In order to satisfy the soil preparation requirements of a rapeseed combined transplanter in the middle-lower Yangtze River region in China where rice–rapeseed rotation cropping system was performed, a seedbed preparation machine composed of a rotary tillage device, ditch cleaning shovel, and soil leveling auger was designed to realize the function of rotary tillage, stubble ploughing, ditching, and soil leveling. The seedbed preparation machine was designed as the two parts of the middle section and the left–right symmetrical section to realize the need for middle ditching. Based on the principle of active scraping and anti-blocking, the curves of the soil contact section, soil throwing section, and transition section of the ditch cleaning shovel were analyzed. The structure parameters of the soil leveling auger with end reversal structure were designed. In order to further improve the working performance of the seedbed preparation machine, the response surface tests were designed, selecting the forward speed(X₁), the rotation speed of rotary tillage blade roller(X₂), and the rotation speed of soil leveling auger(X₃) as the main influencing factors, taking the soil breaking rate and the straw coverage rate and the soil flatness as the test indexes. The optimal parameter combination was obtained as a forward speed of 0.94 m/s, rotation speed of rotary blade roller of 268 rpm, and rotation speed of soil leveling auger of 204 rpm. Under the optimal parameters combination, the soil breaking rate, straw coverage rate, and soil flatness were 92.06%, 93.01%, and 8.35 mm respectively, which satisfied the agronomic requirements of rapeseed blanket seedling transplanting. This study can provide a reference for the design of a seedbed preparation machine of a rapeseed combined transplanter.

Rapeseed blanket seedling transplanters have developed rapidly due to their high efficiency and adaptability to the soil in many areas of China. However, during the transplanter’s longitudinal seedling conveying process, seedling blanket compression leads to inaccurate conveying and thus declined seedling picking performance. In this paper, a mechanical compression test was carried out on rapeseed seedling blankets. The longitudinal compression force of the rapeseed seedling blanket on a transplanter was calculated through mechanical analysis. A compression model of the rapeseed seedling blanket was established to determine how the blanket’s mechanical characteristics and the device’s structural parameters affect blanket compression. In addition, with the index of longitudinal compression Y₁, the coefficient of variation in the longitudinal seedling conveying distance Y₂, and the qualified-block-cutting rate Y₃, the interactive influence between the seedling tray tilt angle A, the seedling blanket moisture content B, and the seedling blanket thickness C were analyzed using response surface analysis. Aiming to reduce blanket compression and enhance the accuracy of longitudinal seedling conveying and block-cutting quality, the optimized results show that the predicted optimal parameters were a 50.14° seedling tray tilt angle, a 71.86% seedling blanket moisture content, and a 22.13 mm seedling blanket thickness. Using these optimized parameters, the transplanter achieved a blanket longitudinal compression of 18.17 mm, a coefficient of variation in the longitudinal seedling conveying distance of 1.142, and a qualified-block-cutting rate of 90%. Subsequently, a validation test was performed, revealing a high degree of conformity between the optimization model and the experimental data. Thus, the predicted optimal parameters can provide significantly reduced compression and a high seedling conveying performance. The results of this study provide theoretical and empirical support for the optimized design and operation of mechanized rapeseed blanket seedling transplanting.

To address the lack of available information on the soil physical conditions suitable for rapeseed blanket-shaped seedling transplanting, as well as the lack of protocols for the optimisation of soil tillage components in the utilisation of an integrated rapeseed blanket seedling combined transplanter, the physical parameters of different soil conditions and their impact on the growth of rapeseed after transplanting were investigated in this study. The aim was to determine the suitable soil physical parameters for rapeseed blanket-shaped seedling transplanting. First, the changes in soil firmness, soil bulk density, and soil moisture content during the installation of the rapeseed blanket seedling combined transplanter were tested and analysed, providing preliminary data for subsequent research. Using the variables of soil firmness and soil moisture content in the micro-environment around the roots and stems (30–50 mm) after rapeseed seedling transplantation and indicators such as the survival rate, root diameter, seedling height, and dry weight, an experiment on the growth of rapeseed blanket-shaped seedlings was conducted based on the furrow cutting transplanting principle. The results indicated that during the initial stage of rapeseed transplanting, the soil moisture content significantly influenced the vitality of the rapeseed plants. Under a high soil moisture content, the typically lengthy seedling period was shortened, and the effect on vitality was good, with minimal influence from the soil firmness. After seedling establishment, the rapeseed growth was significantly affected by the soil firmness. When the soil moisture content was less than 20%, increasing the soil firmness to 500 kPa was beneficial for moisture retention and rapeseed seedling growth. At a soil moisture content ranging from 20 to 25%, a soil firmness of 400 kPa was most suitable for both rapeseed vitality and late-stage growth. When the soil moisture content exceeded 25%, reducing the soil firmness to 300 kPa was beneficial for rapeseed growth, as an excessively high moisture content may lead to soil compaction, affecting seedling development. This study provides a theoretical basis for optimizing the design of soil tillage components in the application of an integrated rapeseed blanket seedling combined transplanter and for the high-yield management of rapeseed after transplanting.

The risk of soil compaction by agricultural machinery threatens the structure and productivity of tilled soils. However, a quantitative understanding of how specific compaction loads alter the three-dimensional (3D) macropore architecture of tilled soil is still limited. This study employed X-ray computed tomography (CT) to quantitatively characterize the evolution of the 3D macropore network in clay soil under a series of controlled compaction pressures (0, 30, 60, 90, and 120 kPa). Our results revealed a non-monotonic response of macropore number to compaction, which initially increased due to the fragmentation of large pores before declining, peaking at 90 kPa. Most critically, we identified 90 kPa as a critical threshold, beyond which macroporosity and the volume of elongated beneficial pores underwent drastic reductions of 64.8% and 46.6%, respectively. Compaction significantly reduced pore connectivity and surface area, with larger macropores (>1000 μm) proving most vulnerable. The study establishes a quantitative link between applied pressure and specific pore-scale damage, providing a scientific basis for designing agricultural machinery with ground pressures below this critical threshold to preserve soil structure and function after tillage.

In this paper, A new texture mapping algorithm for 3D model is proposed. The proposed algorithm starts with a 3D model and several color images of this model. First, we match pixels of each image with the 3D model. Then the boundaries between images are determined by minimizing a boundary-based cost function. In this paper, two different cost functions are proposed. Finally, an image blending method is proposed to smooth the color around the boundaries. The proposed algorithm is robust to the illuminant difference among images and can generate texture map with much less texture discontinuity. Experimental results demonstrate the effectiveness of the proposed algorithm.