Impact of agricultural residual plastic film on the growth and yield of drip-irrigated cotton in arid region of Xinjiang, China

In China, especially in Xinjiang Region, mulch film remaining in the soil has severely jeopardized the safety of soil resources. To numerically simulate the residual film-soil-recovery implementation system, a virtual mulch film model with consistent physical and mechanical properties with real mulch film needs to be established. In this study, a flexible deformable virtual mulch film model was constructed using YADE software based on the Minkowski Sum principle and the ball-ball force-displacement constitutive rule, as well as the contact failure rule were established. The deformation behaviors of cylinders and PFacet elements, such as stretching, bending, and torsion, were described. By splicing the basic PFacet elements, a virtual mulch model was established. The mechanical model of a virtual mulch film under tension was established and the axial tensile stiffness coefficient k(n) was determined to be 43.30 N.m. To verify the physical and mechanical properties of this virtual mulch film, both real and virtual stretching and tearing tests were conducted. The experimental results showed that: in the process of stretching and tearing of real and virtual films, the properties of morphological features of both are basically identical; however, they clearly differ in force-displacement. The viscoelastic constitutive model between balls and yield judgment conditions requires further study.

In densely planted solar greenhouses, tomato crops face increasing challenges with pest and disease control due to high temperature and humidity conditions. The existing spraying equipment often suffers from low mechanization and inadequate foliar deposition coverage. This study presents the design of a vertical spray bar electrostatic sprayer, which combines a multi-nozzle vertical spray bar with electrostatic spraying technology, making it suitable for greenhouse applications. In order to obtain the best working parameters of the sprayer, the coverage rate of the front and back sides of the tomato leaves was taken as the performance target. Key influencing factors, including electrostatic voltage, spray pressure, and target distance, were investigated using a multi-factor response surface methodology. Field experiments were conducted in a greenhouse environment based on the optimized parameters to validate the performance. The results indicate that: (1) The factors influencing droplet adherence on the upper surface of tomato leaves ranked in the order of target distance, spray pressure, and electrostatic voltage, while for the underside, the order was electrostatic voltage, target distance, and spray pressure. (2) Under the conditions of electrostatic voltage of 10 kV, spray pressure of 0.7 MPa, and target distance of 35 cm, the sprayer achieves the optimal operation of leaf comprehensive coverage. (3) Compared to non-electrostatic spraying, the greenhouse electrostatic sprayer significantly improved the coverage on both sides of the leaves, enhancing pesticide utilization efficiency. This novel electrostatic sprayer meets the operational requirements for greenhouse crop protection in the Xinjiang region of China.

INMATEH Agricultural Engineering is an open access international journal that publishes reviewed original research papers of both experimental and theoretical nature in the following areas: Technologies and technical equipment for agriculture and food industry, Environmental-friendly agriculture, Renewable energies, Technical equipment testing, Environment, Transport in agriculture, others