Could Peace be Worse than War for Colombia's Forests?

The forests of Colombia are influenced by the actions of armed groups and, in many cases, their settlers are economically dependent on illicit crops. Up to the present armed conflict has simultaneously discouraged organized exploitation in some frontier areas, and encouraged unsustainable use of natural resources therein. The Colombian government seeks to end the conflict by pursuing peace negotiations, and to eradicate illicit crops. How will these policies affect the forests? The environmental consequences of these policies are not only dependent on the unlikely economic success of alternative development, but on making informed decisions about infrastructure development in affected areas.     

安徽省农作物干旱损失动态评估模型及其试用

利用安徽省78个气象站1971-2005年资料,采用FAO Penman-Monteith模型和一季稻作物系数计算作物需水量,得到针对一季稻的农业干旱指标;在分析了1980年以来一季稻主要发育期变化不大的基础上,利用多年农业气象观测资料,采用詹森乘法作物-水分模型新解法进行一季稻干旱敏感性系数分解,得到一季稻逐旬敏感性系数;建立了基于农业干旱强度、作物敏感性和区域脆弱性的一季稻旱灾损失评估模型。试用结果表明,模型的相对误差大部分为20%～35%,绝对误差为2.9～4.0,基本满足业务应用。由于各地水稻品种不同,抗灾能力也有差异,因此模型误差仍偏大,需进一步修正模型,并加强抗灾能力对减轻灾害损失贡献的研究。     

环境材料对作物吸收重金属Pb、Cd及土壤特性研究

重金属固化是原位修复污染土壤和减小作物吸收污染物、提高农产品质量的重要途径.采用盆栽实验方法,研究了单个环境材料(煤基营养材料HA、高分子保水材料SAP、煤基复合材料FM和吸附性矿物材料FS)及复合材料对作物(玉米、大豆)生长及其对土壤重金属Pb、Cd(土壤Pb≤150mg·kg-1、Cd≤10mg·kg-1)吸收的影响,并探讨了相关的土壤理化性能变化机理.结果表明,单个环境材料及复合材料处理较对照能明显减少作物对土壤重金属Pb、Cd的吸收量,并促进作物生长.除个别处理外,大部分处理下玉米地上部分的重金属Pb、Cd吸收量较对照减少51%～71%和66%～84%;所有处理下大豆地上部分的重金属Pb、Cd吸收量较对照减少54%～76%和33%～58%.实验还证明,所用环境材料对重金属Pb、Cd有一定的改良效应,并对土壤pH、EC、土壤有机质、速效氮磷养分及土壤脲酶、磷酸酶活性等有一定的调节作用.相较而言,高分子保水材料SAP及其复合材料F3(FM+SAP+HA)、F2(FS+SAP+HA)能明显降低玉米和大豆对土壤重金属Pb、Cd的吸收量,具有作为重金属污染土壤治理修复剂的可能性.     

秦巴山区水稻油菜配方施肥效益分析

为了解陕南秦巴山区主要农作物水稻、油菜测土配方施肥实施效果,更好地指导农户科学合理施肥。依据2009~2013年连续5 a测土配方施肥试验中主要农作物水稻、油菜3种不同施肥处理(农民习惯施肥、推荐施肥和不施肥处理)的326个试验数据,同时结合连续2 a调查数据,对陕南秦巴山区主要农作物施肥经济效益评价。结果显示,与农民习惯施肥相比,水稻施肥量为:氮(N)159±32 kg/hm~2,磷(P2O5)79±20 kg/hm~2,钾(K2O)86±26 kg/hm~2;油菜:氮(N)154±25 kg/hm~2,磷(P2O5)77±13 kg/hm~2,钾(K2O)65±21 kg/hm~2条件下作物分别增产703、341 kg/hm~2,增产率分别为8.3%和14.9%,纯收益增加0.12万元/hm~2和0.10万元/hm~2。肥料贡献率分别提高了5.2、7.1个百分点;农学效率每kg分别提高了0.5、0.6 kg。农户习惯施肥中作物产量、纯收益、肥料贡献率并未随肥料投入量的增大而增产增收。     

转基因作物对鱼类的生态毒理效应研究综述

转基因作物潜在的健康和环境风险一直以来颇受争议,转基因作物加工成动物饲料后可能会诱导动物产生免疫应激反应,影响动物的生长发育、繁殖等。鱼类是水生脊椎动物的代表,已广泛应用于水环境的监测,但目前转基因作物对鱼类的饲用安全性研究还相对较少。文章基于转基因作物作为鱼饲料原料对鱼类生态毒理学效应的研究现状,综述了转基因作物对鱼的生长表现、生理生化、脏器功能及发育、组织病理以及行为活动等方面的生态毒理学效应,分析了当前研究中存在的问题,并对今后的研究趋势进行了探讨。     

Precipitation as the Primary Driver of Variability in River Nitrogen Loads in the Midwest United States

Nitrogen (N) losses from agricultural lands in the Midwest United States are contributing to the expansion of the hypoxic zone in the Gulf of Mexico. This study evaluated the importance of inter‐annual variability in precipitation, land cover, and N fertilizer use on NO₃ + NO₂‐N loads in seven United States Midwestern Rivers using the backward stepwise regression analysis. At the annual scale, fluctuations in the current and previous years’ precipitations explained much of the variation in streamflow, baseflow, and N‐load. Previous years precipitation effects were associated with fillable soil porosity. In some years, higher residual soil N from previous dry years also contributed to an increase in N‐load. Area under soybean production (SOY), a surrogate for replacement of prairies and small grains was generally not a significant explanatory variable. Fertilizer use from 1987 to 2012 was also not a significant explanatory variable in the annual analysis. Precipitation in both the current and previous months and previous year were important in explaining variation in monthly streamflow, baseflow, and N‐load. SOY was significant in one or two months from June to August, but had a higher p‐value than precipitation. We conclude recent increases in river N‐loads are primarily due to wet climate and minimally due to the changes in land cover or N fertilizer use. Under current cropping systems and agronomic N application rates, tile water remediation will be necessary to reduce river N‐loads.     

Feedstock quality and growth of bioenergy crops fertilized with sewage sludge

Sewage sludge is rich in essential plant nutrients, but its use is restricted for crop production due to the pollutants it contains, such as metalloids and heavy metals. Sludge is also very sticky and compact. Therefore, the objectives of this work were to evaluate (1) the impact of various amounts of sludge on bioenergy crop productivity and quality and (2) the use of peat as an adjuvant to reduce the stickiness, density and nutrient richness of the sludge. Three different applications of sludge were examined, high, low (50% of high) and low mixed with an equal volume of peat. The sludge-peat mix increased significantly leaf area and biomass accumulation of maize and hemp. High sludge and sludge-peat mix applications increased significantly the leaf area and biomass accumulation as well as the net photosynthesis of oilseed rape. High sludge application resulted in the highest heavy metal and metalloid accumulation in maize and hemp. Sludge-peat mix resulted in the highest heavy metal and metalloid accumulation in oilseed rape. However, the sludge-peat mix application provided the best feedstock quality in all three crops, since chloride, silicon and sulfur concentrations and ash content in plant material were the lowest of the three sludge treatments.     

钢丝绳产业区重金属对土壤－农产品的复合污染及生态风险评价?

选取钢丝绳行业比较发达的某乡镇为研究区域,对其地区周边土壤及农产品的污染状况进行了野外调查和实验分析研究。结果表明：（1）土壤中铅、锌的含量均有不同程度的污染。（2）土壤中重金属含量与废水灌溉方式有关。（3）废水灌溉的农产品均有不同程度的污染。（4）重金属主要富集在农产品的根部,果实中富集的量很少。     

北京市农作物虚拟水含量分布

采用灌溉定额法对北京市各区县粮食虚拟水含量和蔬菜虚拟水含量历年的分布进行了计算和分析,并将其与北京市地下水资源分布和开采状况进行了现状对比.结果表明:①各区县粮食虚拟水含量总体上均呈下降趋势,但延庆县的粮食生产会给当地地下水资源带来较大的压力;②顺义区、大兴区,平谷区蔬菜历年的虚拟水含量总体呈增长趋势,在全市蔬菜虚拟水总量中所占的比例依次逐渐增大,而海淀区、丰台区、朝阳区蔬菜历年的虚拟水含量在全市所占的比例呈逐渐减小趋势;③北京地区历年的粮食虚拟水含量总和整体呈现下降趋势,蔬菜虚拟水含量总和略呈增长趋势,但是二者虚拟水含量的总和呈现下降趋势,这与北京市近年来的农业种植结构调整政策是相符合的.     

西南高镉地质背景区农田土壤与农作物的重金属富集特征

为探明高地质背景区农田土壤与农作物系统中重金属富集与转运特征,通过对采自重庆黑色岩系高镉地质背景区的土壤和农作物样品进行分析,并与其他典型黑色页岩区域进行对比研究.发现研究区部分农田土壤pH极低; Cd、Cr、Ni和Zn显著富集.土壤样品Cd的超标率为100%,其次为Cr和Ni,91. 3%的土壤样品Cd污染级别为严重污染及以上.土壤Zn、Cu、Cr和Ni的残渣态占比为80%以上,Cd和Pb较低;弱酸提取态Cd占比27. 0%±6. 4%,Zn和Ni次之.黑色岩系母质风化导致研究区土壤重金属富集,Cd是区域内的特征污染元素,其生物有效性较高,并易于在农作物中富集. Cd的转运系数高于其他元素,农作物中Cd的富集和污染程度最高,特别是叶类蔬菜,平均Cd含量(干重)高达11. 5 mg·kg~(-1),不适于种植和食用;部分农作物Cr超标,存在一定风险.因此,有必要对研究区农田土壤进行污染等级划分,实行科学管控,并进行农作物种植结构调整,以保障当地人群健康.