Selection of Superior Tillage and Fertilizer Practices Based on Rainfall and Soil Moisture Effects on Pearl Millet Yield under Semiarid Inceptisols

Based on seven field experiments of pearl millet with nine treatment combinations of tillage and fertilizer nutrients conducted during 2000–2006 in a semiarid inceptisol at Agra, an assessment is made in this paper about sustainability of treatments using rainfall received during the crop growing period and available soil moisture at sowing, 20, 40, and 60?days after sowing (DAS) and harvest. Three practices, each of tillage: conventional tillage+mechanical weed control, low tillage+mechanical weed control, and low tillage+mechanical weed control+herbicide; and fertilizer application of 60?kg?N [farm?yard?manure?(FYM)]+40?kg?P/ha, 30?kg?N (FYM)+30?kg?N (urea)+40?kg?P/ha and 60?kg?N (urea)+40?kg?P/ha were tested in the same site over seven years. The F-test indicated significant soil moisture differences on different DAS and also between different tillage treatments. Significant yield differences were found among treatments of tillage and fertilizer and their interaction in all seasons, except 2001 and 2002. Treatment-wise correlation of yield with monthly rainfall received in June–September and available soil moisture on different DAS indicated that September rainfall had a negative and significant correlation with yield attained by tillage and fertilizer treatments. The soil moisture at 20 DAS had a negative and significant correlation with yield under all treatments except conventional tillage+mechanical weed control. The soil moisture at 60 DAS and harvest had a positive and significant correlation with yield attained under different tillage and fertilizer treatments. Regression models of yield were calibrated for tillage and fertilizer treatments through monthly rainfall during July–September and soil moisture on different DAS. The predictability of yield improved significantly by inclusion of both rainfall and soil moisture variables in the models compared to either of the two groups of variables. Ranks were assigned to tillage and fertilizer treatments for yield attained in individual years and mean yield, prediction error, and sustainable yield index over years. The study indicated that conventional tillage+mechanical weed control among tillage together with 30?kg?N (FYM)+30?kg?N (urea)+40?kg?P/ha was superior with a minimum rank sum compared to other treatments. The treatment gave a maximum sustainable yield of 1,683?kg/ha with a net return of Rs 5,670?ha, benefit–cost ratio of 1.16, and sustainable yield index of 47.2% under semiarid inceptisols of Agra.     

Subirrigation Systems to Minimize Nitrate Leaching

Nitrate leaching from corn production systems and the subsequent contamination of ground and surface waters is a major environmental problem. In field plots 75 m long by 15 m wide, the writers tested the hypothesis that subirrigation and intercropping will reduce leaching losses from cultivated corn and minimize water pollution. Nitrate leaching under subirrigation at a depth of either 0.7 m or 0.8 m below the soil surface was compared with leaching under free drainage. The cropping systems investigated were corn (Zea mays L.) monoculture and corn intercropped with annual Italian ryegrass (Lolium multiflorum Lam. cv. Barmultra). The effects of three fertilizer application rates (0, 180, and 270 kg N ha?1) on leaching were investigated in the freely drained plots. The greatest annual loss of NO3?-N in tile drainage water (21.9 kg N ha?1) occurred in freely draining, monocropped plots fertilized with 270 kg N ha?1. Monocropped plots fertilized with 270 kg N ha?1, with subirrigation at 0.7 m depth, resulted in annual nitrate losses into tile drainage of 6.6 kg N ha?1, 70% less than under free drainage. Annual soil denitrification rates (60 kg N ha?1) with subirrigation at 0.7 m were about three-fold greater than under free drainage. Intercropping under free drainage resulted in a 50% reduction in tile drainage loss of NO3?-N compared with monocropping. Off-season (November 1, 1993, to May 31, 1994) tile drainage losses of NO3?-N (7.8 kg N ha?1) from freely draining monocropped plots accounted for 30% of the annual tile drainage losses.     

A windowless 13N production target for use with low energy deuteron accelerators

The recent development of low energy accelerators for positron emission tomography has necessitated the development of new targets for 13N production. 12C(d,n)13N reaction yields in graphite at low deuteron beam energies (0.8-3.2 MeV) are presented and a new technique for the in situ extraction of 13N activity from solid graphite and subsequent conversion to [13N] ammonia is described. The target is windowless and is reusable for multiple isotope production runs. This technique utilizes radio frequency induction heating to rapidly heat the graphite to combustion temperatures in an O2 gas stream. The conversion of activity induced in the target to [13N] ammonia in under 10 min with an overall decay-corrected efficiency of 45% is reported.     

Prediction of excretion of manure and nitrogen by Holstein dairy cattle

A compilation of N balance data (n = 1801) was partitioned into four groups to define the mean excretion of manure and N and to develop empirical equations to estimate these excretions from Holstein herds. Mean excretion of manure for cows that averaged 29 kg/d of milk production was 3 kg/d per 1000 kg of body weight (BW) more than the value for dairy cows reported by the American Society of Agricultural Engineers; N excretion was 0.09 kg/d per 1000 kg of BW higher than the value reported by the American Society of Agricultural Engineers. Mean excretion of manure and N for cows that averaged 14 kg/d of milk production and that for nonlactating cows were substantially lower than the values reported by the American Society of Agricultural Engineers. Growing and replacement cattle excreted 10 kg/d per 1000 kg of BW more manure and 0.11 kg/d per 1000 kg of BW more N than was reported by the American Society for Agricultural Engineers for beef cattle. Estimation of manure and N excretion was more accurate than mean values when using regression equations that included variables for milk production, concentration of crude protein and neutral detergent fiber in the diet, BW, days in milk, and days of pregnancy. Equations that contained intake variables did not significantly affect predictions of manure and N excretion, and the use of such equations is discouraged unless dry matter intake is measured and not estimated. Accurate estimates of excreta output could improve the planning of storage and handling systems for manure and the calculation of nutrient balances on dairy farms.     

球团烟气SNCR与嵌入式SCR耦合脱硝新技术

在中国大力推动绿色低碳发展的形势下,钢铁行业全面实施烧结、球团工业大气污染物超低排放,球团NOx减排迫在眉睫,减排效果将关乎球团行业的生存与发展.针对国内主流的链箅机-回转窑球团生产工艺NOx排放质量浓度高的问题,在系统分析球团烟气特性与NOx分布的基础上,开展了选择性非催化还原法脱硝技术(SNCR)与嵌入式选择性催化...     

Respiration rates for determining the effects of urea on the soil-surface organic horizon of a black spruce stand

The respiration rates of microflora of layers of soil-surface organic horizon of a black spruce (Picea mariana (Mill.) B.S.P.) stand have been studied manometrically under controlled conditions of moisture, temperature, and aeration in the presence of urea and other nitrogen and mineral amendments. L.F., and F2 samples from field plots fertilized with 448 kg N/ha as urea in 1961 had still in 1971 greater respiration rates than similar samples from unfertilized field plots. In lab tests, addition of urea (112, 280, and 448 kg N/ha or 875, 2187, and 3500 ppm N) stimulated the endogenous respiration of each layer. The stimulation was greater when 2187 ppm N was applied and when moisture and temperature of the layers were maintained at 60% water-holding capacity and 20 degrees C during the 42-day incubation period. Addition of Mg, Ca, and K to urea-fertilized layers increased respiration while P and S decreased it. Addition of NH4NO3 and (NH4)2SO4 impaired the endogenous respiration. The endogenous respiration and moisture, temperature, and fertilizer effects decreased in the order L,F1, and F2 layers.     

Nutrient Removal in a Cold-Region Wastewater Stabilization Pond: Importance of Ammonia Volatilization

Nitrogen (N), phosphorus (P), and carbon (C) flux through a three pond wastewater stabilization system (WWSP) was measured over the course of a year in a cold weather region (Minnesota) with 4?months of ice cover. The system was surprisingly efficient at N removal (averaging 80%) primarily through volatilization of un-ionized ammonia during the late spring when the pH was above 8 and ammonia levels were still high. P removal was less efficient, with over 50% of influent P leaving the system in the effluent. Soluble carbonaceous biochemical oxygen demand (CBOD) removal was >90%, with most of the removal occurring in the primary pond. Algal carbon requirements were met by a combination of CO2 released by bacterial oxidation of influent organic matter and inorganic carbon in the influent. Photosynthesis provided much of the oxygen needed for CBOD removal in the primary pond, and the onset of aerobic conditions was nearly coincident with the highest rates of ammonia volatilization. Bacterial respiration in the sediment returned >80% of the sedimented C back to the water column long term. These results demonstrate the importance of ammonia volatilization as a N sink in WWSPs that experience ice cover setting up conditions for both high primary production and high ammonia levels in spring.     

Forage characteristics, steer performance, and water quality from bermudagrass pastures fertilized with two levels of nitrogen from swine lagoon effluent

Four .8-ha pastures of bermudagrass (Cynodon dactylon [L.] Pers.) were fertilized with either 456 or 873 kg/ha of nitrogen (N) from swine lagoon effluent (two replicates per treatment) and grazed by steers over two summers. Within each pasture, steers received forage only, an energy source (corn), a mixture of corn and soybean meal, or a mixture of corn and blood meal via electronic Calan feeders. All supplements were offered at a level of 1.36 kg/d, and the soybean meal and blood meal supplements provided similar among quantities of protein. Weight gains were similar among supplemented steers, but supplemented steers gained faster (P < .05) than controls. Nitrogen fertilization level had no effect on steer gains, steer grazing days per hectare, or in vitro dry matter disappearance, NDF, and ADF of clipped forage samples. Plant protein and nitrate ion concentrations were greater (P < .06) in clipped forage samples receiving the higher N application rate. Nitrate ion concentrations were greater in available forage samples from the pastures with the high N application rate. Mean total N and nitrate N concentrations were similar in water samples obtained from monitoring wells for the two N treatments over the 2 yr and there were no year x N interactions. Chloride concentrations were greater (P < .05) and pH and specific conductance were less in water samples collected from the 873 kg than from the 456 kg/ha N treatment. Long-term studies are needed to examine the possible cumulative effects of applying various levels of swine waste to the same land area.     

烧结烟气中NOx减排进展

 铁矿石烧结是钢铁工业生产的重要一环,同时也是大气中NO_x污染物的主要排放源。随着人们对大气环境的要求越来越高,烟气排放标准日益严格,如何高效、低成本脱除烧结烟气中的NO_x已经成为了钢铁企业面临的一个巨大挑战。首先介绍了烧结工序烟气NO_x的排放规律及现状,然后从烟气中NO_x生成机理出发,深入解析了煤燃料在热解和燃烧中氮的氧化还原机制,详细阐述了温度、氧及某些金属对煤中氮转化的不同影响,再结合NO_x的理化属性进一步指出了氧化/还原脱硝路径,并介绍了现阶段根据这2条路径开发的各种源头、末端和过程烟气治理手段;同时,结合不同的脱硝路径,深入分析了SCR催化还原机制、催化氧化机制和铁酸钙催化还原脱硝机制,全面总结对比了近期常见的各种NO_x减排举措的研究进展,其中铁酸钙催化过程脱硝以其低成本、显著的脱硝效果和不增加任何气、固污染物的特点而展示出巨大的潜力。最后,结合国家超低排放新的要求和钢铁企业烧结生产的现状,指出了当前钢铁工业烧结烟气高效、经济脱硝所面临的研究挑战,并展望了铁酸钙催化过程脱硝的应用前景和发展方向。     

Application of the Nitritation and Anammox Process into Inorganic Nitrogenous Wastewater from Semiconductor Factory

The first full-scale nitritation and anaerobic ammonium oxidation (Anammox) processes for an inorganic wastewater of semiconductor factory were installed and performances were evaluated. Existing facilities of conventional nitrification and denitrification were retrofitted to a combination of the nitritation and Anammox process. Novel nitritation method, selective acceleration of ammonia oxidation by high concentration of inorganic carbon, was evaluated in full-scale aeration tank with carrier material. The ammonia conversion rate of the nitritation reactor was in the range of 0.27–0.48?kg?NO2-N/m3?day after start-up period, and stable nitritation was achieved for over 10 months. In an Anammox reactor, on-site cultivation of anammox bacteria was performed, and the most plausible reason for slower nitrogen conversion at the beginning was oxygen contamination into the reactor. After minimizing influence of oxygen contamination, design loading was achieved within 3 months of operation. After start-up period, stable Anammox reactions are maintained for over 10 months. The nitrogen removal rate after start-up period was in the range of 1.04–3.29?kg?N/m3?day. In combination with conventional denitrification process, soluble nitrogen in the final effluent was reduced below 8 mg/L.     

Economics of Nitrate Losses from Drained Agricultural Land

Some of the highest losses of nitrate to surface waters come from drained agricultural land. This research studied, for Belgian farming conditions, (i) the effect of subsurface drainage density on nitrate losses and (ii) the economics of nitrate losses, using the nitrogen version of the program DRAINMOD-N. DRAINMOD was used to simulate the performance of the drainage system of the Hooibeekhoeve experiment, situated in the sandy region of the Kempen (Belgium) for a 14-year (1985–1998) period. A continuous cropping with maize was assumed. Daily NO3-N losses were predicted for a range of drain spacings and depths, two drainage strategies (conventional and controlled), and three fertilizer application rates (225, 275, and 325 kg?N?ha?1). Losses of N in subsurface drainage were assumed to occur almost entirely in the NO3-N form. Losses of organic and inorganic N in the form of NO3-N in surface runoff are small and were neglected. Hydrologic results indicated that increasing drain spacing or decreasing drain depth reduces drainage discharge while it increases runoff. The use of controlled drainage reduces subsurface drainage and increases runoff. Results also revealed that increasing the drain spacing or decreasing the drain depth reduces nitrate-nitrogen (NO3-N) drainage losses and net mineralization, while increasing denitrification and runoff losses. Controlled drainage caused a predicted reduction in drainage losses and an increase in denitrification and runoff losses. The optimal combination of drain density and management is one that maximizes profits and minimizes environmental impacts. Simulated results indicated that NO3-N losses to the environment could be substantially reduced by reducing the drainage density below the level required for maximum profits based on grain sales. The study concluded that, if the environmental objective is of importance equal to or greater than profits, drainage systems can be designed and managed to reduce NO3-N losses while still providing an acceptable profit.     

烧结烟气脱硝废弃钒钨钛催化剂资源化利用途径分析

2019年生态环境部等五部联合印发《关于推进实施钢铁行业超低排放的意见》提出,到2025年底前,全国力争80%以上的钢铁产能完成超低排放改造。目前,烧结烟气中NO_x减排成为重中之重。以钒钨钛系催化剂为核心的氨气选择性催化还原法(NH₃-SCR)成为烟气脱硝主流技术之一,并已广泛在钢铁企业投入使用。而随着催化剂使用寿命到期,废弃催化剂产生量逐年增加。据估计,2027年前后中国烧结烟气脱硝废弃催化剂产生量将达到100 000 m³/a。钒钨钛系催化剂含有V₂O₅,具有较强的生物毒性,新版《国家危险废物名录》中,已明确将这类废弃催化剂归为“HW50”危废。随着环保要求日益严厉,加强对钒钨钛系催化剂的有效处置利用已成为钢铁工业急需解决的关键共性难题。围绕废弃催化剂的处理思路和技术手段,总结了国内外废弃催化剂处置现状。主要处理思路分为有价元素提取、废弃催化剂循环利用和无害化处置等。有价元素提取相应的技术手段包括浸出、萃取、沉淀、水热合成、碳热还原等;废弃催化剂循环利用包括掺混制备新催化剂...     

Hydrology and Nitrogen Components of a Simple Rye Growth Model

Cover cropping practices are being researched to reduce artificial subsurface drainage nitrate-nitrogen (nitrate-N) losses from agricultural lands in the upper Mississippi watershed. A soil-plant-atmosphere simulation model, RyeGro, was developed to quantify the influence of a winter cereal rye cover crop on nitrate-N losses given climatic variability in the region. This paper describes the hydrology and nitrogen cycle submodels of RyeGro, which was developed with a low level of complexity and conceptualizes the soil profile as three soil layers. The model was calibrated with data from a three-year rye cover crop field study conducted at Lamberton, Minnesota, and validated with data from a previous study. During model calibration, field subsurface drainage nitrate-N loadings were predicted within 0.2, 0, and 1.6?kg?N?ha?1 (1, 0, and ?3%) of measured loadings for the corn-soybean treatment and within 1.2, 0, and 1.6?kg?N?ha?1 (11, 0, and 3%) of measured loadings for the corn-rye-soybean treatment. The model validation showed nitrate-N loading differences of 7 and 1?kg?N?ha?1 (?22 and 4%) for the two years tested.     

Fertilizer 15N Presence in Lysimeter Drainage Water

Agricultural and natural N cycling systems have been intensively studied via the stable isotope 15N. Tracing N translocation over time by applying 15N-tagged fertilizer has been used extensively. Our objective was to quantify fertilizer 15N translocation for an extended time in irrigated lysimeters containing sandy loam soil and cropped with corn and potato. Tagged fertilizer was applied to two lysimeters in 1989 and one in 1990. One lysimeter remained untreated. Breakthrough of 15N, above the background level of 0.366 atom %, was detected in drain effluent from 2.3-m-deep drains on treated lysimeters one year after initial preplant 15N application. Drainage water 15N concentration then increased rapidly to about 0.48 atom %, followed by a gradual decrease. However, 9 years after application there was still elevated 15N, 0.39 atom %, in the drainage water and 26–31% of the applied excess 15N remained in the soil profile. Cumulative 15N removed from lysimeters via drainage water during the first 7 years was between 3.0 and 3.7%. Estimated gaseous loss was 16%.     

日本钢铁工业环境保护措施

日本钢铁工业为可持续发展一直在寻找优良环境.综述了为减少20世纪后10年日本所造成的环境影响而做出的各种努力.1996年日本钢铁联合会(JISF)推出了一项解决环境问题的义务行动计划.计划优先针对两个主要问题,即防止全球变暖和建立循环利用型社会.行动计划提出具体目标,假设钢铁产量维持在每年1亿t水平,到2010年钢铁生产所用能量要比1990年减少10%.附加计划(废塑料利用)的实施将使能量比1990年减少11.5%,增加节能1.5%.经钢铁工业自身努力,2001年CO2排放比1990年下降了9.2%.另外,高性能钢的使用和副产品的利用在2000年使CO2减少了6.1%.对行动计划的另一目标--循环利用型社会,到2010年可成功实现减少钢铁废物,增加铁皮罐的回收利用.     

链箅机铁矿球团料层催化脱硝的反应行为及影响因素

 在资源约束、环保压力趋紧的形势下,新时期球团环保的重点是减少NO_x的排放,其高效控制关系着球团行业的生存。以铁矿球团为对象,研究了球团料层温度对不同铁精矿球团脱硝的影响,在此基础上研究了链箅机抽风干燥段(DDD段)催化脱硝的反应行为,并通过脱硝率、氨利用率等来表征烟气成分对DDD段喷氨脱硝的影响。研究结果表明,在相同条件下,赤铁精矿的催化性能优于磁铁精矿和混合铁精矿,同时分析了链箅机各段温度分布的特点,最终选择DDD段作为SCR脱硝的反应区域。DDD段适宜的脱硝条件为,温度为300～350 ℃,氧气体积分数为15%～20%,氨氮比(物质的量比)为0.5;在链箅机抽风干燥段进行SCR脱硝时,烟气中的SO₂体积分数由0提高到0.050%,反应脱硝率由51.0%降低到34.4%;随着烟气中水蒸气含量的提高,反应脱硝率降低,在水蒸气体积分数为9%时,脱硝率仅为44.9%,总体来讲,控制SO₂体积分数小于0.040%,水蒸气体积分数小于6%,可以获得40%左右的脱硝率,在DDD段喷氨催化法脱硝是高效可行的。     

Intrathecal IgA synthesis in X-linked cerebral adrenoleukodystrophy

The study included 162 second-grade children (85 boys and 77 girls) aged 8-9 years, attending two schools in an area with a fertilizer production plant, and 59 second-graders of the same age (32 boys and 27 girls) from a small neighbouring town located 20 km west of the plant, without any particular source of pollution. During the period from December 1990 to May 1991 the incidence of acute respiratory diseases was surveyed in children and their family members, and forced expiratory volumes were measured in selected second-graders in December 1990 and April 1991. In the area with the fertilizer plant as well as in the compared area ammonia, hydrogen fluoride, nitrogen dioxide, total suspended particulate matter and smoke were measured daily in ambient air and inside the school buildings. The mean concentrations of pollutants during the study period were below the recommended limits, with only a few exceptions, but daily fluctuations, particularly of ammonia and hydrogen fluoride in the area around the plant happened to exceed these values. The observed differences in the levels of air pollution correlated to some extent with the health parameters followed up during the study period. The incidence of acute respiratory diseases corresponded to the registered differences in the exposure to measured pollutants. Forced expiratory volume values in the compared groups of children did not consistently reflect the differences in exposure levels.     

好氧颗粒污泥的培养及处理低碳氮比废水效果

采用"搅拌-曝气-搅拌"间歇曝气运行模式,探索好氧颗粒污泥(AGS)在低碳氮比(1～6)废水中的形成规律及其对污染物的降解效果,旨在为低碳氮比污水的高效处理提供技术支持.当进水碳氮比为1～2.25时,接种污泥表现出明显的不适应,污泥量及颗粒化率增长缓慢,化学需氧量(COD)、总无机氮(TIN)及总磷(TP)的去除率较低...     

Pathogenesis of simian immunodeficiency virus pneumonia: an immunopathological response to virus

We investigated the effects of dietary factors on the pH and the ammonia emission from slurry of growing-finishing pigs. Sixteen male hybrid pigs (80 to 90 kg BW) were allotted to one of four diets based on barley-wheat, tapioca, barley-tapioca, and sugar beet pulp. Diets were formulated to have similar NE and CP contents and a similar lysine:NE ratio. Diets differed in nonstarch polysaccharide content (NSP) and dietary electrolyte balance (dEB). Urine and feces were daily collected quantitatively in metabolism cages and mixed as a slurry at the end of the collection period. After mixing, the pH and the ammonia emission from the slurry were measured daily in a laboratory setup for 7 d at 20 degrees C. The type of diet affected the pH of the slurry and the ammonia emission (P < .001). The pH of the slurry from pigs fed the sugar beet pulp-based diet was .8 unit lower and ammonia emission was 52 to 53% lower than that of the other three diets. The low dEB and high NPS sugar beet pulp-based diet increased the VFA concentration and reduced the pH and ammonia emission from the slurry. We conclude that dietary NSP and dEB influence the pH and ammonia emission from slurry of growing-finishing pigs.     

SBR System for Phosphorus Removal: ASM2 and Simplified Linear Model

An SBR (sequencing batch reactor) system was evaluated for nutrient removal. The system is capable of removing 95% of influent PO3?4, or from 6.7 to 0.4 mg P∕L, with the addition of acetate of 120–150 mg COD∕L in the feed solution (primary effluent). Nitrification was also achieved within the preset aeration cycle time in reducing the effluent ammonia level from 16.3–19.8 mg N∕L to 0.2–0.3 mg N∕L. However, denitrification was incomplete due to a slower endogenous nitrate respiration rate in the idle period, resulting in an effluent nitrate level of 7–8 mg N∕L. A linear version of the ASM2 (Activated Sludge Model No. 2) was developed to model the performance of an SBR system for nutrient removal. The developed model appropriately predicts the dynamic behavior of the SBR system with respect to phosphate release∕uptake, nitrification, ammonification, and denitrification. Compared with the full ASM2, the calibration of model parameters and model simulation require less computational time for practical implementation of the linear model into a process control system for the SBR.