Organic materials added to soil create anaerobic conditions that can reduce soil-borne pathogens that reduce the yield and quality of agricultural crops. Anaerobic soil disinfestation (ASD) requires relatively large quantities of readily available, inexpensive organic materials. We evaluated the impact of ASD with rice bran and biochar organic materials on changes to the soil’s physicochemical properties, microbial taxa, and strawberry fruit yield. We found that the organic materials applied at different dose rates significantly increased the control effect of the soil Fusarium spp. and Phytophthora spp. to 69–99% and 63–98%, respectively. In addition, ASD significantly increased soil organic matter and ammonium nitrogen contents. Strawberry yield also increased significantly after ASD treatment with biochar applied at 10 t/ha, which was positively correlated with increased soil nutrients and a significant reduction in pathogens. High-throughput gene sequencing showed that ASD significantly increased the abundance of some beneficial microorganisms such as Bacillus, Pseudomonas, and Mortierella, possibly due to changes in the soil’s physicochemical properties that favored their survival. We found for the first time that biochar applied at 10 t/ha could create anaerobic conditions that effectively reduced soil-borne pathogens and increased crop yield.

Soil fumigation can kill soil pathogens and solve the problem of crop continuous cropping. However, soil fumigation also has negative effects on the soil environment. One way to mitigate the negative effects is to apply soil amendments, but there is limited evidence of the effects of combining soil fumigation and amendments. This study was a controlled environmental pot trial. We measured the effects of dazomet fumigation combined with soil amendments on soil-borne pathogens, soil nutrients, enzyme activities, and strawberry growth. The results showed that dazomet fumigation combined with soil amendments significantly increased the content of ammonium nitrogen, available phosphorus and organic matter and increased soil activities by varying degrees. We also found that the control effect of soil-borne pathogens Fusarium spp. and Phytophthora spp. was further enhanced, reaching 88.97–96.88%. Correlation analysis showed that the growth indices of strawberries such as plant height, stem diameter, chlorophyll content, and fresh weight were negatively correlated with Fusarium spp. (R = −0.75, R= −0.62, R = −0.71, R = −0.88; p < 0.01) and Phytophthora spp. (R = −0.72, R= −0.72, R = −0.78, R = −0.91; p ≤ 0.001), respectively. The effect of fumigation combined with soil amendments was better than that of fumigation alone, and silicon fertilizer had the best effect. Our study suggests that dazomet fumigation combined with soil amendments can improve soil nutrient supply, activate soil enzyme activities, enhance the control effect of soil-borne pathogens, and thus promote strawberry growth.

Pesticides are considered the most effective way to protect crops. However, irrational use has caused resources waste and environmental pollution. Dazomet (DZ) is a soil fumigant that has been used in many countries for decades, although it has caused occasional crop damage or insufficient control efficacy in some circumstances. In this study, the effects of DZ’s granule size and exposure to various environmental conditions on DZ degradation when used as a fumigant were demonstrated. The degradation rate of DZ was closely related to granule size. The half-life of larger DZ granules was longer than smaller granules with all studied environmental factors. The degradation rate decreased as the DZ usage (90–360 mg/kg) increased and different granule sizes showed the same variation trend. The half-life in each of the five granule size ranges tested decreased significantly as the temperature increased. DZ half-life decreased by 4.67–6.59 times as the temperature increased from 4 to 35 °C. Moreover, DZ usage and temperature affected the half-life of granules >400 and 300–400 μm in diameter significantly more than <100 μm granules. The half-life of all DZ granule sizes was reduced by 13.9–47.4% in alkaline compared to acidic conditions (pH from 9 to 5). Moreover, elevated temperatures could not only promote the production of methyl isothiocyanate (MITC) but accelerate its dissipation. The interactions between DZ granule size, dosage, temperature, and pH provide practical guidance on methods to improve DZ’s efficacy against pests and reduce the risk of phytotoxicity.

Soil fumigation is considered a method to control soil-borne diseases and solve crop continuous cropping obstacles. However, fumigant residues in the soil are detrimental to soil health. Though substrate cultivation is a cultivation mode that can promote plant growth, studies to date on whether substrate cultivation can replace soil fumigation for the control of soil pathogens are limited. In this study, the effects of chloropicrin fumigation (Pic) and substrate cultivation (SC) on yam growth, soil pathogens, soil nutrients, and microbial communities were demonstrated using a 2-year field experiment. The results showed that SC significantly increased the content of soil organic matter (SOM), available phosphorus, and available potassium compared with Pic. In addition, SC could effectively reduce the number of Fusarium spp. and Phytophthora spp., decrease the rate of diseased yam plants, and significantly increase the yam yield. Moreover, SC significantly increased the abundance of beneficial microorganisms such as Actinobacteriota, Acidobacteriota, and Bacillus in soil. Correlation analysis showed that yam yield exhibited a negative relation with the number of soil pathogens and a positive correlation with SOM. Our study suggests that substrate cultivation can be an alternative to soil fumigation to control soil pathogens and protect soil health.

Dazomet (DZ) is a soil fumigant that has been used for decades at many countries, however it was reported to have caused phytotoxicity and reduced crop yield in many countries. In this experiment, in order to clarify whether the diameter of DZ is related to phytotoxicity, this research investigated the degradation rate of DZ with different diameter ranges under three soil types held at 15, 20 or 30% soil water content at 4, 15, 25 or 37 °C, and monitored concentrations of methyl isothiocyanate (MITC) produced when Shunyi soil was fumigated with DZ using the different particle sizes ranges. When the soil water content and temperature increased, the degradation rate of DZ with different particle sizes accelerated. However, the degradation rate of DZ with large particle sizes was still lower than small particle sizes. NO₃⁻-N, available phosphorus (AP), available potassium (AK), pH and silt content in the soil were all significantly positively correlated with 400 μm DZ. However, organic matter (OM) and sand content produced the opposite result. The maximum concentration of MITC produced by 100–300 μm of DZ in 25 °C Shunyi soil at 30% water content were 102.2 mg/kg at 24 h. DZ produced peaks significantly higher and earlier at 30% than at 20% soil water content. We recommend selecting DZ manufactured with particle in the range of 100 to 300 μm, fumigating at about 25 °C and ensuring that about 30% soil water content is present in the soil immediately after fumigation.

This study investigates the uptake, translocation, and pathogen control efficacy of ethylicin in tomato plants using a combination of indoor root irrigation, spraying, and field root irrigation experiments. The results indicate that ethylicin shows dual-directional translocation in tomato plants. On the third day after foliar spraying, ethylicin was detected in the roots at a concentration of 2.93 mg/kg, indicating downward movement. On the third day after root irrigation, ethylicin was detected in the leaves at a concentration of 3.44 mg/kg, confirming upward movement. In the field experiments, ethylicin was absorbed and transported to the upper leaves within six hours of root irrigation at a concentration of 3.85 mg/kg for a single-agent ethylicin and 5.87 mg/kg for an ethylicin–oligosaccharin compound. These results indicate that oligosaccharins enhance the absorption of ethylicin. Ethylicin residue dissipated by the fifth day. No ethylicin was detected in the untreated controls. Root irrigation during the growing period showed an effective reduction of Fusarium spp. and Phytophthora spp. populations in the soil and control of soil-borne diseases. These findings provide theoretical support for the efficient application of ethylicin in the field.