Enzymatic characterization of organic phosphorus in animal manure

Information on the forms of P present in animal manure may improve our ability to manage manure P. In most investigations of manure P composition, only inorganic and total P are determined, and the difference between them is assigned as organic P. In this study, we explored the possibility of identifying and quantifying more specific organic P forms in animal manure with orthophosphate-releasing enzymes. Pig (Sus scrofa) manure and cattle (Bos taurus) manure were first sequentially fractionated into water-soluble P, NaHCO3-soluble P, NaOH-soluble P, HCl-soluble P, and residual P. The fractions were separately incubated with wheat phytase, alkaline phosphatase, nuclease P1, nucleotide pyrophosphatase, or their combinations. The released orthophosphate was determined by a molybdate blue method. Part of the organic P in those fractions could be identified by the enzymatic treatments as phytate (i.e., 39% for pig manure and 17% for cattle manure in water-soluble organic P), simple phosphomonoesters (i.e., 43% for pig manure and 15% for cattle manure in NaOH-soluble organic P), nucleotide-like phosphodiesters (2-12%), and nucleotide pyrophosphate (0-4%). Our data indicate that the enzymatic treatment is an effective approach to identify and quantify the organic P forms present in animal manures.     

137Cs and 90Sr behavioural regularities in the southeastern part of the Baltic Sea

Variations in 137Cs concentrations were investigated over the period 1986-1997 in the southeastern part of the Baltic Sea, following the Chernobyl power plant accident. The rate of "self-cleaning" was demonstrated to be very slow, the average concentration of 137Cs in 1996 being almost the same as that measured directly after the accident, in 1986. Measurements of both 137Cs and 90Sr concentrations generally revealed homogeneous distributions in this region of the Baltic Sea, though patchy distributions did develop under some hydrometeorological conditions. Specifically, the 137Cs concentration distribution became heterogeneous with values varying in the range 60-92 Bq/m3 under south-southwesterly wind conditions whilst the 90Sr concentration distribution developed similar characteristics with values ranging from 15 to 64 Bq/m3 under east-southeasterly wind conditions. In addition, in coastal waters, over extensive periods of north-northwesterly winds in 1995, 137Cs concentrations increased to values 1.5-2 times the overall average concentration, which was registered in 1986 and 1996. These data therefore reveal a continuing significant pollution of the waters of the Baltic Sea resulting from the Chernobyl power plant accident, a pollution compounded by the slow rate of radionuclide self-cleaning and significant probability of sudden regional concentration increase.     

Determination of T-2 toxin in grain and grain products by HPLC and TLC

The purpose of this study was to investigate the T-2 toxin contaminated grain and grain products consumed especially by Turkish population. The T-2 toxin was detected using the high performance liquid chromatography (HPLC) with UV detector at 208 nm and the identify of T-2 was further confirmed by thin layer chromatography (TLC). The recovery was 91 +/- 4.24% for corn flour fortified with the known amount of T-2 toxin (1 ppm). The detection limits of T-2 toxin for the HPLC and the TLC were 25 ng and 50 ng, respectively. A total of 30 commercially available grain and grain product samples were analyzed. Two corn flour samples were found to contain detectable levels of T-2 toxin at a level of 1.60 ppm and 4.08 ppm.     

Effects of bio-organic fertilizers on pineapple heart rot and bacterial community structure北大核心CSCD

Heart rot is a common soil-borne disease in the pineapple industry, but the situation can be alleviated by the application of bio-fertilizers with beneficial microbiomes. Clarifying the controlling mechanism of bio-organic fertilizer on the high incidence of heart rot is critical in monocultural pineapple cropping patterns. In our study, the soil of continuous cropping pineapple orchards was collected. Three types of carriers (rapeseed cake, peat soil, and coconut bran), biocontrol strains (Bacillus subtilis HL2 and Streptomyces strain HL3), and organic fertilizer (YJ) were composted into different bio-fertilizers (KC, KN, KY, LC, LN, and LY), which were used in pot experiments. The controlling effect of the bio-fertilizer was determined based on the response of pineapple heart rot and bacterial communities to different fertilizing methods. Our results revealed that the incidence of heart rot in bio-fertilizer KC was the lowest, which decreased by 20% and 13.3%, respectively, compared to HF (chemical fertilizer, 16-16-16) and YJ (organic fertilizer). The richness and diversity of soil bacterial communities in all biofertilized treatments (KC, KN, KY, LC, LN, and LY) were significantly higher than those in HF. However, the α-diversity indices of the bio-fertilizers (KC, KN, and KY) were higher than those of LC, LN, and LY, and the bacterial community composition was significantly different. The bacteria GP4, GP6, Bacillus, and Azohydromonas were enriched in KC, KN, and KY, while the relative abundance of Streptomyces increased significantly in LC, LN, and LY. Furthermore, Spearman correlation analysis showed that the relative abundance of these bacterial groups was significantly negatively correlated with the incidence of pineapple heart rot. In summary, the application of bio-organic fertilizers can decrease the incidence of pineapple heart rot by altering the soil bacterial community structure and stimulating beneficial soil microorganisms, which is important for reconstructing the ecological balance in continuous pineapple orchards. © 2022 Authors. All rights reserved.     

Copper contamination in paddy soils irrigated with wastewater

Copper (Cu) contamination was investigated in paddy soils where Cu-rich wastewater (12 mg Cu/l) was used for irrigation. The results showed that Cu contamination increased the soil Cu content from 17.0 mg Cu/kg in the non-wastewater irrigated soils (NWIS) to 101.2 mg Cu/kg in the wastewater irrigated soils (WIS), and Cu accumulated mostly in the surface layer (0-10 cm) of the paddy soil. The average Cu contents in brown rice, rice hull and rice straw from NWIS were 1.4, 7.3 and 14.5 mg Cu/kg, while those from WIS were 15.5, 133.2, and 101.4 mg Cu/kg, respectively. Correlation analysis revealed that the relationship between the Cu content in the rice straw and the rice hull with the total Cu content of the soil could be described by an exponential function (R2 = 0.921 and 0.831, respectively; P <0.01). Rice plants grown in the WIS showed symptoms of black roots, less effective tiller, etc. Subsequently, the rice yield decreased by 18-25%, compared with that grown in NWIS.     

Predicting future invasion risk of three widespread malignant weeds on Qinghai-Tibet Plateau,using multi-algorithm ensemble models北大核心CSCD

农田恶性杂草相比普通杂草的传播更为迅速且难以有效防治,对农业生产危害严重.明确典型恶性杂草当前潜在分布面积及未来气候变化下对耕地的潜在入侵风险对农业生产管理具有重要意义.以广泛分布于青藏高原农田中的3种常见恶性杂草,即野燕麦(Avena fatua L.)、一年生早熟禾(Poa annua L.)和狗尾草[Setaria viridis(L.)P.Beauv.]为研究对象,利用广义增强模型(GBM)、广义线性模型(GLM)、人工神经网络(ANN)、最大熵(MaxEnt)、随机森林(RF)及多元自适应回归样条(MARS)算法集合预测上述3种杂草在青藏高原的潜在地理分布以及驱动其变化的关键因子,以评估其对耕地的入侵风险.未来气候场景采用最新的第六次国际耦合模式比较计划(CMIP6)框架下2050年的4种共享经济路线(SSP1-2.6、2-4.5、3-7.0、5-8.5).结果显示:野燕麦适宜分布区面积约为3.5912×10^(5) km^(2),主要分布于四川西南部及青海东部,零星分布于甘肃、西藏和新疆;一年生早熟禾和狗尾草的适宜分布区面积约为4.3046×10^(5) km^(2)和2.0036×10^(5) km^(2),均主要分布于四川西南部和西藏东南部,零星分布于青海东部和甘肃南部.年均温是3种杂草分布的最主要驱动因子.此外,人类足迹和土壤有效氮是影响野燕麦分布的相对重要因子;土壤酸碱度、最暖季降水量是影响一年生早熟禾分布的重要因子;温度季节性、最暖季降水量是影响狗尾草分布的重要因子.预计至2050年,3种杂草在4种情境下均会出现不同程度的扩张,狗尾草的扩张面积表现出随辐射强迫的增强呈先升高后趋于稳定的趋势,而另两种杂草则呈先升后降的趋势.预计3种杂草的潜在分布面积在耕地中的占比与扩张面积的变化趋势一致,且在主产区的占比高于非主产区.模拟结果表明,未来气候变化下,随着3种恶性杂草的适宜分布区面积的扩张,其对青藏高原耕地的入侵风险将增加,尤其是粮食主产区所面临威胁更为严峻,建议应重点关注青藏高原粮食主产区恶性杂草的生理生态、迁移扩散和防治技术研究.(图6表2参61)     

Diatom Thalassiosira weissflogii in oligotrophic versus eutrophic culture: models and ultrastructure

Populations of marine diatom Thalassiosira weissflogii were grown in continuous cultures enriched with f/2 medium. One of the two contrasting cultures (‘eutrophic’) received 5.6 times more nutrients than the other (‘oligotrophic’). Two mathematical models are analyzed to estimate eutrophication differences. The second model based on the Michaelis–Menten uptake and Droop growth shows that cells in the eutrophic culture should have about 56% higher content of silica which is the limiting nutrient. Diatom samples were prepared for the transmission electron microscopy after cells have been kept in chemostats for 37 days. The structure of diatom cells was investigated and a comparison is made between cells grown in oligotrophic and eutrophic conditions. In eutrophic culture, dividing cells were encountered more frequently while cell concentration was approximately equal in both chemostats. The central vacuole of cells in eutrophic culture accumulated dispersed and compact material from amorphous to spherical shape. In some cells the large central vacuole had fibrilar and peppered dense materials in addition to translucent granules, vesicules and multivesicular bodies. In the cytoplasm we found increased number of multivesicular bodies, dense and lucent granules some of which enclose membrane particles and lucent vesicules. Dense material depositions observed in the vacuole are also seen in the cytoplasm associated with organelles, mitochondria and plasmalemma. Cells have well-developed, active and slightly increased number of dictyosomes (5–6). Some dictyosomes with dense secretory material in the cistern are apparently engaged in a granule formation process. Functional significance of dense material in the central vacuole, which has not been observed in cells grown in oligotrophic condition, is discussed.     

Multi-component adsorption of copper,nickel and zinc from aqueous solutions onto activated carbon prepared from date stones

The removal of Cu²⁺, Ni²⁺, and Zn²⁺ ions from their multi-component aqueous mixture by sorption on activated carbon prepared from date stones was investigated. In the batch tests, experimental parameters were studied, including solution pH, contact time, initial metal ions concentration, and temperature. Adsorption efficiency of the heavy metals was pH-dependent and the maximum adsorption was found to occur at around 5.5 for Cu, Zn, and Ni. The maximum sorption capacities calculated by applying the Langmuir isotherm were 18.68 mg/g for Cu, 16.12 mg/g for Ni, and 12.19 mg/g for Zn. The competitive adsorption studies showed that the adsorption affinity order of the three heavy metals was Cu²⁺?>?Ni²⁺?>?Zn²⁺. The test results using real wastewater indicated that the prepared activated carbon could be used as a cheap adsorbent for the removal of heavy metals in aqueous solutions.