The effects of harvesting intensity on the growth of Hydrilla verticillata (L. fil.) Royle as well as water quality were studied in controlled experiments to provide a reference for managing submerged vegetation and purifying the water. The results showed that harvesting had a significant effect on the recovery of shoot growth and H. verticillata height. The harvested group recovered completely or mostly after two harvests, but the recovery time was significantly longer than the control group. The final biomasses of the harvested groups (15%, 30%, 45%, 60%, and 75% harvested) decreased to 66.61%, 49.13%, 43.95%, 43.77%, and 29.94% of the control group, respectively. The greater the harvesting intensity, the fewer the winter buds. Harvesting reduced the number of H. verticillata branches. Repeated harvesting at medium and low intensities during the rapid growth of H. verticillata effectively improved the water quality and inhibited the propagation and growth of phytoplankton. These results show that harvesting controlled the growth of H. verticillata, and that medium and low harvesting intensities were best when considering water quality.

Microplastic pollution in agricultural soils has drawn significant attention in recent years. The objective of this study is to investigate the forms and characteristics of microplastic pollution in agricultural soils, specifically focusing on rice and vegetable soil in Xiangtan City. Various analytical techniques including stereomicroscopy, SEM, and FTIR spectroscopy were used to analyze the color, particle size, abundance, and types of microplastics in the study area. The findings indicated that the average abundance of microplastics in the soils in the study area was 4377.44 items/kg, with a maximum of 12,292.33 items/kg. Microplastics with smaller particle sizes were more prevalent, with their colors mainly being yellow, transparent, and black. The shapes of the microplastics were mainly thin-filmy and fibrous, and the types mainly included PE and PP. The abundance of microplastics in the vegetable soil with agricultural films applied was four times more than that without agricultural films. In the research area, the use of agricultural films was the most significant source of microplastics. The study’s findings describe the characteristics of microplastic pollution in agricultural soils in Xiangtan City. The findings could serve as a reference for establishing standardized assessments of microplastic pollution in agricultural soils, in addition to offering data support for Xiangtan City’s future efforts to safeguard agricultural soils and regulate microplastic pollution.