Purpose: Careless burning, discarding, or overfertilization of spent mushroom substrate (SMS) is environmentally harmful. The reuse of SMS resources is a matter of concern. Methods: Spent seafood mushroom substrate solid-state fermentation combined with Rhizobium pusense solution was added to soil to evaluate its environmental and Cenchrus fungigraminus seedling growth effects in pot trial experiments. Results: The 40% fermented seafood mushroom SMS (fresh weight) with R. pusense treatment had significantly higher total nitrogen (TN), ammonium nitrogen (AMN), organic matter, etc., and decreased soil electrical conductivity (EC) and increased pH compared with other treatment. Soil catalase (CAT), dehydrogenase (DHA), and urease (UE) activities were significantly improved; there were no differences in CAT and UE activities between 40% (T4) and 50% (T5) SMS additions. C. fungigraminus seedling height and leaf length increased gradually and were significantly different from those of the positive control. The 30–50% seafood mushroom SMS treatment increased plant TN by 5.76–10.00% and total phosphorus by 15.44–16.55%. Plant root length and root activity peaked in T4; however, plant split root number and root activity in T5 decreased by 43.96% and 26.97% compared with those in T4. According to Pearson correlation and one-dimensional regression analyses, the seafood mushroom SMS content affected fertility > enzyme activity > plant growth. Principal component analysis and redundancy analysis showed that the effect of the seafood mushroom SMS concentration on the soil environment was mainly reflected in plant aboveground and root activity. Conclusions: Under an SMS addition amount of 40%, plant growth-promoting rhizobacteria promoted the growth of C. fungigraminus seedlings to a greater extent.

Long-term plant residue retention can effectively replenish soil quality and fertility. In this study, we collected rhizosphere soil from the residual roots of annual Cenchrus fungigraminus in the Ulan Buh Desert over the past 10 years. The area, depth, and length of these roots decreased over time. The cellulose content of the residual roots was significantly higher in the later 5 years (2018–2022) than the former 5 years (2013–2017), reaching its highest value in 2021. The lignin content of the residual roots did not differ across samples except in 2015 and reached its highest level in 2021. The total sugar of the residual roots in 2022 was 227.88 ± 30.69 mg·g⁻¹, which was significantly higher than that in other years. Compared to the original sandy soil, the soil organic matter and soil microbial biomass carbon (SMBC) contents were 2.17–2.41 times and 31.52–35.58% higher in the later 3 years (2020–2022) and reached the highest values in 2020. The residual roots also significantly enhanced the soil carbon stocks from 2018–2022. Soil dehydrogenase, nitrogenase, and N-acetyl-β-D-glucosidase (S-NAG) were significantly affected from 2019–2022. The rhizosphere soil community richness and diversity of the bacterial and fungal communities significantly decreased with the duration of the residual roots in the sandy soil, and there was a significant difference for 10 years. Streptomyces, Bacillus, and Sphigomonas were the representative bacteria in the residual root rhizosphere soil, while Agaricales and Panaeolus were the enriched fungal genera. The distance-based redundancy analysis and partial least square path model results showed that the duration of residual roots in the sandy soil, S-NAG, and SMBC were the primary environmental characteristics that shaped the microbial community. These insights provide new ideas on how to foster the exploration of the use of annual herbaceous plants for sandy soil improvement in the future.

Oyster mushrooms are regarded as one of the most significant edible mushrooms in terms of commercial value because of their rich nutritional profile. Many bioactive extracts from Pleurotus species have been found to exhibit antitumor and antioxidant activities. However, to grow oyster mushrooms in this study, the pasteurized Cenchrus fungigraminus was used as culture material, a type of grass that proliferates and has a high root growth rate. It contains high levels of sugar and protein and yields a large amount of biomass. Because of these characteristics, it is considered an efficient and cost-effective energy crop with various applications, including phytoremediation and fodder production. A pasteurization technique for this grass that is suited for the simplest formulation is simple and cost-effective for growing oyster mushrooms on small farms. This study used pasteurized Cenchrus fungigraminus as a substrate to grow three mushroom species: Pleurotus ostreatus, Pleurotus pulmonarius and Pleurotus florida. The aim was to evaluate their enzyme activities, growth rate, and yields. The findings demonstrated that the average growth rate of three species grown in pasteurized C. fungigraminus was between 25 days and 36 days. Therefore, the mycelium growth rate of P. ostreatus was faster than other pleurotus species in this study. The highest biological efficiency was recorded with P. ostreatus at 78.23%, then P. pulmonarius at 59.88, and lastly, 39.66% P. florida. The changes in five enzyme activities in distinct developmental stages of three different pleurotus species were evaluated. Therefore, the laccase had the highest peak with 13.8 U/g on the 20th day during the growth phase and gradually decreased to the fruiting body stage of P. ostreatus. The expression of manganese peroxidase reached the highest activity of 3.6 U/g in P. ostreatus compared to P. florida and P. pulmonarius on the 10th day. The expression of other enzymes varied between species and developmental phases. The results indicate the usefulness of pasteurized C. fungigraminus for cultivating Pleurotus species and expression enzyme activity in different Pleurotus species.

Cenchrus fungigraminus is a new species and is largely used as forage and mushroom substrate. However, it can usually not be planted on farmland on account of local agricultural land policy. Interplanting Cenchrus fungigraminus with other crops annually (short-term) is an innovative strategy to promote the sustainable development of the grass industry in southern China. To further investigate this, C. fungigraminus mono-planting (MC), C. fungigraminus–potato interplanting (CIP) and C. fungigraminus–broad bean interplanting (CIB) were performed. Compared to MC, soil microbial biomass carbon (SMBC), soil organic matter (SOM), ammoniacal nitrogen (AMN), pH and soil amino sugars had a positive effect on the rhizosphere soil of CIP and CIB, as well as enhancing soil nitrogenase, nitrite reductase, and peroxidase activities (p < 0.05). Moreover, CIP improved the root vitality (2.08 times) and crude protein (1.11 times). In addition, CIB enhanced the crude fiber of C. fungigraminus seedlings. These two interplanting models also improved the microbial composition and diversity (Actinobacteria, Firmicutes, and Bacteroidota, etc.) in the rhizosphere soil of C. fungigraminus seedlings. Among all the samples, 189 and 59 genes were involved in methane cycling and nitrogen cycling, respectively, which improved the presence of the serine cycle, ribulose monophosphate, assimilatory nitrate reduction, methane absorption, and glutamate synthesis and inhibited denitrification. Through correlation analysis and the Mantel test, the putative functional genes, encoding functions in both nitrogen and methane cycling, were shown to have a significant positive effect on pH, moisture, AMN, SOM, SMBC, and soil peroxidase activity, while not displaying a significant effect on soil nitrogenase activity and total amino sugar (p < 0.05). The short-term influence of the interplanting model was shown to improve land use efficiency and economic profitability per unit land area, and the models could provide sustainable agricultural production for rural revitalization.

Agrocybe cylindracea is an important mushroom highly valued as a functional food for its nutritional and medicinal benefits. Many bioactive extracts from A. cylindracea have been found to exhibit antitumor and antioxidant activities. This research investigated the distinct substrates that affected the physicochemical and biocomponent properties and biological efficiency of A. cylindracea. The substrates used were 48% giant juncao grass mixed with 30% Dicranopteris dichotoma grasses, 48% wasted tea leaves mixed with 30% sawdust, and 78% cottonseed hulls, all supplemented with 20% wheat bran and 2% lime. The findings indicated that A. cylindracea grown in the cotton seed hulls had a significant biological efficiency, at 35.8%, followed by the GD + DD (31.5%) and WTL + SD (28.7%). The ash content peaked in the fruiting bodies grown on giant juncao grass and D. dichotoma, while the fat content was highest in those grown on giant juncao grass and D. dichotoma, followed by wasted tea leaves and sawdust. The protein content was significantly higher in the fruiting bodies cultivated on wasted tea leaves and sawdust, followed by cottonseed hulls. The carbon dioxide emissions varied across substrates, with the highest emissions observed during the maturity stage of the fruiting bodies grown on giant juncao grass with D. dichotoma and wasted tea leaves and sawdust. Emissions decreased sharply 110 days after cultivation. Essential metabolites, such as dopamine and caffeine, were enriched in the fruiting bodies grown on wasted tea leaves, sawdust, and cottonseed hulls. In contrast, tyramine and uracil were enriched in those grown on cottonseed hulls.