提高化肥利用率途径的土壤磁学研究

通过土壤磁学的角度来探讨我国农业生产急需解决的前沿课题之一——提高化肥利用率问题。125组土壤磁化率、营养元素氮、磷、钾和有机碳含量数据来自杭嘉湖平原的平湖地区,分布在560 km²面积内的36个深度剖面。分析这批数据随深度的变化规律,发现非耕作层的土壤磁化率与钾、氮、磷含量具有较好的相关性,而与有机碳含量相关性较差,说明决定土壤磁性的矿物具有保持营养元素的能力。耕作层的土壤磁化率与有机碳、磷含量具有较好的相关性,而与氮、钾含量相关性较差。耕作层的土壤磁化率以及氮、磷和有机碳含量高于非耕作层的土壤磁化率以及氮、磷和有机碳含量,钾含量则相反。从非耕作层至耕作层,土壤磁化率增幅为23.8%,远低于氮增幅55.3%、磷增幅36.6%和钾减幅95.8%,说明该区存在化肥施用不均衡现象,导致土壤磁化率与营养元素含量关系的失衡。提高磁肥或磁化肥的施用量,是提高肥效的持久性与利用率的途径之一。     

稻壳灰作为海水硅酸盐肥料的肥效和安全性研究

增加硅酸盐供给可缓解海域硅酸盐相对缺乏现象,稻壳灰中含有大量无定形态SiO2,是一种理想的海水硅酸盐肥料。为验证稻壳灰的硅酸盐释放性能以及在环境中应用时的安全性,我们在实验室内将稻壳灰添加到海水中测定了Si、P、N营养盐的释放能力及释放周期,并将稻壳灰放于自然海域浸泡一段时间后测定其4种重金属及Mg元素含量的变化。实验结果表明,稻壳灰在海水中可持续缓慢地释放硅酸盐,释放周期可达3个月以上,同时释放少量磷酸盐,不会增加水体中无机氮营养盐含量;稻壳灰向海水中释放极少量的Cd,但不易造成重金属污染,而对海水中的Cu、Pb、Hg有一定地吸附效果,吸附量远小于Mg离子。     

Impacts of Anthropogenic Land Use Changes on Nutrient Concentrations in Surface Waterbodies: A Review

Increased population leads to land use (LU) changes from natural to urban and agricultural LU. These disturbances not only decrease the natural treatment potential but they also worsen surface water quality (SWQ). The aim of this review is to assess studies about impacts of anthropogenic LU changes on levels of nutrient concentrations in surface waterbodies, highlighting the important parameters needed for an integrated simulation. The results reported in the literature are not always fully consistent. These contradictory results can sometimes be explained by field measurements under different climatic conditions, different features of landscapes, air deposition rates on ground surfaces, and groundwater flow interactions with surface water. Integrated modelling has been suggested to overcome these inconsistencies. Physical‐based and empirical models are the most popular approaches for LU‐SWQ studies. Generally, anthropogenic LU such as agricultural and urban areas usually enhances nutrient concentrations much more than natural lands such as forest and barren. Developing sustainable metropolitan areas instead of rural areas, establishing high‐standard wastewater treatment plants, and practicing efficient fertiliser application would ameliorate the poor nutrient conditions in SWQ. Riparian vegetation, grassed swales, and construction of artificial wetlands as buffer zones are the most promising natural water quality control measures.     

低品位磷矿的生物选矿、化工冶金一体化研究

利用生物冶金的方法,将不溶性磷源转化为水溶性或枸溶性磷源,从而提供了一条利用低品位磷矿的新途径.讨论了生物和微生物在磷化工中的研究与应用,介绍了用自制菌磷肥在田间试验所取得的结果,提出了利用生物工程的方法处理低品位磷矿而直接生产磷肥的技术路线.     

我国钾肥工业回顾分析与展望

我国钾肥工业目前存在资源短缺、数量少、规模小、工艺技术落后、供需矛盾突出、进口量与施用量逐年增长等问题。 2 1世纪我国钾肥工业的发展将乘“西部大开发战略”之东风 ,在国家产业政策的支持下 ,通过加强宏观管理、增大投入、加强科研与综合利用工作 ,从而实现规模化、效益化 ,使开发工作取得重大进展。预期 2 0 10年国产钾肥可满足国内需求量的 2 0 %。     

改进后的CTM模型在半干旱区作物生长中的应用

将改进后含有温度和水肥补偿效应的CTM模型应用于半干旱区作物研究中,分析了水分因子与土壤养分因子间的生态学补偿效应,模拟了半干旱区作物生长过程,并对在不同水分和不同施肥量下的作物生长状况进行了数值模拟。结果表明,在水分变化梯度上,随着土壤水分的增加,主要作物春小麦的产量呈上升趋势,试验条件下春小麦籽粒产量的最大值为462.35g·m^-2;一定限度内通过合理施肥可以补偿土壤水分不足。模拟计算结果表明,丰水条件下施中肥效果最好。     

我国钾长石矿产资源分布、开发利用、问题与对策

我国钾长石矿产资源丰富,分布广泛,其中安徽、内蒙古、新疆、四川、山西等省(区)的钾长石分布相对集中,储量丰富,成为当地的优势非金属矿产资源。随着科学技术的发展,钾长石广泛应用于工业生产。我国在利用钾长石生产玻璃、陶瓷、化肥等方面都取得了一些进展。但还存在钾长石市场不完善;生产企业缺乏竞争力;钾长石产品技术含量低等问题。应通过进一步深入研究制定解决市场、技术、产品等问题的相应对策,促进钾长石在相应领域的开发利用。     

Unexpected nationwide nitrate declines in groundwater of Korea

Elevated levels of nitrate in groundwater are an important concern for health and the environment. The overapplication of nitrogen fertilizer to croplands is one of the major sources of high nitrate content in groundwater. In this study, we analyse the nitrate concentrations in Korean groundwater based on data from groundwater quality monitoring wells (n = 1,022–2,072), which were sampled twice annually over a recent 13‐year analysis period (2001–2013). We report that groundwater nitrate levels are decreasing, despite steadily increasing groundwater use. The maximum nitrate concentration decreased from 168.91 to 48.11 mg/L, whereas the mean values also show a gradual decreasing trend. Non‐parametric Mann–Kendall tests on nitrate concentrations also confirm the decreasing trend. The nitrate decrease is more clearly evident in agricultural groundwater as compared to domestic and drinking groundwaters. This decrease of nitrate in groundwater coincides with a large decline in nitrogen fertilizer application due to reduced cropland areas, more sustainable agricultural practices, and progressive improvement of sewage disposal services. This study proposes that the long‐term adoption of best practices in agriculture has had a positive impact on groundwater nitrate control.     

干旱胁迫下钠复合肥对霸王(Zygophyllum xanthoxylum)根系生长的促进作用

霸王(Zygophyllum xanthoxylum)是荒漠区广为分布的一种多浆旱生植物。采用盆栽育苗的方法,初步评价了干旱胁迫下Na+对霸王根系生长的贡献,探讨了一种新型钠复合肥对霸王根系形态、生理学指标的影响。结果显示,钠复合肥能显著促进霸王根系的生长并提高其抗旱性:(1)正常浇水时,钠复合肥对霸王的促进作用主要体现在株高的增加和侧根的增长上,根系活力显著增强;(2)自然干旱15d后,钠复合肥使得霸王根系活跃吸收面积显著提高24%,促进主根的加粗和伸长以吸收更多的水分和矿质养分;(3)干旱胁迫下,钠复合肥处理使霸王根部Na+浓度保持较高水平,K+浓度下降42%。因此认为,干旱前钠复合肥显著促进了霸王侧根的生长和根系活力的提高,干旱后钠复合肥通过促进根系活跃吸收面积的扩大和主根的生长以提高霸王的抗旱性,其主要原因是根和叶中积累了较多的Na+、而非K+。