Chlorophyll fluorescence is an important tool in the study of photosynthesis and its effect on the physiological indicators of crop growth is worth exploring. The trial was conducted to investigate the effect of biochar (CK, 0%; BA₃, 3%; BA₅, 5%; by mass of soil) and vermicompost (VA₃, 3%; VA₅, 5%) on photosynthesis, chlorophyll fluorescence, and tomato yield under greenhouse condition. Results revealed that photosynthetic parameters and chlorophyll fluorescence traits of BA₃, VA₃, BA₅, and VA₅ were significantly higher than those of CK, and the improvement of vermicompost was more effective than biochar at the same application rate. VA₃ treatment had the highest net photosynthetic rate (Pn), intercellular CO₂ concentration (Ci), variable fluorescence (Fv), maximum fluorescence (Fm), PSII maximum photochemical efficiency (Fv/Fm), PSII potential photochemical activity (Fv/Fo), absorption flux per cross section (CS; ABC/CSm), trapped energy flux per CS (TRo/CSm), and electron transport flux per CS (ETo/CSm), which increased by 49%, 65%, 17%, 12%, 4%, 25%, 10%, 15%, and 30%, respectively, compared with CK. The study also found that BA and VA rates could effectively improve tomato yield and water use efficiency (WUE). The yield under BA₃, VA₃, BA₅, and VA₅ treatments was 21%, 33%, 23%, and 25% higher than that under CK, and the WUE increased from 31.2 kg·m⁻³ under CK to 41.4 kg·m⁻³ under VA₃. Pearson correlation analysis indicated that the increment of photosynthesis showed a highly significant correlation with Fv/Fo, ABC/CSm, TRo/CSm, and ETo/CSm and enhanced the light energy absorbed, trapped, and transported per CS of plant leaves, thereby contributing to the increase in tomato yield. Therefore, for one-season tomato production, the application of 3% vermicompost was considered economical with regard to improving photosynthesis, enhancing WUE, and increasing tomato yield.

Significant research has been conducted on the effects of fertilizers or agents on the sustainable development of agriculture in salinization areas. By contrast, limited consideration has been given to the interactive effects of microbial fertilizer (MF) and salinity on hydraulic properties in secondary salinization soil (SS) and coastal saline soil (CS). An incubation experiment was conducted to investigate the effects of saline soil types, salinity levels (non-saline, low-salinity, and high-salinity soils), and MF amounts (32.89 g kg⁻¹ and 0 g kg⁻¹) on soil hydraulic properties. Applied MF improved soil water holding capacity in each saline soil compared with that in CK, and SS was higher than CS. Applied MF increased saturated moisture, field capacity, capillary fracture moisture, the wilting coefficient, and the hygroscopic coefficient by 0.02–18.91% in SS, while it was increased by 11.62–181.88% in CS. It increased soil water supply capacity in SS (except for high-salinity soil) and CS by 0.02–14.53% and 0.04–2.34%, respectively, compared with that in CK. Soil available, readily available, and unavailable water were positively correlated with MF, while soil gravity and readily available and unavailable water were positively correlated with salinity in SS. Therefore, a potential fertilization program with MF should be developed to increase hydraulic properties or mitigate the adverse effects of salinity on plants in similar SS or CS areas.

Amendment significantly improves soil structure and promotes crop growth. To combat soil degradation and low crop yields in facility agriculture, it is crucial to study the optimal application rate of amendments. This study analyzed the effects of biochar, vermicompost, and mineral-source potassium fulvic acid on the stability of aggregate structure, soil nutrient content, and tomato yield in cambisols, providing a theoretical basis for improving the soil quality of plastic greenhouses in Southern China. A pot experiment on tomato cultivation was carried out in yellow-brown soil in plastic greenhouses. The experiment included eight treatments: 1% biochar (B1); 3% biochar (B3); 5% biochar (B5); 3% vermicompost (V3); 5% vermicompost (V5); 0.1% mineral-source potassium fulvic acid (F1); 0.2% mineral-source potassium fulvic acid (F2); and the control condition without adding soil amendments (CK). The results showed that the biochar and vermicompost treatments effectively reduced soil bulk density and increased total soil porosity. Compared to the control, treatments with soil amendments significantly increased soil pH and had different effects on soil nutrients: F2 showed the most significant improvement in the content of available nitrogen, available phosphorus, and available potassium, with an increase of 133.33%, 834.59%, and 74.34%, respectively; B3 treatment had the highest increase in dissolved organic carbon (DOC), while B5 treatment had the highest organic matter content. Compared to the CK, the particle size of the biochar treatment was mainly 0.053~0.25 mm, while the V3, F1, and F2 mainly occurred with a particle size > 0.25 mm; and V3 has the best aggregate stability. Biochar, vermicompost, and mineral potassium fulvic acid can all promote tomato yield, with the F2 and V3 treatments having a yield increase effect of over 30%. Furthermore, Pearson’s correlation analysis showed a highly significant positive correlation between geometric mean diameter (GMD) and mean weight diameter (MWD), water-stable macroaggregate content (R_0.25), and a positive correlation between alkaline-dissolved nitrogen, available phosphorus, dissolved organic carbon content, and aggregate stability indicators. Adding 0.2% mineral-source potassium fulvic acid optimizes cambisols’ properties, enhances aggregate formation and stability, boosts tomato yield, and shows great application potential.

Southwestern China is receiving excessive chemical fertilizers to meet the challenges of continuous cropping. These practices are deteriorating the soil environment and affecting tobacco (Nicotiana tabacum L.) yield and quality adversely. A novel microbially enriched biochar-based fertilizer was synthesized using effective microorganisms, tobacco stalk biochar and basal fertilizer. A field-scale study was conducted to evaluate the yield response of tobacco grown on degraded soil amended with our novel biochar-based microbial fertilizer (BF). Four treatments of BF (0%, 1.5%, 2.5% and 5%) were applied in the contaminated field to grow tobacco. The application of BF_1.5, BF_2.5 and BF_5.0 increased the available water contents by 9.47%, 1.18% and 2.19% compared to that with BF₀ respectively. Maximum growth of tobacco in terms of plant height and leaf area was recorded for BF_1.5 compared to BF₀. BF_1.5, BF_2.5 and BF_5.0 increased SPAD by 13.18–40.53%, net photosynthetic rate by 5.44–60.42%, stomatal conductance by 8.33–44.44%, instantaneous water use efficiency by 55.41–93.24% and intrinsic water use efficiency by 0.09–24.11%, while they decreased the intercellular CO₂ concentration and transpiration rate by 3.85–6.84% and 0.29–47.18% relative to BF₀, respectively (p < 0.05). The maximum increase in tobacco yield was recorded with BF_1.5 (23.81%) compared to that with BF₀. The present study concludes that the application of BF_1.5 improves and restores the degraded soil by improving the hydraulic conductivity and by increasing the tobacco yield.

High temperature has seriously impacted the production of wheat in many countries. We examined four wheat cultivars (PBW343, Berkurt, Janz, and Attila) under heat stress (35/25 °C) and control treatments (23/15 °C) for 3 days at the meiosis and anthesis stages to evaluate the response and recovery of the four cultivars to heat stress and the relationship between photosynthetic parameters related to heat tolerance. Photosynthetic activity in all cultivars declined in plants that were treated at 35 °C, even for only 1 d compared with control plants. However, the differences among the four cultivars were obvious in net photosynthetic rate (Pn). At meiosis, the reduction of Pn in Berkut and PBW343 was lower and could nearly fully recover after 3 d of recovery and showed higher heat tolerance characteristics. The highest reduction in Pn occurred in Janz, which did not recover completely after 3 d of recovery. The same trend was observed at the anthesis stage, but Pn in all cultivars could not fully recover. Taking transpiration rate (Tr), stomatal conductance (gs), intercellular CO₂ concentration (Ci), and limitation of stomatal conductance (Ls) into account, results suggested the decline in Pn under heat stress was mainly caused by non-stomatal restriction. In parallel with the decline in Pn, the maximum photochemical efficiency (Fv/Fm) decreased. In addition, both the maximum rate of net photosynthesis (Pmax) and the light saturation point declined after heat stress in all cultivars. However, the relevant photosynthetic parameters of PBW343 and Berkut recovered more quickly at both the meiotic and flowering stages. In summary, there were significant differences in the adaptability of different cultivars to high temperatures, with Berkut and PBW343 being more adaptable to heat stress than Janz and Attila. These may be used as valuable resources for further studies in breeding to understand the physiological mechanisms of heat sensitivity. This paper provides detailed information on the ecophysiological responses of wheat under heat stress.