Every year, approximately 2 billion tons of plant-derived waste (such as straw and crop residues) are generated globally, most of which are either incinerated, dumped, or landfilled without proper planning, leading to severe environmental pollution and resource wastage. Plant-derived waste exhibits potential advantages as a growing media component in various aspects. However, numerous studies have also indicated that plant-derived waste generally possesses strong phytotoxicity, which must be removed or reduced before being utilized as a growing media component. Therefore, accurately assessing their phytotoxicity and appropriately modifying it to ensure their support for plant growth when used as a growing media component is crucial. This paper reviews the manifestation and assessment methods of phytotoxicity in plant-derived waste; systematically summarizes the phytotoxicity sources of three common types of plant-derived waste (garden waste, crop straw, and spent mushroom substrate), as well as the toxic mechanisms of two representative phytotoxic substances (phenolic compounds and organic acids); and proposes some insights into further research directions. By consolidating insights from these studies, this review aims to deepen our understanding of phytotoxicity and its implications, and offer valuable references and guidance for future research endeavors and practical applications.

Wood fiber substrates are widely used as peat substitutes in horticulture, but the impact of their high carbon-to-nitrogen ratio on nitrogen immobilization and crop photosynthetic performance remains unclear. This study systematically examined the effects of wood fiber substrates on lettuce photosynthetic performance and underlying physiological mechanisms using pot experiments. Two substrate treatments—peat (control) and wood fiber—were combined with three nitrogen levels: low, medium, and high (63, 127, and 210 mg N·L⁻¹). Results indicated that wood fiber substrates significantly reduced the availability of fast-acting nitrogen, leading to a substantial decrease in lettuce biomass (39.0–56.8%), total nitrogen content (7.2–39.9%), and chlorophyll content (13.7–36.2%). Chlorophyll fluorescence kinetics analysis revealed that wood fiber substrates impair photosystem function through multiple pathways. At the early stage (15 days), key effects included structural damage to the donor side of PSII(Photosystem II), indicated by L and K peaks, and inhibited electron transfer on the PSI(Photosystem I) acceptor side (δRo decreased by 15.08–27.90%, along with a reduction in W_OI amplitude). The findings provide an important theoretical basis for optimising nitrogen management strategies for wood fibre substrates.

Substrate is the key material of soilless culture. The physical and chemical properties of the solidified cultivation medium are good and relatively stable, and there is no need to use plastic cultivation containers in the cultivation process, which has a broad application prospect in three-dimensional greening and fruit and vegetable planting. We have developed a novel substrate solidified process with high-frequency electromagnetic heating, which significantly reduces energy consumption compared to the traditional curing process with steam heating. In this study, the effects of three modification methods (alkali modification, APTES modification, and alkali + APTES combined modification) on the physicochemical properties of jute were studied, and the strengthening effects of different modified jute fibers on solidification substrate were investigated. The results showed that the addition of jute fiber could improve the mechanical properties of the solidification substrate. Compared with the control group, the modified jute fiber could increase the breaking tension by 13.1~24.2 N, the impact toughness by 0.85~2.09 KJ/m², and the hardness by 21.6~35.6 HA. Moreover, the addition of a small amount of jute fiber can effectively improve the mechanical properties and will not affect the growth of plant roots.