Resumo em Inglês:

ABSTRACT Efficient products can be developed for the ornamental plant sector using agro-industrial waste. This study evaluated the agronomic performance and ornamental quality of calendula plants (Calendula officinalis) cultivated in substrates formulated with solarized aerobic sewage sludge (SASS), rice husk ash (RHA), and sugarcane bagasse (SB). Five additive rates were used: S2: 33.33% SASS + 33.33% RHA + 33.33% SB; S3: 16.65% SASS + 41.67% RHA + 41.67% SB; S4: 12.48% SASS + 43.76% RHA + 43.76 % SB; S5: 8.32% SASS + 45.84% RHA + 45.84 % SB; S6: 4.16% SASS + 41.07% RHA + 54.76% SB; and S1: commercial substrate (reference). Raw materials and substrate formulations were characterized and agronomic and ornamental aspects were evaluated in calendula plants cropped in all substrates. The lowest agronomic performance was observed in S6 (lowest SASS rate), while the highest occurred in S3 compared to the other treatments. Regarding the ornamental potential, S3 and S4 and the commercial substrate (S1) were classified as excellent. This study highlights the successful use of organic raw materials (SASS and agro-industrial waste) to compose substrates for calendula production in pots, with the recommended proportions ranging from 12.48 to 16.65% of SASS combined with RHA and SB.

Resumo em Inglês:

ABSTRACT Phosphorus concentration is one of the main attributes determined in laboratory analyses of soil samples collected in the field. The objective is to develop a soil phosphorus test using a low-cost spectrophotometer and a machine learning technique. For reflectance measurements, a low-cost system consisting of a Sparkfun AS7625x spectrophotometer and an Arduino Uno is used. Ion exchange resins under standard saturated solutions and modified conditions are used to extract phosphorus ions from the soil samples. Reflectance and phosphorus concentrations determined by the reference method are used in the training and testing of a machine learning. A modification procedure of the ion-exchange resin saturation solution allows the establishment of a strong correlation between the reflectance in 18 spectral bands and P concentration of the soil samples. The obtained model uses five reflectance of the modified resins at wavelengths of 410, 460, 560, 705, and 645 nm to predict the phosphorus concentration. This model presents an R2t accuracy of 0.97 in the training stage with an R2v of 0.96, RMSEv of 9.05, and ratio of prediction to deviation) of 3.81 in the test step.

Resumo em Inglês:

ABSTRACT In high speed seeding operation, the random collisions of seeds in the seed delivery tube seriously affect the seeding accuracy. In order to improve seeding uniformity and stability in high speed operation, the seed delivery device with a rotating brush wheel was designed, including U-shaped groove seed tube and flexible brush wheel. The optimization experiment was carried out by quadratic-regression rotatable orthogonal design method in JPS-12 seeding performance test bench. The three main factors were the rotate speed of seed metering device, the brush wheel diameter and the brush wheel speed. The evaluation indexes were the qualified rate of seeding spacing, miss seeding rate and coefficient of variation of seeding spacing. The results showed that the optimal parameters were rotate speed of seed metering device of 30 r/min, brush wheel diameter of 66 mm and brush wheel speed of 850 r/min. Finally, the verification experiment was carried out. The test results showed that the working performance of seed delivery device with a rotating brush wheel was obviously better than that of common seed delivery tube, especially at the forward speed of 15 km/h and above. The research provides a reference for the innovative design for a high speed precision seeder.

Resumo em Inglês:

ABSTRACT The use of Precision Agriculture tools and soil attributes has contributed to local agricultural management in the identification of different productive potentials and quality of pastures. The present study aimed to use Precision Agriculture tools to investigate the spatial variability of soil organic matter fractions and soil chemical and physical attributes and to delineate management zones in pasture soils cultivated under tropical conditions. The study was conducted on a hay production farm located in Seropédica, Brazil. Fifty points were collected on a irregular grid and soil samples were taken at depths of 0-0.20 and 0.20-0.40 m and crop productivity was evaluated. Chemical and physical soil organic matter fractionation was performed to obtain data on fulvic acid, humic and humin fractions, mineral-associated and particulate organic carbon, and light organic matter. Geostatistics and multivariate analysis (principal component analysis and k-means clustering) were performed to define the management zones. The results obtained contributed to the division of the pasture area into two regions that can be managed in different ways aiming to increase soil organic matter in a localized manner with the possibility of reducing the use of inputs and directed management that respects the productive potential of the pasture on the farm.

Resumo em Inglês:

ABSTRACT Companies are looking for reliable partners, including suppliers, that offer high-quality services. The decision-making process involves several stakeholders with different objectives that require different types of relevant criteria to be considered. This study used the Analytic Hierarchy Process (AHP), a multiple-criteria decision analysis and decision-making method, to select a new supplier for a coffee-roasting plant. For this, the type of coffee was selected, and the relevant criteria were established: percentage of extrinsic defects, loss in precleaning, price, and taste. Four different potential suppliers were compared in relation to all criteria using the AHP. We achieved our research objective by establishing an order of priority for the criteria and suppliers. As a result, supplier B was the leading supplier with a 35.29% priority, followed by suppliers A and D. Our findings show great potential for using a formal method in the decision-making process in the agro-industry and applying the AHP method in an important problem and in relevant plant culture. Furthermore, other problems in agricultural engineering can benefit from the reasoning steps employed.

Resumo em Inglês:

ABSTRACT Studies on the operational adaptability of slope corn harvesters on hilly slopes are of great significance to improve the performance and safety of the whole machine, but there are few studies on this aspect at the present. Therefore, this paper takes a self-developed small sloping land crawler corn harvester as the object combined with the special topography of the hilly sloping land and the technology adopted by the machine to make a mathematical analysis of its operational adaptability on the sloping land. Through the field test, the forward speed of the corn harvester, track wheel spacing and slope angle are used as the test factors, and the harvest loss rate of the corn ear is used as the assessment index to carry out the orthogonal test on the slope land. The analysis of the results based on the Design-expert response surface was completed. The results show that the ear loss rate of the experiment under different conditions is less than 5% of the national standard. The corn harvester has good adaptability to sloped land, which can realize the mechanized operation of corn on the hilly and sloped land, and has good agricultural production application value.

Resumo em Inglês:

ABSTRACT To solve the current problems of poor seeding stability and complex maintenance of maize seed-metering devices, a clamp-holding precision maize-seed-metering device is designed. The structure and working principle of the seed-metering device are described, the optimum state of maize seed clamping is analyzed, and the range of each working area of the seed-metering device is determined. The profile and structural parameters of the limit guide plate are designed by analyzing the laws of motion of the seed-picking block. A mechanical model of maize seeds under the critical state in each working area of the seed-metering device is established. The influence of the seed-metering device's rotational speed and the clamping force of the seed-picking block on the seeding performance are analyzed. A physical prototype of the seed-metering device was made for bench tests and field verification tests. The qualified, multiple seeding, and missed seeding rates of the designed seed-metering device were 94.21%, 3.52%, and 2.27%, respectively, meeting the agronomic requirements of maize sowing. The study provides theoretical guidance for designing and optimizing precision maize-seed-metering devices.