The application of fertilizer is necessary for the growth and yield of crops, especially for paddy rice. Precision application is important for the fertilizer utilization rate and sustainable development of agriculture. However, the crushing of fertilizer grains will reduce the quality of fertilization, for the decrease in the size and mass of the fertilizer particles and the degree of crushing mainly depend on the physical and mechanical properties of the fertilizer grains. In this study, the compression strength and critical impact speed of four typical commonly used fertilizer grains, a compound fertilizer of nitrogen, phosphorus, and potassium (NPK compound fertilizer), organic fertilizer, large granular urea, and small granular urea, were measured and analyzed. The static compression test was carried out using a TMS-Pro texture analyzer and the results show that the four kinds of fertilizer grains are brittle materials, and their elastic moduli are 208 MPa, 233 MPa, 140 MPa, and 107 MPa, respectively; the theoretical impact model of fertilizer granules is established based on the compression test result and Hertz elastic contact theory, the theoretical formula for the critical impact speed of fertilizer grains is derived, and the theoretical critical impact strength and speed are worked out. An image capture system for the impact process of fertilizer grains was developed, and the impact test was conducted. The results show that the critical impact speed of the four kinds of fertilizer grains decreases with the increase in granule size, while the variance analysis shows that the effect is not significant. The comparison of the experimental results with the theoretical values shows that the theoretical formula could be used to predict the trends of the critical impact speed of fertilizer grains. The model was optimized with the MATLAB 2018 function fitting tool based on the test and analysis. The goodness of fit of the formula is 0.824, which is 13.43% greater than that of the original theoretical formula, indicating that the modified formula based on the compression test data might estimate the critical impact speed of the granular fertilizer with brittle material properties more accurately. The results may provide a reference for the parameter design of a precision fertilization machine.

Previous studies have demonstrated that slightly acidic electrolyzed water (SAEW) treatment can enhance rice seed growth and promote the accumulation of γ-aminobutyric acid (GABA), a bioactive compound. However, the underlying mechanisms remain unexplored. This study systematically investigated the effects of pH and available chlorine concentration (ACC) of SAEW on rice seed germination and GABA biosynthesis. The changing trends were monitored within 7 days. The results revealed that the treatment group with moderate pH (S2, pH 5.74 ± 0.04) showed significantly higher GABA accumulation (71.27 ± 0.45 mg/100 g) compared with S1 (pH 5.04 ± 0.03) and S3 (pH 6.38 ± 0.04) (p < 0.05). Furthermore, a positive correlation was observed between ACC levels and GABA accumulation, suggesting that ACC plays a crucial regulatory role in rice seed germination. These findings were further substantiated by monitoring the enzymatic activity of glutamate decarboxylase (GAD) throughout the germination process. Notably, while higher ACCs negatively impacted rice seed growth, pH variations within the tested range showed no adverse effects on seed development. The results show that optimal SAEW parameters, considering both pH and ACC, should be carefully determined for practical applications in rice seed production.

A soil removal device for the root-soil complex of Gentian imitating the percussion function of a woodpecker was designed to improve the soil removal efficiency of harvesting devices for rhizome-type traditional Chinese herbal medicines. Based on the physical parameters of roots and the root-soil complex of Gentian, the structure parameters of the striking arm and the actual profile of the cam are determined according to the physical parameters when the woodpecker knocks on the tree. The key parameters that affect the working performance of the soil removal device and their suitable value ranges have been identified through the impact test and analysis of the root-soil complex of Gentian. The mass of the striking hammer, the swing angle of the striking arm, and the rotation speed of the cam were taken as the experimental factors and the soil removal rate and the energy consumption per hammer percussion were taken as the experimental indicators. The ternary quadratic orthogonal regression combination experiment was carried out using Design-Expert. The regression model of the influence factors and evaluation indicators was established through the analysis of variance. The interaction effects of the influence factors on the indicators were analyzed using the response surface method. Using multiobjective optimization method, the optimal parameter combination was obtained as that of the mass of the striking hammer of 0.9 kg, the swing angle of the striking arm of 47°, and the rotation speed of the cam of 100 r/min, then the soil removal rate was the maximum and the energy consumption of single-hammer knocking was the minimum, with the values of 89.12% and 31.21 J, respectively. This study can provide a reference for the design and optimization of soil removal devices for rhizome-type traditional Chinese herbal medicines.

In order to solve the problem of poor mixing effect of inclined spiral conveyor, this paper designed an inclined spiral and ribbon blade combination conveying device. The mechanics and kinematics analysis of the movement process of the material unit in each mechanism was carried out, on which key devices and components were designed based. Effects of the speed of main shaft (X1), the full coefficient (X2) and the angle of inclination (X3) on the mixing uniformity (Y1) and the residual rate of material (Y2) were explored. Three-dimensional quadratic regression orthogonal rotation central combination experiment method combined with response surface method was used to conduct experiments and explore the interaction effects of influence factors on indicators. A regression model of influence factors and evaluation indicators was established through the analysis of variance. The significant factors affecting Y1 were ordered of X3, X2, X1, and the significant factors affecting Y2 were ordered of X2, X1, and X3. In the interaction of factors, X1X2 had a significant impact on Y1 and Y2; X1X3 had an extremely significant impact on Y1; X2X3 had an extremely significant effect on Y1 and a significant impact on Y2. The optimal structure and working parameters combination were determined to be 50 rpm for the speed of main shaft, 60% for the full coefficient, and 19° for the angle of inclination, while the verification experiments demonstrated that the mixing uniformity and residual rate of material corresponding to the verification test were 90.37% and 5.31%, respectively. The inclined device with combined spiral and ribbon blade developed in this study meets the design requirements for the misprocess of the fertilizer utilization of agricultural organic wastes.

To improve the environment perception ability of wheeled mobile robots (WMRs), the visual behavior mechanism of the negative-correlation motion of chameleons is introduced into the binocular vision system of WMRs, and a shifty-behavior-based environment perception model with chameleon-inspired active vision for WMRs is established, where vision–motor coordination is achieved. First, a target search sub-model with chameleon-inspired binocular negative-correlation motion is built. The relationship between the rotation angles of two cameras and the neck and the camera’s field of view (FOV), overlapping angle, region of interest, etc., is analyzed to highlight the binocular negative-correlation motion compared with binocular synchronous motion. The search efficiency of the negative-correlation motion is doubled compared with binocular synchronous motion, and the search range is also greatly improved. Second, the FOV model of chameleon-inspired vision perception based on a shifty-behavior mode is set up. According to the different functional requirements of target searching and tracking stages, the shift of the robot visual behavior is analyzed from two aspects, measuring range and accuracy. Finally, a chameleon-inspired active-vision-based environment perception strategy for mobile robots is constructed based on the shifty-behavior mode, and experimental verification is deployed, which achieves the reproduction of the visual behavior of chameleons in the vision system of mobile robots with satisfactory results.

The aim of this study was to detect the electrochemical characteristics of rice leaves under low‐temperature stress. This study uses the electrical impedance graph method and the electrolyte exostosis method under the condition of low‐temperature cold case study in the seedling stage of rice leaves, with a normal seedling stage of rice crops grown as controls. The shape of the electrical impedance map of rice leaves under low‐temperature stress and its change with the increase of low‐temperature stress were studied, and the change trend of electrical impedance map parameters with the increase of low‐temperature stress was statistically analyzed. At the same time, the two detection methods are discussed to establish the correlation. The results showed that the electrical impedance pattern was a complete, symmetrical, single half arc with rice leaves subjected to reversible damage. The left side of the arc starts to disappear with an irreversible injury. Rice tended to die when the arc on the right side of the impedance spectrum began to scatter. Moreover, the change in the electrical impedance spectrum was consistent with that of relative conductivity. When the rice was not dead, the extracellular resistance and relaxation time of leaves decreased with the increase of stress degree, and intracellular resistance increased. Indicating the electrical impedance spectroscopy (EIS) can be employed as a nondestructive testing method to detect physiological characteristics of rice leaves under low‐temperature stress.