Revista Verde de Agroecologia e Desenvolvimento Sustentável

Vegetables in the bioremediation of nitrogen compounds from biofloc effluents

2024-02-14T10:38:35-03:00

Our work aims to evaluate the changes in the water quality parameters of the effluent of a biofloc system (BFT) after the insertion of vegetables. Vegetable seedlings of three species were used: lettuce (Lactuca sativa), arugula (Eruca sativa), and green onion (Allium schoenoprasum). Twelve polyethylene terephthalate bottles were used, divided into four groups (three different vegetables and control), in triplicate, equipped with an aeration system (individually) to avoid BFT sedimentation. The bottles were kept in a polyethylene box (180L). The bottles were filled with 1 L of BFT water used as the initial sample (zero time). The pH, total ammonia, nitrite and nitrate were measured at time zero, 24 hours and 72 hours after the insertion of the different vegetables in the experimental system. It was possible to observe improvements in the ammonia levels 24 h after the insertion of vegetables, as the treatments (Lettuce, Chives and Arugula) reduced the amount of ammonia when compared to the control group. However, there was little influence on pH, nitrite and nitrate. Therefore, we can conclude that the insertion of vegetables in the effluent reduces ammonia levels, improving water quality parameters and, therefore, can reduce the environmental impact or act as bioremediators of the cultivation environment.

Producers and potentialities of Pereskia aculeata in the Vale do Paraíba Paulista, São Paulo, Brazil

2024-02-14T10:38:38-03:00

The objective of this research was to collect online data about the cultivation of 'ora-pro-nóbis' (OPN) in the Vale do Paraíba Paulista to support research planning and public policies. A questionnaire with 24 questions was created using a remote research management application and covered the cultivation, consumption and commercialization of OPN. Applied to the agroecology group Rede Agroflorestal do Vale do Paraíba (Rede) and food security group Roda de Saberes (ROSA), made up of farmers, producers and rural owners, agriculture, health and education professionals, we obtained 52 completed questionnaires with OPN valued for its high protein and nutritional content, as a traditional food widely used by 96% of respondents who keep few plants in backyards and farms (82%) for the consumption of 0.5-1, 0kg of leaves per month in fresh form (29%), green juice (22%), cakes and breads (21%) and sautéed with meat (17%). Research should focus on pruning management (67%), necessary to maintain the low size of the plants and prevent the spikes from increasing in size as the branches age. This research provided a current overview of the growing popular interest in the consumption of OPN, which justifies investments to improve management and expand the scale of production to also serve the food and pharmaceutical industries.

Community Supported Agriculture: another look at agriculture

2024-02-14T10:38:44-03:00

The Community Supported Agriculture (CSA) is a global movement that brings together consumers and farmers around the same ideal: to offer a new form of economy, in a joint action for the production and marketing of food. Thus, to better understand this movement, we propose to investigate the work done by CSA Nossa Horta, an association located in the city of Belo Horizonte (Minas Gerais), which contributes to the construction of a differentiated network for the production and commercialization of food, as well as to analyze the relationships established therein. For this, we opted for qualitative research as a methodological approach, using semi-structured interviews and participant observation. The results showed that CSA Nossa Horta, besides supporting agroecological production and short marketing circuits, seeks greater involvement of its members in its management, besides encouraging and strengthening the relationships of proximity and solidarity between those who produce and those who consume, developing another look for agriculture.

Implementation Costs of Lettuce in No-Tillage Vegetable Farming in Laranjeiras do Sul, Paraná, Brazil

2024-02-14T10:38:47-03:00

The production of vegetables in the state of Paraná primarily stems from conventional farming systems. One technological strategy to assist rural producers in transitioning to sustainable production is the implementation no-till vegetable farming system. Vegetable production entails high investment costs, particularly for inputs, a major obstacle in the production system. The objective of this research was to determine the main costs and technical coefficients involved in establishing and managing a hectare of lettuce produced using the no-till vegetable farming system during the agroecological transition in Laranjeiras do Sul, Paraná. The study was conducted during the 2021 agricultural season through the installation of an experiment to validate the costs of implementing and managing the no-till vegetable farming system. The establishment and management of one production cycle of 1 hectare of lettuce using the no-till vegetable farming system in Laranjeiras do Sul indicated a total cost of U$7.891,32. The most significant components of the total cost were inputs and manual operations.

Composition and diversity of plants in homrgardens in the community of Genipaúba, Santa Bárbara do Pará, Brazil

2024-02-14T10:38:31-03:00

Agroforestry homegardens are considered older land use systems, traditionally practiced by family members who manage a diversity of plants around their residences for various purposes. The objective of this study was to evaluate the richness and floristic composition of agroforestry homegardens in the Genipaúba community, located in the municipality of Santa Bárbara, Pará state. Twenty homegardens were analyzed, selected through convenience sampling, taking into consideration the availability of the homegarden maintainers. Botanical identification was conducted on-site. Phytosociological parameters (frequency and density) were used to estimate horizontal structure, while Shannon-Wiener Index and Pielou's Evenness were used to estimate homegarden diversity. Eighty-four plant species distributed across 49 botanical families were identified, with Arecaceae being the family with the highest number of individuals (130). The most common species among the homegardens were Theobroma grandiflorum (cupuaçu) and Euterpe oleracea (açaí), which also had the highest relative frequencies of 7.33% and 6.47%, respectively. Regarding life form, the arboreal stratum had the highest predominance. The most prominent category of use in the Genipaúba homegardens was food. The calculated Shannon-Wiener Index for the agroforestry homegardens indicated a high diversity of species within these areas. The homegardens exhibited high richness and diversity.

Use of microsatellite markers to evaluate the genetic diversity of local cassava landraces

2024-02-14T10:38:42-03:00

Cassava is cultivated by family farmers who preserve local landraces in their proprieties, acting as guardians of this genetic resource. The existing genetic diversity for the species can be estimated using microsatellite molecular markers. Thus, the objective was then to carry out the molecular characterization of four local varieties of cassava (Cacau Branca, Cacau Roxa, Cacau Amarela and Mandioca Pão) cultivated by family farmers in the municipality of Apiacás, Mato Grosso state, Brazil using microsatellite markers. Four local landraces of cassava were sampled, totaling 40 individuals. Leaf material was used for DNA extraction and PCR amplification. A total of 67 alleles were amplified, with SSRY126 and SSRY21 amplifying the highest and lowest number of alleles, respectively. Among the amplified alleles, 33 rare alleles (49%) were identified. The observed heterozygosity (0.840) was higher than the expected heterozygosity (0.643), reflecting negative fixation indices. Loci with PIC values above 0.5 were GA12, GA131, GA140, SSRY27, SSRY28, and SSRY126. The dendrogram formed by the UPGMA hierarchical clustering generated five genetic clusters, which were in agreement with the Bayesian analysis. Thus, genetic diversity was observed among the local landraces cultivated in the family farmers' fields in the municipality of Apiacás. The AP5 and AP20 individuals are the most genetically divergent among the analyzed group, and the Mandioca pão landrace is the most genetically distant from the other three landraces.

Genetic parameters and dissimilarity between progenies of ‘cupuaçu’ tree (Theobroma grandiflorum, Malvaceae) from free pollination in southeastern Pará, Brazil

2024-02-14T15:47:21-03:00

The genetic diversity assessment can provide valuable information for conservation and genetic improvement programs, aiming to maximize the expression of traits of interest in production. In this context, the cupuaçu tree (Theobroma grandiflorum Malvaceae) stands out because it is a native tree of the Amazonia basin and its fruit, cupuaçu, is widely used in the production and sale of various foods. We performed the progeny test at the Instituto Federal de Educação Ciência e Tecnologia do Pará Campus Marabá Rural. The experimental design consisted of 200 genotypes distributed in randomized blocks, considering one plant per plot. The genotypes come from 10 progenies, with seeds derived from free pollination. We used silvicultural and morphological leaf characters to estimate genetic parameters and dissimilarity measures. Variance estimates indicated high individual heritability, with all characters showing values greater than 0.80. Accuracy estimates for all characters were greater than 0.90, providing high precision for potential selection. The results of the multivariate analysis suggest that the collar diameter contributed most to explaining the total variation in the analyzed material. The Tocher grouping method based on Mahalanobis genetic distances constituted eight dissimilarity groups, demonstrating genetic diversity for the observed characters. Based on the characters herein tested, we found genetic diversity in the progenies, with the potential for genetic conservation and selection.

Extracts of Ocimum campechianum for the control of Ascia monuste orseis caterpillars

2024-02-14T10:38:25-03:00

Ascia monuste orseis Godart, stands out as a pest insect in brassica crops. Among control strategies, the use of pesticides is the most common, however, continuous and indiscriminate use poses problems for the environment and human health. Botanical insecticides are a promising alternative. Thisvstudy investigated the stimulus-response of the hydroalcoholic crude extract of Ocimum campechianum Mill. (Lamiaceae) and its dichloromethane (DCM) fraction on the toxicity, feeding preference, and development of A. monuste orseis caterpillars. Toxicity, feeding preference (choice and no-choice tests), and development of the caterpillars to the adult stage were evaluated. In the development and feeding preference tests, sublethal concentrations were used based on the toxicity test: 10.00 and 2.50 mg mL^-1 for the "crude extract" and its "DCM fraction," respectively. Eight replicates with five caterpillars each were used. It was observed that the crude extract and the DCM fraction of O. campechianum were toxic and reduced the feeding of three-day-old caterpillars (days after hatching), with LC₅₀ values of 52.95 and 20.90 mg mL^-1, respectively. However, they did not affect the insects development. Therefore, the crude extract and its DCM fraction from O. campechianum show potential for alternative control of A. monuste orseis caterpillars.

Shoot regrowth potential and root development of Digitaria insularis subjected to mowing

2024-02-14T10:38:28-03:00

Digitaria insularis is a Poaceae disseminated mainly by seeds that can cause problems in agroecosystems. The objective of this work was to evaluate the influence of the age of D. insularis submitted to mowing on morphophysiological characteristics. Plants were grown in a greenhouse and cut close to the substrate at 21, 35, 49 and 77 days after emergence (DAE) or uncut, with evaluation of the variables up to 105 DAE. Except for chlorophyll b, the other variables were influenced by the age of the plants when cutting (p<0.05). Plant height and number of leaves decreased with increasing cutting age. The highest chlorophyll a content was observed in the cut at 51 DAE. Epicuticular wax mass was greater in the 49 DAE (0.4 mg cm^-2) cut. The shoot dry mass decreased with increasing age at the cut, reaching zero (0 g) after 54 DAE. The root dry mass reached the minimum point when the aerial part was cut at 57 DAE. Shoot water content decreased with increasing cutting age. The root water content showed a biphasic behavior, with the lowest water content (18.8%) in the cut at 49 DAE. These results suggest that mowing close to 21 DAE favors the development of D. insularis. Therefore, D. insularis plants in optimal development conditions should be managed by mowing priority between 49 and 60 DAE.