有机肥与化肥配施对土壤养分的影响研究

不同有机肥与化肥配施比例都有促进土壤养分含量的作用,土壤中有机质、碱解氮、速效磷和速效钾含量均随有机肥在肥料中比例的增加而增加,增幅分别为1.04％～63.49％、5.57％～24.50％、28.65％～48.42％、16.7％ ～ 28.65％.有机肥与化肥配施能够明显改善土壤理化性质,降低土壤pH值和土壤容重,提高土壤总孔隙度,提高土壤有机质、碱解氮、速效磷、速效钾的含量,表明有机肥与化肥配施对土壤养分的提高效果明显,并明显高于单施化肥和不施肥.综合分析,有机肥与化肥配施比例为7∶3是值得推广应用的优化方案.     

排除COD无汞快速测定法中氯离子干扰的方法

目前对COD的测定都采用国家标准(GB11914— 89)重铬酸钾法。该法存在的主要问题是氯离子在强酸性介质中很容易被重铬酸钾氧化成氯气而使测定结果偏高。所以该法要采用硫酸汞作掩蔽剂 ,使之与氯离子反应生成难以离解的可溶性氯汞络合物 ,以减少氯离子的干扰。即使这样 ,当水样中氯离子质量浓度超过 10 0 0mg/L时 ,COD最低允许值为 2 5 0mg/L。不仅如此 ,汞属有害物质 ,易造成二次污染。因此 ,有人建议不用汞盐而以氯化银的形式来沉淀氯离子 ,即在水样中加入硫酸银或硝酸银将其去除。但这些方法对氯离子浓度较高、COD相对较低水样的抑制…     

药用红花氮,磷,钾吸收与转运规律

药用红花Ｎ、Ｐ、Ｋ三要素在整个生育期中，主要向该时期生长最活跃的部位运转，以确保其生长发育所需。在植株各器官形成初期，该器官中的Ｎ、Ｐ、Ｋ含量较高．在植株不同器官中，以叶中的养分含量最高。植株中Ｎ、Ｐ、Ｋ三要素含量的顺序为：Ｋ＞Ｎ＞Ｐ。药用红花对Ｎ、Ｐ、Ｋ养分吸收的高峰时期为分枝孕蕾期，占整个生育期的百分率分别为：８３．３％、５５．４％、５２．９％．Ｋ的吸收主要在生育前期和中期，Ｎ和Ｐ在生育后期还有较大的吸收量。每生产５００ｋｇ干花需吸收Ｋ２Ｏ０．８２ｋｇ、Ｎ０．３２ｋｇ、Ｐ２Ｏ５０．１７ｋｇ．Ｎ、Ｐ、Ｋ养分的转移主要发生在主茎叶和茎，其中以Ｋ的转移率最大．     

Effect of water regimes and organic matters on transport of arsenic in summer rice （Oryza sativa L.）

The arsenic contamination in soil-water-plant systems is a major concern of where, the groundwater is being contaminated with arsenic (above 0.01 mg/L) in the Indian subcontinent. The study was conducted with organic matter to find out the reducing e ect on arsenic load to rice (cv. Khitish). It was observed that intermittent ponding reduced arsenic uptake (23.33% in root, 13.84% in shoot and 19.84% in leaf) at panicle initiation stage, instead of continuous ponding. A decreasing trend of arsenic accumulation (root > straw > husk > whole grain > milled grain) was observed in di erent plant parts at harvest. Combined applications of lathyrus + vermicompost + poultry manure reduced arsenic transport in plant parts (root, straw, husk, whole grains and milled grain) which was significantly at par (p > 0.05) with chopped rice straw (5 tons/ha ) + lathyrus green manuring (5 tons/ha) in comparison to control and corresponding soils. A significant negative correlation of arsenic with phosphorus (grain P with arsenic in di erent parts R2= 0.627–0.726 at p > 0.01) was observed. Similarly, soil arsenic had a negative correlation with soil available phosphorus (R2 = 0.822 at p > 0.001) followed by soil nitrogen (R2= 0.762 at p > 0.01) and soil potassium (R2 = 0.626 at p > 0.01). Hence, e ective management of contaminated irrigation water along with organic matter could reduce the arsenic build up to plants and soil.     

Chelation of heavy metals by potassium butyl dithiophosphate

Potassium butyl dithiophosphate (PBD) was developed and introduced as a new chelating agent for heavy metal removal. The synthesized PBD were characterized by IR and NMR. The e ects of pH, chelating agent dosage, and other heavy metal ions on the performance of PBD in Cd2+ removal from water are investigated. Experimental results showed that the chelating agent could be used to treat acidic heavy metal wastewater. The Cd2+ removal was not a ected by solution pH value within the range of 2 to 6. The Cd2+ removal rate could reach over 99%. Therefore, the deficiency of the precipitation process using hydroxide under alkaline condition can be overcome.Without the need for pH adjustment, the method could save on costs. If Cd2+ co-exists with Pb2+ and Cu2+, the a nity of the chelating agent with these three heavy metal ions was in the order of: Cu2+ > Pb2+ > Cd2+. Through PBD chelating precipitation, all the contents of Pb2+, Cd2+, and Cu2+ in wastewater met the standard levels through a one-step treatment. The one-step treatment process was superior to the process (sectional treatment is required) of precipitation with hydroxide. When the pH was between 3 and 11, the amount of leached chelated Cd2+ was much lower than that obtained by precipitation with hydroxide. Therefore, the risk of environmental pollution could be further reduced.     

利用BAF提取糖蜜酒精废液中钾的实验研究

研究α-改性沸石对钾的吸附性能,分离和提取钾元素。通过静态试验,得出了改性沸石对K+的吸附容量为36.13mg/g沸石,当温度为25℃时,吸附等温线可以用Freundlich吸附公式来进行拟合,相关系数R2>0.983。利用α-改性沸石为介质的BAF反应器对糖蜜酒精废液进行提钾的实验研究,结果表明,在温度25～30℃,进水COD浓度1500～1800mg/L,NH3-N浓度180～210mg/L,钾(K+)浓度0.65～0.75g/L、pH7～9,水力负荷3.0m3(/m.2d)和气水比为3:1条件下,系统稳定运行,钾的吸附率达90%以上,洗脱富钾液中钾(K+)浓度可达38g/L。为生态型提钾的工程应用奠定基础。     

三江平原退化湿地和农田土壤养分的比较研究

三江平原农业开垦导致地表水位和土壤水分下降,原生湿地退化为沼泽化草甸和典型草甸,或者直接转化为水田和旱田.退化湿地与农田土壤养分的对比研究结果表明,4种样地类型0-30 cm土层土壤有机质含量为水田＞沼泽化草甸＞旱田＞典型草甸,全氮含量差异与有机质含量差异相一致,速效磷含量为水田＞旱田＞沼泽化草甸＞典型草甸.这说明在湿地退化为典型草甸的过程中土壤养分严重下降,水分状况是影响湿地土壤养分下降的关键因素;但是农田土壤养分仍然保持较高水平,主要是由于耕作、施肥等非水分因素的影响.由此可见,水分条件和人为干扰共同决定了退化湿地和农田土壤养分状况.     

定位施肥紫色菜园土壤钾素效应研究

基于紫色菜园土壤3年12季连续蔬菜(莴笋-白菜轮作)定位施肥试验,研究不同施肥条件对土壤钾素形态和供钾水平的影响。采用田间试验和室内化学分析结合的方法测定不同施肥处理土壤钾素形态的变化和蔬菜产量的关系。结果表明:紫色菜园土壤钾素主要以矿物钾为主,占全钾的95.11%~97.33%,土壤缓效钾和速效钾分别占土壤全钾的2.22%~3.38%和0.44%~1.52%。连续施用钾肥显著提高土壤速效钾和缓效钾含量,以增钾处理作用最优。定位施肥显著提高土壤水溶性钾、非特殊吸附钾、特殊吸附钾含量,以有机无机肥料配施作用优于单施化学肥料。土壤水溶性钾、非交换性钾与土壤有效磷含量呈显著或极显著正相关,莴笋和白菜产量与紫色菜园土壤速效钾、缓效钾含量呈显著正相关。定位施肥协调紫色菜园土壤钾形态,改善土壤供钾能力,以有机无机肥料配施作用为优。