几种水稻土对磷的吸附及解吸特性研究

水稻土对磷的吸附曲线与简单Ｌａｎｇｍｕｉｒ等温吸附方程基本吻合,土壤对磷的吸附及解吸能力主要受土壤物理性粘粒含量及土壤活性铁、活性铝含量的影响,而与土壤本身有效磷含量无关。同一种水稻土随吸附磷量的增加,其解吸率有增加的趋势     

有机肥料对土壤硅素吸附的影响

通过室内土壤培养试验,初步研究了有机肥料对土壤硅素吸附的影响,结果表明：土壤对硅有较强的吸附性能,活性氧化铁、铝含量是影响土壤硅吸附性能的重要因素;添加有机肥料使土壤吸附硅量降低,其降低幅度受有机肥料种类的和土壤性质的影响;添加有机肥料后,土壤对硅的吸附也具等温吸附特征,其等温吸附曲线可用简单ｌａｎｇｍｕｉｒ 方程和Ｆｒｅｕｎｄｌｉｃｈ 方程描述。     

pH值对土壤硅素吸附特性的影响

本文采用等温吸附法研究了安徽省16种土壤对硅的吸附作用,研究了三种pH值条件下土壤对硅吸附特征,结果表明:土壤对硅的吸附与土壤活性铁、活性铝含量呈极明显正相关,相关系数分别为0.8572和0.6776.在加入硅溶液pH值3-9范围内,平衡液硅浓度随溶液pH值升高而降低.     

土壤对硅的吸附与解吸特性研究

对几种代表性土壤进行了硅的吸附———解吸试验,并用三种等温吸附方程对实验结果进行了拟合。结果表明：实测值与Ｌａｎｇｍｕｉｒ,Ｆｒｅｕｎｄｌｉｃｈ和Ｔｅｍｋｉｎ方程都有较好的相关性,相关系数０．９１９８～０．９９９４,达到显著或极显著水平,其中以简单Ｌａｎｇｍｕｉｒ等温式与本实验资料最为吻合。根据Ｌａｎｇｍｕｉｒ方程计算的最大吸硅量ｘｍ和最大缓冲容量ＭＢＣ与土壤物理性粘粒和活性氧化铁、铝含量有关,能较好反映土壤供硅特性。几种供试土壤ＭＢＣ大小排序为：湖泥田＞马肝泥田＞砖红壤＞青泥田＞粉砂泥田＞壤质潮土。土壤吸附硅的解吸受土壤粘粒和氧化铁、铝含量影响,也与土壤吸附位硅饱和度有关,供试土壤吸附硅解吸率在２６．６％～５２．７％之间。     

pH值对土壤硅素及吸附特性的影响

本文采用等温吸附法研究了安徽省16种土壤对硅的吸附作用，研究了三种pH值条件下土壤对硅吸附特征，结果表明：土壤对硅的吸附与土壤活性铁、活性铝含量呈极明显正相关，相关系数分别为0.8572和0.6776。在加入硅溶剂pH值3-9范围内，平衡液硅浓度随溶液pH值升高而降低。     

柠檬酸对土壤磷释放与吸附的影响

本文研究了柠檬酸对土壤磷释放和吸附的影响。结果表明:柠檬酸对土壤磷素的释放有促进作用,土壤磷释放量与柠檬酸浓度之间的关系可用数学模型定量表示。在柠檬酸浓度较低时,外源加入磷量对平衡液中磷浓度起主导控制;当柠檬酸浓度较高时,柠檬酸起主导作用。柠檬酸处理后,平衡液中磷含量与土壤磷吸附量之间可以用肥力—产量模型来表示。     

钢渣对水溶液中磷、砷的吸附特性

采用廉价易得的钢渣作为吸附剂,研究其对水中磷、砷的吸附特性。结果表明,随着钢渣投加量的增加,磷、砷的去除率增加,在磷的初始浓度小于50 mg/L,投加量为0.75 g/100 m L时,磷去除率达99%以上;在砷的初始浓度小于10 mg/L,投加量为6 g/100 m L时,砷去除率也可达99%以上。p H影响钢渣对磷、砷的去除性能,中性条件下,钢渣对磷的去除效果最好;p H 9~11,有利于钢渣对砷的去除。钢渣对磷、砷的吸附均符合Langergren准二级动力学模型,具有"快速吸附、缓慢平衡"的特点。钢渣是一种良好的吸附除磷材料,对砷也有一定的吸附能力,磷和砷在钢渣上的吸附为竞争性吸附。     

安徽省土壤磷素形态及其影响因素研究

对安徽省不同性质土壤中的无机磷和有机磷进行了分析 ,结果表明 :土壤磷的含量与形态与成土母质、成土条件和耕作方式有很大关系。土壤无机磷以O P和Ca10 P为主 ,有机磷则以中活性及中稳态有机磷为主     

海南岛东北部红树林盐土的化学性质

研究结果表明,海南岛红树林盐土呈强酸性和酸性。其酸度与红树富硫有密切关系。土壤阳离子交换量随剖面深度而减少。土壤水溶性Cl~-与Na~+含量,SO_4~(2-)含量与 Ca~(2+)和Mg~(2+)合量紧密相关。土壤中磷在表层明显积累,钙、铁、锰在表层有所淋溶,钛、钾在剖面分布较均匀,硅、铝上下层多少不定。     

土壤镍污染对小麦幼苗生长及生理生化指标的影响

研究了褐土土壤中添加镍对盆栽小麦苗生长及生理生化指标的影响。并通过小麦地上部分的含Ｎｉ量、生物减产量和幼苗ＰＯＤ活性突变点对所应的土壤含Ｎｉ量表征土壤Ｎｉ污染。结果表明,土壤中全Ｎｉ量与土壤有效态Ｎｉ和幼苗中Ｎｉ含量呈极显著正相关,幼苗含Ｎｉ量与叶绿素含量及幼苗ＰＯＤ活性变化呈显著负相关,土壤中有效态Ｎｉ含量与小麦幼苗生物量呈极显著负相关,同时苗叶绿素含量和ＰＯＤ活性均与小麦幼苗生物量呈极显著正相     

Physico-chemical characterization of a farmland affected by wastewater in relation to heavy metals

This study investigated selected properties of soils affected by wastewater and its relationship with some heavy metals A free survey technique involving target sampling was used in siting soil profile pits. Soil samples were collected based on horizon differentiation and analyzed using routine and special analytical techniques. Soil data were subjected to correlation analysis using SAS program. Results show that all heavy metals studied had values above critical limits in the polluted soils using known standards and that these biotoxic metals decreased with soil depths. Highly significant （P=0.01 and 0.05） relationships were established between investigated heavy metals and some soil properties, especially soil pH and organic matter. Further studies involving more edaphic properties, biotoxic metals and their bioaccessibility in crops growing on wastewater soils will surely enhance knowledge and management of these highly anthropogenically influenced soils of the study site.     

水稻土磷吸附-解吸特性测定条件研究

通过对水稻土的磷等温吸附特征以及pH、振荡时间、液土比、支持电解质等4大因素对水稻土磷吸附-解吸影响的研究,得出结论:在水稻土对磷的吸附解吸特性研究中,较适宜的测定条件为pH=5,振荡时间为1h,液土比为20:1,支持电解质为0.01 mol.L-1的KCl溶液或0.01 mol.L-1的NaCl溶液。     

生物菌肥在不同水分条件下对土壤碱解氮的影响

通过玉米盆栽试验,研究了不同水分条件下菌肥对土壤碱解氮的影响。结果表明:土壤含水量范围在9％-20％时,施用生物菌肥对提高土壤碱解氮有显著效果;不同的水分条件下菌肥发挥的肥效不同,土壤含水量为13％-16％时,菌肥对土壤碱解氮的影响最大,且玉米的生长状况良好。     

法国土壤污染防治法律研究

我国土壤污染形势严峻,然而在土壤污染防治方面不仅没有专门性单行法律、法规,现有的法律、法规中也只有些零散规定,防治土壤污染的法律基本上是一项空白。本文主要根据法国土壤污染现状分析了法国土壤污染防治法的制度和法律责任。     

土壤原生动物的应用

土壤原生动物具有丰富的种类和巨大的生物量,在土壤生态系统中具有十分重要的地位.土壤原生动物可以影响植物的生长、防治有害生物、评价和监测自然环境变化及人类活动带来的环境污染.现参照国内外相关文献,简要概述了土壤原生动物对植物生长的促进作用、生物防治作用和生物指示作用,并对土壤原生动物的应用前景进行展望.     

How silicon fertilizer improves nitrogen and phosphorus nutrient availability in paddy soil?

In order to reveal the mechanism of silicon(Si) fertilizer in improving nitrogen(N) and phosphorus(P) nutrient availability in paddy soil, we designed a series of soil culture experiments by combining application of varying Si fertilizer concentrations with fixed N and P fertilizer concentrations. Following the recommendations of fertilizer manufacturers and local farmers, we applied Si in concentrations of 0, 5.2, 10.4, 15.6, and 20.8 μg/kg. At each concentration of added Si, the availability of soil N and P nutrients, soil microbial activity, numbers of ammonia-oxidizing bacteria and P-decomposing bacteria which means that the organic P is decomposed into inorganic nutrients which can be absorbed and utilized by plants, and urease and phosphatase activity first increased, and then decreased, as Si was added to the soil. These indicators reached their highest levels with a Si application rate of 15.6 μg/kg, showing values respectively 19.78%, 105.09%, 8.34%, 73.12%, 130.36%, 28.12%,and 20.15% higher than those of the controls. Appropriate Si application(10.4 to 15.6 μg/kg) could significantly increase the richness of the soil microbial community involved in cycling of N and P nutrients in the soil. When the Si application rate was15.6 μg/kg, parameters for characterizing microbial abundance such as sequence numbers, operational taxonomic unit(OTU)number, and correlation indices of microbial community richness such as Chao1 index, the adaptive coherence estimator(ACE)index, Shannon index, and Simpson index all reached maximum values, with amounts increased by 14.46%, 10.01%, 23.80%,30.54%, 0.18%, and 2.64%, respectively, compared with the control group. There is also a good correlation between N and P mineralization and addition of Si fertilizer. The correlation coefficients between the ratio of available P/total P(AP/TP) and the number of ammonia-oxidizing bacteria, AP/TP and acid phosphatase activity(AcPA), AP/TP and the Shannon index, the ratio of available N/total amount of N(AN/TN) and the number of ammoniated bacteria, and AN/TN and AcPA were 0.9290, 0.9508,0.9202, 0.9140, and 0.9366, respectively. In summary, these results revealed that enhancement of soil microbial community structure diversity and soil microbial activity by appropriate application of Si is the key ecological mechanism by which application of Si fertilizer improves N and P nutrient availability.     

基于破碎行为的土壤切削实验与仿真研究

构建了微型土条切削实验台,由于充分缩小刀具和土条的尺寸,而具有制样的快捷性、操作的可重复性及切后土壤破碎体统计分析的方便性,是土壤破碎适合的实验测试手段。土壤破碎仿真则以离散单元法为主的土壤切削失效、经由Image-Pro Plus实现的微裂纹生长、在Matlab中进行土壤破碎体的尺度统计3个步骤实现。使用目前提供的计算参数仿真,得到的平均土块径与含水率10%条件的切削实验结果一致,而仿真所得的土壤破碎体分形维数则与25%条件的切削实验结果一致。     

Targeted yield concept and a framework of fertilizer recommendation in irrigated rice domains of subtropical India

Soil test crop response （STCR） correlation studies were carried out in Vindhyan alluvial plain during 2001 to 2004 taking IR-36 as test crop to quantify rice production in the context of the variability of soil properties and use of balanced fertilizers based on targeted yield concept. The soils were developed on gently sloping alluvial plain with different physiographic settings and notable variation in drainage condition. Soil properties show moderate variation in texture （loamy to clay）, organic carbon content （4.4 to 9.8 g/kg）, cation exchange capacity （10,2 to 22.4 cmol （p＋）/kg） and pH （5.3 to 6,4）, Soil fertility status for N is low to medium （224 to 348 kg/ha）, P is medium to high （87 to 320 kg/ha） and K ranges from medium to high （158 to 678 kg/ha）. Database regarding nutrient requirement in kg/t of grain produce （NR）, the percent contribution from the soil available nutrients [CS （%）] and the percent contribution from the applied fertilizer nutrients [CF （%）] were computed for calibrating and fbrmulating fertilizer recommendations. Validity of the yield target for 7 and 8 t/ha was tested in farmers＇ fields and yields targets varied at less than 10%. The percent achievement of targets aimed at different level was more than 90%, indicating soil test based fertilizer recommendation approach was economically viable within the agro-ecological zone with relatively uniform cropping practices and socio-economic conditions.     

川南地区耕地土壤pH时空变化分析——以宜宾市南溪区长兴镇为例

基于1982年全国第二次土壤普查数据和2008年国家测土配方项目数据,利用SPSS17.0和Arc GIS9.0软件平台对宜宾市南溪区长兴镇耕地土壤pH进行研究.结果表明,长兴镇耕地土壤整体偏酸性,呈北高南低的特点,pH范围在4.2～9.4之间.经过近30年的时间,长兴镇土壤pH已由1982年时的6.8降到2008年的5.9,其中以沙溪庙组紫色砂泥岩下发育的淹育型水稻土下降得最快.