转基因作物对土壤生物的影响

综述了转基因作物根系分泌物和转基因作物残茬对土壤微生物和土壤动物的影响,主要表现在3方面:(1)对某些微生物和土壤动物有毒害作用;(2)为特定的微生物和土壤生物提供营养;(3)对土壤生物可能产生长期累积影响,但对此尚无定论。     

基于GGE双标图和纤维长度选择的长江流域棉花区域试验环境评价

采用GGE双标图方法对2000~2010年期间27个独立的长江流域棉花品种区域试验的安庆、南阳、黄冈、荆州、武汉、襄阳、常德、岳阳、南京、南通、盐城、九江、简阳、射洪和慈溪等15个试验环境（试验点）在棉纤维长度选择上的鉴别力、代表性、理想指数和离优度指数进行了全面分析和综合评价。对各试验环境基于纤维长度选择的综合评价表明,荆州、九江、安庆和常德是最理想的试验环境,对以长江流域为目标环境的广适性新品种选育和作为区域试验环境鉴别理想新品种的效率最高,而江苏和浙江省沿海棉区的试验环境（南通、盐城和慈溪）和四川盆地棉区试验环境（简阳和射洪）不适宜作为针对长江流域的纤维长度选择与推荐环境,从而展示了GGE双标图在棉花区域试验环境评价方面的应用效果,也为长江流域国家棉花区域试验方案的决策提供理论依据     

玉米对土壤中重金属铅的吸收特性及污染防治

通过山东五莲玉米盆栽试验,研究作物对土壤中铅的吸收效应,探讨环境土壤重金属元素对作物和人类健康的影响.玉米盆栽试验表明,当土壤中加入不同比例的铅时(0～4 000 mg/kg),基本没有观察到铅对玉米的毒害病症,铅对作物的生长发育没有明显的宏观影响.但微区调查揭示,玉米对土壤中的铅具有强烈的吸收性,并可残留在作物的各个部位,且吸收量随土壤中铅添加量的增加而提高;其中根系的吸收性最强,是秸杆、籽实的几十至几千倍,表明作物根系为秸杆、籽实对铅的吸收提供了良好的屏障.不同铅化合物对作物吸收铅的影响不尽相同,用Pb(NO3)2处理的铅吸收量比用PbCl2处理的明显偏高,特别是当土壤中铅添加量较高时,该特征更为显著;而用PbCl2处理的作物,当铅添加量达到一定程度后,除根系外,作物对铅的吸收趋于饱和.运用根系对土壤中铅的特殊吸收性,可以在铅污染的土壤区通过自然作物栽培,并将作物根系从土壤中清除,来逐渐达到环境土壤修复的目的.     

典型铅锌矿区耕地土壤团聚体重金属含量与农作物含量相关性及其风险评价

土壤团聚体重金属对生态环境产生的危害不容忽视.为考察农作物与土壤团聚体重金属之间的相关性及可能产生的风险,以贵州都匀马坡铅锌矿段菜园河铅锌矿区农作物为例,研究土壤团聚体重金属的分布状况和农作物对土壤团聚体重金属的富集特征.采用Pearson相关性分析农作物与耕地土壤不同粒径团聚体重金属之间的关系,同时分别采用生态危害指...     

Direct N2O emissions following transition from conventional till to no-till in a cover cropped Mediterranean vineyard (Vitis vinifera)

Knowing underlying practices for current greenhouse gas (GHG) emissions is a necessary precursor for developing best management practices aimed at reducing N₂O emissions. The effect of no-till management on nitrous oxide (N₂O), a potent greenhouse gas, remains largely unclear, especially in perennial agroecosystems. The objective of this study was to compare direct N₂O emissions associated with management events in a cover-cropped Mediterranean vineyard under conventional tillage (CT) versus no-till (NT) practices. This study took place in a wine grape vineyard over one full growing season, with a focus on the seven to ten days following vineyard floor management and precipitation events. Cumulative N₂O emissions in the NT system were greater under both the vine and the tractor row compared to CT, with 0.15 ± 0.026 kg N₂O-N ha⁻¹ growing season⁻¹ emitted from the CT vine compared to 0.22 ± 0.032 kg N₂O-N ha⁻¹ growing season⁻¹ emitted from the NT vine and 0.13 ± 0.048 kg N₂O-N ha⁻¹growing season⁻¹ emitted from the CT row compared to 0.19 ± 0.019 kg N₂O-N ha⁻¹ growing season⁻¹ from the NT row. Yet these variations were not significant, indicating no differences in seasonal N₂O emissions following conversion from CT to NT compared to long-term CT management. Individual management events such as fertilization and cover cropping, however, had a major impact on seasonal emissions, indicating that management events play a critical role in N₂O emission patterns.     

作物植株残体还田土壤对除草剂的截留作用

加入成熟作物植株残体还田的土壤（简称秸秆还田土壤）与自然土壤的土柱淋洗对比实验，研究了玉米秸秆还田土壤对除草剂乙草胺和阿特拉津的截留作用以及水稻秸秆还田土壤对丁草胺的截留作用。结果表明，作物秸秆还田土壤对所研究的三种除草剂有明显的截留作用，在土桩的最上部10cm内，秸秆还田土壤对乙草胺、丁草胺和阿特拉津的截留量分别是自然土壤对其截留量的1.33、1.77和1.88倍。     

控制稻田甲烷排放的农业管理措施研究

１９９０～１９９２年连续３ａ,对北京和南京具有代表性稻田进行了甲烷排放通量测定。结果表明,甲烷排放日变化规律受土壤理化性质、农业管理措施、气候变化等影响而变化,在下午１５:００～１８:００出现高峰值￣(１－６),甲烷排放季节变化规律在分蘖期和孕穗期两次出现高峰。采取不同的农业管理措施对稻田甲烷排放的影响显著:间歇灌溉对烤田后的稻田能降低甲烷排放又可增加水稻产量;南方地区垅作栽培有利于减少冬水田甲烷排放,北方地区旱种可减少甲烷排放;有机肥能促进甲烷排放,稻田分蘖期和孕穗期施用硫酸铵和尿素能抑制甲烷排放。      

中国红黄壤地区作物生产的气候生态适应性研究

以３０ａ的气象资料和８种作物生长发育特性为基础，运用模糊数学的隶属函数原理分析中国红黄壤地区作物生长的气候生态适应性。研究结果表明，春播作物全生育期温、光、降水适应性隶属度分别呈低、高、低，低、一般、高，高、一般、低的形式；夏播作物分别呈低、高、低，高、一般、低，低、低、低的形式；秋播作物分别呈一般、高、低、高，高、低、低，低、较高、一般的形式。提出了优化管理的对策。     

Comparison of in vitro digestion methods for determining bioaccessibility of Hg in rice of China

Rice consumption can be a major pathway for mercury(Hg) exposure, which can cause health hazards to Chinese residents. To accurately assess the potential health risks, the bioaccessibility of Hg in rice samples collected at background and Hg-contamination sites was examined using four in vitro methods. The results showed that 50% of the total mercury(THg) was bioaccessible in the studied rice samples. The THg bioaccessibility in the rice samples collected at the Hg-contaminated site was higher than that observed at the background area. The bioaccessibility of arsenic(As) and cadmium(Cd) was also evaluated for comparison of the four in vitro methods used in this study. The Physiologically Based Extraction Test was found to be the most accurate method based on the consistency of the results compared to those reported in previous studies. The estimated daily intakes of THg via rice consumption using the bioaccessibility data were found to meet the recommendation value set by the JECFA and the WHO in both sites. However, the potential health risk was not negligible at the Hg-contaminated sites, due to the high THg concentration and bioaccessibility in the rice samples.     

Investigation on emission factors of particulate matter and gaseous pollutants from crop residue burning

Emission factors of particulate matter (PM), element carbon (EC), organic carbon (OC), SO_2, NO_x, CO, CO_2, and ten ions (Na~ , NH_4~ , K~ , Mg~(2 ), Ca~(2 ), F~-, Cl~-, NO_2~-, NO_3~-, SO_4~(2-)) were estimated from the domestic burning of four types of commonly produced crop residues in rural China: rice straw, wheat straw, corn stover, and cotton stalk, which were collected from the representative regions across China. A combustion tower was designed to simulate the cooking conditions under which the peasants burned their crop residues in rural China, to measure the emission factors. Results showed that wheat straw had the highest emission factor for the total PM (8.75 g/kg) among the four crop residues, whereas, corn stover and wheat straw have the highest emission factor for EC (0.95 g/kg) and OC (3.46 g/kg), respectively. Corn stover also presents as having the highest emission factors of NO, NO_x, and CO_2, whereas, wheat straw, rice straw, and cotton stalk had the highest emission factors of NO_2, SO_2, and CO, respectively. The water-soluble ions, K~ and Cl~-, had the highest emission factors from all the crops. Wheat straw had a relatively higher emission factor of cation species and F~-, Cl~-, NO_2~- than other residues.