Characterization of the soil compaction based on the mapping of the apparent electrical conductivity

Based on the measurement of soil penetration resistance (PR), it is possible to identify compacted soil layers, where root growth may be harmed, affecting crop development and yield. The objective of this work was to analyze the use of management zones (MZ), delimited on the basis of mapping of the spatial variability of the soil apparent electrical conductivity (ECa), in the differentiation of soil compaction levels. The work was carried out in a 25.8-ha no-tillage area, cultivated under a center pivot. The ECa was measured under two soil moisture conditions (13.7 and 16.45%), using the Terram® equipment. Soil penetration resistance (PR) was measured using the SoloStar PLG5500 penetrograph. Based on the spatial variability ECa mapping, management zones (2, 3, and 4 zones) were delimited. The mean PR values ??of each MZ were compared by the t-test of means. It was possible to differentiate mean values ??of penetration resistance (PR), which vary from 0.9 to 2.10 MPa, from the characterization of management classes generated on the basis of the ECa spatial variability. The highest stratification of PR values ??was obtained as a function of sampling directed at delimited management zones when the soil had lower moisture content (13.7%). The highest mean PR values ??were obtained for the split of the ECa map into at least three classes. It was identified that for the study area there is no need to perform any mechanical decompaction operation.

Development of a low-cost electromechanical penetrometer to verify resistance to soil penetration

Soil compaction is one of the great obstacles in modern agriculture. With the increase in size, weight and intensity of use of machines in crops in recent decades, the soil has suffered damage to its structure, compromising the productivity of vegetable crops. One of the ways to indirectly obtain the compaction state of the soil is through the resistance to penetration imposed by it on a standardized metal rod. Invariably, commercial equipment for this purpose is expensive. The objective of this study was to develop a low-cost system for evaluating the resistance to soil penetration, using a prototyping platform and specific sensors. The developed equipment, when compared with a calibrated standard equipment, presented a high correlation in the results of resistance to penetration in two soil conditions. The development cost of the proposed equipment was 800% lower than the average value of commercial equipment available on the market, so the measurements met the purpose of the project, showing the possibility of developing low-cost solutions through prototyping platforms, for the assessment of resistance to soil penetration.

Reference crop evapotranspiration in distinct agricultural regions of Southern Brazil: a comparison of improved empirical models

The FAO56 Penman-Monteith model is globally accepted for the accurate determination of reference evapotranspiration (ETo). However, a lack of appropriate data encouraged the improved model’s approach to estimate ETo. This study compared the performance of 10 empirical models of ETo estimation (Penman, Priestley & Taylor, Tanner & Pelton, Makkink, Jensen & Haise, Hargreaves & Samani, Camargo, Benevides & Lopes, Turc, and Linacre) contrasted with the FAO56 model in two regions in Southern Brazil. Data were collected from automatic stations of the Brazilian National Institute of Meteorology (INMET) from December 21, 2019, to February 28, 2021. The determination coefficient (R²), mean square error (nRMSE), mean bias error (MBE), Willmott index (d), and Pearson’s correlation coefficient (r), clustering, and Principal Component Analysis (PCA) were performed. For the different regions, the radiation-based model proposed by Penman was the best alternative for estimating ETo. The model showed the most appropriated values for R2 (0.9015) and r (0.9494). The clustering and PCA analyses indicated the interrelations of the meteorological data and the combination of the models according to the parameters used for the determination of ETo.

Nitrogen, phosphorus, water and sediment losses under sugarcane (Saccharum spp.) and peanut (Arachis hypogaea l.) cultivation

Sertãozinho-SP is a major world producer of sugarcane and peanuts. The crop rotation technique recovers soils and brings commercial benefits to producers. Objective: to determine the losses of water, nitrogen (N), phosphorus (P) and sediments, due to the use and occupation of the soil in the peanut and sugarcane crop, using the SWAT model, maintaining the topographic and physical attributes and climatic conditions of the Mogi-Guaçu River sub-watershed, in the Sertãozinho city – SP. To carry out this study, local data from digital elevation maps and soil pedological maps, precipitation, wind, solar radiation, and relative humidity were used. The actual accumulated evapotranspiration was higher in sugarcane (906.7 mm) when compared to peanuts (886.1 mm). Sediment losses were higher in peanuts (300.66 mm) when compared to sugarcane (280.69 mm), as well as losses of N (118.44 and 34.48 kg ha-1) and P (5.456 and 0.805 kg ha-1), respectively. It is concluded that the peanut crop showed the greatest losses of water, nutrients, and sediments, when compared to sugarcane, showing that the land cover directly influenced these losses. Studies like these can aid in decision-making about environmental policies, helping with soil and water conservation in Brazilian sub-watershed.

Performance of constructed wetland system using different species of macrophytes in the treatment of domestic sewage treatment

The objective is to assess the initial performance of a constructed wetland system and the development of the macrophyte species cattail(Typha spp.) (CWt), piripiri (Cyperus giganteus) (CWp), and white garland lily (Hedychium coronarium Koehne) (CWl) and an suncultivated (UNc) on the treatment of sewage from toilets and from a restaurant. Changes in hydrogen potential, electrical conductivity, total suspended solids, total solids, biochemical oxygen demand, chemical oxygen demand, turbidity, nitrate, ammonium nitrogen, total phosphate, hydraulic retention time (HRT), and potential evapotranspiration (PET) and the development and adaptation of macrophytes were measured. The surface area of ??each constructed wetland (CW) had a surface area of 16.25 m2 and average volume treated of 0.40 m3 d-1, with continuous variable horizontal subsurface flow equally fed with sewage previously treated in three septic tanks in series, with an individual useful volume of 5.100 L. The PET in CWt, CWp and CWl was higher than that of UNc. The highest pH values were obtained in the effluent of CWp, CWt, and CWl. The use of macrophytes did not influence the EC, TS, BOD5,20, COD, and nitrate were lower and ammonium nitrogen and total phosphate were higher in the effluent of CWs and UNc in relation to the influent. The efficiency indexes that showed a very strong Pearson correlations (> 90%) were pH correlated with N-NH4+, turbidity correlated with COD, TS correlated with EC, and BOD5,20 and COD correlated with NO3-.Piripiri and cattails showed the best development of plants in the second half of CW.

Creation of an environmental protection area in a public supply source: possibilities and challenges in Cianorte - Paraná

This work analyzed the contribution that the creation of Environmental Protection Areas (EPA) may bring to the conservation of hydrographic basins used as public water sources. The object of study of this work was the hydrographic basin of the Ligeiro River which, by 2022 onwards, will be the new source of public supply in the city of Cianorte-Paraná, replacing the hydrographic basin of the Bolívar stream. The latter has environmental impacts caused mainly by the expansion of urban areas and inadequate practice of land use, occupation, and management, which affects the population’s supply, particularly on days with high levels of rainfall. The study area involved the creation of two municipal EPAs in the hydrographic basin of the Ligeiro River, located in the municipalities of Araruna and Cianorte, with areas of 209.76 km² and 219.82 km², respectively. It is believed that the creation of Environmental Protection Areas in the Ligeiro River hydrographic basin will also present challenges, but it will enable the conservation of natural resources and, especially, of water resources, given the quality of the water. It is expected that these actions will help to minimize or even prevent, in the future, the Ligeiro river hydrographic basin from being as or more impacted as the Bolivar stream basin.

Wood processing for energy use

Forest biomass has been used as an energy source since ancient times. Since then, several ways of using them have emerged, along with technologies to improve their energy quality. One can cite genetic improvement, thermal transformation through pyrolysis for charcoal and torrefied biomass production, and mechanical transformation through compaction, to produce pellets and briquettes and chipping for the production of chips. However, it is somehow difficult to find articles on these topics that are clearly and objectively presented, making it difficult to read them. The objective of this work was to search data on the ways of processing forest biomass and solutions for the better use of this biomass and its energy use. Therefore, Google Scholar was used as a database from which articles already recognized and others with less impact were obtained. The following search words were used: Eucalyptus, Pinus, wood chips, pellets, briquettes, charcoal, and torrefied wood. To filter the results obtained, the articles that appeared as the most relevant were selected first, then filtered for articles with less than five years from publication, and those at less than two years of publication. Next, the selected articles went through a verification of the data contained in them, and the necessary information was removed from each, which were the species, immediate analysis, extractives, HCV, etc. These data were organized in tables according to the type of processing, prioritizing the values of greatest interest in each analysis, along with the appropriate references. It was observed from the data obtained that the results are compatible among different researchers in their analyses. For samples processed without thermal treatment, the initial characteristics of the wood are maintained, and when going through pyrolysis or torrefaction, these characteristics are changed.

Influence of nickel on butanol production by Clostridium beijerinckii using hydrolyzate from green coconut shell

The improvement of biotechnological processes capable of transforming agro-industrial waste into products with high added value has stood out in the area of renewable energies, promoting positive impacts to the environment. Thus, the present work evaluated the influence of nickel on the conversion of fermentable sugars, present in the green coconut shell hydrolyzate (GCSH), into butanol and other products. Fermentation assays were performed at 37 °C, starting with 19.4 g.L-1 of sugars and 1.0 g.L-1 of inoculum (C. beijerinckii). The GCSH was supplemented with tryptone, yeast extract, ammonium acetate, minerals and phosphate buffer. Two conditions were tested: with and without addition of nickel. Concentrations of sugars (glucose and xylose), intermediate products (organic acids), acetone, butanol, and ethanol were determined by high performance liquid chromatography (HPLC). The results show that the butanol production was higher from GCSH without addition of nickel, reaching a concentration of 2.14 g.L-1 of butanol. Therefore, the presence of nickel in the hydrolyzate was not favorable in the production of butanol under the studied process conditions.

Conservation conditions of chainsaws and electric chainsaws and safety of the farmers who operate these machines

The increasing use of chainsaws in rural areas has demanded the health of rural producers who operate these machines. Thus, the objective of this work was to evaluate the conservation conditions of chainsaws with a 2-stroke Otto Cycle engine and check if they meet NR12 Annex V, as well as confirm whether users meet NR31 in terms of training for use. With the aid of a questionnaire and visits to farms, 103 chainsaws were verified in six municipalities in the central region of the State of Rio Grande do Sul. After organizing the data in an electronic spreadsheet, descriptive statistics and canonical correlation were performed. The questions were divided into four groups, namely: operational, mandatory machine safety equipment, cutting set, and engine. The conservation condition of the machines was seen as worrisome. This is because it was found that 66.01% of machines did not have a saber guard and 49.51% of these were worn out. In addition, 97.08% of the producers did not take a chainsaw operation course, and 85.44% reported not using Personal Protective Equipment (PPE), therefore, in disagreement with the NR6, NR12 Annex V, and NR31 standards. It was clear the need for the operators to carry out training on the safe use and handling of chainsaws.

Reuse of aquaculture wastewater treated in constructed wetlands

Water reuse in fish farming is a practice that has been spreading significantly, therefore requiring more efficient and vigorous treatment systems. The objective of this study was to evaluate the potential reuse of aquaculture wastewater after being treated in horizontal subsurface flow constructed wetlands (HSSF-CW). Three HSSF-CWs with dimensions of 1.0 m in width, 3.0 m in length, and 0.30 m in depth were evaluated. One HSSF-CW had stargrass (Cynodon nlemfuensis) cultivated; the other had cattail (Typha latifolia), and the third was used as a control, where there was no cultivation. The wastewater was provided from three Nile tilapia breeding tanks, which recirculated the entire system after going through the HSSF-CW. The following variables were determined every five days at the HSSF-CW influent and effluent: temperature, pH, turbidity, electrical conductivity, redox potential, dissolved oxygen, ammonium, and nitrate. The treatment in the HSSF-CW allowed the reuse of aquaculture wastewater as it provides water quality levels according to the recommendation for Nile tilapia breeding. Furthermore, the water quality parameters monitored in HSSF-CW effluent remained within limits established by CONAMA Resolution No. 357/2005 for aquaculture and fishing activity.