长年关水稻田耕作改制的选择

试验研究表明,当早稻收获时间作晚稻才开始幼穗分化,即适宜早、晚稻出穗开花之间有60多天的时间,种植双杂间作稻就可获得好的收成,效果、效益都很显著。1992年用D 优287间汕优63,在达县永进乡的示范田中个别田块产量已达15t/ha,而盆地丘陵区适宜早、晚稻出穗开花之间的时间多数地区不到70天,种植双杂连作稻有困难。且双杂间作稻在抗灾增产,合理利用农村劳动力,提高稻田复种等方面优于双杂连作稻。因此,四川盆地丘陵区的中稻→冬水田在耕作改制中发展部分双杂间作稻是恰当的,其范围在巴中、盐亭、简阳一线以南海拔400m 以下的广大丘陵区。     

模拟氮沉降对土壤酸化及土壤酸缓冲能力的影响

为探讨N沉降对酸雨区森林土壤酸化和土壤酸缓冲能力的影响,于2012年4—12月在重庆缙云山地区选取针阔混交林和常绿阔叶林2种典型林分进行模拟N沉降试验,设N0、N1、N2、N3 4个处理,施N量(模拟N沉降量)分别为0、60、120、240 kg/(hm2·a),每月月初将NH₄NO₃溶液均匀喷洒在所选样方内,8个月后进行取样分析. 结果表明:①不同pH下2种林分土壤的酸缓冲能力存在较大差异,pH越低土壤酸缓冲能力越高. ②2种林分的土壤酸缓冲能力随N沉降量的增加而降低. 在相同的N沉降量下,常绿阔叶林土壤酸缓冲能力略高于针阔混交林. ③N沉降会加快土壤酸化速率. 与N0处理相比,N1、N2、N3处理常绿阔叶林土壤pH分别下降了0.03、0.06、0.16,而针阔混交林则分别下降了0.08、0.10、0.26. ④2种林分土壤中盐基离子含量均随N沉降量的增加而降低,交换性Al3+含量则相反. 与N0处理相比,常绿阔叶林N1、N2、N3处理盐基离子含量分别下降了55.76%、66.00%、70.38%,交换性Al3+含量分别增加了16.03%、21.37%、31.81%;针阔混交林盐基离子含量分别下降了24.12%、43.38%、62.24%,交换性Al3+含量分别增加了19.19%、23.48%、34.85%. 研究表明,氮沉降会降低森林土壤酸缓冲能力,加快酸化速率,并且常绿阔叶林土壤对N沉降的敏感性高于针阔混交林.      

大气污染总量控制规划专家系统中知识库子系统的研究

论述了大气污染总量控制规划专家系统（ＥＡＳＰＴＥＣＥＰ）中知识库的基本设计思想,知识库分为无级知识库和领域级知识库,元级知识库由类文件和元规则文件构成,领域级知识库则文件和参量文件构成,并在此基础上阐述了ＥＳＡＰＴＥＣＰ中知识库演绎推理系统,知识库解释系统,知识库管理系统等的设计与实现方法。     

GSM移动通信基站电磁辐射污染状况研究

介绍了GSM移动通信基站系统,指出,在进行GSM移动通信基站环境影响分析时,要注意采样点位的设置和测量要求.现场监测结果表明,GSM移动通信基站对环境电磁辐射水平有一定的影响,特别是对50 m内建筑物影响显著,但绝大多数基站基本符合国家有关电磁辐射环境影响标准的要求,在设备正常运行情况下,不会对周围环境造成电磁辐射污染.     

Occurrence and source analysis of typical veterinary antibiotics in manure, soil, vegetables and groundwater from organic vegetable bases, northern China

The residue of antibiotics is becoming an intractable environmental problem in many organic vegetable bases. However, their residual levels and distribution are still obscure. This work systematically analyzed the occurrence and migration of typical veterinary antibiotics in organic vegetable bases, northern China. The results showed that there was no obvious geographical difference in antibiotic distribution between soil and manure. A simple migration model can be easy and quick to predict the accumulation of antibiotics in soil. Antibiotics were mainly taken up through water transport and passive absorption in vegetables. The distribution of antibiotics in a plant was in the sequence leaf > stem > root, and performed biological accumulation. The residues of antibiotics in all samples in winter were significantly higher than those in summer. Overall, this work can lay the foundation for understanding ecological risk of antibiotics and their potential adverse effects on human health by food chain.     

南京市城郊蔬菜生产基地有机氯农药残留特征

以网格法在南京市无公害蔬菜生产基地八卦洲采集70个土壤样品,用加速溶剂萃取、固相萃取柱净化后GC-μECD测定土壤中有机氯农药(α-HCH,β-HCH,γ-HCH和δ-HCH以及o,p'-DDT,p,p'-DDT,o,p'-DDE,p,p'-DDE 和p,p'-DDD)残留量.结果表明,土壤中有机氯农药残留总量在6.18～84.72 μg·kg-1之间,平均18.63 μg·kg-1.DDT残留量高于HCH,为3.36～74.19 μg·kg-1,平均12.61 μg·kg-1.土壤中HCH残留量为2.48～17.80 μg·kg-1,平均6.02 μg·kg-1.DDT同系物中以p,p'-DDE和p,p'-DDT为主,而HCH中δ-HCH含量较低,其他3种异构体含量水平相当.所有土样中DDT和HCH残留量均远远低于GB/T 18407 无公害蔬菜产地土壤标准限定值500 μg·kg-1,但大多数土样中DDT和HCH残留量远远高于荷兰无污染土壤标准.     

黑龙江绥化大宗农作物硒含量特征及影响因素分析

通过对松嫩平原绥化地区农作物及根系土样品的研究,开展了土壤理化性质、总硒、有效硒、硒形态及农作物硒含量测试,结合统计学方法探究了研究区内主要农作物的样品硒水平差异及其影响因素.结果 表明,农作物硒含量为0.002～0.096 mg/kg,土壤总硒含量为0.13～0.52 mg/kg,土壤有效硒含量为0.002～0.00...     

A method to estimate pre-exploitation population size

Antarctic fur seals (Arctocephalus gazella) were commercially exploited on the subantarctic island of South Georgia for over 100 years and nearly driven to extinction. Since the cessation of harvesting, however, their populations have rebounded, and they are now often considered a nuisance species whose impact on the terrestrial landscape should be mitigated. Any evaluation of their current population requires the context provided by their historic, pre-exploitation abundance, lest ecologists fall prey to shifting baseline syndrome in which their perspective on current abundance is compared only with an altered state resulting from past anthropogenic disturbance. Estimating pre-exploitation abundance is critical to defining species recovery and setting recovery targets, both of which are needed for the International Union for the Conservation of Nature's recent efforts to develop a green list of recovering species. To address this issue, we reconstructed the South Georgia fur seal harvest from 1786 to 1908 from ship logbooks and other historical records and interpolated missing harvest data as necessary with a generalized linear model fit to the historical record. Using an approximate Bayesian computation framework, harvest data, and a stochastic age-structured population model, we estimated the pre-exploitation abundance of Antarctic fur seals on South Georgia was 2.5 million females (95% CI 1.5–3.5 million). This estimate is similar to recent abundance estimates, and suggests current populations, and the ecological consequences of so many fur seals on the island, may be similar to conditions prior to human harvest. Although the historic archive on the fur sealing era is unavoidably patchy, the use of archival records is essential for reconstructing the past and, correspondingly, to understanding the present. Article impact statement: Defining species recovery requires an understanding of baseline population state, which can be estimated through statistical methods.     

Effects of simulated acid rain on cation releasing in soils of South China

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利用Al（OH）3凝胶废渣生产聚合氯化铝（PAC）

介绍了对处理铝材加工含Ａｌ＾３＋的酸性废液过程中产生的二次污染物Ａｌ（ＯＨ）３凝胶废渣的应用。