ABSTRACT Constructed wetland systems have been used to treat different wastewater; among their essential components are the cultivated plant species and type of substrate used to fill them. The choice of plant species and type of substrate are important for the good system performance in wastewater treatment. This study aimed to evaluate the extraction capacity of Napier and Tifton 85 grasses when cultivated at different positions in horizontal subsurface flow constructed wetlands (HSSF-CWs) filled with different substrates in wastewater treatment from a bulk milk-cooling tank (MTWW). The experimental unit consisted of four HSSF-CWs, in which an average surface organic loading rate of 318 kg ha−1 d−1 of BOD5,20 was imposed and a hydraulic holding time of 1.8 and 3.0 d, respectively, in units filled with gravel or crushed PET bottles. Tifton 85 grass presented the highest Na extraction capacity, with better results obtained in HSSF-CWs filled with crushed PET bottles, while Napier grass was more effective in extracting N, K, and P from MTWW. When cultivated in the second half of gravel-filled HSSF-CWs, both grasses provided higher average N extractions when compared to those filled with crushed PET bottles, which had higher extractions in the first half of HSSF-CWs.

ABSTRACT Knowing the relationship between the total suspended solids concentration (TSS), turbidity in the waters, and that turbidity analysis can be done faster and in less expensive way, this study aimed to obtain mathematical model to estimate the total suspended solids (TSS) concentration from the turbidity values for waters of Doce river basin. For this purpose, it was used the water quality database of the Minas Gerais Institute of Water Management (IGAM). The data were pre-treated using the adjusted boxplot technique followed by adjustment of curves for the different management units and rainfall regime period. It was verified the possibility of a single curve through the dummy variable technique, subsequently. With the results it was observed that the adjusted boxplot technique proved to be useful for environmental data. Linear relationships with R2 values, as a rule, were higher than 0.6, however, it was not possible to develop a single model. It is concluded that the generated models presented good adjustments being able to be used for predicting the concentration of TSS as a function of turbidity. However, each management unit in each period of rainfall regime presents particularities that were reflected in the prediction models.

ABSTRACT The achievement of all the water quality parameters that constitute the water quality indices can be a hamper to their use. The objective of this study was to analyze the viability of using minimum indices to monitor water quality, comparing different methods. For this purpose, the Environmental Company of the State of São Paulo database for the year 2016 of the Tietê/Jacaré and the Tietê/Batalha units was used. Four indices present in the literature were compared with the indices currently practiced in the states of São Paulo and Minas Gerais (“standard indices”). For feasibility analysis, the indices were classified by the “standard indices” methods and compared to them. The minimum indices were significantly correlated with the “standard indices”, from moderate to strong degree. The minimum indices, as a rule, overestimated water quality when compared to the index of the state of Minas Gerais; and underestimated when compared to the index of the state of São Paulo. It is concluded that the minimum indices are useful and practicable tools, with respect to the use of the WQI for management purposes. However, such indices should be evaluated periodically to avoid making mistaken decisions.

ABSTRACT We aimed to evaluate the efficiency of six different horizontal subsurface flow constructed wetlands (HSSF-CWs), with different substrates (gravel and crushed PET bottles), which also varied in relation to the presence and arrangement of plant species (elephant grass and Tifton 85 bermudagrass) in the removal of pollutants from a bulk milk cooling tank (MTWW). Each bed was fed at a flow rate of 0.18 m3 d-1 and average organic load rate (OLR) of 318 kg ha-1 d-1 of BOD5, with hydraulic detention time (HRT) of 1.84 days in the gravel-filled HSSF-CWs (CWS-G) and 2.97 days in the PET-filled HSSF-CWs (CWs-P). The CWs-P were as efficient as the CWs-G in the removal of BOD5, COD, Total-P, and K-Total, being in some cases even more effective (turbidity, TS, TSS and Na). The gravel, on the other hand, provided greater removals of Total-N from the MTWW. In the non-cultivated CWs and those cultivated with elephant grass, in its first half and Tifton 85 grass in its second half, there were higher average efficiencies in COD and TSS removal sand, in the latter, the highest average removal of Total-N.

ABSTRACT In Brazil, a large portion of peanut production is found under conventional soil preparation. Due to the fact that there is a lack in studies related to the cultivation of peanuts in conservationists soil preparation, mainly in the field of losses and mechanized harvesting. Thus, it was aimed to assess the quality of digging and gathering operation of peanut, based on losses, using statistical process control techniques in two tillages. The sowing was carried out under conventional and conservationist preparation, revolving only the sowing line. Losses were evaluated in the digging and gathering operation, being that in the gathering it was evaluated the harvest losses in three displacement speeds (4, 6 and 8 km h-1) in two tillages. The quality of the process was affected by the soil preparation based on the visible and invisible losses, respectively. Regarding the gathering, the conservationist preparation, it was unstable in all indicators, whereas in the conventional preparation it was noticed reduction of the variability for all the displacement speeds. The peanut sowing under conservationist preparation provided a better quality digging. In contrast, the gathering of pods in areas under conventional tillage showed a better quality of the operation.

ABSTRACT The peanuts harvesting mechanization is affected by the soil physical characteristics and it may increase the losses due to the production of pods in subsurface. The objective of the experiment was to identify the clusters through multivariate exploratory approaches from similarity in six soil textures (very clayey, clayey, silty clayey loam, clayey loam, sandy loam and sandy) in the state of São Paulo, Brazil, determining the main agronomic variables that most influenced the clustering division to assist the decision-making process in peanuts mechanized harvesting. The data were analyzed by the multivariate exploratory that is performed to simplify the description of a set of interrelated variables, using: yield, maturity, soil and pod moisture content, windrow width and height, visible and invisible digging losses, and gathering losses, as agronomic indicators of quality. The low and high clay content were grouped into clusters I and III, respectively, according to the agronomic traits of the peanut crop. The principal components analysis (PC) allowed a single distribution of accesses since only two eigenvalues were higher than “one”: the highest eigenvalues of 4.51 and 1.79, resulted in a Biplot that explained 70% of the original variability, 50.11% and 19.89% of which in the PC1 and PC2, respectively. The multivariate analysis indicated that high peanut yields in soils with low clay are correlated with the losses during the peanut mechanized harvesting operation.

RESUMO Objetivou-se neste trabalho avaliar a remediação de água contendo o inseticida clorpirifós, por meio de sistemas alagados construídos (SAC) cultivados com as espécies Polygonum punctatum, Cynodon spp. e Mentha aquatica operados sob diferentes tempos de retenção hidráulica: 24, 48, 96, 144 e 192 h. A eficiência do sistema foi baseada na redução da concentração inicial do clorpirifós e toxicidade da água contaminada. Os resultados mostraram que os sistemas alagados construídos são uma excelente alternativa na biorremediação do inseticida clorpirifós no meio aquoso. Observou-se média geral de eficiência na remoção do inseticida de 98,6%, sendo que no primeiro tempo de retenção hidráulica, 24 h, houve remoção do clorpirifós para valores inferiores ao limite detecção para todos os SAC. Tal resultado é atribuído principalmente aos processos de adsorção e degradação microbiana. Para os ensaios padronizados qualitativos de toxicidade aguda com Daphnia similis, para a maioria das amostras observou-se a redução de toxicidade acima de 80%. Constatou-se que os testes ecotoxicológicos com os efluentes dos sistemas alagados construídos estudados são uma boa opção como indicativo da eficiência dos tratamentos e uma promissora alternativa na complementação de análises físicas e químicas.

ABSTRACT The objective of this study was to evaluate the remediation of water containing the insecticide chlorpyrifos by using constructed wetlands (CW) cultivated with Polygonum punctatum, Cynodon spp. and Mentha aquatica, operated under different hydraulic retention times: 24, 48, 96, 144 and 192 h. The system efficiency was based on reduction of the initial concentration of chlorpyrifos and toxicity of the contaminated water. The results showed that constructed wetlands are an excellent alternative for remediation of the insecticide chlorpyrifos in aqueous medium. It was observed that the average overall removal efficiency of the insecticide was 98.6%, and in the first hydraulic retention time, 24 h, chlorpyrifos was removed to levels below the detection limit in all CW. This result is mainly attributed to adsorption and microbial degradation. For the qualitative standard acute toxicity tests with Daphnia similis, for most samples there was a reduction in toxicity greater than 80%. It was reported that the ecotoxicological tests with the effluents of the constructed wetland are a good option as an indicator of the effectiveness of treatments and a promising alternative to complement the physical and chemical analyses.

RESUMO Os erros de posicionamento pelo GNSS são inevitáveis, independentemente do tipo de posicionamento adotado. Na agricultura esses erros podem representar maior ou menor taxa de sobreposição entre as passadas dos conjuntos mecanizados, o que afeta, consequentemente, a qualidade da operação. Objetivou-se, neste sentido, avaliar os principais erros ocasionados durante a operação de semeadura de amendoim utilizando direcionamento automático com sinal RTX, por meio da análise do Controle Estatístico de Processo. Foram avaliados o erro de deslocamento do trator, o erro de execução do projeto, em quatro passadas, além do erro de paralelismo entre as passadas do conjunto trator-semeadora. O erro médio de execução ficou, em todas as passadas, dentro do estipulado pelo fornecedor do sinal, com valores menores que 3,8 cm. O erro médio do conjunto trator-semeadora encontrou-se no limite do aceitável. Já para o deslocamento lateral do trator, pela análise das cartas de controle, houve interferência da declividade na ocorrência de erros acima do estipulado. Com base na análise das cartas de controle constata-se que houve precisão para o erro de execução de projeto e que é possível utilizar o sinal RTX em operações agrícolas que requerem precisão menor que 3,8 cm, como a semeadura de amendoim.

ABSTRACT GNSS positioning errors are certain, regardless of the adopted positioning method. In agriculture, these errors may represent higher or lower overlapping rates between passes of a mechanical assembly, affecting operation quality. Therefore, this study evaluated the main errors arising from peanut sowing operation performed with an auto-steer guidance system by an RTX signal, using the Statistical Process Control techniques. The errors evaluated were: in tractor lateral displacement, project execution, and parallelism between passes of tractor-seeder set. The average errors of project execution in all passes were within the range specified by the manufacturer, i.e. lower than 3.8 cm. The average error of tractor-seeder set was also within the accepted range. However, as shown in control charts, lateral tractor displacement had interference of terrain slope, causing average errors higher than the accepted range. Based on the control charts, project execution accuracy was satisfactory, and it is possible to use the RTX signal in agricultural operations that require accuracy lower than 3.8 cm, such as peanut sowing.

ABSTRACT Semi-mechanical and mechanical harvesting methods may influence the content of impurities in harvested sugarcane. This study aimed to evaluate the quality of three mechanical methods of sugarcane harvesting: one semi-mechanical, and two mechanical ones - self-performed and outsourced, during three working shifts. As quality indicators, both mineral and vegetal impurities were accounted. About 50 random samples were collected in the studied area during 35 harvest days and in three working shifts, for each harvesting method. Mineral impurities showed similar behavior for both self-performed and outsourced mechanical harvesting, thus displaying a low variability. On the other hand, vegetal impurities showed to be unstable for all three shifts. Additionally, the statistical process control analysis showed that the semi-mechanical method had the greatest variability.

ABSTRACT This study aimed to characterize the material composition responsible for clogging the porous medium of horizontal subsurface flow constructed wetland (HSSF–CW) systems, which is detrimental to a proper system operation. Six completely clogged HSSF–CWs were used after treatment of swine wastewater. Operating conditions of these systems were named CW–C (HSSF– CW 1 and HSSF–CW 4, non-cultivated, i.e. controls), CW–T (HSSF–CW 2 and HSSF–CW 5, cultivated with Tifton 85 (Cynodon spp.)), and CW–A (HSSF–CW 3 and HSSF–CW 6, cultivated with alligator weed (Alternanthera philoxeroides)). The results showed that most of the clogging material was composed of total fixed solids (95, 84, and 82% in CW–C, CW–T, and CW–A, respectively). However, total volatile solids (TVS) mostly affected pore clogging. The larger accumulations and productions of TVS in CWs might have originated from dead plants.

ABSTRACT Many modifications in hydrodynamic conditions occur inside the bed of a horizontal subsurface flow constructed wetland (HSSF–CW) in operation. Studies on hydraulic conductivity measurement techniques in HSSF–CW are imperative since the monitoring of flow conditions is essential for understanding and controlling its clogging. This study aimed to assess the hydrodynamic behavior in HSSF–CW by means of saturated hydraulic conductivity (Ks) analysis. For this, six HSSF–CW were used: two non-cultivated (control), two cultivated with Tifton 85 (Cynodon spp.), and two cultivated with alligator weed (Alternanthera philoxeroides). Application of swine wastewater (SW) in HSSF–CW started on June 15, 2011, with Ks measurement period between September 9 and November 11, 2011, in which five measurements were performed in different positions along the system length and over experimental period in order to assess the effects of vegetation, position, and time factors on this variable. Ks values ranged from 1,392 to 2,834 m d−1. Plant presence led to Ks decreasing in the systems, but cultivated species had no influence on this variable. Monitoring time of HSSF–CW was no longer enough to provide a reduction in Ks, at 10% probability level.

ABSTRACT We evaluate the application of treated sanitary wastewater (TSW) to provide potassium for crops and reduce demand for fresh water and mineral nutrients. The field experiment was arranged in randomized block design with four replications and five treatments: 50, 100, 150 and 200% of potassium requirements and a control with conventional fertilizer. The TSW was applied to maize (November 2012 to February 2013), cotton (June to November 2013) and bean (April to June 2014). After bean, soil chemical properties were evaluated until 0.8 m depth. Fertigation with TSW to potassium fertilization provided about 50% of water, nitrogen and phosphorus to the bean. The soil nutrient availability and soil organic matter did not increase, whereas sodium had linear increased with TSW levels in investigated soil depth. Soil pH showed same behavior that sodium, with the highest pH level of 6.5 in 0-0.2 m soil layer. Soil nutrients and organic matter did not increase with TSW doses up to 0.8 m depth. Soil pH and sodium had linear increasing with TSW doses, respectively up to 0.6 and 0.8 m soil depth. Fertigation with potassium recommendation also provided a high content of sodium, threatening the balance of soil-plant system with continuous use. The sodium should be the first reference to permanent wastewater reuse in agriculture.

RESUMO O melhoramento genético do tomateiro para dupla finalidade, mesa e indústria, é de relevante importância para a produção com forte impacto no desenvolvimento socioeconômico do Brasil. No presente estudo utilizou-se a metodologia de modelos mistos para estimar a capacidade combinatória de cinco linhagens de tomateiro avaliadas em esquema de dialélico completo sem recíproco, e análise de agrupamento para prospectar novas constituições híbridas (híbridos duplos e triplos). Sendo assim, foi possível observar que valores positivos de capacidade geral de combinação ocorrem em ‘B13LD’, ‘Viradoro’ e ‘Rio Grande’ (para firmeza do fruto), ‘B13LD’, ‘Castone’ e ‘Massag-72’ (para teor de sólidos solúveis); e, ‘Viradoro’ e ‘Rio Grande’ (para produtividade). Dos cruzamentos avaliados apenas ‘B13LD x Rio Grande’ e ‘Massag-72 x Viradoro’ apresentaram estimativas positivas de capacidade especifica de combinação para teor de sólidos solúveis, firmeza do fruto e produtividade. O híbrido ‘B13LD x Rio Grande’ mostrou-se promissor por figurar entre os que apresentaram as maiores estimativas do valor genético do cruzamento para as três características já referidas. Pela análise de divergência genética e da estimativa da capacidade combinatória foi possível indicar dois híbridos duplos e três híbridos triplos.

ABSTRACT Dual-purpose tomato breeding, for table and industry, has great importance for tomato production and strong impact on Brazilian socioeconomic development. In the present study, we used the methodology of mixed models to estimate the combinatorial ability of five tomato lines evaluated in complete diallel scheme without reciprocal, and cluster analysis to prospect new double and triple hybrids constitutions. Thus, we observed that positive values of general combining ability occur in ‘B13LD’, ‘Viradoro’ and ‘Rio Grande’ (for fruit firmness), ‘B13LD’, ‘Castone’ and ‘Massag-72’ (for soluble solids content); and ‘Viradoro’ and ‘Rio Grande’ (for productivity). The crosses ‘B13LD x Rio Grande’ and ‘Massag-72 x Viradoro’ showed positive estimates of specific combination ability for soluble solids content, fruit firmness and productivity. The hybrid ‘B13LD x Rio Grande’ showed itself promising to be among those with the highest estimates of the genetic value of the cross for the three aforementioned traits. For the analysis of genetic divergence and estimate of combining ability it was possible to indicate two double and three triple hybrids.

ABSTRACT Swine wastewater have high pollution load, requiring treatment before its disposal into the environment. Methane (CH4) potentially emitted for such waste is considered 21 times more polluting than Carbon dioxide (CO2), and the nitrous oxide (N2O) is considered 310 times. In this way, projects of the Clean Development Mechanism (CDM) and energy use related to the CH4 are worldwide diffused. It was evaluated the potential greenhouse gas emissions in the influent and effluent from digesters and stabilization ponds used to treat the swine wastewaters in two commercial farms operating in full cycle, located in the municipality of Oratorios-MG, Brazil. Using the methodology “AM0006” to estimate the average potential of greenhouse gases, it was identified 55% and 23% of reduction in emissions from digesters and stabilization ponds, respectively. Thus, when comparing the two systems, in the conditions that they were operated, it can be concluded that the digestion treatment system was more suitable for the treatment of swine wastewater, when taking into account only the emission of the mentioned gases, subjects of this study.

ABSTRACT This study aimed to monitor degradation of compost from undigested sewage sludge disposed on soil surface or incorporated it. The sewage sludge was blended with wood sawdust during a 90-day composting to achieve a C/N ratio of 9. Each waste was dosed based on its total content of nitrogen and on an annual dose of 500 kg ha-1, which is broadly recommended for forage fertilization. After incorporation and surface applied (five replicates each), waste mineralization was monitored for 131 days by samplings taken from both conditions for further analyses. The samples were measured for total organic carbon (TOC); easily oxidizable carbon (OOC); total nitrogen (TN); ammonia and nitric nitrogen, and from them the total organic nitrogen (ON); volatile solids; and water content. The findings pointed to a decrease in TOC, OOC and ON contents throughout monitoring, regardless of disposal method, however, most remarkable whether incorporated to the soil, computing mineralization rates above 87%.