Effects of Different Farming Methods and Their Effects on Soil Physicochemical Properties of Guilin Maojian Tea Gardens

In order to further optimize the cultivation and agronomic technology of Guilin Maojian tea gardens, the effects, efficiencies and costs of different farming methods and their effects on the physiochemical properties of tea garden soil were studied through the modification of the test sites with the non-farming land as the control. The results showed that human farming, mini-tiller farming and crawler tractor farming could improve the physical and chemical properties of soil. After farming, the soil had good water retention but low moisture content compared to the control group, while the soil bulk density and hardness value were significantly lower than those of the control, and the porosity of soil was significantly higher than that of contrast. With the passage of time, soil bulk density and hardness value gradually increased after farming, while the porosity of soil decreased gradually. There were great differences in the effects, efficiencies and costs of different farming methods. Crawler tractor had the best and most stable farming effect, and the operation efficiency was 10 times that of human farming while the cost was only 0.39 times of human farming. Therefore, it was feasible to adopt mini-tiller or crawler tractor to carry out mechanical farming of Guilin Maojian tea garden, which provided theoretical references for the soil property improvement using mechanical farming and was favorable for promoting the popularization of farming machines and the acceleration of mechanization of tea gardens. But for tea plantations that are intended to be mechanized, apart from the mechanical and technical personnel to be configured in place, the site conditions, planting modes and mechanical way reservation of tea garden should be planned accordingly. It is recommended to select flat or gentle slope for reclamation, and preference is given to non-sexual tea tree varieties with big line spacing over 180 cm long. Moreover, the main road construction should be more than 3.0 m, and trunk road 2.0 m or above. And isolation ditch and drain should be set between the tea garden and the surrounding mountain forests and farmland.

ER‐Mapping: An extrinsic robust coloured mapping system using residual evaluation and selection

The colour-enhanced point cloud map is increasingly being employed in fields such as robotics,3D reconstruction and virtual reality.The authors propose ER-Mapping(Extrinsic Robust coloured Mapping system using residual evaluation and selection).ER-Mapping consists of two components:the simultaneous localisation and mapping(SLAM)subsystem and the colouring subsystem.The SLAM subsystem reconstructs the geometric structure,where it employs a dynamic threshold-based residual selection in LiDAR-inertial odometry to improve mapping accuracy.On the other hand,the col-ouring subsystem focuses on recovering texture information from input images and innovatively utilises 3D–2D feature selection and optimisation methods,eliminating the need for strict hardware time synchronisation and highly accurate extrinsic parameters.Experiments were conducted in both indoor and outdoor environments.The results demonstrate that our system can enhance accuracy,reduce computational costs and achieve extrinsic robustness.

Unmanned aerial vehicle orthogonal laser localization by Gaussian mixture model‐based map representation

Localization is a core problem in mobile robot navigation.Simultaneous localization and mapping(SLAM)costs much for an unmanned aerial vehicle(UAV).This research aims to design an orthogonal laser scan device for localization and to save computation costs.Based on disturbance analysis,residual influences on sensor state are quantitative,and they are related to uncertainty and sensitivity.This research applied the residual selection method to a UAV.The feature point detection utilises multi‐scale and Gaussian model fitting techniques to guarantee true positives.The map is represented by Gaussian Mixture Models(GMM)with lower memory costs.The orthogonal laser scan device is composed and placed on a UAV for real‐time three‐dimensional localization,whose er-rors are at the centimeter level.