Within the context of precision agriculture, the use of automatic guidance is without a doubt one of the most popular tools among farmers, however, are few producers of peanuts using this technology, the benefits from this technology can bring significant gains for culture even more when thinking about reducing the indices of losses in the digging. Thus, it objective was to evaluate the variability of quantitative losses of peanut mechanized digging with use the autopilot, using the Statistical Process Control. The treatments consisted of absence of autopilot use in sowing and digging, pilot's absence at sowing and presence in the digging, pilot use at sowing and absence in the digging and the pilot use in sowing and digging. In each treatment, 15 points of each variable was collected from distance of 50 m apart. Visible, invisible and total losses in the digging and parallelism were evaluated. The reduction of the plant material on the vibratory mat affected the levels of visible losses. Total losses are strongly correlated with the invisible losses. The use of the autopilot allows the operator to pay more attention to the digging operation improving the quality of the operation. The average error found between passes of the mechanized set using autopilot was 0.35 m. The variability of the losses as well as of parallelism was reduced when using the autopilot in two operations, providing a higher quality process.

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.

A B S T R A C TGNSS 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 tractorseeder 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.Erros de paralelismo provenientes da operação de semeadura de amendoim com direcionamento automático R E S U M O 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 tratorsemeadora. 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.

Cotton price is determined by the quality of the fiber, which can be damaged at the time of harvest, in addition to quantitative losses of non-harvested plume. Therefore, this study aimed to analyse soil and plant losses, and the quality of cotton fiber in relation to five harvest speeds (5, 6, 7, 8, and 9 km h-1) in the spindle system (picker). The experiment was conducted in Lucas do Rio Verde, Mato Grosso, Brazil. A randomized complete block design was used on plots of 0.9 ha, with 20 plot, five speeds, and four blocks. The results showed that the studied speeds did not significantly influence losses on the soil and plant, or the quality of the cotton fiber; therefore, the highest speed may be recommended.

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.

The intensifying use of machines in agriculture to increase operational capacity requires investments in more powerful and automated machines capable of working at higher speeds to meet the demands of agricultural activities. The objective of this study was to evaluate the sowing quality of a second crop maize using a pneumatic sowing machine equipped with two seed-metering devices at different displacement speeds. The statistical design was a randomized block design arranged in 6 × 2 factorial, with 4 replications, totaling 48 experimental plots. Where it was tested two seed-metering mechanisms from different manufacturers denominated A and B, and 6 displacement speeds of approximately 2.0; 4.7; 6.5; 9.1; 10.3 and 12.3 km h -1. The seed-metering mechanisms were compared by mean test while displacement speeds were compared by regression plots. The initial and final plant populations, seed depth, seedling longitudinal distribution (normal, faulty and double spacing) and grain yield were also evaluated. Displacement speed and seed-metering devices showed significant interaction only for the percentages of normal, faulty, and double spacings. The initial and final population presented an isolated effect for both the seed-metering devices and velocities. The seed depth showed an isolated velocity effect. The grain yield showed a significant isolated effect from the analyzed seed-metering devices. The seed-metering device B operating at lower speeds had better performance in the sowing process.

The successful establishment of agricultural crops depends on sowing quality, machinery performance, soil type and conditions, among other factors. This study evaluates the operational quality of mechanized peanut sowing in three soil types (sand, silt, and clay) with variable moisture contents. The experiment was conducted in three locations in the state of São Paulo, Brazil. The track-sampling scheme was used for 80 sampling locations of each soil type. Descriptive statistics and statistical process control (SPC) were used to evaluate the quality indicators of mechanized peanut sowing. The variables had normal distributions and were stable from the viewpoint of SPC. The best performance for peanut sowing density, normal spacing, and the initial seedling growing stand was found for clayey soil followed by sandy soil and then silty soil. Sandy or clayey soils displayed similar results regarding sowing depth, which was deeper than in the silty soil. Overall, the texture and the moisture of clayey soil provided the best operational performance for mechanized peanut sowing.

Considerando-se que modificações relacionadas à população de plantas podem influenciar positiva ou negativamente na produtividade, objetivou-se com o presente trabalho avaliar as características agronômicas relacionadas com a produção de soja em sistemas de semeadura convencional e cruzada. Para tanto, utilizaram-se as ferramentas do controle estatístico de processo. O experimento foi realizado no município de Jaboticabal - SP, em solo classificado como LATOSSOLO VERMELHO Eutroférrico, sendo empregado um conjunto trator MF660, 4x2 TDA (tração dianteira auxiliar), com 110 kW e semeadoraadubadora de precisão da marca Marchesan, modelo COP Suprema 7/4, com disco vertical pneumático. O delineamento estatístico utilizado foi baseado na metodologia do controle estatístico de processo, na qual os pontos foram coletados ao longo da operação. Os tratamentos consistiram de dois sistemas de semeadura da soja, sendo: convencional e cruzada. Empregou-se uma malha regular espaçada de 20 x 20 m, além de avaliações em duas linhas nos dois sistemas de semeadura. Os indicadores de qualidade ou variáveis avaliados foram: altura de plantas; altura da inserção da primeira vagem; número de vagem por planta; altura de corte; distribuição de palha e produtividade de grãos. As características agronômicas da soja foram influenciadas em função dos sistemas de semeadura convencional e cruzada. A altura de corte e a produtividade de grãos apresentaram estabilidade do processo para ambos os sistemas de semeadura.