scholarly journals Opinião dos agricultores sobre o uso e manejo do solo e sua relação com o retorno da erosão em sistemas de plantio direto

2018 ◽  
Vol 39 (6) ◽  
pp. 2843
Author(s):  
Claudia Maria Prado Furquim ◽  
Adriana Pereira da Silva ◽  
João Tavares Filho

The non-tillage system (NTS), until now considered an effective management tool for the control of erosion, has gradually increased the loss of soil. The objective of this research is to identify and understand the probable causes of the return of erosion in rural properties under the NTS in three municipalities in northern Paraná. For this research, a questionnaire was used to collect information on soil management and the use of agricultural terraces. Data collection was completed with 145 landowners and NTS users, along with rural extension and agricultural cooperatives. The results demonstrated that the return of erosion is likely due to the absence of crop rotation in favor of repetitive year-to-year planting of the same plant species (early soybean/maize [second harvest]/wheat), soil revolving to decompress the surface layer, and the elimination of agricultural terraces and the consequential downslope planting.

2019 ◽  
Vol 42 ◽  
pp. e43039 ◽  
Author(s):  
Alexandre Cunha de Barcellos Ferreira ◽  
Ana Luiza Dias Coelho Borin ◽  
Fernando Mendes Lamas ◽  
Julio Cesar Bogiani ◽  
Mellissa Ananias Soler da Silva ◽  
...  

Sustainable production systems, such as the no-tillage system (NTS), have a tendency to increase organic carbon in the soil. However, in Brazilian cotton production, the conventional tillage system (CTS) is predominant, and long-term studies on cotton crop under the NTS are scarce. The present study aimed to evaluate the effect of soil management and crop rotation systems on the cotton fiber yield as well as on the carbon and nitrogen accumulation in the soil. This study was conducted in the Brazilian savanna over 9 years and consisted of the following four treatments with different soil management systems: the NTS and CTS with the succession or rotation of crops (cotton, soybean, maize, and Urochloa ruziziensis). The NTS increased the carbon content by 55% in the top 5 cm after 9 years and increased the carbon stock by approximately 20% at a depth of up to 40 cm. Crop rotation with soybean, maize, and cotton was insufficient to increase the carbon stock in the soil under the CTS. In addition to increasing the fiber yield, the cotton crop in a NTS rotated with soybean + U. ruziziensis and with maize + U. ruziziensis increases the carbon stock and nitrogen content in soil.


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1438
Author(s):  
Snežana Jakšić ◽  
Jordana Ninkov ◽  
Stanko Milić ◽  
Jovica Vasin ◽  
Milorad Živanov ◽  
...  

Spatial distribution of soil organic carbon (SOC) is the result of a combination of various factors related to both the natural environment and anthropogenic activities. The aim of this study was to examine (i) the state of SOC in topsoil and subsoil of vineyards compared to the nearest forest, (ii) the influence of soil management on SOC, (iii) the variation in SOC content with topographic position, (iv) the intensity of soil erosion in order to estimate the leaching of SOC from upper to lower topographic positions, and (v) the significance of SOC for the reduction of soil’s susceptibility to compaction. The study area was the vineyard region of Niš, which represents a medium-sized vineyard region in Serbia. About 32% of the total land area is affected, to some degree, by soil erosion. However, according to the mean annual soil loss rate, the total area is classified as having tolerable erosion risk. Land use was shown to be an important factor that controls SOC content. The vineyards contained less SOC than forest land. The SOC content was affected by topographic position. The interactive effect of topographic position and land use on SOC was significant. The SOC of forest land was significantly higher at the upper position than at the middle and lower positions. Spatial distribution of organic carbon in vineyards was not influenced by altitude, but occurred as a consequence of different soil management practices. The deep tillage at 60–80 cm, along with application of organic amendments, showed the potential to preserve SOC in the subsoil and prevent carbon loss from the surface layer. Penetrometric resistance values indicated optimum soil compaction in the surface layer of the soil, while low permeability was observed in deeper layers. Increases in SOC content reduce soil compaction and thus the risk of erosion and landslides. Knowledge of soil carbon distribution as a function of topographic position, land use and soil management is important for sustainable production and climate change mitigation.


2018 ◽  
Vol 177 ◽  
pp. 97-104 ◽  
Author(s):  
Émilie Maillard ◽  
Brian G. McConkey ◽  
Mervin St. Luce ◽  
Denis A. Angers ◽  
Jianling Fan

2008 ◽  
Vol 8 ◽  
pp. 1184-1196 ◽  
Author(s):  
Xia Zhang ◽  
Ping Xie ◽  
Xiaoping Huang

The aim of this review is to identify problems, find general patterns, and extract recommendations for successful management using nontraditional biomanipulation to improve water quality. There are many obstacles that prevent traditional biomanipulation from achieving expectations: expending largely to remove planktivorous fish, reduction of external and internal phosphorus, and macrophyte re-establishment. Grazing pressure from large zooplankton is decoupled in hypereutrophic waters where cyanobacterial blooms flourish. The original idea of biomanipulation (increased zooplankton grazing rate as a tool for controlling nuisance algae) is not the only means of controlling nuisance algae via biotic manipulations. Stocking phytoplanktivorous fish may be considered to be a nontraditional method; however, it can be an effective management tool to control nuisance algal blooms in tropical lakes that are highly productive and unmanageable to reduce nutrient concentrations to low levels.Although small enclosures increase spatial overlap between predators and prey, leading to overestimates of the impact of predation, microcosm and whole-lake experiments have revealed similar community responses to major factors that regulate lake communities, such as nutrients and planktivorous fish. Both enclosure experiments and large-scale observations revealed that the initial phytoplankton community composition greatly impacted the success of biomanipulation. Long-term observations in Lake Donghu and Lake Qiandaohu have documented that silver carp (Hypophthalmichthys molitrix) and bighead carp (H. nobilis) (two filter-feeding planktivorous species commonly used in management) can suppress Microcystis blooms efficiently. The introduction of silver and bighead carp could be an effective management technique in eutrophic systems that lack macrozooplankton. We confirmed that nontraditional biomanipulation is only appropriate if the primary aim is to reduce nuisance blooms of large algal species, which cannot be controlled effectively by large herbivorous zooplankton. Alternatively, this type of biomanipulation did not work efficiently in less eutrophic systems where nanophytoplankton dominated.


Author(s):  
Paulo R. Pezzuto ◽  
Caroline Schio ◽  
Tito C.M. Almeida

In Florianópolis, southern Brazil, the venerid clam Anomalocardia brasiliana has supported subsistence and small-scale commercial fisheries for decades. The introduction of a hand dredge (gancho) since 1987 led to the development of a significant fishery supplying both local and regional shellfish markets. In 1992 one of the main fishing areas in the region was designated as the first Brazilian Marine Extractive Reserve (Pirajubaé RESEX), a federal form of governance intended to promote sustainable exploitation of natural resources by assigning exclusive fishing rights to traditional users. However, excessive fishing effort, institutional shortcomings and lack of a negotiated management plan have resulted in the overexploitation of the species since 2000. This study was aimed at evaluating the efficiency and selectivity of the hand dredge currently in use at the RESEX, through a field experiment conducted in October 2006. Quantitative samples of A. brasiliana were collected before and after dredging 15 experimental plots. Additional samples were obtained inside the dredge (catch) and respective cover cod-end (discard) for selectivity analysis. A single haul of the hand dredge can dislocate up to 76% of the individuals present in the sediment irrespective of their size, and retain up to 69% of the commercial-sized organisms. The gear has a knife-edge selection pattern, which enables the use of the minimum spacing between the iron bars of the dredge's basket as an effective management tool.


2021 ◽  
Vol 78 (5) ◽  
Author(s):  
André Guareschi ◽  
Joanei Cechin ◽  
Mario Antonio Bianchi ◽  
Ivan Carlos Maldaner ◽  
Sergio Luiz de Oliveira Machado

Author(s):  
Tiago S. Telles ◽  
Ana J. Righetto ◽  
Marco A. P. Lourenço ◽  
Graziela M. C. Barbosa

ABSTRACT The no-tillage system participatory quality index aims to evaluate the quality and efficiency of soil management under no-tillage systems and consists of a weighted sum of eight indicators: intensity of crop rotation, diversity of crop rotation, persistence of crop residues in the soil surface, frequency of soil tillage, use of agricultural terraces, evaluation of soil conservation, balance of soil fertilization and time of adoption of the no-tillage system. The aim of this study was to assess the extent to which these indicators correlate with the no-tillage system participatory quality index and to characterize the farmers who participated in the research. The data used were provided by ITAIPU Binacional for the indicators of the no-tillage system participatory quality index II. Descriptive analyses were performed, and the Pearson correlation coefficient between the index and each indicator was calculated. To assess the relationship between the indicators and the farmers’ behavior toward the indicators, principal component analysis and cluster analysis were performed. Although all correlations are significant at p-value ≤ 0.05, some correlations are weak, indicating a need for improvement of the index. The principal component analysis identified three principal components, which explained 66% of the variability of the data, and the cluster analysis separated the 121 farmers into five groups. It was verified that the no-tillage system participatory quality index II has some limitations and should therefore be reevaluated to increase its efficiency as an indicator of the quality of the no-tillage system.


1970 ◽  
Vol 4 ◽  
pp. 223-234
Author(s):  
Prakash Prasad Sapkota

Human- plant relation is tightly attached on life of human beings. From the beginning of civilization, people used many plants and their products for different purpose to adopt with their environment. The essential and valuable materials including plant species are gathered, used, saved and always remain hunger for knowledge yet now. They developed different kinds of ceremonies and rituals and include valuable materials and plants within it to protect and remains as indigenous knowledge in particular communities and groups. In this context, I want to raise the issue of material culture to search why people used plants in their rituals with reference to a plant species the Jhakro the Magars inhabitant of Baglung district, western Nepal. The research was carried out by using descriptive and exploratory research design. Observation, interview and group discussion were used in the field for primary data collection. The Magars are rich in their rituals among them death and kul pujane rituals are significant for cohesive and solidarity of the group; within these rituals a shrub plant species with special type of smell remains in central position for purity and soul. They believed that in death ritual all the polluted activities are purified and in kul pujane Jhakro acts as purity as well as help to join their ancestors with them. Unfortunately, they are unknown of the materialistic meaning of it due to lack of transferring knowledge. In etic aspect, this plant has important medicinal properties and the Magar preserved by keeping it in important rituals within their community. Keywords: Ritual; Jhakro; the Magars; ethno-botany; ancestors DOI: 10.3126/dsaj.v4i0.4522 Dhaulagiri Journal of Sociology and Anthropology Vol.4 2010 pp.223-234


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