Application Of Thiourea Research Articles

Exogenous thiourea modulates antioxidant defence and glyoxalase systems in lentil genotypes under arsenic stress

<p>Arsenic (As) is a wide-spread toxic and carcinogenic metalloid, affecting crop productivity worldwide. Lentil, an edible grain legume, is increasingly exposed to soil arsenic contamination. However, our understandings regarding mechanistic details and mitigation strategies against arsenic toxicity in edible legume are extremely poor. Main purpose of the present study was to investigate the As-effects and its mitigation by thiourea (TU), a sulfhydryl bioregulator, in lentil. Four widely grown lentil genotypes were grown in nutrient media, supplemented with 30 μM sodium arsenate (As), As + 6.5 mM TU and As + 13 mM TU, keeping an untreated control for 10 d. As severely affected plant dry weight by accumulating in shoots and roots. However, TU application sequestered As in crop roots and prevented up-ward translocation of As. TU coordinately modulated glyoxalase system I and II (Gly I and II) and ascorbate (AsA)-glutathione (GSH) redox, and antioxidant defense enzymes in both leaves and roots of four genotypes. Elevation of Gly system prevented toxic methyl glyoxal overaccumulation whereas stimulated AsA-GSH cycle enzymes and Glutathione s-transferase and catalase effectively scavenged H<sub>2</sub>O<sub>2</sub> and prevented reactive oxygen species (ROS) -mediated onset of oxidative damage in four genotypes, as was evident from ROS-imaging study. Results suggested exogenous TU stimulated the Gly and antioxidant defense in fine tune against As-induced oxidative damage in lentil genotypes.</p>

Impact of on farm testing on low yield of potato due to frost in Bharatpur district of eastern Rajasthan

HIND AGRICULTURAL RESEARCH AND TRAINING INSTITUTE ABSTRACT : The Present study was carried out at Bharatpur district of Eastern Rajasthan during 2012-13, 2013-14 and 2014-15. Potato is one of the most important vegetable crops of the country. The development of the agriculture is primarily depends on the application of the scientific technologies by making the best use of available resources. One of the major constraints of traditional potato farming is low productivity because of non-adoption of advanced technologies to protect the crop from frost. To increase the production, productivity and quality of agricultural produce, on farm testing are being conducted at various farmer’s field. All the recommended practices were provided to the selected farmers. The data related to the cost of cultivation, production, productivity, gross return and net return were collected as per schedule and analyzed. Result of the present study revealed that the application of concentrated H 2 SO 4 @ 1.0 ml/l water on standing crop recorded the higher yield (307.0 q/ha) as compared to application of thio-urea @ 0.1 per cent on standing crop (294.50 q/ha) and control (265.06 q/ha). The percentage increase in the yield over control 15.82 was recorded.The technology gap in terms of productivity(43.00 q/ha.) were computed. The technology index values 12.28 per cent was recorded.The result of the study indicated the gap existed in the potential yield and demonstration yield is due to soil fertility and weather conditions. By conducting on farm testing of proven technologies of saving the crop by low temperature, yield potential of potato can be increased upto great extent. This will substantially increase the income as well as the livelihood of the farming community.

The influence of mechanochemical modification on prevention of toxic ability of humic acids towards phenanthrene in aquatic environment

The aim of the research work is to quantify interaction between phenanthrene with modified humic acids in aquatic environment. The changes in the structure and properties of humic acids after modifications were studied with 1H NMR spectroscopy and potentiometric titration methods. Our research demonstrates that the application of thiourea as a modified agent increases the binding capacity of humic acids towards phenanthrene.

Thiourea-induced metabolic changes in two mung bean [Vigna radiata (L.) Wilczek] (Fabaceae) varieties under salt stress

A pot experiment was conducted to assess the effect of foliar application of thiourea on two mung bean (Vigna radiata (L.) Wilczek) varieties (NM-2006 and NM-2011) under salt stress. Experiment was laid-out in a completely randomized design with four replicates. Two salt treatments [non-saline (control) and 75 mM NaCl] were applied to 28-day-old mung bean plants. Three levels of TU [0 (water spray), 10, and 20 mM] were foliarly sprayed after 1 week of salt treatment. Data for various growth and physio-chemical attributes were collected of 64-day-old mung bean plants, while two plants were left for obtaining yield. Salt stress significantly decreased all growth and yield attributes, while increased anthocyanin, relative membrane permeability (% RMP), malondialdehyde, total soluble sugars, total soluble proteins, activities of catalase and peroxidase enzymes, total phenolics, free proline, and glycinebetaine contents. Foliar application of varying TU levels significantly increased shoot and root fresh and dry weights, shoot and root lengths, seed yield per plant, pod fresh and dry weights, number of seeds per plant, 100-seed weight, chlorophyll b (in NM-2006), total soluble sugars, total soluble proteins, POD activity, and total phenolic contents, while decreased RMP (%), total free amino acids, and GB contents. Of the two mung bean varieties, NM-2006 was superior to NM-2011 in most of growth and physio-chemical attributes under both salt stress and non-stress conditions as well as foliarly applied varying levels of TU. Overall, 20 mM TU proved more effective in reducing adverse effects of salt stress in both mung bean varieties.

Optimization of bio-regulators dose based on photosynthetic and yield performance of chickpea (Cicer arietinum L.) genotypes

A pot experiment was conducted using two contrasting chickpea varieties, viz., Pusa 362 (Desi type) and Pusa 1108 (Kabuli type) with the objective of optimizing dose of bio-regulators namely thiourea (TU), benzyladenine (BA) and thidiazuron (TDZ). Varying doses of foliar application of TU (0, 500, 1000, 1500 ppm), BA (0, 20, 40, 60 ppm), TDZ (0, 10, 15, 20 ppm) and salicylic acid (0, 50, 100, 150 ppm) were applied before flowering stage. Rates of photosynthesis were recorded at flowering and podding stages and seed yield was obtained at harvest. The results revealed that photosynthetic rate in both varieties increased with increasing doses of bio-regulators at both flowering and podding stages and grain yield also exhibited similar trend. Highest photosynthetic rates and grain yield were recorded with the foliar application of TU, BA, TDZ and SA @ 1000, 40, 10 and 100 ppm, respectively. After curve fitting, optimum dose for TU, BA, TDZ and SA foliar application were estimated to be 878.33, 52.75, 11.78 and 90.63 ppm, respectively.

Effect of application of SH-compounds on yield, protein and economics of summer green gram [Vigna radiata(L.) WILCZEK] under moisture stress in north Gujarat conditions

A quadreplicated split plot design field experiment with two main plot treatments and weight subplot treatments were conducted during summer 2011. Both the SH compounds and water was sprayed twice i.e., 25 and 45 DAS. Seed yield was not influenced but stover yield was significantly reduced due to moisture stress at vegetative stage (M2). Moisture stress did not influence protein content and protein yield. Crop without moisture stress (M1) produced higher net return and cost benefit ratio (CBR). Use of Thiourea 500 ppm (S4) increased seed and stover yield by 58 and 84% respectively over control (S1). Protein content and yield also increased with thiourea application @ 500 ppm (S4) over the SH compounds. Net return and CBR was highest with Thiourea 500 ppm. Use of thiourea @ 500 ppm without moisture stress earned maximum while moisture stress with control recorded the lowest net return and CBR. Foliar spray of thiourea@ 500 ppm twice at 25 and 45 DAS proved most effective to get higher yield and net return from summer greengram.

Promotive effect of exogenously applied thiourea on key physiological parametersand oxidative defense mechanism in salt-stressed Zea mays L. plants

A greenhouse experiment was conducted to examine the alleviating role of thiourea (TU) on antioxidants and some vital physiological attributes in salt-stressed plants of two maize cultivars. The maize cv. DK 5783 performed better than cv. Apex 836 in an initial experiment. Of the six TU levels used in the initial experiment, 400 and 500 mg L-1 were chosen for subsequent studies. The two cultivars were subjected to saline stress (100 mM NaCl) and two levels of TU were applied presowing or as foliage spray. Salt stress suppressed total biomass, maximum fluorescence yield (Fv/Fm), chlorophyll, and leaf water potential ($\Psi$w), but it increased proline, hydrogen peroxide (H2O2), malondialdehyde (MDA), leaf osmolality (LO), membrane permeability (MP), and antioxidant enzymes. Exogenous TU application resulted in considerable increases in the dry weight of salt sensitive and tolerant cultivars (38% and 35%, respectively). TU partially improved the salt tolerance of maize plants; it reduced Na+ but increased N, K+, Ca2+, and P in the maize plants under saline regimes. TU regulated the growth of maize plants under stress conditions by reducing MP, MDA, and H2O2 levels, and altering activities of antioxidant enzymes as well as increasing photosynthetic pigments under a saline regime.

PCDD/Fs’ suppression by sulfur–amine/ammonium compounds

Three distinct –S and –NH2 or NH4+ containing compounds, including ammonium thiosulfate, aminosulfonic acid and thiourea, were studied as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) inhibitors. All these three –S and –N containing compounds tested show strong suppression of PCDD/Fs formation, especially for thiourea which has not been studied before. With a (S+N)/Cl molar ratio of only 0.47, thiourea could inhibit 97.3% of PCDD/Fs and even 99.8% of I-TEQ. At an unusually high de novo test temperature (650°C), the PCDD/Fs’ formation was still very low but also the inhibition capacity of thiourea was weak, with an efficiency of 59% for PCDD/Fs when with a (S+N)/Cl molar ratio of 1.40. The results also revealed that the inhibition capability of the combined –S/–NH2 or –S/NH4+ suppressant was strongly influenced by both the nature of the functional group of nitrogen and the value of the molar ratio (S+N)/Cl. The amine functional group –NH2 tends to be more efficient than ammonium NH4+ and within a certain range a higher (S+N)/Cl value leads to a higher inhibition efficiency. Moreover, the emission of gases was continuously monitored: the Gasmet results revealed that SO2, HCN and NH3 were the most important decomposition products of thiourea. Thiourea is non-toxic, environment-friendly and can be sprayed into the post-combustion zone in form of powder or aqueous solution. The cost of thiourea at least can be partially compensated by its high inhibition efficiency. Therefore, the application of thiourea in a full-scale incinerator system is promising and encouraging.

Effects of Thiourea on Metals Availability and Maize Physiological Characteristics in Acid Soils from South China

It has been confirmed that thiourea (TU) was effective in inhibiting urea hydrolysis and nitrite formation. However, few studies focused on the toxicological effects and environmental impacts of TU. In this study, the influences of TU on the soil pH and available metals contents were reported. The addition of thiourea to the urea-treated soils led to a slower decrease or even increase in soil pH. The application of thiourea had slight influence on the content of available Cu in soils. Mn content increased with increasing TU concentration, however, the changes of Zn and Al contents were opposite. Pot culture experiments were conducted to investigate the effects of TU on the physiological characteristics of maize seedlings, including the plant growth, chlorophyll (CHL) content, metal ions uptakes and malondialdehyde (MAD) content in the leaves. 1 mmol kg-1 soil thiourea significantly inhibited the growth of maize seedlings. The application of thiourea enhanced the Mn accumulation in leaves, and negatively affected the Fe uptake, which thereby inhibited the biosynthesis of CHL. There was not any noticeable difference in MDA content in plants treated with 1-2.5 mmol kg-1 soil thiourea. An obvious increase of MDA content was found at 5 mmol kg-1 soil thiourea.

Variation of invertase activities in four wheat cultivars as influenced by thiourea and high temperature

The effects of metal ions and thiourea on the activities of invertases in relation to the accumulation of free sugars and soluble protein were studied in four germinating wheat (Triticum aestivum) cultivars PBW 343, PBW 534 (heat susceptible), C 306 and C 273 (heat tolerant) under normal (25 °C) and high temperature (HT, 32 °C) conditions. High temperature significantly increased the activities of soluble acid, neutral and cell wall-bound invertases in correspondence with an increase in reducing sugar and soluble protein whereas the content of non reducing sugar was decreased in both root and shoot. Thiourea application under HT stress further elevated invertase activities and soluble protein content in all the four cultivars studied. Invertase activities of C 306 and C 273 cultivars were more sensitive to sulfhydryl group modifiers whereas the inhibitory effect of Ca2+, Hg2+, Mg2+ and Zn2+ was much more pronounced in PBW 343 and PBW 534. Apparently, inhibitory effect of iodine and Hg2+ on invertase activities in root and shoot of wheat confirmed the presence of sulfhydryl group at the active site of the enzyme. The results indicate that differential response of wheat cultivars may be anticipated to in vitro modulation of invertases to metal ions and TU that leads to selective modification of carbon metabolism under the influence of HT.

Improving Growth and Productivity of Faba Bean Plants by Foliar Application of Thiourea and Aspartic Acid

Two field experiments were carried out at the Research and Production Station of the National Research Centre, Noubaria, Egypt, during the winter season of 2010/2011 and 2011/2012. This study aimed to investigate the response of vegetative growth, yield and some metabolic constituents of field bean (Vicia faba L. var minor) cv. Giza402 to foliar application of bio-regulator Thiourea (TU; 250, 500 or 1000 mg L), and amino acid Aspartic acid (AspA; 50, 100 or 150 mg L) either alone or in combination. Foliar application of TU and Asp A either alone or in combination significantly increased the values of number of branches, leaves and pods/plant, total dry weight/plant, leaf area index, specific leaf weight and crop growth rate criteria. Total photosynthetic pigments content in leaves were increased by increasing TU (up to 1000 mg L) and Asp A (upto150 mg L) singly or in combination. Straw, seed and biological yields of faba bean plants were significantly increased by increasing TU and Asp A concentrations up to 1000 and 150 mgL, respectively. Application of 1000 mgL TU, singly and combined with Asp Conference Proceeding Full Paper Amin et al.; IJPSS, Article no. IJPSS.2014.6.015 725 A at 150 mg L caused significant increments in harvest index (2.9 and 25.5%) and seed yield ha (46.4 and 101.9%), respectively, compared to their control plants. TU and Asp A, when applied alone, significantly improved the nutritional value and quality of faba bean seeds by increasing total carbohydrates, total crude protein, phosphorus, potassium, and calcium contents. In conclusion, foliar application of TU at 1000 mg L and Asp A at 150 mg L, singly or combined could be recommended to improve the yield, nutritional value and quality of faba bean seeds.

Influence of thiourea application on some physiological and molecular criteria of sunflower (Helianthus annuus L.) plants under conditions of heat stress

High temperature is a major factor limiting the growth of plant species during summer. Understanding the mechanisms of plant tolerance to high temperature would help in developing effective management practices and heat-tolerant cultivars through breeding or biotechnology. The present investigation was carried out to study the role of thiourea in enhancing the tolerance of sunflower plants to heat stress. Sunflower plants were subjected to temperature stress by exposing plants to 35 or 45°C for 12h. Two levels of thiourea (10 and 20mM) were applied before sowing (seed treatment). The results indicated that the plants exposed to temperature stress exhibited a significant decline in growth parameters, chlorophylls, relative leaf water content, oil content, leaf nutrient status, and nitrate reductase activity. Treatment with thiourea, especially when applied at 10mM, improved the above parameters and induced non-enzymatic and enzymatic antioxidants responsible for antioxidation. SDS-PAGE of protein revealed that high-temperature treatments alone or in combination with thiourea were associated with the disappearance of some bands or the appearance of unique ones. The result of RAPD analysis using five primers showed variable qualitative and quantitative changes. These findings confirm the effectiveness of applying thiourea on alleviating heat injuries in sunflower plants.

Thiourea, a ROS Scavenger, Regulates Source-to-Sink Relationship to Enhance Crop Yield and Oil Content in Brassica juncea (L.)

In the present agricultural scenario, the major thrust is to increase crop productivity so as to ensure sustainability. In an earlier study, foliar application of thiourea (TU; a non physiological thiol based ROS scavenger) has been demonstrated to enhance the stress tolerance and yield of different crops under field condition. Towards this endeavor, present work deals with the effect of TU on photosynthetic efficiency and source-to-sink relationship of Indian mustard (Brassica juncea) for understanding its mode of action. The application of TU increased the efficiency of both PSI and PSII photosystems and vegetative growth of plant. The comparative analysis of sucrose to starch ratio and expression level of sugar transporters confirmed the higher source and sink strength in response to TU treatment. The biochemical evidence in support of this was derived from higher activities of sucrose phosphate synthase and fructose-1,6-bis-phosphatase at source; and sucrose synthase and different classes of invertases at both source and sink. This indicated an overall increase in photoassimilate level at sink. An additional contribution through pod photosynthesis was confirmed through the analysis of phosphoenol pyruvate carboxylase enzyme activity and level of organic acids. The increased photoassimilate level was also co-ordinated with acetyl coA carboxylase mediated oil biosynthesis. All these changes were ultimately reflected in the form of 10 and 20% increase in total yield and oil content, respectively under TU treatment as compared to control. Additionally, no change was observed in oil composition of seeds derived from TU treated plants. The study thus signifies the co-ordinated regulation of key steps of photosynthesis and source-to-sink relationship through the external application of TU resulting in increased crop yield and oil content.

Sulphur application improves the growth, seed yield and oil quality of canola

Sulphur (S) nutrition is very important for harvesting potential seed and oil yield of rapeseed. This study evaluated response of foliage applied thiourea on the performance of two canola cultivars Shiralee and Dunkeld. Sulphur was applied to soil (40 kg ha−1) or foliage (500 and 1,000 mg L−1) at rosette, bud initiation and flowering stages using elemental S or thiourea as source, respectively; no S application was taken as control. Among all the treatments, soil application of S improved the crop growth, yield and oil quality in both cultivars and was followed by foliar application of thiourea at 1,000 mg L−1 compared with no application. Soil applied S and foliar thiourea (1,000 mg L−1) delayed the flowering and maturity. Soil and foliar applied S significantly improved leaf area index, crop growth rate, net assimilation rate and chlorophyll contents. Plant height, number of branches, siliqua per plant, seed number per siliqua, 1,000-seed weight, biological and seed yield were also increased by soil applied S and foliage applied thiourea (1,000 mg L−1). Nonetheless, improvement in harvest index, seed oil, protein and glucosinolate contents was only observed from foliage applied thiourea (1,000 mg L−1). Response of cv. Shiralee to sulphur application was better than cv. Dunkeld. In conclusion, foliar applied thiourea (1,000 mg L−1) can have potential to improve growth, yield and oil quality in canola and can be economically viable and attractive alternative source.

Genetic Expression of Yield Ability in Wheat (Triticum aestivumL.) under Sulphydryl Enriched Biophysio-Environment

The effect of thiourea (TU), a sulphydryl compound was assessed in wheat (Triticum aestivum L.) via soil application treatments. The effect was assessed during rabi 2007–2008, 2008–2009 and 2009–2010. The four soil treatments (0, 5, 10 and 20 Kg/ha TU) were combined with four varieties, that is, Raj 1482, Raj 1555, Raj 3077 and PBW 343). These 16 treatments (four soil x four varieties) were arranged in a factorial randomized complete block design with four replicates. Results showed that all the four varieties of wheat differ significantly for yield and yield attributes indicating genetic differences among the varieties. However, the interaction component of varieties with different doses of TU was found to be non-significant. This indicated non-differential response of TU with different wheat genotypes. Thus, response of TU was similarly effective irrespective of wheat varieties. Soil application of TU at 5 and 10 kg/ha tended to increase all of the yield components: plant height, ears/m row, ear length, seeds/ear, TW, harvest index, and grain yield. While the straw yield showed a decrease trend with the application of TU. Decrease in straw yield, although marginal was statistically insignificant. Soil application of TU at 10 kg/ha significantly increased harvest index and grain yield. TU at 10 kg/ha significantly increased the harvest index by 10.11%, albeit at 20 kg/ha only marginally (4.75). Furthermore, application of TU at 10 kg/ha significantly increased the grain yield. However, TU at 5 and 20 kg/ha increased only the grain yield slightly over control, but as compared with TU at 10 kg/ha there was a significant reduction at 20 kg/ha. TU at 10 kg/ha signifi cantly increased grain yield by 8.0%, whereas TU at 10 kg had benefi cial effects on the crop, 20 kg/ha applied TU proved largely ineffective possibly because of growth inhibitory effects.

Standardized pod collection time, pod length and pre-sowing treatment of Albizia lebbeck at terai zone of West Bengal, India

Three pod lengths ( 20 cm) and 13 pre-sowing treatments were considered with four dates of collection (9 February, 19 February, 1 March and 11 March) to investigate their effect on germination rate and growth of seedlings of Albizia lebbeck (L.) Benth. at Pundibari, West Bengal, India. The best time of pod collection was on 19 February as the germination rate of the seeds collected on this date was 92.5% without requiring any pre-sowing treatments. This clearly indicated that the seeds collected on 19 February were nondormant, viable and physiologically mature. Significantly better seedling growth was also obtained when the seeds were sown on 19 February which was extracted from pods of length 10–20 cm. Application of thiourea as a pre-treatment did not significantly enhanced seed germination rate, but its application in lower concentration (100 μL-L-1) resulted in better seedling growth and development.

Mechanism of photoprotection of wool with formaldehyde and thiol derivatives

The application of thiourea and formaldehyde offers significant reductions in photoyellowing for natural, bleached and fluorescent‐brightened wools. We have examined the use of alternative thiol derivates to thiourea and shown that a mixture of N‐acetylcysteine and formaldehyde is similarly effective. Photo‐induced chemiluminescence studies on treated wool fabrics show that the intensity of chemiluminescence following a brief exposure to ultraviolet A radiation is reduced for wool treated with thiourea and formaldehyde, N‐acetylcysteine–formaldehyde and thiourea dioxide–formaldehyde, but not for formaldehyde alone. This demonstrates that a lower population of free radicals is formed in irradiated thiol‐derivative formaldehyde‐treated wools because of free radical scavenging by the sulphur‐containing species. This free radical scavenging results in reduced photoyellowing. The effect of thiourea and formaldehyde treatment on the intrinsic fluorescence of wool is significantly different to N‐acetylcysteine–formaldehyde. Thiourea and formaldehyde quenches tryptophan fluorescence relative to untreated wool, whereas N‐acetylcysteine–formaldehyde treatment results in an increase in intensity probably because of a reduction in disulphide quenching.

Interactive effects of phosphorus, nitrogen, and thiourea on clusterbean (Cyamopsis tetragonoloba L.) under rainfed conditions of the Indian arid zone

AbstractA two‐year field study was undertaken with clusterbean (Cyamopsis tetragonoloba L. Taub. cv. RGC‐936) under rainfed conditions. The experiments were set up in a split‐split‐plot design with three levels of phosphorus (0, 20, and 40 kg ha–1) and two levels of nitrogen (0 and 20 kg ha–1) with and without thiourea application (seed treatment with 500 mg kg–1 followed by two foliar sprays of 1000 mg kg–1 each at 25 and 40 d after sowing). The years varied in their pattern of precipitation and, consequently, in the available soil moisture at different growth stages. Phosphorous (P) and nitrogen (N) application either alone or in combination with thiourea resulted in significantly higher net photosynthetic rates and concentrations of chlorophyll, starch, soluble protein, and total free amino acids as well as nitrate reductase activity compared to control plants at both vegetative and flowering stages. However, the magnitude of favorable changes varied with soil moisture due to varying rainfall, and the effects of N, P, and thiourea were generally more pronounced in the vegetative stage. Seed yield, dry‐matter production, harvest index, and water‐use efficiency were significantly enhanced by the above mentioned treatments. The favorable effects of the treatments were realized through significant improvements of metabolic efficiency and maintenance of higher photosynthesis and nitrate reductase activity for more efficient N utilization. It is concluded that the improvement of P and N status of arid‐zone soils coupled with thiourea application can significantly improve the yield of clusterbean under rainfed conditions, though the potential gains may vary with soil‐moisture availability.

A butenolide, isolated from smoke, can overcome the detrimental effects of extreme temperatures during tomato seed germination

A 2-year field trial was conducted to study the effects of seed treatment (500 ppm) or foliar application of 1000 ppm thiourea (at 25 and 40 days after sowing) or a combination of these, on growth, yield, net photosynthesis and nitrogen metabolism of clusterbean (Cyamopsis tetragonoloba (L.) Taub.) grown for two consecutive years (1999 and 2000) under rainfed conditions of the Indian arid zone. Thiourea application either as pre-sowing seed treatment or as foliar spray significantly increased plant height, leaf area, dry matter production and seed yield as compared to the untreated control plants during both the years. However, maximum favourable effects were obtained with combined application of seed treatment and foliar spray. The beneficial effects of thiourea were attributed to its role in significantly increasing the net photosynthetic rates and the concentrations of total chlorophyll and starch in the leaves. Thiourea also reflected a positive role in enhancing nitrogen metabolism as it significantly increased nitrate reductase activity and concentration of soluble protein in the treated plants. It has been concluded that seed treatment with thiourea followed by foliar spray could significantly improve growth, yield and water use efficiency of rainfed clusterbean under arid conditions due to enhanced photosynthesis and more efficient nitrogen metabolism.

Reducing 1,3-Dichloropropene Emissions from Soil Columns Amended with Thiourea

Soil fumigants are becoming an important source of volatile organic compounds (VOCs) in air, especially in some agricultural areas. In this study, we used thiourea to construct a reactive surface barrier (RSB) at the soil surface for reducing 1,3-dichloropropene (1,3-D) volatilization. The agrochemical thiourea could rapidly transform volatile 1,3-D to nonvolatile products via an SN2 nucleophilic substitution reaction. A catalytic mechanism in thiourea-amended soil facilitated the conversion process. A packed soil column system was employed to investigate the emissions and distribution of 1,3-D and optimize the original fumigant emission-reduction strategy. Volatilization of 1,3-D from the soil surface was significantly reduced in columns amended with a thiourea RSB compared with that of bare soil. Volatilization flux and cumulative emissions decreased with increasing thiourea application rate and increasing fumigation depth in packed soil columns. Surface amendment with the RSB did not affect the subsurface distribution of 1,3-D in the soil profile. Combined application of a thiourea RSB and plastic tarps had a synergetic effect in emission control and could eliminate the relatively high fumigant flux that occurs upon tarp disruption. Therefore, this reduced-risk practice was very effective in reducing atmospheric emissions of VOCs from soil treatment with halogenated fumigants.