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Differences in responses of ammonia volatilization and greenhouse gas emissions to straw return and paddy-upland rotations
2022
Liu, Yu | Wang, Kunkun | Liao, Shipeng | Ren, Tao | Li, Xiaokun | Cong, Rihuan | Lü, Jianwei
Paddy-upland rotation and/or straw return could improve soil structure and soil nutrient availability. Different previous crops (wheat and/or oilseed rape) and straw return methods (straw mulching and/or returning) might increase soil organic carbon (C) and total nitrogen (N) content, and further affected the ammonia (NH₃) volatilization, nitrous oxide (N₂O), and methane (CH₄) emissions. A comparison study was carried out in a located field experiment started from 2014 in Central China, aiming to exam seasonal and annual NH₃, N₂O, and CH₄ emissions under the wheat-rice (WR) and oilseed rape-rice (OR) rotations. Three treatments were chosen, i.e., (i) no chemical N fertilizer application (PK), (ii) chemical nitrogen-phosphorus-potassium combination (NPK), and (iii) chemical NPK with straw returning (NPK+St). We found that after 3 years of cultivation, treatment with straw return increased soil total N content and organic C by 15.57% and 17.11% on average as compared with the NPK treatment, respectively. Straw return did not generate additional NH₃ and N₂O losses during the rice season after improving soil fertility. However, CH₄ emissions increased by 45.35% on average after straw return in summer. In winter, straw return increased NH₃, N₂O, and CH₄ emissions by 70.12–85.23%, 16.93–22.97%, and 7.18–9.17%, respectively. The stimulation of NH₃ volatilization mainly occurred in the topdressing stage. Compared with WR rotation, OR rotation had no significant effect on NH₃ and CH₄ emissions, and the change of N₂O emission might be related to the increase of soil C and N pools. The retention of residues in the process of straw decomposition may be the main factor leading to the difference of gas emission between the paddy-upland rotation and straw return.
Afficher plus [+] Moins [-]Effect of Biofumigants on Soil Microbial Communities and Ecotoxicology of Earthworms (Eisenia andrei)
2016
Fouché, Tanya | Maboeta, Mark | Claassens, Sarina
Biofumigation is considered a good alternative to chemical fumigation because it can control crop pathogens and diseases with lower health and environmental risks than chemical fumigants. Glucosinolates are volatile compounds found in most Brassica species, and when hydrolysed, it forms a range of natural toxins including isothiocyanates that act as biofumigants. However, the effect of glucosinolates and their breakdown products on non-target and beneficial soil organisms is not well documented. Three biofumigants, broccoli, mustard and oilseed radish, were evaluated for their effect on earthworms (Eisenia andrei) and the soil microbial community. Sub-lethal endpoints, including growth and reproductive success of the earthworms, were monitored. Genotoxicity of the biofumigants towards earthworms was evaluated by means of the comet assay. Broccoli reduced earthworm reproduction while mustard induced more DNA strand breaks in earthworm cells compared to the control. Soil microbial community function and structure were evaluated by means of community level physiological profiling and phospholipid fatty acid analyses. The effects exerted by the biofumigants on the microbial community were the most pronounced within the first 14 days after application. Carbon substrate utilisation was most affected by the oilseed radish treatment and microbial community structure by the mustard treatment.
Afficher plus [+] Moins [-]Feasibility of growing Salicornia species in a coastal environment through planting date and density management in a direct seawater irrigation system
2022
Ranjbar, Gholamhassan | Pirasteh-Anosheh, Hadi | Dehghanie, Farhad | Keshtkar, Sardar | Race, Marco
Two field experiments were conducted to evaluate six Salicornia species (Salicornia bigelovii Torr., S. europaea L., S. persica Gorgan ecotype, S. persica Urmia ecotype, S. sinus persica Bushehr ecotype, and S. persica Central Plateau ecotype) at different planting dates and densities under irrigation with Persian Gulf water. Evaluated planting dates were 14 November and 18 December 2016 and 16 January, 8 February, 8 March, and 28 March 2017. Examined planting densities included 13, 20, and 40 plant m⁻². Only S. bigelovii and S. europaea produced measurable yield in all planting dates. The highest dry weight (651.1 gm⁻²) was obtained in S. sinus persica (Bu) planted on 8 February. Dry weight of S. bigelovii, S. europaea, S. sinus persica Bushehr, S. persica Central Plateau, S. persica Gorgan, and S. persica Urmia planted on 8 March were 174.2, 220.7, 542.5, 240.9, 158.0, and 147.5 g m⁻², respectively. The ash contents of S. bigelovii, S. europaea, S. sinus persica Bushehr, S. persica Central Plateau, S. persica Gorgan, and S. persica Urmia were 46.3%, 45.0%, 49.6%, 49.6%, 50.0%, and 53.1%, respectively. Sodium and chloride contents of different Salicornia species varied from 13–15% and 16–17%, respectively. The oilseed content of S. bigelovii and S. sinus persica Bushehr was about 24.0% for both species. The highest and lowest dry weight, from the second experiment, were for S. sinus persica Bushehr and S. persica Central Plateau, respectively, in all planting density. The highest dry weight equal to 1336.2 gm⁻² was obtained for S. sinus persica Bushehr in 40 plant m⁻² density. Under such conditions, forage production potential of Salicornia is more achievable rather than seed production. Nevertheless, high ash content is a serious constraint to direct consumption by livestock; therefore, determining the nutritional value of Salicornia fodder requires further evaluations.
Afficher plus [+] Moins [-]Organic waste streams as feedstock for the production of high volume-low value products
2021
Pawar, Pratik R. | Rao, Poornima | Prakash, Gunjan | Lali, Arvind M.
Valorisation of organic wastes to produce industrially relevant commodity products is a sustainable, cost-effective and viable alternative providing a green platform for chemical production while simultaneously leading to waste disposal management. In the present study, organic wastes such as agricultural residue-derived sugars, oilseed meals, poultry waste and molasses were used for substituting expensive organic fermentation medium components. Moorella thermoacetica and Aurantiochytrium limacinum were adapted on these waste-derived hydrolysates to produce high volume-low value products such as bio-acetic acid (80% theoretical yields) and oil-rich fish/animal feed (more than 85% dry cell weight as compared with conventional nutrient sources) respectively. Use of these waste-derived nutrients led to ~ 75% and ~ 90% reduction in media cost for acetic acid and oil-rich biomass production respectively as compared with that of traditionally used high-priced medium components. The strategy will assist in the cost reduction for high volume-low value products while also ensuring waste recovery.
Afficher plus [+] Moins [-]Validation, residue analysis, and risk assessment of fipronil and flonicamid in cotton (Gossypium sp.) samples and soil
2018
Chawla, Suchi | Gor, Hetal N. | Patel, Hemlatta K. | Parmar, Kaushik D. | Patel, Anil R. | Shukla, Varsha | Ilyas, Mohammad | Parsai, Satish K. | Somashekar, | Meena, Roop Singh | Shah, Paresh G.
Cotton crop is highly susceptible to attack by sucking pests. Being an important oilseed and feed crop, it is essential to monitor the pesticides and ensure health protection at consumer level. Therefore, a method was validated to estimate fipronil and flonicamid in various cotton samples and risk assessment was performed. Contamination of oil in the extracts from the various oil seeds and cake samples is a major problem as this oil contaminates the column and interferes with the detection of pesticides. The present manuscript for the first time describes successful analysis of the pesticides from various cotton samples including cotton oil, seed, and cake. Quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based methods were validated for estimation of fipronil and flonicamid in cotton samples and in soil by LC-MS/MS. Recoveries were within the acceptable range of 70–120% with relative standard deviation ≤ 20% and HorRat values < 0.3–1.3. R² was > 0.99. Matrix effects of 150 and 13.5% were observed for fipronil and flonicamid, respectively, in cotton leaves. Limits of quantitation (LOQs) were in the range of 0.0004 to 0.004 mg kg⁻¹ for fipronil and flonicamid. Cotton samples collected from a field study at different locations were analyzed. Half-life ranged from 2.2 to 5.8 for fipronil and 4.6 to 7.0 days for flonicamid. A pre-harvest interval of 33 days is suggested. The risk assessment studies at maximum residue level values showed HQ < 1 at pre-harvest interval (PHI). The methods being short and easy can be extended to estimate more types of pesticides in different oilseeds. Following a PHI of 33 days, fipronil and flonicamid can be used on cotton at standard dose. As the levels of fipronil and flonicamid were below determination limit in all the soils, the environmental risk is negligible.
Afficher plus [+] Moins [-]Detection of feral GT73 transgenic oilseed rape (Brassica napus) along railway lines on entry routes to oilseed factories in Switzerland
2014
Hecht, Mirco | Oehen, Bernadette | Schulze, Jürg | Brodmann-Kron, Peter | Bagutti, Claudia
To obtain a reference status prior to cultivation of genetically modified oilseed rape (OSR, Brassica napus L.) in Switzerland, the occurrence of feral OSR was monitored along transportation routes and at processing sites. The focus was set on the detection of (transgenic) OSR along railway lines from the Swiss borders with Italy and France to the respective oilseed processing factories in Southern and Northern Switzerland (Ticino and region of Basel). A monitoring concept was developed to identify sites of largest risk of escape of genetically modified plants into the environment in Switzerland. Transport spillage of OSR seeds from railway goods cars particularly at risk hot spots such as switch yards and (un)loading points but also incidental and continuous spillage were considered. All OSR plants, including their hybridization partners which were collected at the respective monitoring sites were analyzed for the presence of transgenes by real-time PCR. On sampling lengths each of 4.2 and 5.7 km, respectively, 461 and 1,574 plants were sampled in Ticino and the region of Basel. OSR plants were found most frequently along the routes to the oilseed facilities, and in larger amounts on risk hot spots compared to sites of random sampling. At three locations in both monitored regions, transgenic B. napus line GT73 carrying the glyphosate resistance transgenes gox and CP4 epsps were detected (Ticino, 22 plants; in the region of Basel, 159).
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