妊娠猪舍氨气及氧化亚氮浓度测定与排放通量的估算

在北京选择一典型猪场，对不同季节妊娠舍的氨气及氧化亚氮浓度进行了为期1年的试验测定，并根据二氧化碳平衡原理，对猪场不同生长阶段的妊娠猪含氮气体的排放通量进行了估算。结果表明：冬季2004年11月氨气和氧化亚氮的平均浓度分别为11.64±4.36，（1.17±0.2）mg／m³，夏季7月舍内氨气和氧化亚氮的平均浓度分别为3.31±2.67，（0.6±0.02）mg／m³；妊娠猪饲养期间的氨气排放通量为每头（185.2～500.8）mg／h，氧化亚氮为（3.85～35.93）mg／h。     

改善农学管理措施减少太湖稻麦轮作NH3和NO排放

以稻麦轮作为对象,采用密闭室-通气法和静态箱-化学发光法对太湖地区空白（不施氮肥）、当地常规（农民习惯管理方式）和保产增效（与当地常规相比,改善作物种植、水分和养分管理方式）3个处理下的氨（NH3）挥发和一氧化氮（NO）排放进行田间原位观测,研究保产增效措施对稻麦轮作NH3 挥发和NO排放的综合影响。结果表明,与当地常规相比,保产增效在施氮量减少25%的情况下,总作物产量没有降低,且农学利用率提高了39%;保产增效NH3挥发量在稻季和麦季分别减少了26%和44%;保产增效在稻季NO排放量较低（0.75±0.03 kg N/hm2）,与空白和当地常规均没有显著差异（p<0.05）,在麦季NO排放量则显著降低了49%。因此,保产增效措施不仅能保障高产和提高氮利用率,还能减少NH3和NO排放,值得在太湖地区推广。     

Leaching of dissolved organic carbon in soil following anhydrous ammonia application

The transport of anhydrous NH₃-solubilized soil organic matter from surface to subsurface soils may affect subsurface microbial activity. In the present study we determined the impact of anhydrous NH₃-N fertilizer on organic C solubilization and the propensity of solubilized C to leach with percolating water. In fertilized treatments, anhydrous NH₃ was subsurface-banded at 20g N m^-2 in ridge or valley areas of a ridge tillage system. In contol treatments, 0g N m^-2 was banded into the valley area of a ridge tillage system. Rainfall (17 cm) was applied with a drop-type artificial rainfall simulator 3, 10, and 24 days after the fertilizer application. The treatments were replicated twice. Grid lysimeters (15 by 15 cm) were placed 75 cm below the soil surface of a Brandt silty clay loam (fine-silty over sandy or sandy skeletal mixed Pachic Udic Haploboroll). Lysimeters were used to collect percolating water temporally and spatially. The application of N fertilizer increased dissolved organic C concentrations in percolating water when rainfall was applied 3 days after the fertilizer application. However, when the rainfall was applied 24 days after the fertilizer application the dissolved organic C concentrations in percolating water was not influenced by anhydrous NH₃ application. The smaller dissolved organic C concentrations in percolating water with a longer incubation time were most likely the result of microbial assimilation or respiration of solubilized C.     

丹麦舍饲散养自然通风奶牛舍的空气环境分析

近年来，奶牛全舍饲散养工艺技术被欧美等国家越来越普遍地使用。全舍饲工艺中的舍内空气质量对奶牛的健康和生产性能影响很大，为较深入了解该工艺中热环境与其它有害气体的相应关系，通过对丹麦7个有代表性奶牛场进行温度、含湿量及几种主要有害气体的现场测试，对该工艺下舍内空气环境条件进行分析研究。结果表明：丹麦气候条件下全舍饲的自然通风牛舍，其舍内热湿状况受舍外温湿度及牛体本身的影响，在0～25℃范围内，舍温一般比舍外高1～3℃，舍外温度每升高1℃，舍内温度上升0.8℃，含湿量约增加1000 mg/m³；舍内各环境因素之间具有显著的相关性，温度、含湿量的高低对NH₃、CO₂、CH₄浓度均有影响；白天，由于自然通风量较大，这3种气体的平均浓度比夜间低20%左右。而N₂O在整个测量过程中并未发现显著变化。     

肥液氮素浓度在线检测装置研制

为实现肥液自动混合过程中氮素浓度的实时检测,设计了一个检测装置,该装置主要由硝酸根离子选择电极、电极信号调理电路、温度传感器、数据采集以及显示电路组成。在10-6~10-1 mol/L范围内配制了一系列标准浓度的NO3-溶液,对该检测装置进行了性能测试试验:1)以标准毫伏计PHS-3CT作为对比,测试了装置对电极响应电势的测量准确性,其相对误差最大为5.2%;2)在5~45℃范围内,分析了离子选择电极的温度变异性,结果表明电极响应电势随着待测溶液温度升高而呈线性变化,在此基础上采用最小二乘法的逐步拟合方法建立了温度参数模型,并对模型进行了验证,其测量误差最大为9.2%;3)采用固定干扰法分析了Cl-、SO42-、H2PO4-和HPO42-等4种干扰离子对装置测量结果的影响,结果表明Cl-引起的干扰最大,电极对Cl-的敏感性是NO3-的0.2%,因而肥液中少量的干扰离子对测量结果的影响不大。因此,该装置可满足工程上自动混肥过程中氮素浓度检测的应用要求。     

棕壤和褐土的酸淋溶特征

用室内模拟淋洗土柱的方法 ,对棕壤和褐土的酸淋容特征进行了研究。结果表明 ,p H低的酸雨使棕壤严重酸化且有活性铝测出 ,但对褐土的影响相对较轻。 4种盐基离子淋失总量与酸雨的氢离子浓度呈极显著的正相关关系 ,淋失量 Ca2 >Mg2 >Na >K ,其中 Na 对酸雨的酸度最不敏感。电导率的变化与盐基淋失量的变化有相同趋势 ,但不同处理之间的差别倍数大于盐基淋失差别的倍数 ,4种酸雨对土壤的危害程度为 p H2 >p H3>p H4、p H5 ,其中危害棕壤的程度高于褐土。     

离子注入在生命科学中的应用研究

本文概述了近十几年来离子注入技术在机理研究、生物品种改良及介导外源基因转移等方面的研究进展     

氨气敏电极-标准加入法测定土壤脲酶活性

本文研究了用氨气敏电极－标准加入法测定土壤脲酶活性的新方法。该法使样品液和标准溶液均处于同一条件下测定，消除了土壤中基体对测定的影响，提高了方法的准确性。方法简便、快速，结果可靠，应用于不同土壤样品中脲酶活性的测定，相对标准偏差为1.78%-3.94%，回收率在98.3%-101.8%之间。     

Response of potatoes to different nutrient solution management in a closed hydroponic system

Ion control of nutrient solutions to control nitrogen (N), phosphorus (P), and potassium (K) was developed for Superior (medium-to-early maturing) and Atlantic (mid-late) potato cultivars grown in closed hydroponic systems in which solutions were replenished and recirculated. Results were compared with conventional nutrient solution management strategies. In the “solution replacement” treatment, nutrient solutions were completely replaced each week. In the “electrical conductivity (EC) control” treatment, water use by potato plants was compensated by adding ground water to achieve the original volume (water replenishment) and the diluted EC of the solution was adjusted to the target levels using stock solution. In “ion control” treatment, ammonium dihydrogen phosphate (NH₄H₂PO₄) and potassium nitrate (KNO₃) were added to the EC-controlled nutrient solution. The amounts increased with plant age in both cultivars. The concentrations of nitrate (NO₃), P, and K in the ion control nutrient solution could be maintained at target levels. In water replenishment, recycling of nutrient solution resulted in a progressive decrease in EC and an increase in pH. Root activity increased by 93% and 59% in the Superior and Atlantic cultivars, respectively, compared with the nutrient solution replacement. These changes decreased photosynthesis, plant growth, water use, and thus tuber growth in the Superior cultivar. Decreased growth of shoots and tubers occurred without affecting photosynthesis in the Atlantic cultivar. Although there were no significant differences in root activity, photosynthesis, or plant growth between the ion control treatment and the EC control treatment, increased tuber growth was observed in the ion control treatment, possibly as a result of the constant supply of nutrients. High tuber growth and the capability to maintain solution nutrient concentration in the ion control treatment are highly desirable for closed hydroponic systems.