Determination of key soil characteristic parameters using angle of repose and direct shear stress test

Addressing the issues of low harvesting efficiency and high losses in current pod pepper harvesters, this study presents the design of a bionic comb finger pod pepper picking device and an inclined double-spiral bell pepper harvester to improve the harvest rate and reduce loss rate. Through the utilization of discrete element simulation software EDEM, a discrete element model for pod peppers is established. Additionally, a simulation platform for ground drop loss during pod pepper picking is developed, enabling exploration of the movement trajectory and velocity changes of the pod pepper elements. The study also conducts an analysis on the impact of the speed of the picking rollers X₁, the feeding speed of pod peppers X₂, and the spacing between the two picking rollers X₃ on ground drop losses. Based on the results of the single-factor test, the Box–Behnken response surface test was used to optimize the working parameters of the picking device, which resulted in the optimal combination of the working parameters of the picking device: the speed of the picking rollers was 680.41 rpm, the feeding speed of the pod peppers was 0.5 m/s, and the spacing between the two picking rollers was 12 mm, which resulted in the loss rate of pod peppers on the floor of the ground being 3.526%.

Leading agricultural enterprises attracting farmers to participate in vertical collaboration within the industry chain can expedite the process of agricultural industrialization and help achieve rural revitalization. This study focuses on table grape growers in the Yangtze River Delta region of China as the research subjects. Instead of examining the impact of specific elements individually on farmers’ involvement in vertical collaboration within the industry chain, this study emphasizes the combination of multiple factors influencing farmers’ engagement. Employing a fuzzy-set qualitative comparative analysis and adopting a configurational perspective, this research investigates how six factors—growers’ age, ratio of sales income to household income, production scale, market distance, financial support, and technical support—combine to influence farmers’ participation in vertical collaboration within the industry chain. This study reveals that leading enterprises can indeed promote farmers’ participation in vertical cooperation within the agricultural chain, and four pathways are identified. Based on these findings, three configurations are summarized: risk-averse, resource-constrained, and burden-alleviating. Specific strategies and recommendations for targeting each of these configurations are proposed based on the findings, along with policy suggestions for regulating the six factors, both by the enterprises themselves and by the government.

The inherent complexity of cellulose, hemicellulose, and lignin contributes to the recalcitrance of lignocellulosic biomass, resulting in a low conversion efficiency and high cost of bioethanol conversion. Pretreatment methods that disrupt the plant cell structure of lignocellulose, such as straw, can significantly enhance the conversion efficiency. In this study, we utilized an acid-assisted mechanocatalytic depolymerization technique to pretreat rice straw, and the results demonstrated a significant disruption of the cellulose structure of the straw. Compared to the untreated straw, the particle size of pretreated straw reduced from 279 μm to 11.8 μm, the crystallinity of cellulose decreased from 43.05% to 22.71%, the specific surface area increased by 177%, and the surface oxygen-to-carbon ratio (O/C) ratio was enhanced by 75%. The changes in microstructure enabled the pretreated straw to achieve a total sugar yield of over 95% within 12 h of enzymatic hydrolysis, significantly superior to the 36.24% yield from untreated straw, the 45.20% yield from acid impregnated straw, and the 73.25% yield from ball milled straw. Consequently, acid-assisted mechanocatalytic depolymerization emerges as a highly effective pretreatment strategy to enhance both the enzymatic hydrolysis and the overall conversion efficiency of rice straw.

In automated orchard operations, the straight-line locomotion stability of ground-based weeding robots is critical for ensuring path coverage efficiency and operational reliability. To address the response lag and high-frequency oscillations often observed in conventional PID and fixed-lookahead Pure Pursuit controllers, this study proposes an adaptive lookahead Pure Pursuit method incorporating angular velocity feedback. By dynamically adjusting the lookahead distance according to real-time attitude changes, the method enhances coordination between path curvature and robot stability. To enable systematic evaluation, three time-series-based metrics are introduced: mean absolute yaw error (MAYE), peak-to-peak fluctuation amplitude, and the standard deviation of angular velocity, with overshoot occurrences included as an additional indicator. Field experiments demonstrate that the proposed method outperforms baseline algorithms, achieving lower yaw errors (0.61–0.66°), reduced maximum deviation (≤3.7°), and smaller steady-state variance (<0.44°²), thereby suppressing high-frequency jitter and improving turning convergence. Under typical working conditions, the method achieved a mean yaw deviation of 0.6602°, a fluctuation of 5.59°, an angular velocity standard deviation of 10.79°/s, and 155 overshoot instances. The yaw angle remained concentrated around the target orientation, while angular velocity responses stayed stable without loss-of-control events, indicating a favorable balance between responsiveness and smoothness. Overall, the study validates the robustness and adaptability of the proposed strategy in complex orchard scenarios and establishes a reusable evaluation framework, offering theoretical insights and practical guidance for intelligent agricultural machinery optimization.

Due to the advantages of hole forming and transplanting at the same time, even on a film-covered field ridge, the cup-hanging transplanter has become one of the most widely used transplanters in agricultural operations. The cup-hanging planter is the main operating part of the transplanter. Different shapes of the hanging cup can affect the soil action mechanism, cavitation performance, and planting quality. In this study, the discrete element simulation software EDEM and the multi-body system dynamics analysis software RecurDyn are used to carry out the coupling simulation analysis. The results showed that the planting holes formed by hanging cups with two different shapes and under four different planting frequencies all met the planting requirements. After soil reflow, the transverse dimensions of the two holes are similar, and the longitudinal dimensions of the hole of the conical hanging cup are smaller than those of the multilateral hanging cup. Under the same planting frequency, the tear film size and hole-forming performance of the conical cup were better than those of the multilateral hanging cup. The result of the simulation test is consistent with that of the bench test, which proved the feasibility of using EDEM-RecurDyn coupling simulation to predict the hole-forming characteristics of the cup-hanging planter. The filmless hole-forming performances of two different shapes of hanging cups are close to each other. In terms of the film damage of film hole-forming, the conical cup is better than that of the multilateral hanging cup.