Minimal tillage methods mainly include subsoiling technology and topsoil tillage technology. Based on the analysis of domestic technical modes and application status of minimal tillage, this paper reviewed the working principle, technical characteristics and research status of subsoiling and topsoil tillage in two key parts. Current technical difficulties were analyzed and generalized, combined with the research progress and application requirements of minimal tillage in China, and future research emphasis and development direction were provided.
Subsoiling has been acknowledged worldwide to break compacted hardpan, improve soil permeability and water storage capacity, and promote topsoil deepening and root growth. However, there exist certain factors which limit the wide in-field application of subsoiling machines. Of these factors, the main two are poor subsoiling quality and high energy consumption, especially the undesired tillage depth obtained in the field with cover crops. Based on the analysis of global adoption and benefits of subsoiling technology, and application status of subsoiling machines, this article reviewed the research methods, technical characteristics, and developing trends in five key aspects, including subsoiling shovel design, anti-drag technologies, technologies of tillage depth detection and control, and research on soil mechanical interaction. Combined with the research progress and application requirements of subsoiling machines across the globe, current problems and technical difficulties were analyzed and summarized. Aiming to solve these problems, improve subsoiling quality, and reduce energy consumption, this article proposed future directions for the development of subsoiling machines, including optimizing the soil model in computer simulation, strengthening research on the subsoiling mechanism and comprehensive effect, developing new tillage depth monitoring and control systems, and improving wear-resisting properties of subsoiling shovels.
No-till planting method is widely used for maize-wheat two-crops-a-year area in the North China Plain. However, cruel soil conditions, especially the large number of maize stalks which are hard to cutoff covering, often cause an unsatisfying planting quality. Based on the authors' previous investigation, ultrahigh-pressure (UHP) waterjet is capable to solve this problem and obtain qualified seedbeds. Thus, a UHP waterjet assisted furrow opener for no-till seeder was designed. Field tests showed that double-disc furrow openers worked well with UHP waterjet, since the sharpened disc blades could help to cut soil and residue, meanwhile, minimize soil disturbance. Response surface method (RSM) was used to investigate the relationship among forward speed, waterjet pressure, jet impingement angle and anti-blocking performance (stalks cutoff ratio and depth of soil cutting), and a Box-Behnken three-factor design was used to identify the optional operation parameters. A total of 17 combinations were conducted, and the results showed all three operation parameters significantly affected anti-blocking performance. Stalks cutoff ratio and depth of soil cutting increased with the increase of waterjet pressure, jet impingement angle, and decreased with the increase of forward speed. The optimization analysis indicated that when waterjet pressure was 267-280 MPa, jet impingement angle was 80.2° to 90.0° and forward speed was 4.00-4.42 km/h, the overall performance of UHP waterjet assisted double-disc furrow opener for no-till seeder was maximized. Stalks cutoff ratio could be above 95% and no blockage occurred. This study may provide a new approach and reference for the anti-blocking technology of no-tillage seeding.
Infertility has a detrimental impact on the sexual function of involuntarily childless couples. However, the effect of male sexual function on female partner's sexual function in infertile couples remains unknown. In order to explore the association between these couples' sexual function, 324 consecutive couples with infertility and 326 female‐age‐matched fertile couples were enrolled in this study. The female sexual function index (FSFI) and sexual history were evaluated in female partners. In addition to the international index of erectile function‐15 (IIEF‐15) and sexual history, self‐reported intravaginal ejaculation latency time was evaluated in male partners. The demographics and depression status of couples were also recorded. We observed a higher occurrence of female sexual dysfunction (FSD) in infertile females than in fertile females (58.6% vs. 50.3%, p = 0.033). FSD was associated with a number of risk variables, including partner's erectile dysfunction (ED), depression and sexual frequency. The overall FSFI score was positively associated with the IIEF‐15 score (r = 0.347, p < 0.001). Besides, six FSFI domains were positively correlated with five IIEF‐15 domains (p < 0.05). In conclusion, it is critical to assess and address FSD as well as the sexual problems in male partners in infertile couples.
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