the high melon (Cucumis melo L.) production demand in the Northeastern region of Brazil. This cultivating practice culminates in up to three crop cycles per year being used in the same growing area. The main objective of this study was to evaluate if the incorporation of plant material used with polyethylene mulch and or in association with commercial soil amendment products can help to condition an environment that is beneficial to soil microbial communities. Two identical greenhouse experiments were conducted using a completely randomized design with seven treatments and seven replications. The treatments were: (C) – Control, (M) - polyethylene mulch, (C+M) - incorporation of Crotalaria juncea L. + polyethylene mulch, (P+M) - incorporation of Pennisetum glaucum L. + polyethylene mulch, (M+CS) - polyethylene mulch + (Compost-Aid® + Soil-Set®, trade names of products produced by Alltech Crop Science), (C+M+CS) - incorporation of C. juncea L. + polyethylene mulch + (Compost-Aid® + Soil-Set®), and (P+M+CS) - incorporation of P. glaucum L. + polyethylene mulch + (Compost-Aid® + Soil-Set®). To quantify the target soil microbiota (fungi, bacteria, sporulating bacteria, and actinomycetes), isolations were attempted on selective culture media specific for each group of microorganisms. The incorporation of P. glaucum together with the use of polyethylene mulch and commercial products (Compost-Aid® and Soil-Set®), (P+M+CS), increased the total fungal population by 183%, total bacteria by 55%, sporulating bacteria by 21%, and actinomycetes by 146% in relation to the control treatment.

Soda pulping of sunn hemp (Crotalaria juncea L.) and its usage in molded pulp packaging

Petroleum-based materials are often used in the packaging industry. However, the single use value of such products can be problematic with regard to proper waste disposal. As such, molded pulp packaging can be used as an alternative, given its ease of recycling, composting, and eventual biodegradation. In this work, we aims to study the pulp properties of sunn hemp and its usage as molded pulp products. For this purpose, unbleached beaten and unbeaten soda pulps derived from the whole stem of sunn hemp were examined for their fiber morphology, fibrillation, fiber classification, and physical properties. The sunn hemp pulp was subsequently molded using a batch molding machine. To determine the hydrophobicity of the molded pulp products, the molded samples were manufactured with and without additives. Finally, some properties of the molded pulp products were examined and compared with the commercially available bleached bagasse molded pulp products. It was observed that the molded products made from sunn hemp pulp with additives had a higher water contact angle than that of the commercial products. In terms of general usage, the molded products from sunn hemp pulp with additives were found to be capable of storing hot water, hot cooking oil, as well as microwaving water. We concluded that the sunn hemp pulp could be used as an alternative fibrous raw material in the production of molded pulp packaging.

The Potential for Cover Crops to Reduce the Load of Escherichia coli in Contaminated Agricultural Soil

Cover crops are plants seeded before or after cash crops to improve soil health, reduce weed pressure, and prevent erosion. Cover crops also produce various antimicrobial secondary metabolites (i.e., glucosinolates, quercetin), yet the role of cover crops in moderating the population of human pathogens in the soil has rarely been investigated. This study aims to determine the antimicrobial capacity of three cover crop species to reduce the population of generic Escherichia coli (E. coli) in contaminated agricultural soil. Four-week-old mustard greens (Brassicajuncea), sunn hemp (Crotalaria juncea), and buckwheat (Fagopyrum esculentum) were mixed into autoclaved soil and inoculated with rifampicin-resistant generic E. coli to achieve a starting concentration of 5 log CFU/g. The surviving microbial populations on days 0, 4, 10, 15, 20, 30, and 40 were enumerated. All three cover crops significantly reduced the population of generic E. coli compared to the control (p < 0.0001), particularly between days 10 and to 30. Buckwheat resulted in the highest reduction (3.92 log CFU/g). An inhibitory effect (p < 0.0001) on microbial growth was also observed in soils containing mustard greens and sunn hemp. This study provides evidence for the bacteriostatic and bactericidal effect of particular cover crops. More research regarding the secondary metabolites produced by certain cover crops and their potential as a bio mitigation strategy to improve on-farm produce safety is warranted.

How does boron modify the growth of Crotalaria juncea? A legume with phytostabilizing potential

ABSTRACT Soil contamination by boron (B) occurs in different ways, such as through mineral fertilisers and irrigation, and in surface waters it has increased significantly over the years. It is an important element for plants, participating in several physiological processes. This work aimed to evaluate the behaviour of Crotalaria juncea, widely used as green manure. The species that tolerates B up to a dose of 60 mg dm−3 has the capacity to phytoremediate B and is classified as a phytostabilizer. It is clear that a dose of 120 mg dm−3 of B is harmful to the growth of the species.