真空回潮对湖南上部烟叶香韵和杂气的影响

[目的]为掌握打叶复烤过程真空回潮工序不同加工强度对郴州、衡阳、邵阳、湘西上部初烤烟叶香韵和杂气的影响,[方法]在同一打叶复烤生产线对上述4种代表性湖南上部初烤烟模块进行了试验和感官质量分析。[结果]结果表明：郴州上部烟焦香、甜香明显增加,花香、木香有所减弱;衡阳上部烟焦香、甜香较明显增加,木香、坚果香有所减弱;邵阳上部烟焦香、甜香较明显增加,木香、树脂香明显减弱;湘西上部烟甜香明显增加,焦香、清香略有增加,树脂香、木香有所减少。[结论]4种湖南上部烟模块经过真空回潮处理,焦香或甜香均有一定幅度的提高;氮杂气和青杂气都有不同程度的降低。     

污水厂臭气生物处理技术研究现状与发展趋势

综述了污水厂臭气生物处理技术的研究现状,包括臭气成分、特征、主要来源、生物脱臭机理以及生物脱臭工艺等,着重介绍了生物滴滤塔工艺的特点和影响其净化效果的因素.文中指出,生物滴滤塔工艺具有构造简单、中等投资、运行费用低、去除效率高、压降低、工艺条件易于控制等优点,是处理污水厂臭气的首选工艺.同时,也指出生物滴滤塔处理污水厂臭气存在的问题和发展方向,包括改进和优化工艺条件、改善填料的性能、改良和构建高效复合型除臭微生物等,特别强调应加强对除臭微生物的研究,以加速我国生物滴滤塔除臭工艺的工业化应用步伐.     

华北旱地土壤硫施用量指标

Fifteen upland soils collected from the major arable areas in North China were used to assess the availability of soil sulfur (S) to plants in a pot experiment. Soils were extracted with various reagents and the extractable S was determined using turbidimetric method or inductively coupled plasma atomic emission spectrometry (ICP-AES), respectively. In addition, mineralizable organic S, organic S, N/S ratio, sulfur availability index (SAI) and available sulfur correction value (ASC) in soils were also determined. The S amount extracted by 1.5 g L^-1 CaCl₂ was nearly equivalent to that by 0.25 mol L^-1 KCl (40 ℃), and both of them were slightly smaller than that by 0.01 mol L^-1 Ca(H₂PO₄)₂ solution, as measured by turbidimetric method or ICP-AES. The extractable S measured by turbidimetric method was consistently smaller than that by ICP-AES. All methods tested except that for organic S and N/S ratio produced satisfactory results in the regression analyses of the relationships between the amounts of S extracted and plant dry matter weight and S uptake in the pot experiment. In general, 0.01 mol L^-1 Ca(H₂PO₄)₂-extracted S determined by ICP-AES or turbidimetric method and 0.25 mol L^-1 KCl (40 ℃)-extracted S determined by ICP-AES appeared to be the best indicators for evaluation of soil available S.     

STABILITY OF FOLIAR NITROGEN:SULFUR RATIO IN SPRING RED WHEAT AND SULFUR DILUTION CURVE

A key aspect of any sulfur (S) availability indicator is its stability throughout the crop cycle. Nine experiments were conducted with the objective to evaluate the stability of the nitrogen (N):S ratio in aerial biomass (W) in spring wheat, and to define the critical curve of S dilution. As the crop cycle progressed, a decrease (P < 0.05) in total N:S was determined. This lack of stability was explained by a lower S dilution in relation to N (P < 0.05). A decrease (P < 0.05) in N accumulation rate in relation to S was obtained as the crop cycle progressed, which points out that S accumulation in relation to N is later. A first approach was determined to the definition of the S dilution critical curve (Sc) from tillering beginning to stem elongation end (Sc = 0.37 W^?0.169; r² = 0.71 and n = 24).     

Effect of Levels and Sources of Sulfur on Yield,Sulfur and Nitrogen Concentration and Uptake and S-Use Efficiency in Basmati Rice

A field experiment was conducted at the Indian Agricultural Research Institute, New Delhi, India to study the effect of levels and sources of sulfur (S) on cultivar ‘Improved Basmati Rice’ (Pusa 1460). Response to S application was obtained up to 45 kg S ha^?1 and Bentonite-S out-performed other than three sources, namely, gypsum, ordinary super phosphate (OSP), and elemental S in several growth characters, yield attributes, S concentration, and uptake but not in grain yield.     

Monocot‐dicot variability in response to an iron oxide‐metallic iron source

Abstract

Iron from a mixture of Fe oxide and metallic Fe was more available to corn (Zea mays L.) than it was to soybeans when the plants wore grown in calcareous soil or in nutrient solution. All this Fe, however, was DTPA (diethylene triamine pentaacetic acid) extractable. In solution culture the Fe was available to the soybean (Glycine max L.) plants unless CaCO₃ was included in the nutrient solution.     

Macronutrient Balance of Nickel-Stressed Lettuce Plants Grown under Different Sulfur Levels

This study investigated whether intensive nutrition with sulfur–sulfate (S-SO₄) (2, 6, or 9 mM S) of nickel-stressed (0, 0.0004, 0.04, or 0.08 mM Ni) butterhead lettuce cv. Justyna may improve macronutrient balance and reduce Ni bioaccumulation. Nickel exposure resulted in various unfavorable changes in the macronutrient content together with increase of Ni accumulation in the biomass. Intensive S nutrition of Ni-treated lettuce seems to have no beneficial effect on macronutrient balance. In general, it significantly reduced the root and foliar phosphorus (P), potassium (K), calcium (Ca), and S content and simultaneously did not affect the magnesium (Mg) content in the biomass. At the same time, the nitrogen (N) content was reduced in roots and elevated in shoots. Supplementation of Ni-exposed lettuce with high S doses raised in roots and reduced foliar Ni accumulation; however, Ni content in useable parts exceeded the acceptable limits established for consumption.     

Sulfonate S: A major form of forest soil organic sulfur

Summary Several forests of varying elevations, soils and vegetation were studied to evaluate the relative importance of sulfonate S, amino acid S, and ester sulfate as constituents of soil organic S. Suflonate S exceeded 40% of total S in the O1 horizon of all but one site examined, and comprised at least 50% of total S in the O2 horizons of 14 out of 18 study sites examined. Sulfonate pool sizes, on a percentage basis, tended to decrease with increasing sample depth within the mineral horizons, but sulfonate S was still a major form of organic S in the C horizon. Amino-acid S pool sizes were, as a general rule, lower than those for sulfonate in the O1 and O2 horizons, and lower than those for both ester sulfate and sulfonate when mineral soil horizons were considered. In no case did amino-acid S represent>25% of total S. Amino-acid S decreased with increasing depth at all but one site examined. Ester sulfate pool sizes were generally less than those of sulfonate S and greater than those of amino-acid S. This trend was observed with the O1, O2, and A horizons, but it was not apparent with samples from the intermediate and lowest soil horizons, where ester sulfate levels exceeded those for sulfonate S in 4 out of 8 and 5 out of 14 sites, respectively, in these latter horizons. Although there were some exceptions, collectively, the data suggest that sulfonate S is a major form of organic S in forest soils, irrespective of depth.     

Soil sulfur fractions dynamics and distribution in a tropical grass pasture amended with nitrogen and sulfur fertilizers

Soil sulfur (S) partitioning among the various pools and changes in tropical pasture ecosystems remain poorly understood. Our study aimed to investigate the dynamics and distribution of soil S fractions in an 8‐year‐old signal grass (Brachiaria decumbens Stapf.) pasture fertilized with nitrogen (N) and S. A factorial combination of two N rates (0 and 600 kg N ha^–1 y^–1, as NH₄NO₃) and two S rates (0 and 60 kg S ha^–1 y^–1, as gypsum) were applied to signal grass pastures during 2 y. Cattle grazing was controlled during the experimental period. Organic S was the major S pool found in the tropical pasture soil, and represented 97% to 99% of total S content. Among the organic S fractions, residual S was the most abundant (42% to 67% of total S), followed by ester‐bonded S (19% to 42%), and C‐bonded S (11% to 19%). Plant‐available inorganic SO₄‐S concentrations were very low, even for the treatments receiving S fertilizers. Low inorganic SO₄‐S stocks suggest that S losses may play a major role in S dynamics of sandy tropical soils. Nitrogen and S additions affected forage yield, S plant uptake, and organic S fractions in the soil. Among the various soil fractions, residual S showed the greatest changes in response to N and S fertilization. Soil organic S increased in plots fertilized with S following the residual S fraction increment (16.6% to 34.8%). Soils cultivated without N and S fertilization showed a decrease in all soil organic S fractions.     

Molybdenum and Copper Uptake by Forage Grasses and Legumes Grown on a Metal‐Contaminated Sludge Site

Abstract

Wastes applied to agricultural land can contain significant concentrations of bioavailable molybdenum (Mo). Because Mo uptake by forage crops could lead to hypocuprosis in ruminants, more knowledge is needed about which crops are most efficient in accumulating Mo. At an old sewage sludge‐amended site, the concentrations of Mo, copper (Cu), and several other trace metals were measured in various grass species. Generally, the grasses grown on the sludge site contained higher Mo concentrations than the same species grown on a nearby control site. However, because Cu concentrations were also higher in the sludge‐grown grasses, Cu:Mo ratios in the grasses were frequently higher on the sludge site. In contrast, all legumes tested (alfalfa, birdsfoot trefoil, red clover, pea), as well as canola and beets, had lower Cu:Mo ratios when grown on the sludge site. Sulfur concentrations in the two crops analyzed for this element (canola and pea) were higher on the sludge site than the control. It is concluded that Mo, Cu, and sulfur (S) bioavailability remains elevated in the soil several decades after sewage sludge application.