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Abstract: Many crops are produced using soil fumigation and chemical pesticides to control soil-borne fungi and bacterial diseases, nematodes and weeds. Fumigation of soil, however, may alter its ability to adsorb, degrade and volatilize pesticides, which can then change the potential for pesticides to leach into groundwater. Soil adsorption kinetics, Freundlich isothermal adsorption and pesticide degradation techniques were used to determine the potential for pesticides to pollute groundwater in fumigated soil. The effect on soil pesticide adsorption in different types of chloropicrin (CP) fumigated soils was also examined. We observed that the equilibrium adsorption (q e) decreased significantly at 24 h. Soil fumigation decreased the Freundlich K f and K foc values, and increased the Freundlich exponent 1/ n values, for pesticides in fumigated Beijing soil. Soil fumigation influenced the K f of pendimethalin, oxyfluorfen and abamectin the most, which themselves had a larger K f in untreated soil. This indicated that the greater the soil pesticide adsorption the greater the influence of a fumigation treatment on that pesticide. The K f was decreased more in the Heilongjiang and Beijing CP-fumigated soils that had high organic carbon content compared to Hunan soil. Fumigation of the soil with CP extended the half-life values of fosthiazate (from 34.3 to 43.1 days) and azoxystrobin (from 52.9 to 64.2 days), which increased their potential to leach into groundwater. Famers should minimize the quantity of some pesticides applied to fumigated soil, or apply some pesticides 60 days after fumigation, in order to avoid ground water pollution when crops are grown in fields or greenhouses. Graphical abstract Image 1 Highlights • Soil fumigation decreased the K f and Koc values of pesticides in Beijing soil. • K f was decreased more in higher organic carbon content soil when fumigated with CP. • CP-fumigated soil extended the degradation half-life of fosthiazate and azoxystrobin. • The potential for pesticides to leach into groundwater increased in CP-fumigated soil. Soil fumigation decreased the Freundlich K f and K foc values of pesticides and increased their potential to leach into groundwater. [ABSTRACT FROM AUTHOR]

Flame soil disinfestation (FSD) is a novel, promising non-chemical method to control soilborne nematodes, fungal and bacterial pathogens in China. The efficacy of FSD on soilborne nematodes, fungal and bacterial pathogens was evaluated during two field trials. The field trials revealed that the treatment with FSD once (FSD1) and treatment with FSD twice (FSD2) sharply reduced the total number of soilborne nematodes (>95%) and completely controlled Meloidogyne incognita in the soil. Both FSD1 and FSD2 also provided promising efficacy against soilborne Fusarium oxysporum (>44%), Phytophthora spp. (>47%) and Ralstonia solanacearum (>67%) on media. However, there was no significant difference between FSD1 and FSD2 in controlling soilborne nematodes, fungal and bacterial pathogens ( P = 0.05). Currently, there are two challenges to distribute the technology in China: its high cost and relatively low efficiency because of the low speed of application compared with soil chemical fumigation. Despite the drawbacks, FSD is still promising in organic agriculture for controlling soilborne nematodes, fungal and bacterial pathogens. [ABSTRACT FROM AUTHOR]

It is highly challenging but imperative to develop highly efficient, low-cost and environmentally friendly bifunctional electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we successfully prepared hierarchically porous Ni 3 S 2 nanorod array foam through a simple hydrothermal process assisted by the pretreatment with HCl. The resulting hierarchically porous Ni 3 S 2 nanostructures exhibits excellent catalytic activity and stability towards both HER and OER with low overpotential of 200 mV and 217 mV at current density of 10 mA cm −2 for HER and OER, respectively, which are among the best non-noble metal HER/OER electrocatalysts reported in literatures. The as-prepared bifunctional electrocatalyst for both HER and OER could act as the promising electrode materials for water splitting. [ABSTRACT FROM AUTHOR]

We investigated the ability of fresh chicken manure (FCM) to control pathogens, to promote strawberry plant growth, strawberry yield and farmer income. Laboratory tests showed that FCM inhibited the growth of Fusarium oxysporum , Pestalotiopsis spp., Phytophthora infestans and Rhizoctonia solani , and root-knot nematode (Meloidogyne spp.). Although the CFU of Fusarium spp. and Phytophthora spp. in FCM was higher than in the chloropicrin (CP) treatment, it was significantly lower than in the control. Additionally, FCM and CP both promoted the growth of strawberry plants in laboratory tests. In field tests and compared with control, FCM and CP significantly reduced Fusarium spp. and Phytophthora spp. by 95.71% & 98.89% and 78.06% & 94.81%, respectively. FCM increased chlorophyll in strawberry plant leaves and promoted plant growth, compared with control and CP. Field-applied FCM also increased the content of NO3−-N, available P, K and organic matter, lowered soil pH, increased strawberry marketable yield (20.99%) and farmers' income (21.58%), compared with control. In addition, compared with control, FCM increased strawberry fruits soluble sugar and ascorbic acid content by 14.33% and 73.41%, respectively, and significantly decreased titratable acidity, which are known to contribute to improvement in fruit taste. In addition, FCM as a fumigant is readily available cheaper than chemical fumigants. Fresh chicken manure therefore has the potential to be an effective, environmentally-friendly alternative to chemical fumigants. The use of FCM reduces both environmental pollution from animal waste and the use of chemical fumigants, thereby contributing to China's goal of not increasing the use of chemical fertilizers and pesticides. [Display omitted] • Fresh chicken manure can be used as a eco-friendly soil fumigant. • FCM can effectively prevent soil-borne pathogens, improve soil condition and increase strawberry yield. • FCM contributes to China's goal of " zero growth in the use of chemical fertilizers and pesticides ". [ABSTRACT FROM AUTHOR]

Compared with traditional inorganic second-order nonlinear optical (NLO) materials, organic second-order NLO materials have many advantages in bandwidth, dielectric constant, half-wave voltage, electro-optic (EO) coefficients, processability, and material cost. Due to their potential applications in telecommunications, computing, detection, terahertz generation, and construction of functional photonic crystals, organic NLO materials have been widely studied for several decades. Currently, the poling efficiency and long-term stability are the largest obstacles for the application of organic NLO materials. At the molecular level, these problems are mainly caused by the strong dipole–dipole intermolecular interactions between the NLO chromophores with D-π-A structures. In the molecular design of the polymer system, modification of the chromophores is considered to be an efficient pathway to solve this problem. Since 2009, many studies have been performed by our group to reduce the strong dipole–dipole intermolecular interactions between the chromophores. In this review, the development of organic NLO materials in recent years is summarized, including the following: 1) a brief introduction of organic second-order NLO materials, 2) the requirements of NLO materials for applications in devices, 3) optimization of the first-order hyperpolarizability of NLO chromophores, 4) the optimization of the chromophore loading parameters (N, ), and 5) improvements of the stabilities of organic NLO materials. • Organic second order NLO materials was briefly introduced. • Requirements of NLO materials for applications in devices were discussed. • Optimized method for first-order hyperpolarizability and loading parameters of chromophore were discussed. • Method for improving stability of organic NLO materials was included. [ABSTRACT FROM AUTHOR]

Biofumigation is an effective, non-chemical method to control soil-borne pests and diseases and to maximize crop yield. We studied the responses of soil bacterial and fungal communities, the soil's nutritional state and strawberry yield, when the soil was biofumigated each year for five consecutive years using fresh chicken manure (BioFum). BioFum significantly increased the soil's NH 4 +-N, NO 3 −-N, available P and K and organic matter. Fusarium spp. and Phytophthora spp. which are known to cause plant disease, were significantly decreased after BioFum. In addition, Biofum increased the soil's temperature, enhanced chlorophyll levels in the leaves of strawberry plants, and the soluble sugar and ascorbic acid content in strawberry fruit. We used high-throughput gene sequencing to monitor changes in the soil's bacterial and fungal communities. Although BioFum significantly decreased the diversity of these communities, it increased the relative abundance of some biological control agents in the phylum Actinobacteria and the genera Pseudomonas, Bacillus and Chaetomium. An increase in these biological control agents would reduce the incidence of soil-borne pathogens and plant disease. Although strawberry marketable yield using BioFum was higher in the first three years, the decline in the final two years could be due to the accumulation of P and K which may have delayed flowering and fruiting. Methods to overcome yield losses using BioFum need to be developed in the future. Our research, however, showed that BioFum enhanced soil fertility, reduced the presence of soil pathogens, increased the relative abundance of beneficial bacteria and fungi and improved strawberry quality. Unlike chemical soil treatments that can cause pest and disease resistance when used continuously over many years, our multi-year research program on BioFum showed that this treatment provided significant benefits to the soil, plant and strawberry fruit. Image 1 • Biofumigated each year for five consecutive years (BioFum) could enhance soil fertility, reduce soil pathogens and improve strawberry quality. • The strawberry marketable yield in five consecutive years biofumigation treatment (BioFum) was not always higher than the control treatment. • The relative abundance of beneficial bacteria and fungi were increased in five consecutive years biofumigation treatment (BioFum). • Five successive years of chloropicrin treatments (Pic) significantly changed the diversity and richness of bacterial and fungal community. [ABSTRACT FROM AUTHOR]

• First to show the effect of chloropicrin (CP) on P and phoD -harboring microbes. • CP increased active P and leached-P, but decreased ALP activity and phoD abundance. • The abundance and diversity of phoD microbes briefly increased in CP-fumigated soil. • P changes in CP-fumigated soil associated with bacteria or phoD -harboring microbes. • The increase of active P form was an important source of P leaching after fumigation. The transformation of phosphorus (P) compounds in soil depends largely on soil microbial communities and is sensitive to agricultural practices. However, the effects of soil fumigation on soil P, and microbes involved in P transformation, are unknown. Our results showed that chloropicrin (CP) fumigation significantly increased the available-P, Leached-P and active-P fractionation (inorganic P extracted from H 2 O, NaHCO 3 and NaOH) in Shangdong and Miyun soils in the early stages of culture, while soil alkaline phosphatase (ALP) activity and phoD gene abundance decreased significantly. Leached-P in fumigated soil was positively correlated with increased active-P fractionation, indicating that it was an important source of soil Leached-P after fumigation. The changes in P-fractionation, Leached-P and ALP after fumigation were also significantly correlated with the composition of the microbial communities. CP fumigation briefly stimulated an increase in the abundance and diversity of phoD -harboring microbial communities and promoted the mineralization process of soil P. PICRUSt metagenomic analysis showed an increase in the relative abundance of microorganisms with involved in carbohydrate/lipid transport and metabolism functions after fumigation. These results suggest CP fumigation altered soil P transformation and phoD -harboring microbes that might lead to an increased risk of P enrichment in waterways. [ABSTRACT FROM AUTHOR]

Chloropicrin (Pic) and biofumigation are both considered effective chemical and non-chemical alternatives to methyl bromide, respectively, for controlling crop-limiting soil-borne pests and diseases. In this study, we evaluated the effects of Pic alone and 'chloropicrin alternated with biofumigation' (CAB) on the soil's physico-chemical properties and strawberry yield, as well as their effects on soil bacterial and fungal communities. The contents of NO 3 −-N, available phosphorus and potassium, and electrical conductivity were all significantly increased when CAB was used. In addition, CAB also significantly increased the strawberry marketable yield. High-throughput gene sequencing showed the species abundance of some soil bacteria and fungi was significantly increased such as the phyla Proteobacteria, Bacteroidetes, Actinobacteria and Ascomycota when CAB was used. However, CAB decreased the relative abundance of the phyla Firmicutes, Chloroflexi, Gemmatimonadete and Zygomycota. These results indicated that CAB could improve the physico-chemical properties of soil for strawberry production, increase the genetic diversity of microbes in the soil and enhance marketable fruit yield. Unlabelled Image • Our study introduced a new method of soil fumigation to reduce the use of chemical fumigants. • Chloropicrin alternated with biofumigation (CAB) can improve nutrient elements in chloropicrin fumigation plots. • Chloropicrin alternated with biofumigation (CAB) also increased strawberry yields • Chloropicrin alternated with biofumigation (CAB) significantly impacts soil bacterial and fungal community diversity. [ABSTRACT FROM AUTHOR]

Abstract Despite using fumigants for many decades to control soil-borne pathogens and plant-parasitic nematodes, the influence of soil fumigation on microorganisms involved in the nitrogen-transforming process remains little understood. We used real-time PCR (quantitative polymerase chain reaction) and 16S rRNA gene amplicon sequencing techniques to determine nitrous oxide (N 2 O) emissions from bacterial microorganisms associated with nitrogen (N) transfer when soils were fumigated with dimethyl disulfide (DMDS) or allyl isothiocyanate (AITC). Our results showed that fumigation with DMDS or AITC increased N 2 O emissions 6.5–7.3 and 11.2–20.7 times, respectively. The abundance of 16S rRNA and N cycling functional genes initially decreased, but recovered to the unfumigated levels after fumigation. N 2 O emissions were significantly correlated to the presence of NH 4 +, NO 3 −, dissolved amino acids (DAA) and microbial biomass nitrogen (MBN). N 2 O emissions were not correlated with the abundance of N-transforming functional genes. Metatranscriptomes and dual-label 15N 18O isotope anaylsis revealed DMDS fumigation significantly increased the expression of gene families involved in the N-transforming process, but depressed ammonia oxidation which caused a shift in the N 2 O pathway from nitrification to denitrification. However, AITC fumigation suppressed most genes involved in the N cycle, but increased the expression of genes that transformed NO 2 − to NO and further organic decomposition, so that overall there was a shift in the N 2 O pathway from nitrification to nitrifier denitrification. The information obtained in this study will provide further insights into the N cycling pathways in fumigated soils and into the potential responses of different N-cycling groups after fumigation. Graphical abstract Image 1 Highlights • Both dimethyl disulfide (DMDS) and allyl isothiocyanate (AITC) fumigation of soil resulted in increased N 2 O emissions. • N 2 O production via denitrification was stronger in DMDS-fumigated soil. • Nitrifier denitrification was the dominant pathway of N 2 O production in AITC-fumigated soil. • Populations of nitrogen cycling microbes recovered to unfumigated levels at different times after fumigation. [ABSTRACT FROM AUTHOR]

Abstract The fumigant 1,3-dichloropropene (1,3-D) is widely-used to control pathogenic bacteria, fungi, nematodes and insects in soil before a crop is planted. Although fumigants in general have been reported to have a 'fertilizer effect' in the soil by increasing nitrogen availability, little is known of how a specific fumigant such as 1,3-D affects available nitrogen. This study used real-time quantitative PCR (qPCR) and 16S rRNA gene amplicon sequencing techniques to investigate the effects of 1,3-D on microorganisms involved in nitrogen cycling that were present in 2 soils: Jiangxi lateritic red soil and Beijing fluvo-aquic soil. The fumigant 1,3-D temporarily decreased the abundance of 11 functional genes involved in nitrogen-fixing, nitrification and denitrification in both soil types. Different nitrogen cycling groups recovered to the unfumigated level in various incubation phases. Microorganisms containing nifH , nxrB , napA and qnorB genes were most vulnerable to 1,3-D fumigation. However, a stronger and longer inhibition effect of 1,3-D on these 11 functional genes was observed in Jiangxi soil than in Beijing soil. At the same time, the abundance of nifH , AOBamoA , nirS , qnorB and cnorB genes was significantly increased 59 days after 1,3-D fumigation. Fumigation with 1,3-D significantly reduced the nitrogen-fixing bacteria Azospirillum and Paenibacillus ; the nitrifiers Nitrosomonas and Nitrospira ; and the denitrifiers Pseudomonas , Paracoccus and Sphingomonas. Conversely, fumigation with 1,3-D increased the nitrogen-fixing bacteria Bradyrhizobium and Rhizobium ; the nitrification bacteria Nitrosospira and Nitrolancea ; and the denitrification bacteria Sphingobium , Alcanivorax , Bacillus , Streptomyces and Aeromonas. Fumigation with 1,3-D therefore caused significant shifts in the species composition and number of microbes directly involved in nitrogen cycling in the short-term. These results contribute toward a better understanding of the impact of 1,3-D fumigation on various types of soil nitrogen-cycling groups. Graphical abstract Unlabelled Image Highlights • 1,3-D fumigation initially decreased the abundance of nitrogen cycling functional genes • Microorganisms respectively containing nifH , nxrB , napA , qnorB were most vulnerable to 1,3-D • 1,3-D increased genera Rhizobium , Nitrosospira , Nitrolancea , Alcanivorax , Bacillus and Aeromonas • 1,3-D Fumigation resulted in a stronger and longer inhibition effect on N-cycling microorganisms in Jiangxi than Beijing soil • N cycling groups recovered to the unfumigated control level in post-fumigation incubation phases [ABSTRACT FROM AUTHOR]

Chloropicrin retards the conversion of ammonia to nitrite during the nitrification process in soil. In our study, the dynamic effect of chloropicrin fumigation on soil nitrification was evaluated in five different soil types to identify relationships between soil properties and the effect of fumigation on nitrification. Chloropicrin significantly inhibited nitrification in all soils; however, the recovery of nitrification varied greatly between the soils. Following chloropicrin fumigation, nitrification recovered to the control level in all soils, except in the acidic Guangxi soil. Nitrification recovered faster in fumigated sandy loam Beijing soil than in the other four fumigated soils. Soil texture and pH were two important factors that influenced chloropicrin's inhibitory effect on nitrification. An S-shaped function was fitted to soil NO 3 − -N content to assess the nitrification recovery tendency in different soils. The time taken to reach maximum nitrification ( t max ) ranged from 2.4 to 3.0 weeks in all unfumigated soils. Results demonstrated that t max was greater in all fumigated soils than in untreated soils. Correlation calculations showed that t max was strongly correlated to soil texture. The correlation analysis results indicated that the recovery rate of nitrification after chloropicrin fumigation is much faster in sandy loam soil than silty loam soil. [ABSTRACT FROM AUTHOR]

Biochar is used as a new type of fertilizer in agriculture; however, its effect on the fate of fumigants in soil is not fully understood. The objective of this study was to investigate the effects of biochar on methyl isothiocyanate (MITC) degradation in soil in laboratory incubation experiments, including the effects of biochar composition, amendment rate, moisture, temperature, soil sterilization and soil type. The dissipation pathways of MITC in biochars included adsorption and chemical degradation. The adsorption of MITC by biochars was positively correlated with the specific surface area (SSA) of the biochar. Biochar with a high SSA and low H/C value (such as biochar type BC-1) reduced MITC degradation in soil substantially; following BC-1 amendment, the degradation rate was 73.9% slower than in unamended soil. The degradation of MITC was positively correlated with the H/C value of biochar, and MITC degradation in soil increased 2.2–31.1 times following amendment with biochars with higher H/C values (e.g. biochar types BC-3–6). The biochar with the lowest organic matter and low H/C value did not affect the fate of MITC in soil. Biochars affect abiotic degradation processes more than biodegradation. When soil samples had a higher water content (> 10%), higher temperature (40 °C), and lower organic matter, the addition of BC-1 biochar reduced MITC degradation substantially; and this did not change significantly when the amendment rate increased. However, BC-4 biochar accelerated MITC degradation with increasing amendment rate, increasing temperature, and decreasing soil water content. The differences in degradation rates due to soil type were minimized by amendment with BC-4, but significant differences in BC-1. The results showed that the rational use of biochar has the potential to reduce MITC emission by accelerated degradation and adsorption. [ABSTRACT FROM AUTHOR]

Soil fumigation can increase mineral nitrogen due to the mineralization of soil microbial biomass killed during the fumigation, and as a result nitrous oxide (N 2 O) emission would increase. In addition, a fumigant's impact on soil nitrification and denitrification would also alter the dynamics of N 2 O production in fumigated soils. Laboratory incubation studies were conducted to quantify the dynamic changes in N 2 O production following various fumigant treatments, and to determine the interaction between nitrification, denitrification and N 2 O production in fumigated soils. Results showed a substantial increase in NH 4 + –N and dissolved amino acids (DAA) during 7 days fumigation at 1WAF (week after fumigation). The application of fumigants caused significant inhibition of nitrification. However the results relating to potential denitrification were quite different. The rates of potential denitrification in chloropicrin (Pic) and dazomet (DZ) treatments at 1WAF were 3.5 and 5.6 times higher than the untreated control. Potential denitrification was greatly stimulated after Pic and DZ fumigation. The N 2 O production rates in Pic and DZ fumigated soil were significantly higher than the untreated control at 1WAF in the tested soil type. The cumulative N 2 O emissions in Pic and DZ fumigated soil were also significantly higher than the untreated control, but there were no significant differences among 1,3-dichloropropene (1,3-D), dimethyl disulfide (DMDS) and untreated control. A positive relationship between N 2 O production and potential denitrification (PDN) was observed ( r = 0.951, P < 0.01). Pic and DZ are both nitrogenous compounds. The breakdown products of Pic and DZ would be available for microbial-aided denitrification reactions as nitrogen sources leading to N 2 O production, indicating that Pic and DZ degradation stimulated denitrification activity responsible for soil N 2 O production. [ABSTRACT FROM AUTHOR]

Abstract: A proton and optic dual-responsive fluorescence switch dyad which contains Rhodamine and photochromic diarylethene has been designed and an integrated logic circuit at the molecular level has been proposed. [Copyright &y& Elsevier]

Abstract: A series of axles containing the tetraethyl ester calix[4]arene derivative unit and 1,5-dioxynaphthalene (DNP) unit, with different lengths of ether chains, have been synthesized. Complexation of the axles and the cyclobis(paraquat-p-phenylene) (CBPQT4+) has been investigated by UV–vis and 1H NMR spectra. The effect of the length of ether chain on the threading/dethreading processes has also been demonstrated, which indicated that the efficiency of threading/dethreading process decreases with the extension of ether chain. [Copyright &y& Elsevier]

Allyl isothiocyanate (AITC) is a soil fumigant derived from plants that can effectively control soil-borne diseases. Fully understanding the impact of various factors on its degradation can contribute to its effectiveness against pests and diseases. First, orthogonal design determined the extraction method of AITC in soil, that is using ethyl acetate as the extraction reagent, vortexing for 1 min as the extraction method and holding for 30 min as the method time. Then we studied the effects of soil texture and environmental factors on the rate and extent of AITC degradation in soil. The half-lives of nine origins soils varied from 12.2 to 71.8 h that were affected by the soil's electrical conductivity, available nitrogen, pH and organic matter content. Biotic degradation of AITC contributed significantly (68%–90%) of the total AITC degradation in six soil types. The degradation rate of AITC decreased as the initial dose of AITC increased. The degradation rate of AITC in Suihua soil generally increased with increasing temperature and soil moisture. The effect of temperature on AITC degradation was more pronounced when the soil was moist, which has practical implications for the control of soil pests and diseases. In agricultural soil, the soil's characteristics and environmental factors should be considered when determining the appropriate AITC dose suitable for soil borne disease while at the same time minimizing emissions and impact on the environment. Image 1 • Soil texture and environmental factors affect the AITC degradation. • Orthogonal design establishes the extraction method of AITC in soil. • AITC degradation depends on soil characteristics and application rate. • Microbial degradation is the main pathway for AITC degradation in soil. • AITC degradation generally accelerates with increasing temperature and humidity. [ABSTRACT FROM AUTHOR]