湖泊底泥释氮预测模型及释氮控制研究

双龙湖是浅水型城市湖泊,一度为重富营养化湖泊,经综合治理其外源污染得到有效控制后,内源污染可能成为湖泊营养物主要负荷。采用底泥释氮模拟试验方法,对双龙湖底泥释氮影响显著因子(温度、pH、溶解氧、水动力)进行了分析。经多元回归得到双龙湖底泥平均释氮强度模型r=12.931+0.103[T]-0.36[pH]-0.728[DO]+0.490[K];通过释氮模型可预测不同环境条件下释氮规律,采取适宜措施抑制氮释放。

铝基载氮体在煤化学链制氨过程中的吸氮和释氮行为

以石墨、碳黑、烟煤/无烟煤/褐煤的脱灰半焦为碳源,通过固定床反应器以及多种表征手段探究铝基载氮体(氧化铝与氮化铝)的吸氮反应特性,并研究了TiO 2和ZrO 2对于载氮体释氮反应特性的影响。结果表明:碳源中较高的无序化程度有利于载氮体吸氮反应的进行;Al 2O 3与C的摩尔比为3∶3、吸氮反应温度为1200℃,是制备出适用于化学链反应制氨(CLAG)的多孔型载氮体的最佳工况;通过筛选原煤煤种发现,烟煤对于吸氮反应的促进效果最好,褐煤其次,无烟煤最差;通过优化对烟煤原煤的热解方式,能够将烟煤脱灰半焦的转化率从20%提升至39%。添加TiO 2作为催化剂可明显提高氮化铝的转化率,但由于氨气的高温分解,导致氨气的产率不高;利用对氨气具有分子吸附能力的ZrO 2为催化剂载体,可使得载氮体在释氮反应中的氨气生成率达到80%。

慢性缺血性肾病——中老年人不易解释氮质血症的中医证候分布研究

目的 :了解中老年人患者不易解释氮质血症中医证候分布规律 ,以协助制定具体的诊断分型标准及指导临床治疗。方法 :回顾分析 5 6例患者的症状及舌脉象 ,按本虚标实分别进行中医证候频数分布研究 ,并经统计学处理。结果 :中老年不易解释氮质血症的中医证候组合较复杂 ,可多证同时存在 ;且本虚以阴虚证(肝肾阴虚、阴阳两虚 )为主 ,占 76 5 6 % ;标实以血瘀证为主 ,占 6 3 0 1% .两者均有统计学意义。

长效尿素释氮过程及增产效果研究

长效尿素是氮肥新品种。通过1989、1990两年试验和大面积施用调查,发现长效尿素与普通尿素相比可抑制脲酶活性五十天左右,在施用前期,土壤脲酶活性低于对照区,尿素残余量高于对照,后期则相反,作物的叶绿素和氨基酸总量增加;增产效果明显,亩增产玉米40公斤,大豆10公斤,甜菜150公斤,亩纯增益分别为14.8,18.8和16.8元,经济效益显著。

库滨带土壤释氮负荷模型的构建与田间尺度模拟分析

岸边带生态系统对氮元素的去除机理主要包括化学释放含氮气体过程,植物吸收过程和泥沙截留3方面.其中,土壤反硝化释氮是岸边带系统最为重要的生态功能之一.因此,建立适当的岸边带土壤释氮模型(包括土壤反硝化、硝化和氨挥发过程),对准确评估岸边带生态功能和构建合理的岸边带生态系统具有重要意义.本研究依据岸边带去氮机理,参照已有的土壤释氮模型研究成果,构建了适用于水库库滨带土壤特性的土壤释氮速率估算模型(简称土壤释氮模型),并以官厅水库库滨带小区为研究对象,对水库库滨带土壤释氮特性进行模拟分析与验证.模型模拟结果表明,在监测期间(6～9月)土壤水分平均含量分别为16.6%、37.3%、43.9%和55.2%的情况下,土壤反硝化释氮速率分别为0、(102.1±59.3)、(169.3±87.6)和(203.2±119.6)mg.m-.2d-1(以N计);硝化速率分别为(233.3±121.4)、(177.9±69.3)、(187.7±75.0)和(166.7±121.9)mg.m-2.d-1(以N计);氨挥发速率分别为(3.00±1.13)、(2.64±1.01)、(2.76±1.04)和(2.51±1.89)mg.m-.2d-1(以N计);总释氮量分别为1.18、33.64、92.50和65.74g(以N计).同时,结合同步监测的实验数据,应用总量平衡法对模拟结果进行了验证.验证结果表明,实验小区土壤释氮量模拟值与实验值的决定系数(R2)为0.83,证明了该模型可有效地应用于水库库滨带区域.

双龙湖底泥氮释放强度影响因素正交试验研究

双龙湖是浅水型城市湖泊,一度为重富营养化湖泊。经综合治理其外源污染得到有效控制后,内源污染可能成为湖泊营养物的主要负荷。研究双龙湖限制性营养元素——氮在底泥的释放规律,对修复水体、保持水质具有重要意义,为湖泊内源治理、水环境保持提供科学依据。本文试验分析双龙湖环境因子(温度、pH值、溶解氧、水动力)对底泥总氮释放的影响;通过底泥正交模拟试验测定分析认为温度、溶解氧、pH值、水动力均是影响双龙湖底泥氮释放的显著因素,显著性排序依次为温度>溶解氧>pH值>水动力。

pH与三峡库区底泥氮磷释放关系的试验

通过对三峡库区底泥总氮、总磷(TN、TP)释放特性进行研究,分析了pH对三峡库区底泥TN、TP释放的影响及其原因,结果表明水溶液的pH在3.98～11.05范围内,TN、TP在3d内最大释放量达到最大值,pH在11.05～11.94范围内,TN在3d内最大释放量达到最大值,而TP在1d内最大释放量就达到最大值;pH越低TN的最大释放量越大,pH在3.98～10.07范围内,TP的最大释放量基本相同,pH在10.07～11.94范围内,TP的最大释放量急剧增加。说明了三峡库区底泥TN、TP对库区水质存在的危险性,并为三峡库区富营养化治理从控制氮磷营养盐含量方面提供了参考。

控释肥在苗木生产中的应用

通过室内模拟试验和容器育苗试验 ,研究了控释肥的释氮特性及对火炬松苗木生长的效应 .结果表明 ,与等养分量的普通肥相比 ,控释肥可以减少氮的挥发和淋洗损失 ,明显促进苗木生长 ,火炬松生物量成倍增加 .

控释肥在柑桔上的应用研究

通过室内培育和柑桔田间试验 ,研究了控释肥的释氮速率及对柑桔的效应。结果表明 ,控释肥的氮素释放速率缓慢 ,在柑桔上施用增产效果显著 ,且可提高果实品质。与普通肥相比 ,施用控释肥可增产 12 %～ 2 6% ,并使单果重增加 ,果形大小较匀称 ,果实中可溶性固形物、总糖及还原糖含量增加 ,糖酸比提高 ,Vc含量也略有增加。两种控释肥中 ,控II肥的效果优于控I肥。

碱热处理生物质碳源材料比选研究

针对人工湿地处理污水时反硝化碳源不足的问题,以玉米秆和美人蕉秆为研究对象,对其进行不同条件的碱热预处理,并根据其浸出液连续4 d释放的COD与TN的比值来分析选出最优的碱热预处理条件。结果表明:玉米秆的最优处理条件为在4%氢氧化钠溶液中,95℃水浴加热0.5 h;美人蕉秆的最优处理条件为在1%氢氧化钠溶液中,55℃水浴加热0.5 h;总体上同等条件下预处理后的美人蕉秆的释碳能力明显高于玉米秆;最优预处理条件的美人蕉秆耗能较少,成本更低,更适合作为外加生物质碳源投放到人工湿地中。

Nitrogen recovery and nitrate leaching of controlled release nitrogen fertilizer in irrigated paddy soil

Ordinary high nitrogen fertilizer often results in nitrate (NO3--N) leaching and low recovery. Microplot and field plot experiments were conducted to determine the effect of controlled release nitrogen fertilizer (CRNF) on reco very and nitrate leaching on paddy soils. During two early rice cropping seasons (2002 and 2003), a single basal application of CRNF at 90 kg N ha-1 increased grain yields by 7.7%to 11.6%compared with two applications of urea. Estimated by the difference method fertilizer N recovery of CRNF (mean 76.3%) was 38.9 pe rcentage point higher than that of urea (mean 37.4%); estimated by 15N isotope method (mean 49.6%) CRNF (mean 67.1%) was 35.9 percentage point higher than ur ea (mean 31.2%). NO3--N leaching losses were 9.19 and 6.70 kg ha-1 for urea and CRNF, respectively. NO3--N leaching during the early rice cropping season was 27.1 %lower from CRNF than from two applications of urea. These losses repr esent 10.2%and 7.4%of applied urea-N and CRNF-N. Results from this study ind icate that CRNF improves N recovery and reduces NO3--N leaching and increases rice yield.

Effects of Controlled Release Nitrogen Fertilizer on Seedling Growth and Nutrient Uptake of Bitter Gourd

Different application rates of controlled release nitrogen fertilizer （CRFN） were designed to evaluate their effects on the growth and root morphology of bitter gourd （Momordica charantia L.） seedlings, and thus determine the optimal nitrogen amount and suitable nitrogen content in substrate at seedling transplanting,, in com- parison with conventional fertilizer application. CRFN was applied at five levels, 0, 0.6, 1.2, 2.4 and 4.8 kg N/m3, and conventional fertilizer was applied at 0.6 kg N/m3 as control. Four replicates were included in each treatment. The results showed that 0.6-2.4 kg N/m3 CRFN provided sufficient N nutrient for bitter gourd, with higher shoot and root dry weights, root length and root surface area than control treat- ments. Correspondingly, the total inorganic nitrogen in substrate ranged from 99.3 to 162.5 mg/pot at seedling transplanting in these treatments. 1.2 kg N/m3 was proven to be the optimal CRFN rate. Compared with conventional nitrogen fertilizer applica- tion, 1.2 kg N/m3 CRFN in substrate increased the dry weight, nitrogen uptake and improved root morphology indices of seedlings, and more than 83.3 mg/pot inorgan- ic nitrogen could be carried with substrate at transplanting, revealing a potential to reduce N-deficient risk after rain and basal N input by continuous release of CRFN.

Effect of Controlled Release Nitrogen on Wheat Growth and Yield

[Objective] Effects of controlled release N fertilizers on wheat growth and yield were studied to provide reference for the application of controlled release fertilizers on wheat. [Method] A field experiment was conducted to study the effects of different types and levels of controlled release N fertilizers on the growth and yield of wheat. In this experiment, a treatment with the application of common urea and potassium chloride（common fertilizer） was established, and treatments with controlled release N fertilizers A and B with different coating materials were also established. [Result] The results showed that under the condition of the same P and K levels, controlled release N fertilizer A at a proportion of 100%, controlled release N fertilizer A at a proportion of 80% and controlled release N fertilizer B at a proportion of 80% could promote wheat growth, optimize yield components, and increase the amount of dry matter accumulation and grain yield. [Conclusion] One-time application of controlled release N fertilizer could be adopted in wheat production to achieve the purposes of saving fertilizer, saving labor and increasing efficiency.

Effects of Controlled-Release Nitrogen on Yield and Nitrogen Use Efficiency of Summer Maize

The field experiments were conducted in Anhui during 2016 to investigate the effects of controlled-release nitrogen （CRN） rates and mixture of controlled-re- lease nitrogen and conventional nitrogen （CN） on the yield and nitrogen efficiency of summer maize. Six treatments included CK （with no application of N）, CNIO0% splits （CN）, CRFIO0% （CRN1）, CRN60%＋CN40% （CRN2）, CRN85% （CRN3） and CRN70% （CRN4）. The results showed proper CRN increased yields and output val- ue. Compared with CN, CRN2 significantly increased by 13.74%, CRN1 increased by 4.84%, and CRN3 was equal to CN. CRN increased yield by grain number per spike of yield components. CRN2 had the highest apparent nitrogen fertilizer recov- ery efficiency and CRN1 was the second, which were significantly higher than CN. Nitrogen agronomic efficiency of CRN2 was significantly higher than CN. Nitrogen physiological efficiency of CRN2 was higher than CN. The partial productivity of CRN1 was higher than that with CN. And the effect of nitrogen fertilizer of CRN2 was the highest, which was increased 758 yuan/hm2. Considering yield, nitrogen use efficiency and economic benefit, applying the mixture of CRN and CN was the most beneficial treatment. CRN1 was the second treatment, and CRN3 didn＇t reduce yield.

Effects of a New Long-term Controlled-release Fertilizer on Growth and Development and Yield of Summer Maize

[Objective] The aim was to select the optimal amount of controlled-release fertilizer and provide theoretical references for controlled-release fertilizers use in summer maize. [Method] Long-term controlled-release fertilizers were applied once at sowing summer maize to explore effects on maize growth, yield, economic profits and environment. [Result] Maize yield reduced a little in the treatment group with 60% CRF, and increased in varying degrees in the rest groups in the range of 1.1%-7.4%, and some showed significant differences. [Conclusion] Controlled-release fertilizers can be applied once at the amount of 80% common fertilizer＇s, with con- sideration of maize yield, nitrogen use rate and economic profits, which is beneficial for summer maize application and promotion in North China.

Application Effect of Water-absorbent Slow Release Nitrogen Fertilizer in Latosol

[Objective] A new-type water-absorbent slow release nitrogen fertilizer（WASRNF） was produced through polymerization reaction. Its physicochemical property and application effect in latosol were studied. Feasibility of using WASRNF to improve the serious problems of latosol in rubber planting area in Hainan Island including vulnerable nutrient, free-running fertilizer and water was studied. [Result] The results showed that raw materials of WASRNF, urea and water-retention material formed co-polymer through hydrogen-bond interaction that the WASRNF contained many hydrophilic groups. The p H value of WASRNF is near neutral and its water absorbent rate in tap water could reach 167.17 g·g-1. The water absorbent rates in latosol leach liquors with water/soil ratios of 1：5, 1：10 and 1：20 were 104.66, 122.93 and 145.38 g·g^-1, respectively. The maximum water holding ratio of latosol increased by 23.72%, 30.89% and 39.68% when 0.5%, 1% and 2% WASRNFs were added to latosol, and water evaporation rate of latosol decreased efficiently. Compared with common urea, WASRNF could slow down the leaching rate of nitrogen and the initial leaching amount was only 22.17% of the total amount. [Conclusion]The results indicated that WASRNF in latosol had strong water absorption and water-retention abilities in addition to the good slow release effect, and could efficiently decrease nutrient loss, increase utilization ratio of water and fertilizer and promote interaction between water and fertilizer.

Effects of Controlled Release Fertilizer on Loss of Nitrogen and Phosphorus from Farmland

[Objective] The aim was to study on effects of controlled release fertilizer on loss of nitrogen and phosphorus from farmland. [Method] Experiment was conducted in fields planted with rice and corn around Chao Lake and effects of compound fertilizer, controlled release fertilizer and controlled release fertilizer （reduced by 20%） on loss of nitrogen and phosphorus through runoff and leaching were analyzed. [Result] Loss of nitrogen and phosphorus mainly occurred in early stage of fertilizing; loss caused by runoff accounted for over 98% and caused by leaching was lower than 2%, indicating that nutrients of rice and corn mainly lost through runoff. As for controlled release fertilizers with 20% reduced, total loss of N and P decreased by 60% and 63% in rice field and reduced by 27.8% and 34% in corn field, respectively, indicating that controlled release fertilizer would maintain nutrients in soils high in later period of plant growth, improve use efficiency of N and P, reduce N and P loss in rice and corn fields in rainy season, and decrease non-point pollution. [Conclusion] The research suggested that controlled release fertilizer would slow down the loss of nutrients in farmlands, providing scientific references and technological support for extension of controlled release fertilizer and reduction of agricultural non-point pollution.

Effect of Continuous Application of Controlled Release Nitrogen Fertilizer in Various Types of Soil in Dong-Ting Lake Region under Double Rice Cropping System

[Objective] This study aimed to explore the effects of continuous application of controlled release nitrogen fertilizer under double rice cropping system. [Method] By modeling three types of paddy soils in Dong-Ting Lake area, four treatments as no fertilizer （CK）, urea, controlled release nitrogen fertilizer （CRNF） and 70% controlled release nitrogen fertilizer （70% CRNF） were designed in the micro-plot trials from 2005 to 2008. [Result] The rice yield in treatment CRNF at N 150 kg/hm2 was increased by 10.3%, 8.0% and 2.4% compared with treatment of urea, in alluvial sandy loamy paddy soil （ALS）, purple calcareous clayey paddy soil （PCS）, and reddish yellow loamy paddy soil （RYS）, respectively; and the yield in treatment of 70% CRNF was increased by 6.1%, 2.6% and -0.8%, respectively. The ranking order of nitrogen uptake amount by plant in early rice and late rice was CRNF 70% CRNF urea CK in all three types of soil. Nitrogen utilization efficiency of CRNF in above three types of soil was 60.7%, 59.6% and 56.3%, increased by 23.8%, 19.4% and 16.3% compared with that in treatment of urea, respectively. Nitrogen utilization efficiency of CRNF in early rice was increased year by year, and was higher than that of 70% CRNF during the whole experiment stage, while that in late rice was increased first and then decreased from the 3rd year. [Conclusion] Continuous application CRNF could alleviate the decreasing of soil nitrogen fertility and organic carbon especially in ALS, increase rice yield and nitrogen utilization efficiency in double-rice cropping system.

Study on the Nitrogen Release Law of Bamboo Charcoal-coated Urea and Its Biological Utilization Effects

[Objective] The study about the nitrogen releasing law of bamboo-charcoal coated urea and the biologic utilization effect was to find the coated urea with high efficiency,low price and simple production technology.[Method]Two kinds of bamboo-charcoal coated urea(BCCU)with different coating thickness were made by using bamboo-charcoal and macromolecule polymer as coating material.The experiments of soil eluviate,ammonia volatilization in corn field and potted plant of corn were conducted to study the nitrogen releasing law and the biologic utilization effect of self-made BCCU.[Result]The BCCU showed some slow-release capability and their accumulated nitrogen releasing rates in 29 d were 9.93%-16.27% lower than that of normal urea.Compared with the normal urea,the volatilization rate of ammonia in BCCU reduced to 16.66%-31.8%,the biomass of corn and nitrogen utilization rate increased by 12.8%-24.1% and 10.5%-16.99%,respectively.[Conclusion]Bamboo-charcoal in coated urea not only had some slow-release capability,but also had some adsorbability,which would reduce the eluviation and volatilization of nitrogen and protect environment from N pollution.

Nitrogen Release Kinetics and Nitrification-Denitrification on Surface Sediments under Aerating Disturbance Condition

[Objective] This study aimed to investigate the nitrogen release kinetics and nitrification-denitrification on surface sediments under aerating disturbance condition, with the purpose to solve the sediment nitrogen release and secondary pollution problems. [Method] The effect of in situ sediments aeration on the release of nitrogen pollutants was investigated, and the nitrogen release kinetics parameters were analyzed. The process of nitrification and denitrification under sediments aeration condition was investigated in laboratory. [Result] The nitrogen released from sediments was enhanced by aeration disturbance. The concentration of NH4＋-N and TN reached the maximum value in 30 min, and release rates were proportional to the disturbance strength. In this study, with the distance of aerator to the sediments surface of 0, 1, 2 and 3 cm, the suspended sediments concentrations were 3.52, 3.41, 3.26 and 3.01 g/L, respectively. Maximum release concentration of NH4＋-N and TN were 14.3, 13.8, 13.2, 12.2 mg/L and 33.21, 30.98, 29.83, 27.30 mg/L, respec- tively. In addition, both NH4＋-N and TN release kinetics could be described by Double Constant Equation as InC=A＋Blnt. Nitrification reaction occurred and was promoted by continued aerating to sediments.The concentration of NH4＋-N dropped down from 12.4 mg/L to 0.2 mg/L in 8 d, with the concentration of NO3--N increased to the maximum value of 10.8 mg/L. In addition, concentration of NO3--N and TN decreased from 10.8 mg/L and 37.4 mg/L to 0.36 mg/L and 23.2 mg/L after the stop of aeration for 12 d, indicating the occurrence of denitdfication reaction. Therefore, sediment aeration could accelerate nitrogen release and nitrification reaction, and with intermittent aeration, nitrogen could be removed from sediments in-situ by nitrification and denitrification. [Conclusion] The results provided technical reference for the in situ sediment remediation for the black-odor rivers in cities.