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Huang L.X.,Guangdong Academy of Agricultural Sciences | Huang L.X.,Guangdong Key Laboratory of Nutrient Cycling and Farmland Conservation | Yao L.X.,Guangdong Academy of Agricultural Sciences | Yao L.X.,Guangdong Key Laboratory of Nutrient Cycling and Farmland Conservation | And 9 more authors.
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2013

Roxarsone is an organoarsenic feed additive that can be metabolised to other higher toxic arsenic (As) species in animal manure such as arsenate, arsenite, monomethylarsonic acid, dimethylarsinic acid, 3-amino-4-hydroxyphenylarsonic acid and other unknown As species. The accumulation, transport and distribution of As species in turnip (Brassica rapa L.) and lettuce (Lactuca sativa L.) amended with roxarsone and its metabolites in chicken manure were investigated. Results showed arsenite was the predominant As form, followed by arsenate in turnip and lettuce plants, and a low content of dimethylarsinic acid was detected only in lettuce roots. Compared with the control plants treated with chicken manure without roxarsone and its metabolites, the treatments containing roxarsone and its metabolites increased arsenite content by 2.0-3.2% in turnip shoots, by 6.6-6.7% in lettuce shoots, by 11-44% in turnip tubers and by 18-20% in lettuce roots at two growth stages. The enhanced proportion of arsenate content in turnip shoots, turnip tubers and lettuce roots was 4.3-14%, 20-35% and 70%, respectively, while dimethylarsinic acid content in lettuce roots increased 2.4 times. Results showed that the occurrence of dimethylarsinic acid in lettuce roots might be converted from the inorganic As species and the uptake of both inorganic and organic As compounds in turnip and lettuce plants would be enhanced by roxarsone and its metabolites in chicken manure. The pathway of roxarsone metabolites introduced into the human body via roxarsone → animal → manure → soil → crop was indicated. © 2013 Taylor & Francis. Source


Huang L.,Guangdong Academy of Agricultural Sciences | Huang L.,Key Laboratory of Plant Nutrition and Fertilizer in South Region | Huang L.,Guangdong Key Laboratory of Nutrient Cycling and Farmland Conservation | Yao L.,South China Agricultural University | And 13 more authors.
Chemosphere | Year: 2014

Roxarsone is an organoarsenic feed additive which can be finally degraded to other higher toxic metabolites after excreted by animal. In this work, the uptake of As species by vegetables treated with chicken manure bearing roxarsone and its metabolites was investigated. It was showed that more than 96% of roxarsone added in chicken feed was degraded and converted to arsenite, monomethylarsonic acid, dimethylarsinic acid, arsenate, 4-hydroxyphenylarsonic acid and other unknown As species. Arsenite and arsenate could be found in roots of vegetables but only arsenite transported up to shoots. Chicken manure bearing roxarsone and its metabolites increased 33-175% of arsenite and 28%~seven times of arsenate in vegetable roots, 68-175% of arsenite in edible vegetable shoots. Arsenite, the most toxic As form, was the major extractable As species in vegetables accounted for 79-98%. The results reflected that toxic element As could be absorbed by vegetables via the way: roxarsone in feed. →. animal. →. animal manure. →. soil. →. crop and the uptake of As species would be enhanced by using chicken manure bearing roxarsone and its metabolites as organic fertilizer. © 2014 Elsevier Ltd. Source


HUANG Q.,Guangdong Academy of Agricultural Sciences | HUANG Q.,Key Laboratory of Plant Nutrition and Fertiliser in South Region | HUANG Q.,Guangdong Key Laboratory of Nutrient Cycling and Farmland Conservation | TANG S.,Guangdong Academy of Agricultural Sciences | And 11 more authors.
Journal of Agricultural Science | Year: 2016

Most acid sulphate soils (ASSs) in the Pearl River Delta of South China have been traditionally reclaimed for rice cultivation, but the rice yield in most of these paddy fields is lower than the average rice yield in China due to extremely high soil acidity. In the present study, a range of sulphate and acidity parameters were investigated in ASS profiles in three types of paddy fields in Taishan City (Guangdong Province, China) divided based on the local rice productivity (4500, 3000 and 1500 kg/ha) using an abandoned ASS (uncultivated) as the control treatment to ascertain key yield constraining parameters. Soluble acidity (SA), exchangeable acidity (ExA), soluble sulphate (SS) and net acid-soluble sulphate (NAS) increased with increasing soil depths from 0 to 100 cm and then decreased abruptly with further increases in the depth. However, the depth distribution of exchangeable sulphate (ES) was uniform. The soil acidity and sulphate contents differed significantly in three sampled paddy fields. The values of SA and SS in the soils at depths of 0–100 cm in the studied ASS were lower compared with those in the uncultivated ASS and the ExA in soils at depths of 0–40 cm in ASS were lower compared with those observed in the uncultivated ASS. A correlation analysis revealed that SA was strongly correlated with SS and ExA with NAS. Soluble acidity, ExA, SS and NAS in the ASS were significantly associated with rice yield. Exchangeable acidity in the plough layer (0–20 cm) of soils was the most sensitive indicator of soil quality affecting rice yield among those in soils from 0 to 140 cm depth. It is interesting to note that SA, SS and NAS were more sensitive indicators of soil quality affecting rice yield at 60–100 cm than at 0–40 cm depth. Principal component analysis showed that pH value, ExA and ES in soils at depths of 0–40 cm and SA, SS and NAS in soils at depths of 60–100 cm constituted the critical soil acidity and sulphate characteristics that were strongly correlated with rice yields. This finding implies that controlling the ExA in the plough layer and the SA and NAS in the Jarosite layer should be the major focus of studies aimed at the amelioration of ASSs. Copyright © Cambridge University Press 2016 Source


Tu Y.,Guangdong Academy of Agricultural Sciences | Tu Y.,Key Laboratory of Plant Nutrition and Fertilizer in South Region | Tu Y.,Guangdong Key Laboratory of Nutrient Cycling and Farmland Conservation | Huang J.,Guangdong Academy of Agricultural Sciences | And 14 more authors.
BioResources | Year: 2016

Nutrients were extracted from corn stalks, peanut shells, de-oiled peanut meal, chicken manure, and sewage sludge by a subcritical water (SCW) hydrolysis reaction. Compared with the other feedstock, the aqueous phases extracted from de-oiled peanut meal showed the highest water-soluble organic carbon, amino acid, total nitrogen, and phosphorus contents. The effects of solution pH, final hydrothermal temperature, and reaction time on nutrient extraction from de-oiled peanut meal were investigated. The analysis showed that alkaline reagents promoted liquefaction. The highest yield of the total primary nutrients (82.6%) was obtained with extraction reaction at 180 °C for 1.5 h using 0.1 mol/L KOH. The liquid fraction from this reaction was investigated for its potential use as a fertilizer with germination experiments. A higher germination index and root activity were obtained using the liquid extract with the appropriate dilution. These results indicated that subcritical water hydrothermal treatment is a viable way to recover nutrients from biomass wastes. In addition, de-oiled peanut meal is a suitable feedstock for the production of nutrient-rich liquid extract. Source


Zhang M.,Guangdong Academy of Agricultural Sciences | Zhang M.,Key Laboratory of Plant Nutrition and Fertiliser in South Region | Zhang M.,Guangdong Key Laboratory of Nutrient Cycling and Farmland Conservation | Tang S.,Guangdong Academy of Agricultural Sciences | And 11 more authors.
Soil Science and Plant Nutrition | Year: 2015

A pot experiment was conducted to investigate differences in antioxidative defence and carbon–nitrogen metabolism between acid-tolerant (YJSM) and acid-sensitive (YHSM) rice cultivars under acid stress. Acid-tolerant and acid-sensitive rice were planted in both acidic soil (pH 4.21) and normal soil (pH 6.13). Forty-eight days after sowing, rice shoots and roots from four treatments were collected, and the other four replicates were harvested at seed maturity. The results revealed that the grain yield of acid-tolerant YJSM was significantly higher than that of acid-sensitive YHSM under acid stress. The activities of antioxidant enzymes (superoxide dismutase and catalase) and contents of non-enzymatic antioxidants (ascorbate and reduced glutathione) of acid-tolerant YJSM were both higher than those of acid-sensitive YHSM under acid stress. Moreover, the enzyme activities (nitrate reductase, glutamine synthetase, glutamate synthase and glutamate dehydrogenase) and product contents (soluble sugar and soluble protein) of carbon–nitrogen metabolism of acid-tolerant YJSM were higher than those of acid-sensitive YHSM under acid stress. The NO3–N and carbon (C) contents in leaves of acid-tolerant YJSM were both significantly higher than those of acid-sensitive YHSM under acid stress. This study suggests that the acid-tolerant rice cultivar has better antioxidative defence and carbon–nitrogen metabolism systems than the acid-sensitive rice cultivar and is more effective in resisting acid stress. © 2015 Japanese Society of Soil Science and Plant Nutrition Source

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